Advances in Carbohydrate Chemistry, Volume 16

ADVANCES IN CARBOHYDRATE CHEMISTRY VOLUME 16

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Advances in Carbohydrate Chemistry Editor MELVILLE L. WOLFROM Associate Editor R. STUART TIPSON Board of Advisors J. C. SOWDEN ROYL. WHISTLER

R. C. HOCKETT W. W. PIQMAN C. B. PIJRVEB

Board of Advisors for the British Isles E. L. HIRBT

STANLEY PEAT

MAURICESTACEY

Volume 16

1961 ACADEMIC PRESS

NEW YORK and LONDON

Copyright 0, 1961, by Actldemic Press Lac, ALL RIGHTB REBEBVED NO PART O F T H I S BOOK MAY B E BEPRODUCED I N ANY FORM, BY PHOTOBTAT, MICROFILM, OR ANY OTHER MEANB, WITHOUT WRITTEN PERMIBBION FROM THE PUBLIBHERB.

ACADEMIC PRESS INC. 111 FIFTHAVENUE NEW YORE3, N. Y. United Kingdom Edition Published by ACADEMIC PRESS INC. (LONDON) LTD. 17 OLDQUEENSTREET,LONDON, S.W.1

Libraw of Congreee Culolog Card Number: 46-11361

PBINTED I N T H E UNITED STATE8 O F AMERICA

'

LIST OF CONTRIBUTORS

T. G. BONNER, Department of Chemistry, Royal Holloway College, University of London, Englejield Green, Surrey, England

JOHNR. CLAMP, Department of Chemistry, The University, Bristol, England H. DEUEL, Laboratory of Agricultural Chemistry, Swiss Federal Institute of Technology, Zurich, Switzerland P. DUBACH, Laboratory of Agricultural Chemistry, Swiss Federal Institute of Technology, Zurich, Switzerland

R. D. GUTHRIE,Shirley Institute, Manchester, England* JOHNL. HICKSON, Sugar Research Foundation, Inc., New York, New York L. HOUGH,Department of Chemistry, The University, Bristol, England ALMUTHKLEMER, Organisch-Chemisches Institut der Universitdt, Munster, Westfalen, Germany EDGARLEDERER,Labordoire de Chimie biologique, Facult6 des Sciences, Paris, and Institut de Chimie des Substances Naturelles, Gif sur Yvette, Seine et Oise, France OMPRAKASH MALHOTRA ,Chemisches Laboratorium deer Universitlit, Freiburg im Breisgau, Germany N . C . MEHTA,Laboratory of Agricultural Chemistry, Swiss Federal Institute of Technology, Zurich, Switzerland FRITZMICHEEL,Organisch-Chemisches Institut der Universitat, Munster , Westfalen, Gemnany J. MUETGEERT, Plastics Research Institute T.N.O., Delft, Holland GLYN0. PHILLIPS,Department of chemistry, University College, Cardig, Wales

R. STUART TIPSON, Washington, D. C. KURTWALLENFELS, Chemisches Laboratorium der Universitdt, Freiburg im Breisgau, Germany

ROY L. WHISTLER,Department of Biochemistry, Purdue University, Lafayette,Indiana

* Present address: Chemistry Department, The University, Leioester, England. V

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PREFACE This sixteenth Volume of the Advances in Carbohydrate Chemistry continues with its task of providing comprehensive reviews on matters of interest in the general chemistry of the carbohydrates. A significant problem is treated by Phillips (Cardiff)-the effects produced in carbohydrates by ionizing radiation-a topic which is in its infancy and which can be expected to undergo extensive development. Fluorine chemistry is likewise a modern subject undergoing intensive study, and some phases of its application to carbohydrates are detailed by Bonner (London) and by Micheel and Klemer (Munster). The effects of various glycol-splitting reagents on the carbohydrates have been summarized in previous issues of this Series, and recent results now allow an elaboration of the ring structures of the dialdehydes produced from the pyranoid sugar rings by periodate ion (Guthrie, Manchester). In the early issues of the Advances, the late Claude S. Hudson initiated a set of articles on single sugars (or simple groups of sugars), and lactose was one of those selected for discussion. This account, started in 1954 by Whistler (Purdue) but never completed to his satisfaction, has at last been finished by Hough and Clamp (Bristol). Biochemical aspects have been treated authoritatively by Lederer (Paris), who reports on the interesting new sugars found in the glycolipids of the acid-fast bacteria; Wallenfels and Prakash Malhotra (Freiburg i. B.) detail the fascinating subject of the first isolation and crystallization of a simple glycosidase; and Deuel and associates (Zurich) discuss the carbohydrate residues isolable from the soil. In the first Volume of this Series, T. J. Schoch described a fractionation of starch by which he firmly established the existence of the amylose and amylopectin fractions. His process remained a laboratory procedure only, but, recently, Dutch chemists have developed a large-scale fractionation of potato starch, and pure amylose is now obtainable in commercial quantities; the new process is herein described by Muetgeert (Delft). Finally, an obituary of the late Harold Hibbert is offered by one of his former associates. The Subject Index has been prepared by Dr. R. David Nelson.

M. L. WOLFROM R. STUARTTIPSON

Columbus, Ohio Washington, D. C.

vii

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CONTRIBUTORS TO VOLUME 16 ................................................

v

PREFACE .....................................................................

v i

HAROLD HIBBERT ............................................................

1

Radiation Chemistry of Carbohydrates GLYN0. PHILLIPS

I . Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . I1. Primary and Secondary Effects of Radiation .. . . . . . . . . . . . . . . . . . . . . . . . . . . I11. The Effect of Radiation on Compounds Related to Carbohydrates . . . . . . IV . The Effect of Radiation on Carbohydrates..............................

13 14 22 32

Applications of Trifluoroacetic Anhydride in Carbohydrate Chemistry

.

T. G BONNER I . Introduction ........................................................... I1. Trifluoroacetylation with Trifluoroacetic Anhydride .................... I11 The Trifluoroacetyl Group as a Blocking Group ........................ IV . Acylation with Carboxylic Acid-Trifluoroacetic Anhydride Mixtures ..... V . Selective Ring-opening of Cyclic Acetals with Carboxylic Acid-Trifluoroacetic Anhydride Mixtures ............................................. V I . The Synthesis of Linear Polymeric Esters from Cyclic Trimethylene Acetals and Dibasic Carboxylic Acids ...................................... VII . The Mechanism of Acylation by Acyl Trifluoroacetates . . . . . . . . . . . . . . . . .

.

59

60 63 67 69 77 79

Glycosyl Fluorides and Azides

FRITZMICREELAND ALMUTHKLEMER I . Introduction ........................................................... I1 Preparation of the Glycosyl Fluorides .................................. I11. Reactions of the Glycosyl Fluorides .................................... IV . The o-Fluoro Carbohydrates ........................................... V . The Aldosyl Azides .................................................... VI . Tables of Properties of Glycosyl Fluoride Derivatives ..................

.

is

85 86

88 95 95 97

X

CONTENTS

The “Dialdehydes” From the Periodate Oxidation of Carbohydrates

. .

R D GUTHRIE

I . Introduction ........................................................... 106 I1. Nomenclature . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 106 I11. General Properties of the Oxidation Products ........................... 108 IV . Oxidation Products from Monosaccharide Derivatives and Related Compounds ................................................................ 108 V. Oxidation Products from Di-, Tri-, and Oligo-saccharides . . . . . . . . . . . . . . . 134 V I Oxidation Products from Polysaccharides ............................... 137 V I I . Alkaline Degradation of Periodate-oxidized Carbohydrates.............. 153 VIII . Uses of Periodate-oxidized Carbohydrates .............................. 157

.

Lactose

.

JOHN R . CLAMP.L . HOUOH.JOHN L HICHSON.A N D ROY L . WHISTLER

I . Introduction ........................................................... I1 The Structure of Lactose . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . I11. Occurrence and Biochemical Properties of Lactose ...................... I V . Chemical Properties of Lactose ......................................... V. Some Physical Properties of Lactose . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

.

159 180 165 181 201

Glycolipids of Acid-Fast Bacteria

EDGAR LEDERER I . Introduction ........................................................... 207 I1. Chemistry of Glycolipids of Acid-fast Bacteria ......................... 209 I11. Biological Activities of Glycolipids of Acid-fast Bacteria . . . . . . . . . . . . . . 230 Galactosidases

KURTWALLENFELS AND OM PRAKAEIH MALHOTRA I. Introduction ........................................................... I1. 8-Galactosidases . ...................................................... I11. a.Galactosidases . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

239 240

290

The Fractionation of Starch J . MUETQEERT

I . Introduction ........................................................... I1. Fractionation by Complexing Agents ................................... I11. Fractionation by Leaching Techniques . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

299 300 306

CONTENTS IV. Fractionation by Fractional Precipitation. ............................. V. Industrial Methods of Fractionation.. .................................. VI. General Conclusions.. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

xi 309 325 332

Carbohydrates in the Soil N. C. MEHTA, P. DUBACH AND H. DEUEL

I. Introduction.. .................................................... 11. Isolation and Characterization.. . . 111. Quantitative Determination.. . . . . . IV. Source and Transformation. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 348 V. State and Function.. ........ .... 352 VI. Summary .............................................................. 354 AUTHORINDEX FOR VOLUME16.... . . 35; SUBJECT INDEX FOR VOLUME16... . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 378 CUMULATIVE AUTHORINDEX FOR VOLUMES 1-16.. . . . . . . . . . . . . . . . . 396 CUMULATIVE SUBJECT INDEX FOR VOLUMES1-16 .............................. 402 ERRATA ......................................................................

410

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HAROLD HIBBERT 1877-1945

To few is it given to spend such a varied life, and one so rich in achievement, as that of Harold Hibbert. He was born in Manchester, England, on August 27th, 1877, the second of the four sons of Isaac and Martha (Scholes) Hibbert. All four boys were to make their marks in life. Frank, the eldest, eventually engaged in manufacture in London; Ernest, a British-trained mining engineer was involved in the technical development of the great Noranda strike in the wilds of northwestern Quebec; and Arthur, the youngest, who also was a well-known mining engineer (in Cyprus, India, Peru, and Spain), distinguished himself as a Major in the British Corps of Engineers in the First World War, being in charge of the tunnelling of Hill 60, and receiving the D.S.O. and M.C. Undoubtedly, their accomplishments were partly attributable to their upbringing-their father was a Wesleyan Methodist, a staunch Liberal, and a teetotaler and nonsmoker. Harold attended the Central Board School in Manchester and, at the age of seventeen, was awarded a Manchester Corporation Scholarship. In 1894, he entered Owens’ College of the federal Victoria University, ManChester, and, three years later, graduated with a B. Sc. with First Class Honours in Chemistry. He was awarded the Levinstein Exhibition fellowship, proceeded to conduct his first researches in organic chemistry under Professor William H. Perkin, Jnr., and received his M. Sc. degree from the Victoria University in 1900, the year of his first publication. I n 1899, Hibbert accepted an appointment as Senior Demonstrator and Assistant Lecturer in Chemistry at the University College of Wales, in Aberystwyth. Two years later, Dr. J. J. Sudborough was appointed Professor of Chemistry, and Hibbert published four papers with him, during 1903-04, on addition compounds, on the differentiation and estimation of primary, secondary, and tertiary amines, and on the estimation of hydroxyl groups in organic compounds. Hibbert now decided to study abroad for his doctorate, and he arrived a t the University of Leipaig in October, 1904, to work under Professor Arthur Hantasch on addition products of trialkyl derivatives of arsines, phosphines, and stibines. Hibbert published an article on the preparation of the trialkyl derivatives (by means of the Grignard reaction) in Berichte for 1906, and, in the following year, he and Hantasch described the addition products in the mme Journal. In 1906, Hibbert was awarded the Ph. D. degree summa cum l a d e by the University of Leipaig. During his two years 1

2

OBITUARY-HAROLD

HIBBERT

in Germany, Hibbert learned to speak German fluently and idiomatically, and he acquired a broader knowledge of philosophy, music, and art than he had previously had. The young Englishman also became friendly with several American students who were later to become well-known chemists: W. C. Bray, Colin G. Fink, Arthur B. Lamb, and S. C. Lind. In 1906, at the age of twenty-nine, Hibbert came to the United States on a two-year appointment at Tufts College, in Boston, Massachusetts. There he worked under Professor Arthur Michael on keto-enol tautomerism and the effect of solvent on the equilibrium. Hibbert’s association with Michael, with whom he published some half-dozen papers, was to have a profound and lasting influence on his subsequent career. Hibbert now returned to England and obtained a Chemical Society grant which enabled him to conduct independent research with Sir William Tilden at the Imperial College of Science in London. He completed earlier work, begun a t Aberystwyth, on some quantitative applications of the Grignard reaction (in what is now known as the Tschugaeff-Zerewitinoff method). In 1904, Sudborough and Hibbert had shown the value of a high-boiling ether in this reaction, and they were the first to devise a quantitative procedure. For two years, Hibbert fruitlessly sought an academic position in Great Britain; he therefore came back to the United States and, in 1910, succeeeded in obtaining a post as a research chemist with the E. I. du Pont de Nemours Powder Co. at their Experimental Station in Wilmington, Delaware. Here he did important work on the stability of frozen and liquid glycerol trinitrate (nitroglycerin) which won him international recognition. In 1912, he was awarded the highly coveted D. Sc. degree of the (Victoria) University of Manchester. With the outbreak of the First World War in 1914, Hibbert accepted a position as Research Fellow at the Mellon Institute of Industrial Research in Pittsburgh, Pennsylvania, on a Gulf Refining Co. Fellowship (1914-15); he was then a Senior Fellow on the Union Carbide Acetylene Fellowship (1915-16) and studied new methods for synthesizing (and manufacturing) acetone, acetaldehyde, and acetic acid from acetylene. As a result of these investigations. Hibbert was called into consultation by the Shawinigan Water and Power Company of Montreal, and one of his former associates, Mr. Howard Matheson, was put in charge of erecting, at Shawinigan Falls, Quebec, a large plant for the manufacture of acetic acid. Hibbert also devoted much attention to the syntheais and properties of ethylene glycol and its derivatives-compounds which have found numerous industrial applications-and his patents on glycols were purchased by the Union Carbide Company. The best known of his patents, namely, U. s. Patent 1,213,368 (1917), relates to the use of ethylene glycol as an antifreeze for car and aeroplane radiators. This product was marketed as Prestone, named after the Prestolite Company which sold calcium carbide for acetylene lamps

3

R. STUART TIPSON

and which was bought out by Union Carbide. In addition, he was the first to apply for a patent on the use of ethylene gas for welding and cutting. He published his well-known method for dehydrating alcohols with a trace of iodine, and (with B. T. Brooks) a procedure for synthesizing the higher aliphatic alcohols by high-pressure reactions involving chlorinated petroleum hydrocarbons. He also showed the usefulness of ethylene glycol dinitrate as a liquid explosive; this was tested, with very favorable results, by the U. S. Navy Department, and Dr. Hibbert offered the United States Government the use of his patents, free of all royalties. Hibbert left the Mellon Institute in 1916 to become a private consultant, first in Toronto and then in New York City. During 1917 and 1918,he was Chemical Adviser (on gas warfare) to the British War Mission in Washington, D. C. He also became the Director of the Research and Technical Divisionof RalphL. Fuller and Co., New York, N. Y. (a company organized in order to manufacture certain pharmaceuticals hitherto obtained from Germany), and, in co-operation with the British-American Chemical Co., devoted himself to the erection and operation of chemical plants in Canada and the U. S. A. He married Beulah Virginia Cole on May 14,1917;at this time, she was a teacher of physiography a t the Julia Richman High School in New York City. Much of his subsequent success is attributable to her inspiration and guidance. In 1919, a t the age of forty-two, he realized that the academic life meant more to him than the less challenging, although more lucrative, career of industrial chemist, and he accepted an appointment as Assistant Professor of Chemistry at Yale University in New Haven, Connecticut. In 1921,he was promoted to an Associate Professorship and, two years later, he became an American citizen. He soon embarked on extensive investigation of the chemistry of cellulose, which eventually led to some sixty-nine papers in a series entitled “Studies on Reactions Relating to Carbohydrates and Polysaccharides.” Denham and Woodhouse had previously methylated cellulose and had hydrolyzed the product to 2,3,6-tri-O-methyl-~-glucose. For the supposed “cellulose monomer” (which, according to the ideas then held, could associate through “secondary valence forces” to give the “cellulose polymer”), Hibbert proposed the following formula. CHor

ii”’”” H-0

4

OBITUARY-HAROLD

HIBBERT

However, he did not rule out the then-unpopular possibility that the polymer might consist of units joined by main valences available on opening of the 1 ,Boxygen bridges (at that time, the sugar ring was assumed to be 1 ,4), as follows.

-?“I HH: A! 0Y

or

c:

H 0-

[q:LoCHiOH I

HOH-CHOH-CH-

(!XIOH

He and his students then tried to synthesize simple analogs of the above “monomeric unit,” an endeavor which proved fruitless, but, in the course of their studies, they accumulated a large amount of knowledge regarding the preparation and properties of cyclic acetals. Thus, they found that a trace of acid catalyzes the formation of a polymer from 5,6-dihydroxy-2hexanone, and that aliphatic aldehydes (RCHO) readily combine with ClaCCHO), . chloral to give polymers of the general formula (2 RCHO The condensation of glycerol with aldehydes and ketones was studied; with benzaldehyde, a mixture of the cyclic acetals having the five- and the six-membered ring resulted, showing that presence of hydroxyl groups on vicinal carbon atoms is not essential for occurrence of the reaction. On the other hand, on condensation of acetone with various other polyhydric alcohols, the cyclic acetal having the five-membered ring was alway formed exclusively. The migration of acyl groups was another field of interest. Emil Fischer had suggested that a compound having the dioxolane ring (“orthoester”), m in (l), was the intermediate in the migration, and Hibbert placed the theory on a firm footing.

+

0

I

I

I (1)

For glycerol esters, the migration was found to be toward the primary hydroxyl group. He stated that “The tendency and ease of ring formation will be dependent on: (a) the relatively labile character of the hydrogen attached to the hydroxyl group, (b) the negative polarity of the carbonyl

R. STUART TIPSON

5

group in the acyl radical, and (c) the spatial relationship of the migratory hydrogen atom with reference to the carbonyl group.” Consequently, he predicted that the orthoester structure would be stabilized by the trichloroacetyl radical; confirmation came from the discovery that the trichloroacetate of ethylene glycol can only exist in the cyclic form. On heating, this orthoester decomposes into the carbonate plus chloroform.

These studies involved the concept of “neighboring-group effects” and laid the basis for interpretations of reaction mechanisms that were later to be developed by other carbohydrate chemists and then, eventually, be adopted by organic chemists in general. In contrast to the behavior of esters, no tendency to migrate was found with methyl ethers, an observation of importance at that time, when methylation procedures were being extensively employed in the determination of ring structures of sugar derivatives. Hibbert waa intimately associated with the founding of the Division of Cellulose Chemistry of the American Chemical Society and served as the first Chairman of the Division (1920 to 1922). Formulation of procedures for defining a Standard Cellulose preparation was an early project. Hibbert was a stimulating and vigorous leader of the discussions of the Division, some of which became so heated that they will not be forgotten by those who were in attendance. Outstanding in this regard was one session of the A. C. S. Organic Symposium at Princeton University in 1929, after Hibbert had risen to comment on a lecture on polymerization by Wallace H. Carothers (the inventor of Nylon). After six years at Yale University, Hibbert was honored by appointment, at the invitation of Sir Arthur Currie, to the chair of the E. B. Eddy Professorship of Industrial and Cellulose Chemistry at McGill University, Montreal, Canada, a position he was to hold for eighteen years, while still retaining his American citizenship. In 1925, the Pulp and Paper Research Institute of Canada, erected on the McGill campus by the Canadian Pulp and Paper Association, had just been completed, and Hibbert’s Department moved into part of the magnificent new building. The modern facilities that were placed a t his disposal, together with the unflagging energies of a group of enthusiastic graduate students, needed only Hibbert’s stimulus and inspiration to make this a new center for productive research. His almost 100 predoctoral and postdoctoral students (to whom he was affectionately known, although not to his face, as “Pa Hibbert”) came from abroad and

6

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HIBBERT

from all parts of the Dominion; they were fired by his enthusiasm, respected his ability and his vision regarding research problems, and soon learned to emulate his enormous capacity for work. Nevertheless, he did not believe in “all work and no play.” He would make the rounds of the laboratories at unexpected hours; and the author well remembers being caught running an experiment one glorious, sunny Saturday afternoon in the Fall and being told, in Hibbert’s north-country accent, to “get out of here, and go and play a game of tennis!” Such visits were sometimes embarrassing, as when, one night, Hibbert brought in a visitor to see the library, shortly after midnight, and found one of the research chemists stretched out on one of the library tables, fast asleep after some exhausting experiments; the two tiptoed quietly away and left the student to his slumbers. Hibbert’s valuable library was always available to his students, to whom it was known as “Hibbert’s Cadillac.” The reason for this name throws some light on Hibbert’s interests; his brother Ernest, when visiting him, had been annoyed a t the old car that Harold then drove, and so he gave Harold the money to buy a new one and recommended a Cadillac. (This was the brother who had made a good stake in the Noranda gold-silver-copper strike.) Harold thought the matter over and decided that he would, instead, use the money to develop his personal library, which he kept at home. Hibbert was a taskmaster, but he was also a father to “his boys’’ (and several of “his girls”); besides making sure that each developed himself to the extent of his capabilities, he helped in planning the future of his students and finding a place for them in industry or teaching after they had received their Ph. D. degrees. He never rested until he had found a suitable opening for each of them. Sometimes, a grant would be obtained (often, surreptitiously, out of his own pocket) for those in need of financial assistance. This deep concern for the welfare of his students was fully shared by Mrs. Hibbert, and, together, they established the Hibbert-Cole Scholarship for students at McGill. They especially delighted in entertaining students who were far from home; his students were often invited on a picnic in the summer, a car-ride in the spring or autumn, or to the Hibberts’ home. On Christmas Day, 1929, E. G. V. Percival and the author had the pleasure of a delightful Christmas dinner at their home (and were amazed to receive totally unexpected Christmas presents). In 1929, the first organic microanalytical laboratory in Canada (and one of the first in North America) was started in his Department, under the direction of the author, and graduate students and professors came from all parts of the Dominion to learn the specialized techniques of Fritz Pregl’s procedures (which had been passed from Pregl to H. D. K. Drew and, from him, to the author). It was then that we discovered that all chemists can be divided into two groups-those who, unable to acquire the necessary

7

R. STUART TIPSON

manipulative skills, can never be taught to perform a quantitative microanalysis, and those who learn the essentials with ease, often in a fortnight of concentrated effort. By this time, Hermann Staudinger and Wallace H. Carothers had firmly established that primary (not secondary) valence forces are involved in polymerization. Hibbert and his coworkers then synthesized a series of individual, linear polymers, each of known chain-length, and studied their properties as a function of chain length. The kind of reaction used in these syntheses, for polymers containing 4, 6, 8, 12, 18, 42, 90, and 186 units, was as follows. H 2

H2CONa HOHs

b

\c/

ClCH2 +H2hCI

-+

HOHzC

H H

/ \o/

\c/

H

0

LC/ \c/

d

\H

CHiOH

€f\H

Another example of polymerization that intrigued Hibbert was that brought about by the slime-producingbacteria, that can take sugar residues from certain di- and tri-saccharides and combine them to give polysaccharides. The first such polymer we studied was a fructan, which he renamed levan, produced by the action of Bacillus mesentericus on sucrose; it was the cause of considerable trouble in the sugar industry. Hibbert and coworkers found that the bacillus utilizes the D-glucose moiety and that the nascent D-fructofuranose moieties combine to give levan, a polymer of D-fructofuranose, which differs from inulin [whose structure had already been shown by Haworth and coworkers to be (2+l)-~-fructofuranoid] in having (2+6)-linkages. Methylation of levan, followed by hydrolysis, afforded crystalline 1,3,4-tri-0-methy~-~-frctose. Hibbert and his school were also the first to conduct extensive studies on dextran, a polymer (of D-glucose) produced from sucrose by various strains of Leucmostoc mesenteroides; the principal linkage present was shown to be a-~-(l-+6).Dextran has since found use as a blood extender. Another pioneer study was on the polysaccharide produced, as a membrane, by Acetobacter xylinum; this carbohydrate was shown to be cellulosic and has been called “bacterial cellulose.” I t could be acetylated and spun into a cellulose acetate fiber. In these studies, the general chemical identity of wood cellulose with cotton cellulose was established. He also became interested in the polymeric “humic acid” that is formed by the action of mineral acids on hexoses; a use was developed for it as an extender in lead accumulators (“storage batteries”). All of these investigations bore a relationship to polymerization and to carbohydrate chemistry, but, since the Pulp and Paper Research Institute

8

OBITUARY-HAROLD

HIBBERT

was primarily interested in the chemistry of wood, Professor Hibbert and his associates engaged in an intensive study of cellulose, its behavior with alkali, and the complicated changes occurring during its oxidation. However, Hibbert’s main interest gradually became the other main component of wood, namely, the lignin, which constitutes 30 % of all woods and which was being run into the streams as a total loss in the manufacture of sulfite pulp. Although lignin had been the subject of numerous investigations during the preceding seventy years, but little progress had been made, largely because of the difficulty in isolating it in unchanged form. Hibbert was to establish an international reputation as one of the foremost workers in this field. He developed techniques for isolating lignin in as unchanged a condition as possible, free from the other constituents of wood. The pulp-bleaching process was studied and improved, and the preparation of vanillin from sulfite-pulping waste-liquors was developed and made commercial. Eighty-seven papers were eventually published in a series, starting in 1930, entitled “Studies on Lignin and Related Compounds.” The alkaline degradation products of ligninsulfonic acids from softwoods were found to be guaiacol, vanillin, and acetovanillin, whereas those from hardwoods were the analogous compounds 1 ,3-di-O-niethylpyrogallol, syringaldehyde, and acetosyringone. In addition, wood meal (pre-extracted to remove fats, resins, tannins, and waxes) was extracted with acidified alcohols (for example, ethanol), and the water-soluble fraction of the lignin was found to contain 1-(4hydroxy-3-methoxypheny1)-1,2-propanedione (“methyl vanilloyl ketone”), its 5-methoxy derivative (“methyl syringoyl ketone”), a-ethoxypropiovanillone [2-ethoxy-1- (4 - hydroxy-3 -methoxypheny1)-l-propanone], and a-ethoxypropiosyringone [2-ethoxy-l-(4-hydroxy-3,5-dimethoxyphenyl)-l-propanone] ; the two ethyl ethers were thought to have been formed from the corresponding hydroxy compounds during the ethanolysis. These products are, or are derived from, the building units of lignin. Finally, Hibbert’s work on phenol lignin and related products has been used in the lignin-Bakelite industry. In recognition of his outstanding contributions to both pure and applied chemistry, Harold Hibbert was, in 1936, honored with the LL. D. degree honoris mu8u by the University of British Columbia. He was made an Honorary Member of the Society of Chemical Industry (London) in 1943; on this occasion, the President of the Society stated: “The Council, in deciding to bestow this honour, selected with great care one they considered worthy, for his career illustrates to a remarkable degree the influence which a man of high scientific attainments can exert on industry and the wellbeing of the community.” Two years later (only a few weeks before his death), Hibbert was accorded the highest honor bestowable by the scientists of his adopted country by his election to membership in the National Academy of Sciences (U.S.A.).

R. STUART TIPSON

9

On his retirement from McGill in 1943, his past and then-present students joined in attesting to their high regard for him by presenting him with a bronze plaque engraved with the signatures of the students who had received their advanced training under him,and Mrs. Hibbert was given an Audubon print. Hibbert was honored by election as a Fellow of the Royal Society of Canada, and he was a member (or Fellow) of the American Association for the Advancement of Science; American Chemical Society (Chairman, New Haven Section, 1920, and Chairman, Division of Cellulose Chemistry, 19201922); American Pulp and Paper Association; Canadian Chemical Association; Canadian Pulp and Paper Association; Deutsche chemische Gesellschaft ; Royal Institute of Chemistry (London); The Smithsonian Institution (Washington, D. C.) ; Society of Chemical Industry (Chairman, Montreal Section, 1930); Society of the Sigma Xi; Technical Association of the Pulp and Paper Industry; and the Textile Institute (England). In addition, he served on the editorial board of Cellulosechemie for several years. He was author or co-author of 253 scientific papers and 50 patents (British, Canadian, and U. S.). Hibbert was tall and well-built, and had a bush of hair which, in his later years, was snow-white; he was strikingly handsome and an immaculate dresser. He had a vivid, colorful personality, was always optimistic and high-spirited, and was an indefatigable worker. He had a fine baritone voice, and delighted in singing airs from The Messiah and the rollicking songs of Old England and of the Germany of his student days. He and Mrs. Hibbert were lovers of the great outdoors and were enthusiastic birdwatchers. His country ramblings and canoe trips renewed his strength and helped maintain his buoyancy of spirit. He was a180 keen on golf and tennis, and was a practitioner of daily setting-up exercises. Dr. Hibbert read widely, not only in Chemistry but in other fields, for extension of his knowledge and for pleasure and relaxation. He had an excellent background in English literature and loved to recite the verses of the great English poets, from memory. He was known for his ability to write and speak with forcefulness and clarity, and his skill in debate was particularly in evidence at the meetings of the American Chemical Society. Indeed, his charm and vitality gave color to any gathering he attended. He was keenly interested in baseball, and played the game during his early days in the U. S. He belonged to the Unitarian Church, was a thirty-second degree Mason (Scottish Rite), and was a member of the University Club of Montreal, the Chemists’ Club of New York, the Faculty Club of McGill University, and Golf, Tennis, and Canoe Clubs. Two years after his retirement, Harold Hibbert died of cancer of the pancreas, on May 13, 1945, the day before his twenty-eighth wedding anniversary. His memory is kept alive a t McGill University by the Harold

10

OBITUARY-HAROLD

HIBBERT

Hibbert Memorial Fellowship, established by his millionaire brother Colonel Ernest Hibbert (1879-1948) with an endowment of $1 00,000, which supports a post-Ph. D. Fellowship in the Department of Chemistry; holders to date have been Drs. Conrad Schuerch, Alan H. Vroom, Tore E. Timell, Necmi Sanyer, John Honeyman, Bengt 0. Lindgren, Terrence J. Painter, Ingemar Croon, and Iqbal R. Siddiqui. In 1954, Mrs. Hibbert presented almost $l,OOO to the University of Manchester in his memory; this has been used for endowing two Harold Hibbert Memorial Prizes, awarded annually by the Department of Chemistry for the two best Ph. D. theses submitted during the previous year. His personal chemical library, consisting of some 1,500 volumes (many of them irreplaceable), was kept intact and became the Hibbert Library in the research laboratory of the Crown Zellerbach Corporation in Camas, Washington. His scientific achievements live on in his publications and in the accomplishments of the many students he inspired. As Dr. Emil Heuser remarked, some two weeks after Hibbert’s death, in an address (on Hibbert’s work) before the North-East Wisconsin Section of the American Chemical Society: “Cellulose and lignin chemists, the world over, have lost a great deal through Professor Hibbert’s death. He will long be remembered, not only by his personal friends but also by those who have benefitted from his work and those who will do so for many years to come.”

R. STUARTTIPSON APPENDIX The following is a list of the 118 scientists who published articles in collaboration with Dr. Harold Hibbert. J. S. Allen; C. G. Anderson; W. R. Ashford; S. B. Baker; R. H. Ball; J. Barsha; S. H. Beard; A. Bell; E. M. Bilger; J. R. Bower, Jr.; F. Brauns; C. P. Brewer; L. Brickman; B. T. Brooks; Irene K. Buckland; C. Pauline Burt; Laura T. Cannon; N. M. Carter; J. Compton; L. M. Cooke; A. B. Cramer; R. H. J. Creighton; A. C. Cuthbertson; R. M. Dorland; A. M. Eastham; H. Essex; T. H. Evans; E. C. Fairhead; H. E. Fisher; J. H. Fisher; R. Fordyce; Frances L. Fowler; G. P. Fuller; A. F. Gallaugher; J. A. F. Gardner; R. D. Gibbs; W. F. Gillespie; H. P. Godard; K. R. Gray; Margaret E. Greig; E. G. Hallonquist; A. Hantzsch; F. C. Harrison; S. M. Hassan; W. L. Hawkins; W. F. Henderson; W. B. Hewson; Bertha Hibbert; A. C. Hill; H. s. Hill; E. 0. Houghton; F. Howett; M. J. Hunter; E. C. Jahn; B. Johnsen; E. G. King; M. Kulka; F. Leger; I. Levi; M. Lieff; E. L. Lovell; 0. Maas; J. L. McCarthy; W. S. MacGregor; A. S. MacInnes; H. W. MacKinney; L. Marion; H. B. Marshall; A. Michael; M. Michaelis; J. P. Millington; L. Mitchell; W. Mitchell; W. 0. Mitscherling; R. E. Montonna; L. P. Moore; R. G. D.

R. STUART TIPSON

11

Moore; J. G. Morazain; H. A. Morton; A. C. Neish; A. Paquet; J. L. Parsons; R. F. Patterson; Q . P. Peniston; J. M. Pepper; E. G . V. Percival; S. Perry; S. Z. Perry; J. B. Phillips; Muriel E. Platt; M. Plunguian; J. C. Pullman; J. J. Pyle; R. R. Read; W. L. Reinhardt; R. P. Roberts; H. J. Rowley; C. A. Sankey; H. Schwartz; W. H. Steeves; M. G. Sturrock; J. J. Sudborough; R. F. Suit; J. N. Swartz; H. L. A. Tarr; K. A. Taylor; J. A. Timm; R. S. Tipson; G. H. Tomlinson, Jr.; G. H. Tomlinson, 2nd.; S. M. Trister; E. West; K. A. West; M. S. Whelen; E. V. White; A. Wise; L. E. Wise; and G. F. Wright.

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RADIATION CHEMISTRY OF CARBOHYDRATES

BY GLYN0. PHILLIPS Department of Chemistry, University College, Cardiff, Wales I. Introduction.. .............................. . . . . . . . . . . . 14 11. Primary and Secondary Effects of Radiation.. . 1. Interaction of High-energy Radiations with 2. Radiolysis of Water and Aqueous Solutions 3. Chemical Dosimetry.. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 21 111. The Effect of Radiation on Compounds Related to Carbohydrates. . . . . . . . . . . 22 1. Alcohols.. ................................. ............... 2. Nucleic Acids.. ............................ .................... 26 3. Hydroxy Acids. .......................................... IV. The Effect of R 1. Polysaccharides 2. Aldohexoses, 3. Glycosides, Disaccharides, Trisaccharides, and Lactones. 4. Absorption Spectra and Post-irradiation Processes.. . . . . . 6. Self-decomposition of C14-labeled Carbohydrates.. . . . . .

I. INTRODUCTION Although about 50 years have elapsed since ionizing radiations were first shown to produce chemical systematic progress in the field has taken place only within the last decade. This advance may be attributed to the large range of comparatively cheap radiation-sources which have become available in this period as a result of developments in the nuclearpower industry. The general field of radiation chemistry has been well reviewed? Interest in the biological action of radiations, chemical utilization of fission-product radiations, and the use of radiation in the sterilization of food has stimulated an intensive study into the effects of ionizing radiations on organic compounds?*OIn contrast, chemical studies on the behavior of (1) F. Geisel, Bet., 36, 3608 (1902); 36. 342 (1903). (2) A. T. Cameron and W. Ramsey, J . Chem. Soc., 91, 931 (1907); 93, 966 (1908). (3) A. Debierne, Compt. rend., 148, 703 (1909). (4) M. Kembaum, Compt. rend., 148, 706 (1909); 149. 116 (1909). (6) F. L. Usher, Jahrb. Radioakt. u. Elektronik, 8, 323 (1911); Chem. Abstracts, 6, 322 (1912). (6) W. Duane and 0. Scheuer, Radium, 10, 33 (1913). (7) See Ann. Rev. Phys. Chem., 1 (1960)-10 (1969). (8) E. Collinson and A. J. Swallow, Quart. Revs. (London), 9, 311 (1966). (9) E. Collinson and A. J. Swallow, Chem. Revs., 66, 471 (1966). 13

14

G. 0. PHILLIPS

carbohydrates are meager, although a great deal of attention has been directed toward the physical changes observable during irradiation. However, in reccnt years, in view of the important physiological role of carbohydrates and their wide occurrence in foods, a more fundamental approach has been adopted toward the study of the radiation chemistry of carbohydrates. Consequently, at the present stage in the development of the subject, it is considered that a review will be of greatest value to investigators in this and allied fields if it is broadly based. Therefore in this review, the basic principles of radiation chemistry will be discussed, particularly with regard to the behavior of aqueous solutions. Investigations into compounds which are structurally related to the carbohydrates and which have received more systematic study will be considered, and the present position with regard to carbohydrates will be reviewed. In the broad sense, radiation chemistry embraces photochemistry-the chemistry of rcartions which occur in electrical discharges, and reactions in the atomic nucleus by the agency of neutrons and high-energy radiat]ions. In this review, however, attention will be confined mainly to the chemical changes induced by a-rays, @-rays,x-rays, and y-rays.

11. PI~IMARY AND SECONDARY EFFECTS OF RADIATION 1. Interaction of High-energy Radiations with Matter The processes by which high-energy radiations and particles interact with matter have been described in Whether the radiation be electromagnetic (x-rays or y-rays) or corpuscular (a-rays and @-rays), thc final transfer of rriergy occurs by way of charged particles. With electromagnetic radiation, interacfion of high-energy quanta with atoms of thc medium through which they pass leads to ionization, since the energy of the quanta is substantially greater than the binding energy of an electron. Although there are several mechanisms by which this process may bo brought about,14 it is clear that high-speed electrons are ejected and these give rise to chemical changes. The single atom initially affected by the radiation makes a negligible contribution to the total chemical change, which arises mainly from the ionization and excitation processes initiated by the secondary, high-speed electrons. For corpuscular radiations, the high-speed particles directly applied give rise to effects similar to those of the secondary electrons. (10) F. 8. Dniritori, J . Phys. & Colloid Chem., 62, 490 (1948). (11) J. L. Mugee, A n n . Rev. Nuclear Sci., 9, 171 (1954). (12) D. E. h a , “Actions of Radiations on Living CellB,” Cumbridge Univcrsity Press, London, 1955. (13) J. L. Magee and M. Burton, J . Am. Chem. Soc., 79, 523 (1951). (14) M. Burton, J . Chem. Educ., 28, 404 (1951).

RADIATION CHEMISTRY OF CARBOHYDRATES

15

Charged particles, in the main, interact with the electronic cloud around the molecule. This interaction is directly related to the charge of the particle and inversely related to its velocity. Thus, the energy of the particle may be transferred to the electron cloud and it gives rise to a displacement of the electrons. If the displacement is sufficient and the electron is no longer associated with the parent molecule, ionization has occurred. If, however, the displacement is not so pronounced, excitation has occurred. Such an excitation may be related to the excitation processes encountered in the photochemical, primary act. Other excitation states may arise as a result of slow, secondary electrons (20-100 e.v. of energy). Eyring, Hirshfelder, and Taylor16 first took into account the chemical contribution of such excited molecules, and the present position with regard to their contribution has been summarized by Magee and Burton.1s The density of excitation and ionization is not necessarily the same for all radiation qualities. For example, it is greater along the track of an a-particle than for an electron track. For a primary-recoil electron produced by C060 y-rays in water, the distance between successive ionizations is about 1000 d. The ionized track is, therefore, sparse. At each point of ionization, secondary electrons give rise to further ionizations, forming a group of ionpairs. In contrast, a-particles form a continuous track as a result of overlapping between the spheres of ionization. Experimentally, it has been shown for gases that approximately 25-32 e.v. of energy are required for forming an ion-pair, whereas ionization potentials for gases are in the range of 9-15 e.v. For this reason, it has been suggested that, if the excess energy is dissipated in electronic and excitation processes, half of the energy of the radiation goes into ionization and half into excitation. When ions and excited molecules have been formed in this manner, a variety of secondary processes may occur before the final chemical change takes place. To illustrate the nature of such primary and secondary processes, the behavior of water on exposure to ionizing radiations will be considered; this is a matter of fundamental importance in the present review, because the majority of carbohydrate investigations in this field have been undertaken in aqueous solution. 2. Radiolysis of Water and Aqueous Solutions Probably, no other system in radiation chemistry has been studied in so much detail as the action of ionizing radiations on water and aqueous systems. Nevertheless, knowledge about the detailed processes occurring is still incomplete. The over-all effects are, however, well established. It is generally acknowledged that absorption of energy by water results in the (15)

H.Eyring, J. 0. Hirshfelder and H. S. Taylor, J . Chem. Phys., 4,479 (1936).

16

0. PHILLIPS

Q.

formation of hydroxyl radicals and solvated electrons or hydrogen atoms. Molecular hydrogen and hydrogen peroxide are also produced. The present position of our knowledge of the radiation chemistry of aqueous systems has been demxibed.*6-a1 a. Formation of Hydrogen Atmns and Hydroxyl Radicals,--When electromagnetic radiation or charged particles interact with water, ionization occurs along the track of the particle or primary-recoil electron. At each point of ionization, the secondary electrons possess sufficient energy to induce further ionizations within about 20 A. of the track. These clusters of ionizations are known as b-raya or spurs. At a greater distance, the water molecules will only become electronically excited. The situation22 up to lo-'*10-" sec. after passage of the charged particle may be summarized as: HsO

+ el

-+

H20'

+ es + es

(1 1

where el and e2 are recoil electrons, and erris the secondary electron which can initiate ionization processes of the type: HIO

+

eB

+

Ha"

+ eal + es .

(2)

Reaction ( 1 ) is the primary ionization-process initiated by a recoil electron. It is thought that, subsequently, H20@is converted to a hydroxyl radical within lW1lseconds: HnO'

+ HnO + HsO' + .OH.

(8)

There are two views about the fate of the secondary electron. Samuel and Magee2882' assume that the electron does not leave the field of the parent ion, and that it eventually forms a hydrogen atom by charge-neutraliaaand Baxendale and Hughes:' tion with [email protected] and Frohlich*6*26 on the other hand, favor the idea that the hydrogen atom is created at a considerable distance from the parent ion, mainly by subexcitation electrons. These electrons come principally from the primary ionization of wa(16) F. 5. Dainton, Radiation Research, Suppl. 1, 1 (1969). (17) E. J. Hart, Proc. Intern. conf. Peaceful Uses Atomic Energy, Geneva, OB, 6 (1968). (18) E.J. Hart, J . Chem. Educ., 84, 686 (1967). (19) N.Miller, Revs. Pure and Appl. Chem. (Australia), 7 , 123 (1967). (20) M. Haissinsky, Acta. Chim. Acad. Sci. Hung., 12, 241 (1967). (21) J. Weies, Intern. J . Appl. Radiation and Isotopes, 6, 62 (1969). (22) H. A. Dewhurst, A. H. Samuel and J. L. Magee, Radiation Research, 1, 62 (1964). (23) J. L.Magee, J . A m . C h m . Soc., 78,3270 (1961). (24) A. H.Samuel and J. L. Magee, J . Chem. Phys., 21, lOs0 (1963). (26) R.L.Platemann, Radiation Research, 2, 1 (1966). (26)H. Frohlich and R. L. Platemann, Phys. Rev., 02, 1162 (1963). (27) J. H.Baxendale and C. Hughes, 2.phyeik. Chem. (Frankfurt), 14,306 (1968).

RADIATION CHEMISTRY OF CARBOHYDRATES

17

ter and they lose energy by inelastic collision. When the energy falls below the excitation energy of water, solvation of the electrons may occur and these solvated electrons subsequently form hydrogen atoms. From a general point of view, however, there does not appear to be any serious objection to the view proposed by Leal2 and Gray,28 namely, that the secondary electron is captured by the water molecule, to give H200, which leads to hydrogen atoms according to the equation :

+ OHe.

HzOe + H

It is also probable that free radicals are formed from excited water-molecules outside the ionization spurs. These would contribute to the net formation of hydrogen and hydroxyl free radicals. Therefore, although important refinements have been added, the fundamental description of the action of ionizing radiations on water remains as summarized by A l l e ~ 2 ~ H*O

*

+ ee + HzO OHe + H:q.+

HZ0@ aq. ---t ---t

Net result, HZ0

-+ 11

+ €€&.+ OH OHe + H

H ~ O ee~

Ha0

OH

According to this theory, hydrogen and hydroxyl free radicals would be distributed along the track of the original particle or primary-recoil electron, with the hydroxyl radicals situated near the track. The location of the hydrogen atoms is less certain, and they may be situated several A. units away from the site of electron formation. b. Formation of Hydrogen and Hydrogen Peroxide.-The view most generally held is that the formation of hydrogen and hydrogen peroxide occurs by pair-wise combination of hydrogen arid hydroxyl radicals : (4)

H+H+Hz OH

+ OH

+

HzOz

.

(6)

On this basis, about half of the free radicals would recombine to form water: H

+ OH

---t

HzO.

(6)

Thus, competition is set up between combination and diffusion of the radicals. On the basis of this diffusion-combination model, it is possible to account satisfactorily for the production of hydrogen peroxide and hydrogen. The mathematical treatment permits calculation of the theoretical fraction of the radicals reacting with a solute, and the resulting value is in good

L.H.Gray, J . chim. p h y s . , 48, 172 (1951). (29) A. 0. Allen, J . Phys. & Colloid. Chem., 62, 479 (1948). (28)

a.

18

0. PHILLIPS

agreement with experimental 0bservations.2~ * 2 6 ~ 8 0 * 3 1The combination reactions 4-6 occur within lO-'sec. after passage of the charged particle. When the solute is present in concentrations greater than lo-' M , the hydrogen atoms and hydroxyl radicals which escape by diffusion may react with the solute in an area well removed from the initial ionization. In the absence of a solute, water stabilization results from the following reactions: OH

+ Hz

-+

H + HzOz 3

+H Hz0 + OH, Hz0

These reactions are probably responsible for the low G values of hydrogen and hydrogen peroxide in liquid water. The G value in radiation chemistry refers to the chemical yield in units of molecules formed or disappeared per 100 electron volts of energy input. An alternative method for producing molecular hydrogen and hydrogen peroxide, proposed by Johnson and Weiss," is based on the direct interaction of excited water-molecules. 2 HzO* --t HzOz 2 H a * +Hn

+ HZ

+ 2 OH

More recently, WeissZ1put forward another theory, based on the interaction of ions according to the equations 2 HzO" 4HzOz + 2 He and 2 HsOe -+ Hz

+ 2 OH'.

c. Free-radical and Molecular-product Yields.-Although doubt still remains concerning the mode of formation of free radicals and molecular products, the net process following the interaction of electromagnetic radiation or of charged particles with water may be represented:

Ha0

+a

HZ+ b HZOZ+ c H

+ d (OH).

Accurate measurement of free-radical and molecular-product yields is important in radiation-chemistry studies on aqueous solutions, for these measurements enable quantitative predictions to be made regarding the extent of chemical changes during irradiations, and lead to an understanding of reaction mechanisms. Therefore, recent research has been directed toward the measurement of these yields, which are generally expressed as G values. An excellent account of the chemical methods used for determining G values (30) H. Fricke, Ann. N. Y . dcad. Sci., 69, 667 (1955). 77,4960 (1966). (31) H. A. Schwarr, J . Am. Chem. SOC., (32) G. R. A. Johnson and J. Weiss, Proc. Roy. SOC.(London), A040, 189 (1957).

RADIATION CHEMISTRY OF CARBOHYDRATES

19

of primary products formed in the radiolysis of water is given by Dainton.16 Allenas has surveyed in detail the yields which have been reported. The yields respectively designated G(OH), G(H), G(H2), and G(H202)depend on the reactivity and concentration of the solute, and on the density of energy release along the particle track. Such light-particle radiations as x-rays, y-rays, and electrons generate G(0H) varies between 6 and 7, free radicals mainly. The sum G(H) gradually increasings4as the concentration of solute increases from 10-4 M to M. Yields of molecular hydrogen and hydrogen peroxide are 0.4-0.5. Heavy-particle radiations produce mainly molecular hydrogen and hydrogen peroxide. The highest value yet obtained is with fission recoils, where G(H2) is 1.83, with the G(0H) and G(H) almostss zero. More hydrogen atoms than hydroxyl radicals are formed in y r a y irradiated acid solutions. In 0.8 N sulfuric acid, G(H) is 3.65 and G(0H) is36 2.95. As the pH increases above 3, the difference in G(H) - G(0H) decreases. Recent determinations of radical and molecular yields are in reasonable agreement with these values.2g~37-ag The relative yields of hydrogen atoms and hydroxyl radicals may be substantially affected by addition of either hydrogen or hydrogen peroxide to the system which is irradiated. Hydrogen provides hydrogen atoms and hydrogen peroxide increases the concentration of hydroxyl radical.

+

OH

H

+ Hz + H + HzO

+ Hz0z + OH + Ha0

Consequently, if suitable concentrations of hydrogen and hydrogen peroxide are chosen, it is possible to study the actions of hydrogen and hydroxyl radicals separately. The yields G(H2) and G(H202) decrease, also, with increasing concentration of solute. If a solute reacts with hydrogen atoms, the yield of hydrogen decreases as a result of competition between the reactions: H+H-+Ht H

+ solute + product.

(33) A. 0. Allen, Radiation Research, 1, 85 (1954). (34) E. J. Hart, Radiation Research, 2, 33 (1955). (35) J. W. Boyle, W. F. Kieffer, C. J. Hochanadel, T. J.

Sworski and J. A. Ghormley, Proc. Intern. Conf. Peaceful Uses Atomic Energy, Geneva, 7 , 576 (1956). (36) N. F. Barr and R. H. Schuler, Radiation Research, 7, 302 (1957). (37) M. Lefort and X. Tarrago, Compt. rend., 247,454 (1958). (38) M. Daniels and J. Weiss, J . Chem. Soc., 2467 (1958). (39) W. M. Garrison, B. M. Weeks, J. 0. Ward and W. Bennett, J . Chem. Phys., 27, 1214 (1957).

20

Q. 0.

PHILLIPS

Similarly, an oxidizable solute decreases G(H209): OH

OH

+ OH

+ solute

-+

HnOs

4

product.

When solute concentrations are below 0.1 M ,the chemical change occurs by indirect action. Under these conditions, the energy is absorbed by the water, and chemical changes result from the effect of the species produced in the primary radiolysis of water. At higher concentrations, direct-action effects may become important. Thus, when solid carbohydrates are irradiated, direct-action effectsare responsible for the chemical change, whereas, in solution, the concentration of solute may influence the contribution of indirect- and direct-action processes. d. New Radical Species.-Evidence for new radical species, which has been accumulating recently, has been summarized by Hart." Suggested species which may be present in irradiated water under particular conditions are the hydroperoxy radical, HOz , hydrogen-molecule ion, Ha@,oxygen atom ion, Oe, and subexcitation electrons. There is every reason to believe that the hydroperoxy radical is present in the track of the charged particle. When the concentration of solute is high, this radical is not found, and it may be formed, therefore, within the regions of intense ionization by the reaction: OH

+ HnOa

+ HnO

+ HOI .

(7)

Therefore, if the hydroxyl radicals are effectively scavenged by the solute, reaction (7)cannot take place, and G(H0a) is low. For 7-rays, the value is 0.026, but the value increases to 0.15 for low-energy a-rays.84,'O Evidence for the hydrogen-molecule ion is not definite. This species is proposed in order to explain yields of ferric ion in de-aerated, acid solution.41 Few

+ HI@+ Few + HI

Other explanations have, however, been put forward in order to account for this behavior.@ Hart, Gordon, and Hutchinson," on the basis of pH studies, propose ionization of the hydroxyl radical at pH's above 9: OH Oe + HS There are indications that Oe is more stable than the hydroxyl radical. (40)T. J. Sworski, Radiation Research, 6, 247 (1956). (41) W. G. Rothschild and A. 0. Allen, Radiation Research, 8, 101 (1953). (42) S. Gordon and E. J. Hart, J . Am. Chem. Soc., 77, 3981 (1955). (43) A. Charlesby and A. J. Swallow, Ann. Rev. Phyu. Chem., 10, 295 (1959). (44) E. J. Hart, S. Gordon and D. A. Hutchineon, J . A m . Chem. Soc., 76, 0105 (1963).

RADIATION CHEMISTRY OF CARBOHYDRATES

21

The possibility that subexcitation electrons may be responsible for the formation of hydrogen atoms was mentioned previo~sly.2~~a7 Attempts to confirm reports of solvated electrons have not been successful. No visible color is observable when metallic potassium, distilled onto the walls of a silica absorption-cell, reacts with water a t 0". 3. Chemical Dosimetry For quantitative studies in radiation chemistry, it is essential that the energy input into the irradiated volume should be accurately determined. For this purpose, the most versatile and reliable method is the ferrous sulfate dosimeter, proposed by Fricke and M0rse.~6The method involves the use of an air-saturated solution of 10-' M ferrous sulfate and 10-8 M sodium chloride in 0.8 N sulfuric acid. On exposure of the solution to ionizing radiations, the ferrous ion is oxidized to ferric ion, which may conveniently be determined accurately by spectrophotometry. The amount of chemical change is proportional to the total energy-input, independent of dose rate, and (within wide limits) independent of the concentration of ferrous ion, ferric ion, and oxygen. The main reactions involved are as follows.

+ Ha02 + F e w + OH + OHe Fern + OH + F e w + OHe H + 02 + HOz Few + HOS + Fe- + HOae H O P + H' + H a ,

Few

Thus, according to this mechanism, each peroxide molecule oxidizes two ferrous ions, each hydroxyl radical oxidizes one ferrous ion, and each hydrogen atom oxidizes three ferrous ions. Owing to the high preferential reactivity of organic substances toward hydroxyl radicals, care must be taken to use highly pursed water, free from organic impurities, in preparing the dosimeter. For this reason, also, sodium chloride is generally added. In the presence of chloride ions, the hydroxyl radicals readily react according to the equation : OH

+ Cle + OHe + C1.

The chlorine atom formed is still able to oxidize one ferrous ion, but it is much less reactive toward organic molecules. A constant G value, in the absence and presence of chloride ions, is, therefore, a convenient test for organic impurities in water. Calorimetric methods and ioniaation chambers were used for calibration (46) H.Fricke and 8.Morse, Phil. Mag., 7, 129 (1929).

22

a.

0. PHILLIPS

in this method, but, for a considerable period, there was a lack of correlation between the two methods. The conflict was eventually resolved, and Hochenadel and G h ~ r m l e y using , ~ ~ the (more reliable) calorimetric technique, first established the accepted value G(Feae) as 15.6 f 0.3 for Coeo y-rays in 0.8 N sulfuric acid. Energy input can, therefore, be readily calculated from G(Fe3@)for the radiation quality used, and thc amount of ferric ion formed is given by the expression: E(e.v./l.) = [lo0X 6.02 X 10W]/G(FeSe),

where C is the increase in ferric concentration (in moles/liter) produced by the particular radiation. The value of G(Fe3@)varies from 15.6 for such light particles as electrons, y-rays, and cr-rays to about 3 for fission recoils. Radiations having intermediate, linear-energy transfer have values between these two limit^.^^-^^

111. THEEFFECT OF RADIATION ON COMPOUNDS RELATED TO CARBOHYDRATES 1. Alcohols

Alcohols have been irradiated in the pure state and in aqueous solution, and it is therefore necessary to consider the two cases independently. Cyclotron a-rays were used by McDonnell and Newton63 to irradiate pure alcohols ranging from methanol to decyl alcohol, including the two isomers of propanol and the four isomers of butanol. The chemical changes induced were more specific than would have been anticipated from purely theoretical considerations. Analysis of the gaseous products by mass spectrometry, and of the liquid-phase products for water, carbonyl compounds, aldehydes, total glycols, and vicinal glycols, showed that, although a large number of products were formed, their nature was considerably restricted. Apart from carbon monoxide, no product is formed that is removed from the original alcohol by more than one oxidation state. The only glycols formed are vicinal glycols. Therefore, bonds are not broken indiscriminately by radiation, and the major reaction involves groups di(46) C. J. Hochanadel and J. A. Ghormley, J . Chem. Phys., 21, 880 (1953). (47)E . J. Hart, W. J. Ramler and R. 5.Rocklin, Radiation Research, 4,378 (1956). (48)R.H. Sohuler and A. 0. Allen, J . Am. Chem. SOC.,79, 1565 (1957). (49) W.R. McDonnell and E. J. Hart, J . Am. Chem. SOC.,76,2121 (1954). (50) R.H.Schuler and N. F. Barr, J . Am. C h m . SOC.,78, 6756 (1956). (51)L.Ehrenberg and E . Sneland, JENER Puhls., No. 8, 25 (1954). (52) N . Miller, in “Introduction A la Dosimetrie des Radiations, Actions chimique et biologiques des Radiations,” M. Haissinsky, ed., Masson et Cie, Paris, France, 1966. (53)W.R. McDonnell and A. S. Newton, J . Am. Chem. SOC.,76, 4G51 (1954).

RADIATION CHEMIBTRY OF CARBOHYDRATES

23

rectly attached to the C-OH group. It appears that fission of one of the =C-H bonds occurs, to give a hydrogen atom and a radical. The radical may dimerize to form a glycol, or it may be further oxidized to a carbonyl compound. Combination of the hydrogen atoms gives hydrogen. For ethanol, this may be represented as follows.

CY

CHjCHzOH 2 CHjCHOH

+ CHaCHOH -+

+H

CHaCHOH

I

CHjCHOH H+H+Hz

The l-hydroxyethyl radical may be further oxidized, to form aldehydes from primary alcohols, and ketones from secondary alcohols. The only tertiary alcohol to be studied in detail gave the corresponding ketone on irradiation. Support for the intermediate formation of the l-hydroxyethyl radical and a hydrogen atom was given by Burr.64 During radiolysis of CH3CH20H, CD3CH20H1 CH3CD20H1 CH3CH20D, and CD3CD20H, the proportion of deuterium in the evolved hydrogen was measured. Mass spectrometry showed that the loss of hydrogen was large for CH3CH20Hand CD3CH2OH, and small for CH3CD20H,although the isotope effect should lead to the opposite behavior if there is no preferential attack at the CH2 position. The total yield of hydrogen decreaseafrom G 3.7 to G 3.0 when the hydrogen atoms of the CH2 group are replaced by deuterium.66The main process is, therefore: CHaCHzOH -+ CHsCHOH

+ Hz .

However, deuterium also appears in the radiolytic gas when CH3CH20D is irradiated. This suggests, as a secondary process, the following. H

+ CHaCHzOH

-+

HZ

+ CHjCH,O*

The CH3CH2O* radicals disproportionate to give acetaldehyde and ethanol. On irradiation of liquid ethanols6with helium ions, the radiation yields for hydrogen, total carbonyl compounds, and vicinal glycols decrease markedly over the range 0.029 to 2.7 X 102* e.v./ml. When acetaldehyde or l-hexene were added, even in concentrations of 1%, they were sufficient to decrease the hydrogen yield, indicating a pronounced protective action by the products. It has been suggested that thermalized hydrogen-atoms may be responsible for at least part of the hydrogen formed during the radiolysis (54) J. G. Burr, J . Am. Chem. Soc., 79, 761 (1957). (55) J. G. Burr, J . Phys. Chem., 61, 1477 (1957). (56) W. R. McDonnell and A. S. Newton, J . Am. Chem. Soc., 78, 4554 (1956).

24

0. 0. PHILLIPS

of liquid ethanol, and McDonnell and GordonB7put forward a similar postulate to permit interpretation of the irradiation of methanol. By use of Co60 y-rays and 28 MeV a-rays, it was found that the amount of hydrogen released is similar in both cases, but the formation of formaldehyde is favored by the heavy-particle radiat,ion. Alcohols having very long chains appear to give less aldehyde and less glycol than alcohols having shorter chains. On prolonged irradiation, the primary products are affected, and initial aldehydes give rise to polymers. Finally, there is an increase in the amount of gaseous products formed.68 The effect of oxygen appears to be an increase in the amount of acid formed.6g An interesting aspect of the effects of radiation on alcohols is the extensive changes which may occur in C"-labeled alcohols under the agency of their own radiation (0.155MeV &rays). Methanol-@*undergoes considerable self-decomposition, with consequent formation of compounds of higher molecular weight. Methane is formed, and, in addition, ethylene glycol, glyceritol, and erythritoPO in the ratio 1360:14.9:1. Further consideration of self-decomposition is given for Clclabeled carbohydrates. The indirect action of radiation on aqueous alcohol leads to changes which are broadly similar in pattern to the direct-action effects described for pure alcohols. Hydrogen, aldehydes, glycols, and acids are formed in general, although it has not been established that acids are primary products."'-66 formaldehyde is formed During irradiation of methanol-water in yields proportional to the number of alcohol molecules exposed to radiation. Excess of the "dimer" (ethylene glycol) was formed-no doubt as a result of attack by free radicals formed during the primary radiolysis of water. (57) W. R. McDonnell and 5.Gordon, J . Chem. Phys., Is, 208 (1955). (58) J. C. McLennan, M. W. Perrin and H. J. C. Treton, Proc. Roy. SOC.(London), A126, 246 (1929). (5s) A. Kailan, Silzber Akad. Wiss. Wien, Mulh. nolurw. K l . , Abt. 1111, 140, 419 (1932). (60) W. J. Skraba, J. G. Burr and D. N . Hess, J . Chem. Phys., 21, 1296 (1953). (61) A. Kailan, Sitzber. Akad. Wiss. Wien, Math. nalurw. K l . , Abt. IIa, 143, 163 (1934). (62) H. Fricke, E. J. Hart and H. P. Smith, J . Chem. Phys., 6 , 229 (1938). (63) J. Loiseleur, R. Latarjet and C. Crovisier, Compt. rend. soc. bioZ., 136, 57 (1942). (64) W. R. McDonnell, J . Chem. Phys., 99, 208 (1955). (65) G. Scholes, J . chim. phys., 62, 640 (1966). (66) A. J. Swallow, Biochem. J . , 64, 253 (1953).

RADIATION CHEMISTRY OF CARBOHYDRATES

25

HzO + H + OH + CHsOH + HZ+ *CHsOH OH + CHaOH + Hz0 + *CH*OH H

2 *CHIOH 4CHiOH

I

CHIOH

The mechanism of radiolysis of aqueous solutions has been studied by Jayson, Scholes, and Weiw.67 The amounts of acetaldehyde, hydrogen peroxide, hydrogen, and 2,3-butanediol were measured at various pH’s and ethanol concentrations in oxygenated and in evacuated solutions. The yield of acetaldehyde is not independent of the concentration of ethanol. I n oxygen, the curve for yield of acetaldehyde against concentration of ethanol flattens out at a concentration of lo-* M , but the yield of acetaldehyde increases a t higher concentrations. The range of concentration studied was 1W6to 1 M ethanol. For the initial portion of the curve, the following reactions have been postulated.

+ OH + CHsCHOH + H20 H+ HO2 CHjCHOH + Oz + CHaC(0z)OH HOz + OH + Hz0 + On CH&(O2)OH + H o t + CHsCHO + CHaCHzOH

0 2

0 2

The yield, therefore, should be the over-all result of the competition between the last two reactions, and a G value of about 2 is attained, which corresponds to the available amounts of hydroxyl radicals. For higher concentrations of ethanol, the yield of hydrogen peroxide stays almost constant until the concentration of ethanol approaches M . The increase in aldehyde is, however, attributed either to competition between the reactions: H

+

01 4

HOI

and CHsCHIOH

+ H + CHaCHOH + Hz

or to electronic excitation of the ethanol molecules by subexcitation electrons produced by the (67) G . G. Jayson, G. Scholes and J. Weiss, J . Chem. SOC.,1368 (1957). J. T. Allen, E. M. Hayon and J. Weiss, ibid., 3913 (1969). (68) J. Weiss, J . chim. phys., 62, 40 (1966).

26

0. 0. PHILLIPS

Since, on this view, hydrogen atoms and hydroxyl radicals react to form the products, the sum of theyield of aldehyde (G 1.9) and of 2,3-butanediol (G 1.6) at pH 1.2 under vacuum should approximate to G(H) G(0H). The value 3.55 is in reasonable agreement with values from other Bystems at this pH. It would not appear necessary, therefore, to invoke the concept of sub-excitation electrons. The concentration dependence may be an indication that a solute concentration of 3 or 4 X 1CSM is necessary for scavenging all of the hydroxyl radicals and hydrogen atoms available. More recently, the effect of increasing the ethanol concentration beyond 1 M was examined. The yields of products further increased. Up to 5 M ethanol, the increase could be accounted for on the basis of a decrease in the back reaction H OH 4 HaO, and therefore provide an increase in the number of reactive species. However, above 5 M ethanol, the yields are so great that they cannot be the result of simple radical-solute reactions.

+

+

2. NucleicAd8

Although extensive investigations have been undertaken into the effects of ionizing radiation on nucleic acids, the precise chemical changes which are induced remain uncertain. Attention has been mainly concentrated on the changes in viscosity observed during and after irradiation. On irradiation in aqueous solution, the viscosity decreasesJ69J0and it continues to decrease for many hours after irradiation is terminated?0-73The evidence regarding the effect of oxygen on this process is rather Measurements of streaming birefringence7O and of sedimentation and diff usion constants support the view that degradation is the main effect of irradiation, fragments having molecular weights above 10,000 being produced?' This interpretation is also in keeping with the observed viscosity changes. Numerous investigations have centered on the physical changes accompanying irradiation , particularly changes in molecular weight and hydrogen bonding. A review of this aspect is given by Butler.lo There is ample evidence, from comparisons of the action of radiation A. H. Sparrow and F. M. Rosenfeld, Science, 104, 246 (1946). J. A. V. Butler, Radiation Research, Suppl. 1, 403 (1969). B. Taylor, J. P. Greenstein and A. Hollaender, Science, 106, 263 (1947). B. Taylor, J. P. Greenstein and A. Hollaender, Cold Spring Harbor Symposia Quant. Biol., la, 237 (1947). (73) B. Taylor, J. P. Greenstein and A. Hollaender, Arch. Biochem., 16, 19 (1948) (74) B. E. Conway, Brit. J . Radiol., N, 49 (1964). (76) B. E. Conway, Nature, 175, 679 (19S4). (76) J. A. Crowther and H. Liebmann, Nature, 115, 698 (1939). (77) M. Daniels, G. Scholes and J. Weiss, Nature, 171, 1163 (1966). (78) M. Daniels, G. Scholes and J. Weiss, Ezpen'entia, 11, 219 (1965). (69) (70) (71) (72)

RADIATION CHEMISTRY OF CARBOHYDRATES

27

with the behavior of Fenton’s reagent7g-81 and the effect of hydrogen peroxide photolyeed with ultraviolet light, that hydroxyl radicals79~*2*~~ are, in part or entirely, responsible for the observed changes. Hydrogen-platinum black has no effect on the nucleic acids, indicating that hydrogen atoms do not play a prominent although this observation is by no means proof positive. Attack by free radicals formed during radiolysis of aqueous solutions of nucleic acid does not appear to be specific at particular sites in the molecule. Deamination, liberation of inorganic phosphate, decrease in optical density at 265 mp, increase in Van Slyke amino nitrogen, decrease in purine nitrogen, and an increase in the number of titratable acid groups have all been 0bserved.7~ Nucleosides and nucleotides appear to behave similarly on irradiation. On the information available at present, it is not possible to identify the primary degradation processes following the irradiation of nucleic acid solutions. The following over-all changes have, however, been observed: (a) fission of glycosidic links and liberation of the purine base, (b) deammoniation and ring opening in the bases, (c) breaking of ester links to give inorganic phosphate, and (d) splitting of internucleotide links. It is probable, therefore, that the radiation-induced loss in viscosity is due to a reduction in hydrogen bonding between the molecules as a result of the loss of vital groups, as well as to direct degradation of the polynucleotide chain. The slow, post-irradiation decrease in viscosity (“after-effect”) was investigated by Daniels, Scholes, Weiss, and Wheeler,gOwho relate this phenomenon to the labilization of phosphate bonds by the intermediate formation of labile phosphate esters. Leading to this conclusion is the observation that about fifteen times as much inorganic phosphate can be obtained by acid hydrolysis of irradiated, aqueous solutions of nucleic acid as is formed directly by the radiation. It is, therefore, thought that, after the labile phosphate esters have been formed, they undergo slow acid hydrolysis, and that this mild hydrolysis occurring at the diester phosphate groups, even (79) J. A. V. Butler and B. E. Conway, Proc. Roy. Soc. (London), B141,562 (1953). (80)E. L. Grinnan and W. A. Mosher, J . Biol. Chem., 101, 719 (1951). (81) G. Limperos and W. A. Mosher, Am. J . Roentgenol. Radium Therapy, 63, 681 (1950). (82) J. A. V. Butler and K. A. Smith, Nature, 166,847 (1950). (83) B. E. Conway, Brit. J . Radiol., 27. 42 (1954). 77, 258 (1951). (84) D. B. Smith and G. C. Butler, J . Am. Chem. SOC., (85) E. S. G. Baron, P. Johnson and A. Corbure, Radiation Research, 1, 410 (1951). (86) G. Scholes, G. Stein and J. Weiss, Nature, 164, 709 (1949). (87) G. Scholes and J. Weiss, Ezpll. Cell Research, Suppl. 2, 219 (1952). (88) G. Scholes and J. Weiss, Nature, 166, 640 (1960). (89) G. Scholes and J. Weiss, Biochem. J . , 63, 667 (1963). (90)M. Daniels, G . Scholes, J. Weiss and C. M. Wheeler, J . Chem. SOC.,226 (1957).

28

G. 0. PHILLIPS

though it might not lead to the formation of inorganic phosphate, is sufficient to lead to a decrease in viscosity. Model experiments using purine and pyrimidine nucleotides support this view.e1 When these are irradiated in aqueous solution with x-rays, there is a post-irradiation release of inorganic phosphate in the presence and absence of oxygen. The post-irradiation process is first-order, and it is suggested that this behavior is due to the introduction of activating carbonyl groups in the sugar component. This interpretation of the after-effect appears more convincing than a previous explanation in which it was attributed to the formation of an unstable peroxide which decomposes slowly when irradiation is terminated.81 Hydroperoxides have been detected in nucleic acid solutions irradiated in oxygen, but these appear to be associated with the pyrimidine residue rather than with the sugar moiety.go Related to the interpretation of the effects of radiation on nucleic acids are the studies on the formation of labile phosphate esters in solutions of simple phosphates by irradiation. When glyceritol 1- and 2-phosphates are irradiated with 200 KV x-rays, inorganic phosphate is liberated. The former gives 1,3-dihydroxy-2-propanonephosphate, and the latter, an acid-labile phosphate e ~ t e r . Detailed ~ ~ - ~ ~studies on methyl, ethyl, propyl, butyl, and amyl phosphates have indicated the mode of formation of such labile phosphate esters.96 Two reactions have been recognized: 0

II + 2 (H + OH) + 0% RCH + HsPO, + HaOa + H i 0 RCHaOPOaH3 + (H + OH) + 1.6 Oa RCOPOaHt + H i 0 1 + Hz0.

RCHIOPOaHz

+

4

II

The latter reaction (producing the labile acyl phosphate) is less favored at increasing chain-lengths, and attack occurs along the hydrocarbon chain, with formation of an organic peroxide. In the absence of oxygen, no acyl phosphate or peroxide is formed, but inorganic phosphate is liberated. 3. Hydroxy Acids

When irradiated in aqueous solution, hydroxy acids are converted into the corresponding keto acids, particularly in the presence of oxygen. Lactic acid, for example, gives pyruvic acid,W and malic, citric, and 3-hydroxy(91) (92) (93) (94) (96) (96) (97)

M. Daniels, G. Scholes and J. Weiss, J . Chem. Soc., 3771 (1966). J. A. V. Butler and B. E. Conway, J . Chem. Soc., 3418 (1948). G. Scholes, W. Taylor and J. Weiss, J . Chem. Soc., 236 (1967). G. Scholes and J. Weiss, Nature, 171, 920 (1966). G. Scholes and J. Weiss, Brit. J . Radiol., 27, 47 (1964). R. W. Wilkinson and T. F. Williams, J . chim. phye., 61,600 (1966). G. R. A. Johnson, G . Scholes and J. Weiss, J . Chem. Soc., 3091 (1963).

RADIATION CHEMISTRY OF CARBOHYDRATES

29

butyric acids each give the related keto acid.98 In all the examples studied, the effect of oxygen is similar and leads to an enhanced yield of the product. Many of the reactions induced in organic molecules on irradiation in oxygenated aqueous solution follow a common mechanistic pattern. In this, the hydroxy acids conform strictly, and, because of the obvious relevance of such mechanisms to carbohydrate irradiations, the general pattern will be considered here.90 For a wide group of organic solutes in water, it is generally assumed that hydrogen atoms and hydroxyl radicals formed during primary radiolysis of water are removed by the reactions: H OH

+ Oz + HOz

+ HzM + HMO+ HsO,

where H2M is the solute molecule. Studies based on the measurement of the over-all stoichiometry of such reactions lead to the conclusions that HO2 does not react with organic solutes in the initial step and that the subsequent reactions involve: HMO+ O t + M + H O z 2 H0z

+

HzOz

+ 02.

The following yield-relation may therefore be expected: G(-H&f) = Gp(0H) G(Hz0z) = Gp(Hz0z)

+ 0.5 GP(OH) + 0.5 GP(H),

where Gp(OH), Gp(H), and Gp(H202) represent the primary yields of hydroxyl radicals, hydrogen atoms, and hydrogen peroxide, respectively. The value G(-H2M) is the over-all G for the disappearance of solute, and G(H202)is the observed yield of hydrogen peroxide. Several reactions have been interpreted on this basis.WJo0Jo1Termination occurs by the reaction :

+

2 HOa + H ~ 0 2 0 2 .

Modifications of this general pattern have been encountered, indicating clearly that no mechanism should be proposed unless accurate, initial-yield measurements have been undertaken. Malic acid solutions, for example, on irradiation with x-rays in oxygen, give oxalacetic acid in accordance with the mechanism outlined, with G( -malic acid) initially equal to 2.6. How(98) A. W. Pratt and F. K . Putney, Radiation Research, l, 234 (1964). (99) For a general summary of such mechanisms, see W. M. Garrison, Ann. Rev. Phys. Chem., 8 , 129 (1967). (100) E.J . Hart, J . Am. Chem. Soc., 76,4198 (1964). (101) W. M. Garrison and B. M. Weeks, J . Chem. Phys., 26, 585 (1956).

30

0. 0. PHILLIPS

ever, a parallel oxidation-path yields hydroxyoxalacetic acid with the overall stoichiometry : H N

+ 02

+

MO

+ Hz0.

Therefore, it would seem that this product is formed through an organicperoxy radical as intermediate, rather than through the reaction of a malic acid radical as required by the basic mechanism. An even more marked deviation occurs when L-ascorbic acid is irradiated with Coeo y-rays in oxygenated 0.8 N sulfuric acid.'" Here, the over-all stoichiometry is such that quantitative interpretation is impossible unless hydroxyl radicals and HOz radicals are involved in an initial, abstraction step:

+ H N HMO+ Hz0 HzM + H0z + HMO+ HzOz , OH

-+

followed by reaction of the one-electron oxidation-product HM with oxygen to form a peroxy radical: HMO

+ 02

-+

HM*(Oz).

Finally, HMO(02) is removed through the termination reaction: HM*(Oz)

+ HMO

+2

M

+ HzOz

or 2 HM*(Oz) --* 2 M

+ HzOz + 02 .

For carbohydrate irradiations in solution, also, a general difficulty exists if the mechanism is interpreted on the basis of initial abstraction by hydroxyl radicals only. The value G(-sugar), as will be seen from the subsequent discussion, is greater than the primary yield of hydroxyl radicals. In this respect, therefore, the behavior of carbohydrates on irradiation in solution resembles that of alcohol more closely than that of hydroxy acids. In the absence of oxygen, the mechanism of radiolysis of aqueous hydroxy acids is modified somewhat. During the y-irradiation of glycolic acid solutions under vacuum, the products are glyoxylic, oxalic, and tartaric acids.loSThese acids may be formed as follows. Hz0

--HCI

H

+ OH

HOCH~COZH2*CH(OH)COzH (102) N. F. Barr and C. G. King, J . Am. Chem. Soc., 78, 303 (195G). (103) P. M. Grant and R. B. Ward, J . Chem. Soc., 2654 (1959).

RADIATION CHEMISTRY OF CARBOHYDRATES

31

2 *CH(0H)CO ZH+ HOzCCH(0H)CH (0H)COzH

*CH(OH)COzH

(H0)zCHCOzH [-t CHOCOzH

-

(H0)zCHCOzH *C(OH)zCOzH

OH

+ HzO]

3 *C(OH)&OzH

(H0)sCCOzH [+ HOzCCOzH

+ HzO]

Dehydrogenation of glycolic acid by radicals from water may be anticipated, because of the activation of the a-hydrogen atom by the carboxyl groups. Further strong evidence for the facility of the first step comes from the observation that the direct action of y-rays on polycrystalline glycolic acid results in almost exclusive formation of the (carboxyhydroxymethyl) Quantitative studiesLosindicate that glyoxylic and tartaric acids are primary products and oxalic acid is a secondary product. By including the amounts of formic acid, formaldehyde, and carbon dioxide, a mass balance for carbon may be obtained. Therefore, the over-all degradation pattern under vacuum may be represented as follows. 0 Dimer i so% HOCHZCOZH (Tartaric acid) glycolic acid

glyoxylic acid

I

% ’

I

&HZ formaldehyde

formic acid

HzCzO4 oxalic acid

In oxygen, only a trace of tartaric acid is formed by dimerization of the (carboxyhydroxymethyl) radicals, but the yield of glyoxylic acid is increased to 70%. This is in accordance with the general mechanism for oxygenated solutions previously described. Dimeriaation is diminished following the removal of carboxyhydroxymethyl radicals by the following reactions. CH (OH)CO ZHA *OOCH(OH) COzH

0 *OOCH(OH)COzH

+ HOz

II

+ HC-COzH

+ HzOz + 0 2

Prolonged irradiation of hydroxy acids in the absence of oxygen leads to (104) P. M. Grant, R. B. Ward and D. H. Whiffen, J . Chem. Soc., 4635 (1958). (105) P. M. Grant and R. B. Ward, J . Chem. SOC.,2659 (1959).

32

0. 0. PHILLIPS

the formation of an acidic polymer,106presumably by an extension of the dimeriaation process, with combination of radicals formed by primary and secondary abstractions. This reaction leading to polymer formation is a general feature of irradiations of sugars, hydroxy acids, and amino acids in the absence of oxygen. The products from the irradiation of pure hydroxy acids have not been studied, but calcium glycolate-CI4is degraded, under the action of its own &rays, to formic acid and oxalic acid.1°7J0* Electron-resonance spectroscopy was used for identifying the radical obtained on x-irradiation'OD and 7-irradiation'w of crystalline glycolic acid. The evidence supports the structure HOCHC02H for the trapped radical, with only very slight indications of the presence of another radical. One possihlc step in the formation of the (carboxyhydroxymethyl) radical is as follows.

+ H O C H ~ C O ~+H HOCHCO~H + H This process may, however, occur in two stages - loss of an electron, followed by loss of a proton.

IV. THEEFFECT OF RADIATION ON CARBOHYDRATE^ One of the earliest workers to study the effect of ionizing radiations on carbohydrates was Kailan,lloJ1lwho observed that the radiations emitted from radium salts can induce hydrolysis in sucrose and D-glucose. Later interest centered on the physical changes which accompany irradiation, including changes in pH, optical rotation, reducing power, viscosity, and ultraviolet absorption ~ p e c t r a . ~ l 2Recently, -l~~ however, more attention has been given to the nature of the chemical changes which accompany irradiation, and, in this Section, the emphasis is placed on this aspect, wherever information is available. The subject is, however, far from complete, and, for many of the compounds studied, indications only can be given regarding the chemical changes involved. (106) S. A. Uttrker, P. M. Grant, M. Stacey and R. 13. Ward, J . Chem. Soc., 2648 (1959). (107) R . M . Lemmon, Nucleonics, 11. 44 (1963). (108) B. M. Tolbert, P. T. hdams, E. C. Bennett, A. M. Hughecl, M. R. Kirk, R.M. Lemmon, R . M. Noller, R. Ostwald and M. Calvin, J . Am. Chem. SOC.,76, 1867 (1953). (109) W. Gordy, W. B. Ard, Jr., and H . Shields, Proc. Natl. Acad. Sci. U . S . , 41, 996 (1965). (110) A. Kailan, Monalah., S!l, 1361 (1912). (111) A. Kailan, Monalah., S4, 1269 (1913). (112) P. Holtz and J. P. Becker, Arch. ezptl. Pathol. u.Pharniakol., 182, 160 (1936). (113) P. Holtz, Arch. ezptl. Pathol. u . Pharmakol., 182, 141 (1936). (114) A. Nome, Compt. rend. soc. b i d , 89, 96 (1923).

RADIATION CHEMISTRY OF CARBOHYDRATES

33

1. Polysaccharides

When polysaccharides are irradiated in the solid state or in solution, degradation is the most predominant feature observed. This statement is true for such naturally occurring polysaccharides as cellulose,l16 dextran,l17 starch,119,120 agar,’2l alginic acid,122various gums,119pectin~,l2~-’2~ and hyaluronic acid.126-128 That degradation occurs when aqueous solutions are irradiated is generally inferred from decreases in viscosity observed120,122,127,128 and the formation of reducing substances.l20 It has been claimed that larger doses are needed for degrading polysaccharides in the solid state than in aqueous solutions, and this claim is in keeping with general experience in radiation chemistry. For carbohydrates, however, the claim is based on very scanty evidence, and a quantitative comparison between irradiations of the pure solids and solutions of polysaccharides is urgently required. l ~ ~irWhen pectin powder (9.4% of moisture)lz6 or dry a p p l e - p e ~ t i nare radiated with x-rays or fast electrons, the viscosity of the solution after irradiation is lower than that of the unirradiated controls, and the decrease in viscosity is more pronounced at higher doses. Only slight changes in reducing power were, however, observed. Similar changes occur when aqueous solutions are irradiated. Sucrose, D-glucose, and D-fructose added to a pectin solution exert a protective action, presumably as a result of their scavenging of the hydrogen atoms and hydroxyl radicals formed during the primary radiolysis of water. D-Fructose is reported to be “by far” the most effective protective agent, although, from work discussed later in this article, D-fructose does not appear to be more susceptible to the action of s118

(115) E. J. Lawton, W. D. Bellamy, R. E. Hungate, M. P. Bryant and E. Hall, Tappi, 34, 113A (1951). (116) J. F. Saeman, M. A. Millett and E. J. Lawton, Ind. Eng. Chem., 44, 2848 (1952). (117) F. P. Price, W. D. Bellamy and E. J. Lawton, J . Phys. Chem., 68, 821 (1954); P. 0. Kinell, K. A. Granath and T. Vanngard, Arkiu Fysik, 13, 272 (1958). (118) C. R. Ricketts and C. E. Rowe, Chem. & Ind. (London), 189 (1954). (119) A. Branch, W. Huber and A. Waly, Arch. Biochem. Biophys., 39, 245 (1952). (120) M. A. Khenokh, Zhur. Obshchei Khim., 20, 1560 (1950). (121) H. Kersten and C. H. Dwight, J . Phys. Chem., 41, 687 (1937). (122) R. N. Fenstein and L. L. Nejelski, Radiation Research, 2, 8 (1955). (123) C. H. Dwight and H. Kersten, J . Phys. Chem., 42, 1167 (1938). (124) E. A. Roberts and B. E. Procter, Food Research, 20, 254 (1955). (125) Z. I. Kertesr, B. H. Morgan, L. W. Tuttle and M. Lavin, Radiation Research, 6, 372 (1956). (126) A. Caputo, Nature, 179, 1133 (1957). (127) C. Ragan, C. P. Donlan, J. A. Coss and A. F. Grubin, Proc. Soc. Exptl. Biol. Med., 88, 170 (1947). (128) M. D. Schoenberg, R. E. Brookes, J. J. Hall and M. Schneiderman, Arch. Biochem., SO, 333 (1951).

34

Q. 0 . PHILLIPS

hydrogen atoms and hydroxyl radicals when irradiated in dilute, aqueous solution. Depolymerization of cellulose fibers during irradiation is accompanied by a reduction in crystallinity, and, at high doses, extensive decomposition occurs. A dose of 5 X lo1*equivalent roentgens brings about marked degradation and is sufficient to convert cotton linters into water-soluble materials.116J2e-131 After irradiation, cellulose is more susceptible to acid hydrolysislle and exhibits an after-effect.lgl When irradiation is terminated, the intrinsic viscosity of cupriethylenediamine solutions of the irradiated cellulose continues to decrease. This behavior is initiated by oxygen and terminated by water. A similar effect is encountered with pectins after irradiation. Purified cotton subjected to y-irradiationls0 shows base-exchange properties, and the number of groups exhibiting these properties increases with increasing radiation-dose. Formation of carbonyl and carboxyl groups, decrease in tensile strength of the fibers, and increased solubility in water and alkali accompany irradiation in oxygen and nitrogen. Consideration has been given to the mechanism of the process, and it appears that (a) a fraction of the absorbed energy leads directly to ionization and (b) the remainder is transmitted as r-radiation of lower energy and as projected electrons. When aqueous solutions of amylose or starch are irradiated, degradation occurs, to give lower saccharides and dextrins.1aJ33The process may, however, not be related entirely to simple hydrolysis, for acid is formed and an absorption maximum appears at 265 mp after irradiati~n.'~~ Absorption in this region appears to be a feature characteristic of irradiated-carbohydrate solutions. The degradation of a m y l ~ s was e ~ ~followed ~ by measuring the increase in reducing power and by the reduction in intensity of the color formed on adding iodine to the solution. According to the results obtained by both methods, oxygen inhibits the degradation. Although the products formed have not been identified with certainty, there are indications from paper chromatography that (in addition to D-glucose) maltose, maltotriose, glyoxal, and a tetrose are formed. Production of acid is independent of the (129) A. Charlesby, U.K . Atomic Energy Reeearch Establishment Rept., A.E.R.E. M/R 1342 (1954); U.S . Atomic Energy Comm. Nuclear Sci. Abstr., 8, No. 3288 (1954); A. Charlesby, J . Polymer Sci., 16, 263 (1966). (130) J. C. Arthur and F. A. Blouin, Teztile Research J.,28,198 (1958); J. C. Arthur, ibid., 28, 204 (1968); J. C. Arthur and R.J. Demint, ibid., 2Q, 276 (1959). (131) R.E. Glegg and Z. I. Kertesz, J . Polymer Sn'., 28,289 (1967). See rtlso, Idem, Radiation Reeearch, 8, 469 (1957) and Science, 124, 893 (1966). (132) E. J. Bourne, M. Stacey and G . Vaughan, Chem. & Znd. (London), 189 (1954). (133) H. A. Colwell and 5. Russ, Radium, Q, 230 (1912). (134) M. A. Khenokh, Doklady Akad. Nauk 8.S . S . R . , 104,746 (1966).

RADIATION CHEMISTRY OF CARBOHYDRATES

35

extent of degradation of the amylose, and depends only on the dose. Initial G(acid) in oxygen is 1.5 and, under vacuum, is 1.4. Thus, a t least two primary processes take place simultaneously. One process leads to formation of acid and appears to be independent of oxygen, and the second process leads to degradation and is inhibited by the presence of oxygen. It must also be appreciated that, at any particular irradiation dose, some of the products have arisen by secondary processes. For example, D-glucose, present in Possufficient concentration, gives rise to acids, a tetrose, and gly0xa1.l~~ sibly, acids formed by secondary attack on D-glucose may lead to simple ionic hydrolysis to give lower saccharides. Therefore, unless the products and the primary and secondary degradation-processes are clearly identified, the conclusion is not justifiable that the breakdown of starch, amylose, and amylopectin with 200 KV x-rays and y-rays is similar in pattern to that obtained by biological agencies.136 Irradiation of solid, potato-starch granules (moisture content, 18.5 %) leads to changes similar to those observed in solution.ln After irradiation, the intrinsic viscosity and iodine-staining power of the starch specimens decreased, whereas the reducing power, lability to alkali, carboxyl value, and carbonyl number of the specimens increased with radiation dose. X-ray diffraction patterns showed that the crystalline part of the potato starch is damaged after doses of up to 1.5 X 107 roentgens. By paper chromatography, indications were obtained that D-glucose, maltose, D-arabinose, Dgluconic acid, D-glucuronic acid, and a series of dextrins of low molecular weight are formed by irradiation, with n-glucose and maltose predominating. The gases produced during y-irradiation are hydrogen, carbon monoxide, and carbon dioxide. When aqueous solutions of D-glucose are irradiated, hydrogen is the main gas produced, with carbon dioxide and carbon monoxide being formed in smaller amounts. D-kabinose, D-gluconic acid, and D-glucuronic acids are also among the products.136Therefore, it appears probable that, as for starch solutions, irradiation of starch granules leads, by oxidative and hydrolytic processes, to lower saccharides which subsequently undergo secondary degradation. The irradiation of dextran in the solid state"? and in solution138has been studied in detail. When dry, native dextran of high molecular weight (from Leuconostoc mesenteroides) is irradiated with 800 KV peak electrons,117the initial, molecular weight amounting to several million is diminished to about (135) G. 0. Phillips, G. J. Moody and G. L. Mattok, J . Chem. SOC.,3522 (1958). (136) L. Ehrenberg, M. Jaarma and K. G. Zimmer, Acta. Chem. Scand., 11, 950 (1957). (137) A. Mishina and Z. Nikuni, Mem. Inst. Sci. and Ind. Research Osaka Univ., 17, 215 (1960). (138) G . 0 . Phillips and G. J. Moody, J . Chem. SOC.,3634 (1958).

36

G. 0. PHILLIPS

fifty thousand by doses of about 1oB roentgen equivalents. Irradiation in nitrogen slightly reduces the extent of degradation, indicating that oxygen is involved in secondary processes only. The actual decrease in molecular weight is much less than the apparent degradation indicated by end-group methods of assay. Comparison of the number of end groups with the calculated number of ion pairs produced at each irradiation dose shows that, up to 6 X lo7 roentgen equivalents, there are, on the average, 2.1 f 0.2 end groups formed in the material per ion pair. This implies that the end result of each ionizing act, wherever it occurs in the molecule, is the production of two reducing end-groups. As degradation continues during irradiation, an increase in branching occurs, since, for a twenty-fold decrease in molecular weight, the branching per molecule drops by only a factor of two. All the branch points are probably tetrafunctional. Out of five ionpairs produced by the radiation, 1.0 produces a tetrafunctional branch, 1.1 produce a break in the chain, and the rest lead to a rupture of the D-glucose ring without occurrence of either degradation or eventual branching. The main degradation products have been identified in solution and estimated quantitatively.188 From their nature, it appears that one of the main processes is hydrolysis to D-glucose, isomaltose, and isomaltotriose. Moreover, the yield-dose curve (increase in the concentration of product with the dose) for reducing substances indicates that formation of D-glucose and other lower saccharides is a primary process. Two other major products arc D-gluconic acid and D-glucuronic acid, and the over-all yield-dose curve for acid formation indicates that these acids are also primary products, since they comprise the major acid constituents. It is evident, therefore, that, on irradiation, dextran in solution undergoes degradation by a t least two independent processes involving scission at the (1 + 6)-linkage in the molecule. One leads to D-glucose and lower saccharides, and the other, to Dgluconic acid and D-glucuronic acid. Glyoxal and crythrose, which are prrseiit in smaller proportions, are secondary products from D-glucose. Thus, random attack along the chain, us indicated on p. 37, would lead to all of the main products. 2. AIdohexoses, Ketohexoses, and Hexitols

Unbranched, six-carbon sugars and their derivatives are considerably more stable toward ionizing radiations in the solid state than in solution.139140 This behavior could be anticipated , since recombination of radicals initially formed by irradiation, aided by the “cage effect” of the lattice, would reduce the extent of the reaction with the solids, compared with similar (139) M. L. Wolfrom, W. W. Binkley, L. J. McCabe, T. M. Shen Han, and A, M. Michelakis, Radiation Research, 10, 37 (1969). (140) G. 0. Phillips and G . J. Moody, Chem. d Ind. (London), 1247 (1969).

RADIATION CHIMISTRY OF CARBOHYDRATES

37

changes in solution (which result from the action of the free radicals formed by primary radiolysis of water). It is clear, however, that free radicals are formed within the solid lattice during irradiation ; this was demonstrated

-?

-0

-?

I

7 I i

{>?{

Q

(Lo;o2H+

L 4

by the results of a paramagnetic-resonance study of each of sixteen carbohydrates after irradiation in the powder form.141On exposure of solid carbohydrates to strongly ionizing radiation, electrons can be removed from ground-state, molecular orbitals possessing sufficient energy to free them (141) D. William, J. E. Geusic, M. L. Wolfrom and L. J. McCabe, Proc. Nall. Acad. Sci. U.S., 44, 1128 (1958);G. Abstrom and C. Ehrenstein, Acta Chsm. Scand., 13, 856 (1959).

38

0. 0. PHILLIPS

from the molecule. If, on losing an electron in this way, the ionized molecule does not break up, it will have an unpaired electron in one of its orbitals. The electron removed from one molecule may attach itself to a neighboring molecule and form an excited orbital of this molecule, or it may be trapped at imperfections in the crystal lattice. Ionizing radiation may give rise to positively or negatively charged ions. These ions will be short-lived and will probably become stabilized as uncharged free radicals having unpaired electrons. In most cases, the formation of the final radical will be a complicated process, in which unstable entities are initially produced by irradiation and these, in turn, decay to others, until a stable radical is formed. If the barrier to the return passage of the electrons between the molecules is large, concentrations of free radicals can be built up that are sufficiently high to give a detectable electron-spin resonance.141For a-Dglucopyranose monohydrate, D-glucitol (sorbitol), a-D-galactopyranose, and myo-inositol, the paramagnetic-resonance spectra of samples irradiated either with fast electrons or with x-rays were identical, indicating that the final, radical products produced by x-irradiation are the same as those produccd by fast-electron irr~idiati0n.I~~ Radicals produced in this way may possess a half-life of up to 12.5 weeks at 20"and approximately 8.5 hrs. a t !i0°.117 The formation of colors and fluorescence in the irradiated Samp l e ~ ' ~ is~ a further indication of the excitation of the molecule. Definite physical and chemical changes have also been observed. Changes in optical rotation, mclting point, and acidity show that degradation occurs when u-glucitol, D-glucose, and wfructose are irradiated. Indications were obtained from ultraviolet absorption spectra that keto groups are introduced into the rn0lccule.~40The reducing values of D-glucose and D-fructose decreased on irradiation,I39 and, on the basis of paper-chromatographic evidence, it would appear that D-fructose is more susceptible to radiation damage in the solid state tban are D-glucose and ~ - g l u c i t o l . ~ ~ ~ J ~ ~ The precise nature of the chemical changes have been examined in detail for irradiations of aqueous solutions only.136J3eJ42-148 Oxygen exerts an important influence on the nature of the products, and, in radiation-chemical studies on carbohydrates, it is therefore essential to maintain either evacuated or oxygenated conditions throughout a particular irradiation. If initially air-equilibrated solutions are used, and no provision is made for reC. T. Bothner-By and E. A. Balazs, Radiation Research, 6, 302 (1957). G. 0. Phillips and G. J. Moody, J . Chem. SOC.,754 (1960). G. 0. Phillips and W. J. Criddle, J . Chem. Soc., 3404 (1960). G. 0.Phillips, Nature, 175, 1044 (1964). P. M. Grant and R. R. Ward, J . Chem. Soc., 2871 (1959). G. 0. Phillips, G . L. Mattok and G. J. Moody, Proc. Intern. Conf. Peaceful Uses Atomic Energy, Geneva, 29, 92 (1958). (148) G. 0. Phillips and G. J. Moody, Intern. J . Appl. Radialion and Isotopes, 6 , 78 (1959). (142) (143) (144) (145) (146) (147)

RADIATION CHEMISTRY OF CARBOHYDRATES

39

placing the oxygen consumed during irradiation,142the observations cannot be related either to fully oxygenated or to evacuated conditions, and quantitative measurements undertaken would be difficult to reproduce accurately. Moreover, it should be emphasized that the method of de-aerating the solution by passing nitrogen through is not so satisfactory as the complete-evacuation procedure, and Bourne, Stacey, and Vaughanla2have shown that there are appreciable differences between sugar solutions irradiated under vacuum and under nitrogen. The action of ionizing radiations on ~ - g l u c o s e and * ~ ~ D-mannose solution~~ in~oxygen ' has been studied by use of paper-chromatographic and radioactive-tracer methods. These methods for identification and quantitative estimation of the constituents present in the irradiated solutions have been de~cribed.1~9 Initially, ~-glucose-C~~ or ~ - m a n n o s e - Cis~added ~ to the solution to be irradiated. After a preliminary survey, uing paper chromatography and autoradiography to reveal the nature of the products, carrierdilution analysis is used for confirming or rejecting the indications given by paper chromatography. Crystalline derivatives are necessary for use in carrier-dilution analysis. Thereafter, the yield-dose curves are obtained for the main products by application of individual, carrier-dilution estimations a t each dose level and by direct scanning of spots separating discretely on paper chromatograms at various energy-inputs, by use of an endwindow, Geiger-Muller counter. Correlation between the two methods is therefore possible, and primary and secondary products may be distinguished by reference to the form of the yield-dose curves. The over-all pattern of degradation for D-glucose and D-mannose is similar. Therefore, detailed consideration is given for D-mannose solutions only.144 Table I shows the nature and amounts of the main products after total energy inputs of 3.7 X lon and 2.25 X loz3e.v. In these analyses, the unchanged D-mannose and the sum of the products account for 72 % and 85 % (by weight), respectively, of the original D-mannose present. It is evident that, a t high energy-inputs, part of the complexity of the system is attributable to secondary degradation. Therefore, to elucidate the nature of the primary degradation, particular attention was given to the yield-dose curves for the main products at low energy-inputs. The formation of acid is a primary process and the yield of it is independent of the concentration of D-mannose over a ten-fold range, indicating that the radiation energy is absorbed by the water and that chemical reactions are initiated by the reactive species formed. Since the rate of formation of acid increases with increasing input of energy, it appears that acids are also formed by secondary processes. The initial G for total acid is 1.6 and, for n-mannonic acid, is 0.6-0.7. It is probable that D-mannuronic acid represents the major portion (149) G . 0. Phillips and W. J. Criddle, Proc. Intern. Conf. Radioactive Isotopes (Copenhagen), 1960 (in the press).

TABLE I Constituents Present in Aqueous D-hfannose Solutions After Irradiation with CoaO -prays Yickl Conditwns4 (ma,imolc)

Prtdud

D-Mannoae

A B

1.20 0.16 0.50

A B

0.44 0.26 0.03

A B

0.06

A

1.40 0.40 0.49

A

0.06 0.31 0.21

C

D-Arabinose

C

D-LyXOSe

C

Two-carbon aldehydic fragments

Three-carbon aldehydic fragments

B C €3

C Oxalic acid

A B

0.04 0.74 0.19

A B

0.18 0.18 0.08

A

0.46 0.67

C

Formaldehyde

C

Sugar acids

B

C

D-Erythrose

0.17 0.001

0.38b

A B

0.12

C

0.69 0.10

D-Glucosone

C

0.20

Formic acid

A B

0.22 6.34

Carbon dioxide

A B

0.03 2.33

Key: A. Initial ~-Manno@e, 5.6 millimoles; ener input, 3.7 X lo**e.v. (vol., 40 d.) in oxygen, B. Initial D-Mannose, 5.48 millirn%s; energy input, 2.26 X lopa e.v. (vol., 100 d.) in oxy en. c. Initial D-Mannose, 2.42 millimoles; energy lnput 3.9 X 10" e.v. (vol., 100 m f ) under vacuum. Sum of D-gluconic acid and D-arabznohexuloaonic acid.

40

RADIATION CHEMISTRY OF CARBOHYDRATES

41

of the remaining acid formed initially. D-Arabinose is a primary product and is formed with an initial G of 0.54.6.The rate of formation increases at high energy-inputs, indicating that D-arabinose is formed by a secondary process also. The primary formation arises as a result of scission of the C - 1 4 - 2 bond in D-mannose, and decarboxylation of D-mannonic acid may account for the secondary formation. Experiments with ~-rnannose-I-C'~ show that primary scission of the C-1-C-2 bond leads also to formaldehyde. Initially, the yield-dose curves

m r (lOlev/rnl.).

Fro. 1.-Rate of Formation of Products During Irradiation of Oxygenated Solutions of D-Mannose (A 0 ,D-Arabinose;B 0 , formaldehyde;C A , formaldehyde from n-mannose-1-C9.

for formaldehyde from ~-mannose-I-C1~ and generally-C14-labeled u-mannose are identical, but, at increased energy-inputs, the apparent yield of formaldehyde from ~-mannose-I-C~~ decreases (see Fig. 1). Since, in the latter estimation, only formaldehyde-I-CI4is measured, the fall in concentration probably results from dilution by the formaldehyde formed from the remaining (inactive) portion of the D-mannose molecule. As required by this mechanism, the D-arabinose formed in experiments with D-mann0se-1-C~~ is inactive. Primary scissioii of the hexose molecule into four- and two-carbon, aldehydic fragments occurs, probably to give erythrose and glyoxal. The initial G value for total, two-carbon, fragment formation is 0.64,Using Dmannose-I-P, it is possible to measure the primary formation of those

42

G. 0. PHILLIPS

two-carbon fragments which contain carbon-14 and which are thus formed by scission of the C-2-C-3 bond; this process should also lead to simultaneous formation of a four-carbon fragment. The initial G value for two-carbon fragments derived from measurements of carbon-14 is 0.2, a value in reasonable agreement with the initial G(erythrose) of 0.18. The appreciable difference between these values and the over-all formation of two-carbon fragments (G 0.64) leads to the conclusion that such fragments must be formed by two primary processes, which may be represented as follows. CH,OH

0

+

F"

$--OH

Ho

0

II

/""

6"

$qlH CH,OH

1

HO

/

/

Further oxidation of glyoxal (to oxalic acid) occurs, but this is a secondary process. Symmetrical scission of the hexose molecule into three-carbon fragments takes place, but to tin extent smaller than by the process described. Irradiated solutions of D-mannose show maximum absorption at 275 mp, and it is probable that more than one constituent may account for the absorption spectrum. Enediols absorb strongly in this region and, in particular, reductone, a possible constituent present in irradiated solutions of D-mannose, absorbs a t 290 mp in alkali, The over-all consumption of Dmannose during irradiation shows an initial G 3.5, in excellent agreement with irradiations of D-glucose (G 3.5) .la The main processes may therefore be represented as follows. D-Mannose

n-Erythrose and glyoxal

L

glyoxal I(

Oxalic acid

/

D-mannuronic acid

l.

D-lyxose

D-mannonic acid

1

D-arabinose

D-arabinose

+

formaldehydc

43

RADIATION CHEMISTRY OF CARBOHYDRATES

These primary processes proceed with an initial G 2.84, and therefore account for the main processes of degradation, although a further degradative path is not precluded. Under vacuum, the complications of secondary reactions involving oxygen are excluded, and the degradative pattern follows a rather different path.160The constituents present in evacuated solutions of D-mannose after e.v. are shown in Table I, irradiation to a total energy input of 3.9 X and these account for about 97 % (by weight) of the initial D-mannose present. The initial formation of acid (G 0.5) agrees well with the initial G (mannonic acid), indicating that the acid first produced is D-mannonic acid. Other acids are formed at higher doses by secondary processes, for example, Darabino-hexulosonic acid. D-Mannuronic acid is not present in detectable amounts in irradiations under vacuum, although it is a major product on irradiation in oxygen. D-Glucosone (D-arabino-hexosulose)is a primary product having initial G 0.5. The primary scission between C-1 and C-2 (to give formaldehyde and D-arabinose), encountered in oxygenated solution, does not occur under vacuum, and D-arabinose arises by a secondary decarboxylation of D-mannonic acid. Ring-scission processes similar to those observed in oxygen are indicated by the yielddose curves for two- and three-carbon, aldehydic fragments, although the latter fragments are formed in much higher yields than in the oxygenated system. The primary scission between (2-24-3 and (3-4-C-5, to give three two-carbon fragments, occurs with initial G 0.95, and comparison with the initial G 0.25 for D-erythrose formation indicates that scission to give two- and four-carbon fragments takes place simultaneously with the formation of three two-carbon fragments. Another primary process which is not so pronounced in oxygen is the symmetrical scission giving two three-carbon aldehydic fragments (G 0.5). The degradation under vacuum may, therefore, be represented as follows. D-Mannose

I

1

I

D-Mannonic acid D-glucosone

1

D-Arabinose

I three-carbon aldehydic fragments

1

two-carbon aldehydic fragments

1

four-carbon two-carbon aldehydic fragments

+

D-arabinohexulosonic acid

A distinctive feature (not encountered in oxygen) of irradiations under vacuum is the formation of a polymer at high doses. This behavior was first reported by Stacey and coworkers.10gFrom the yield-dose curve for polymer, (160) G. 0. Phillips and W. J. Criddle, (in the press).

44

Q. 0.

PHILLIPS

Phillips and Criddlelso conclude that polymer is formed by secondary processes, with the rate of formation increasing markedly at high doses. The primary processes described for irradiations under vacuum account for an initial G for the degradation of D-mannose of 2.4, in contrast to the observed value of G 3.5 for disappearance of D-mannose. The primary processes that are unaccounted for probably arise by dimerisation of radicals formed aa the preliminary step in the production of the polymer. The nature of the identified products demonstrates that attack by free radicals formed by the primary radiolysis of water occurs throughout the molecule. Attack at C-1 leads to D-mannonic acid; at the C-34-4 bond, to threecarbon fragments; and at the C - 2 4 - 3 and C-4-C-5 bonds, to give three two-carbon fragments. Thus, the various sugar radicals formed initially (which lead to these products) may dimerize and eventually build up into a branched polymer of complex composition. Further radicals arising from primary and successive degradation products may well account for the acidic character of the polymer. Polymer formation is, therefore, an inefficient coupling-processrather than a chain reaction. Because of the general similarity between the radicals formed in water during irradiations under vacuum and in oxygen, some correlation should be possible between the two systems, and appears to have been made. A striking feature of the processes is the identical rate of disappearance of Dmannose under both conditions (G 3.6), which points to comparable initialabstraction processes. Subsequently, the secondary effect of oxygen and HOBradicals leads to somewhat differing products. Under both conditions, D-mannonic acid is formed, and the products arising from ring scission are also similar. Symmetrical scission of D-mannose in oxygen does not occur easily, although this circumstance is more significant for oxygenated solutions of D-glucose,l**However, in oxygen, attack at C-2 causes ring scission leading to D-arabinose and formaldehyde, but, under vacuum, such attack affords D-glucosone (D-arabino-hexosulose). These reactions may be represented as follows. Under vacuum

RADIATION CHEMISTRY OF CARBOHYDRATES

45

In oxygen H2C=O formaldehyde

HC=O

+

I

HC-0 HObH

I

&Mannose

D-arabinose

This behavior is analogous to that of queous glycolic cid. The carboncarbon scission which occurs in oxygen is diminished under vacuum.1MJO6 Similarly, dimerization is only observed in the absence of oxygen. D-Mannuronk acid is formed in oxygen only, and it is probable that, under vacuum, the eame initial step leads to dimerization, as is observed for irradiations of D-glucitol in the absence of oxygen.lal RCHnOH

5

+ OH + RCHOH + HzO in o x y g e n l A

RCOzH

under vaouum

RCHOH RbHoH

D-G~UCOW solutions behave similarly on irradiation. Grant and Ward146 detected D-gluconic acid and D-glucosone in solutions of D-glucose irradiated under vacuum. They postulated a degradative mechanism analogous to the radiation-induced degradation of glycolic acid: HC-O HbOH (bHOHir

-b

c=o

HbOH

5

( HOH)a

bH,OH

HC=O

+

bOH kHOHil

bHzOH OHIA

O H ~ ~ ' ~ , m d i caddition a l

D-Gluconic polymer D-gluco- polymer acid sone

Summarizing therefore, it would appear that, when aldohexoses are irradiated in dilute solution, attack is not confined to any particular part of the molecule. The products formed in oxygen and under vacuum, respec(161) W. J. Criddle, Ph.D. Thesis, University of Wales, 1960.

46

GI. 0 . PHILLIPS

tively, demonstrate that all bonds are affected. Oxidation occurs at the extremities of the molecule and, simultaneously, ring scission leads to lower fragments. Similar initial processes probably take place in oxygen and under vacuum, although secondary reactions involving oxygen may considerably modify the nature of the end product. Support for this view comes, not only from the nature of the products, but also from the identical G values (3.5) for the disappearance of aldohexose in oxygen and under vacuum. The G value is significant and demonstrates that hydroxyl radicals are not the only species which may initiate reaction, following abstractions of the type: RH

+ OH - + R e + H@.

If all hydroxyl radicals were scavenged by this process, G for the disappearance of the aldohexose could not rise above G,(OH), the primary yield of hydroxyl radicals. The situation is similar to that encountered with alcohols irradiated at high concentration^,^^ and it is probable that hydrogen atoms may also participate in the initiation process. The alternative possibility is that HOs radicals may initiate reaction, as proposed for irradiations of L-ascorbic acid.1M Clearly, therefore, on irradiation in solution, aldohexoses exhibit changes similar in character to those observed under comparable conditions in related compounds, particularly hydroxy acids and alcohols. Further kinetic work is, however, necessary, before intelligent, detailed mechanisms can be advanced in order to explain the observed changes. When D-fructose is irradiated in aqueous solution in the presence of oxygen, the following inter-related degradation processes have been distinguished.14* CHiOH L

HC-0 L

O

COaH O

L

I HOCH

HOkH d

O

HOAH __f

HAOH

H h H

HLOH

HAOH

HLOH

HAOH

bH2OH LHZOH AH20H D-arabino-Hexulose D-arabh-hexosuloee D-arabino(D-Fructose) (D-glucosone) hexulosonic acid

I I - I -

CHzOH

0-AH Glycolaldehyde

HC-0

H =O glyoxal

COiH

A02H oxalic acid

RADIATION CHEMISTRY OF CARBOHYDRATE]S

47

Evidence has also been educed for the formation of two constituents, reductone and 1,3-dihydroxy-2-propanone,by symmetrical scission of the D-fructose molecule; these constituents are mainly responsible for the peak at 285-290 mp in the ultraviolet absorption spectrum of the D-fructose solutions. CHzOH

CHpOH

b=O

b=O

ROAH

b

H =O

H OH

+ +

HAOH

HboH

AHtOH

HC=O

LH2OH

HCOH

e

&OH

A

H =O CHzOH

e b=o bH@H

For the decomposition of D-fructose, G is 4.0, a value of the same order as for the rate of consumption of D-glucose and D-mannose (G 3.5) under comparable conditions. Another primary process may involve oxidation of the primary alcohol group a t C-6 to form ~-2gzo-5-hexulosonicacid, since there is accumulating evidence from the behavior of ~ - g l u c o s e D-glu,~~~ ci t0 1 , ’ ~ ~and J ~ ~~ - m a n n i t o P that ~ J ~ the ~ primary alcohol groups are more reactive than secondary alcohol groups toward free radicals formed by the action of radiation on water. The degradation induced in hexitols on irradiation in aqueous solution is more specific than for hexoses under comparable conditions. In 1954, it was reported that, when D-mannitol solutions (1 %) are irradiated with fast electrons in oxygen, D-mannose is the main product, and that, after prolonged irradiation, D-mannuronic acid is forrned.l45By use of more concentrated solutions (50 %), similar results were subsequently obtained by Wolfrom and coworker^,^^^ and penta-0-acetyl-p-D-mannopyranose was isolated. D-habinose was formed as a secondary product, in addition to D-mannuronic acid (see p. 48). Oxidation of either of the primary hydroxyl groups in D-mannitol would give D-mannose, and hence the characterization of Dmannose is easier than that of the products from irradiations of D-glucitol. Paper-chromatographic evidence reveals the presence of four main products from D-glucitol, namely, glucose, gulose, xylose, and arabin0se.’39J~7J~ Carrier-dilution analyes demonstrate that the stereochemical forms present are D-arabinose, L-xylose, and ~ - g l u c o s e On . ~ ~configurational ~ grounds, therefore, it is deduced that gulose is present as the L isomer. Oxidation of the primary alcohol group at one extremity of the D-glucitol molecule leads to D-glucose, and oxidation of that a t the other end, to ~-gulose.Sim-

a.

48

0. PHILLIPS

ilar considerations apply to formation of pentoses. Simultaneously, the presence of formaldehyde was detected by isotope-dilution analysis. Thus, the degradation may be represented as follows. HC-0 HbOH

HC-0

b

HO H HbOH HboH

b + HbOH Hb ,OH

HO H

+

H HC=O formaldehyde

I

bI

HO H

~ H ~ O H ~ H ~ O H D-glucose D-srabinose CHiOH I

HC-0 I

RADIATION CHPJMISTRY OF CARBOHYDRATES

49

The yield-dose curvesI47for the hexoses and pentoses demonstrate that D-glucose and ~-guloseare the primary products, formed at identical rates (G 1.2), with the formation of D-arabinose and ~-xyloseoccurring subsequently. Reactions proceeding with ring scission are also of a secondary character.14Q As for hexose degradations, G(-D-glucitol) is 3.5 for 1% solutions. To establish whether products formed initially at low rates are formed by primary or secondary processes is a common difficulty. This applies particularly to D-gluconic acid and L-gulonic acid produced during the irradiation of D-glucitol solutions. Potentiometric measurements indicate only slow initial formation of acid (G 0.3),but, from accompanying carrier-dilution estimations, it is probable that the direct conversion to acid, RCHZOH--.) RCO2H, is a primary process with an initial G of about 0.15. Wolfrom and cow~rkers'~Q commented on the similarity of the products from the irradiation of alditol solutions and from the action of Fenton's reagent (ferrous ions and hydrogen peroxide) thereon. Few

+ Ha02 + Fern + .OH + OH-

D-Mannose was synthesized from D-mannitol, in 40% yield, by the latter method'" through the agency of hydroxyl radicals, and it seems probable that a comparable explanation applies to the irradiation process. When conditions of strict evacuation are maintained during irradiations of D-glucitol,l6' the yields of hexoses are lower than in oxygen (G 0.7), although the rate of disappearance of D-glucitol is identical with the rate in oxygen (G 3.5). Under vacuum, ring scission gains in significance, and glycolaldehyde and tetrose are formed. The yieldaose curves for these fragments demonstrate that they are formed by primary processes, with an initial G of about 1.0. CHaOH H LI o H H O ~ H

1"'+""

H =O

CHaOH HboH I

H O ~ H

A

H=O ......I...... H ~ O H

LH,OH

I

H~OH

AHSOH

+

HC=O bHaOH

Gas analysis indicates that primary abstraction processes under vacuum involve hydrogen atoms in addition to hydroxyl radicals.

+ OH + RCHOH + HIO RCHIOH + H -+ RCHOH + Hn

RCHIOH

(162) F. Haber and W. Weiss, Proc. Roy. SOC.,A147.332 (1934).

50

0. 0. PHILLIPS

Under these conditions, initial dimerisation occurs as the primary step in the formation of the polymer-which may easily be isolated from irradiations of D-glucitol in the absence of oxygen (as from hexose irradiations under vacuum). 2 RCHOH + RCHOH

RtrHoH

Three primary processes have, therefore, been identified as occurring when D-glucitol solutions are irradiated under vacuum. D-Glucitol

8

Hexoses

dimer

glycolaldehyde

+ tetroses

With the information at present available, it is not possible to advance detailed mechanisms for the proceases described, and further kinetic investigations are necessary. The behavior of alditols and D-fructose on irradiation in solution support the view that primary alcohol groups are more susceptible to attack than normal secondary alcohol groups, the group at the lactol carbon atom providing an understandable exception. 3. GlycoSides, Disaccharides, Trismharides, and Lactimes

When maltose and cellobiose are irradiated with fast electrons in airequilibrated, 50 % solutions, the predominating reaction is hydrolysis, and the results suggest that the W D linkage is the more labile, a conclusion in accord with the relative ease of hydrolysis of these disaccharides by acids. A number of samples of aqueous maltose solutions (20%) were irradiated with electrons to doses of 20 to 100 M rep. The apparent hydrolysis, as determined by the reducing power, increased linearly with dose, and this result has been interpreted in terms of the hydrolysis of only one bond.139 Hydrolysis at the glycosidic bond occurs also during irradiation of sucrose in aqueous solution, and acid is produced.16a-*aa Changes in the ultraviolet absorption spectrum have also been noted,’u and the over-all change in optical rotation accompanying inversion was proposed by WrightlsBfor use as a pile-radiation dosimeter. The chemical effects of radiation on sucrose solutions have been investigated by Wolfrom, Binkley, and McCabe16’ (163) M. C. Reinhard and I(.L. Tucker, Radiology, 12, 161 (1929). (164) G. L. Clark and K. R. Etch, J . Am. Chem. rSoc., 62,466 (1930). (165) G. L. Clark, L. W. Pickett and E. D. Johnson, Radiology, 18, 245 (1930). , 60 (1962). (156) J. Wright, Discusdons Faraday ~ o c . 1P, (157) M. L. Wolfrom, W. W. Binkley and L. J. McCabe, J . Am. Chem. Soc., 81, 1442 (1969).

RADIATION CHEMISTRY OF CARBOHYDRATE8

51

and by Phillips and Moody.'@ Different experimental conditions were used in the two investigations. Wolfrom and cow0rkers~~7 irradiated 50 % aqueous solutions of sucrose with fast electrons without oxygenation in open, aluminum containers cooled in ethanol-solid carbon dioxide, ice and water, and ambient air, whereas Phillips and Moody1@irradiated dilute solutions (2.9 X 10-2 M ) with CosOy-radiation in oxygen at room temperature. In the former investigation,lS7attention was focused on comparing the effects of fast electrons on sucrose and on methyl a-D-glucopyranoside, since preliminary had suggested that the glycosidic bond might be especially sensitive to ionizing radiations. The only products detected in irradiated sucrose solutions were D-fructose and D-glucose, the former by paper chromatography and the latter as the pentaacetate. Paper-chromatographic evidence indicated the formation of substantial proportions of D-glucose in irradiated solutions of methyl a-D-glucopyranoside. In comparison with sucrose, methyl a-D-glucopyranoside is more resistant to hydrolysis under the same experimental conditions. After an energy input of 104 megareps, the extent of hydrolysis of aqueous sucrose solutions was 22.2, 27.0, and 37.8 % when cooled with ethanol-solid carbon dioxide, ice and water, and ambient air, respectively, whereas, a t the same energy input a t ice-water temperature, methyl a-D-glucopyranoside was hydrolyzed to the extent of 6.3% (based on conversion to D-glucose). Evidence was obtained that about 10 % of the sucrose is transformed into nonreducing substances a t all three temperatures. It should be borne in mind that, in comparison with the energy inputs used in this investigation, a dose of about 3 megareps is required for the sterilization of food. From measurements of the increase in reducing power with dose, reported by Wolfrom and coworkers,'67 the extent of apparent hydrolysis at 3 megareps is about 4, 2, and 1 % when the solution is cooled in ethanol-solid carbon dioxide, icewater, and ambient air (at about 27"), respectively. Yield-dose curves obtained by carrier-dilution analysis and by paper chromatography reveal that D-glucose and D-fructose are primary products of the y-irradiation of dilute, aqueous, sucrose solutions in oxygen, together with smaller amounts of D-glucosone and D-gluconic acid.'& D-G~ucuronic acid, D-arabino-hexulonic acid, D-arabinose, and two- and threecarbon, aldehydic fragments arise by secondary processes. In the final stages, carbon dioxide and formic acid are formed. Hydrogen peroxide is produced continuously. The initial G values for D-glucose and D-fructose are 1.5-1.6; D-gluconic acid and D-glucosone are formed with G 0.4 and 0.6, respectively. (158) G.0.Phillips and G. J. Moody, J . Chem. Soc., 166 (1960). (169)M. L.Wolfrom, W.W.Binkley and L. J. McCabe, Abstracts Papers Am. Chem. Soc., 190. 16A (1956).

52

0. 0. PHILLIP8

The primary formation of D-gluconic acid and D-glucosone simultaneously with D-glucose and n-fructose may be accounted for by two types of oxidative scission of the disaccharide linkage, a t a and b. The former leads to D-fructose and

D-gluconic acid, and the latter, to D-glucose and D-glucosone. A similar type of process was envisaged for the degradation of aqueous dextran with y-radiation.'" If the two types of scission occurred to a comparable extent, the amounts of the four main products would be of the same order. The results show, however, that, although comparable amounts of D-gluconic acid and D-glucosone are formed, the proportions of D-glucose and D-fructose are higher. It appears, therefore, that hydrolysis is the dominant process, but that it is accompanied, to a smaller extent, by the oxidative scission described. The over-all degradation pattern for sucrose has been formulated as follows. Sucrose

3 -

D-Glucose __t D-gluoonio acid D-glucosone

I

I(\

alyoxal

D-glucuronic acid

n-arabinose

I

D-fructose

D-arabino-hexuloeonic acid

Hydrolysis is the predominating process when the trisaccharide raffinose is exposed to y-rays in 2% aqueous solution.luJ*O The extent of hydrolysis increases with dose and, since two bonds are hydrolyzed, the reducing power-dose curve is non-linear. It has been reported by Coleby'eo that, when solutions of D-glucono-1,4lactone, D-gulono-1 ,.Q-lactone,L-galactono-1,4-lactone and L-gulono-1 ,4lactone are irradiated with x-rays (210kV,, lOmA), y-rays (Coao), and fast electrons (4 MeV) under vacuum, the lactones are converted into the corresponding ascorbic acids. (180) B. Coleby, Chem. & Ind. (London), 111 (1967).

RADIATION CHEMISTRY OF CARBOHYDRATES

53

CHOH AH20H

bH2OH

Evidence for the production of ascorbic acids is that, after irradiation, the solution was able to decolorize solutions of 2,G-dichlorophenolindophenol and to produce a red color with an alkaline solution of triphenyltetrazolium chloride. The solution also displayed an absorption maximum at 245 mp similar to that of L-ascorbic acid, and paper chromatography indicated the presence of a product running identically with L-ascorbic acid. The yield of the ascorbic acid was a function of the concentration, rising from G 0.16 at 5 X M to G 0.95 at 4 X 1W2M for a dose of 2.8 X lo1*e.v. ml.-1 of x-rays. The route to the ascorbic acid from the lactone may involve abstraction of a hydrogen atom at C-2 or C-3,followed by enolisation.

4. Absorption Spectra and Post-irradiation Processes Irradiated solutions of carbohydrates have similar, characteristic ultraviolet absorption spectra.'34~'8"18e~142,148.146 A broad absorption occurs in the region of 240-300 mp, and the maxima, which may vary for individual carbohydrates, fall in the region of 260-290 mp; the intensity of the peak increases very markedly on addition of alkali.136For the absorption maximum, a shift to higher wave-lengths and an increase in intensity may accompany the addition of alkali.'" Several of the identified products absorb in this region, either in acid or alkaline solution, and it is probable that more than one absorbing constituent is responsible for the resulting absorption spectrum. One compound which may contribute to the composite spectrum may be 1,3-dihydroxy-2-propanone(A, 265 mp, in neutral solution), formed by isomerization of glycerose, a change which occurs readily (particularly in alka1i).lS6Reductone (Ama in alkali, 287 mp, and, in acid, 268 rnplB1),D-glucosone (Amax in alkali, 265 m ~ ) , and ' ~ ~the dienol (161)

T.C. Laurent, J . Am. Chem. Soc., 78, 1876 (1966).

54

0. 0. PHILLIPS

form of D-urabino-hexulosonic acid (A, in alkali, 275 mp, and, in acid, 230 inp)'61 are other possible absorbing species. However, all enediol structurcs [such as L-ascorbic acid (A, in neutral or acid solution, 265 mp14E)] would be expected to absorb strongly in this region, and, since "D-ghco-ascorbic" acid has been claimed to be a product from the irradiation of D-gluconolactone in aqueous solution,lEOsecondary products may also contribute to the over-all spectrum. There is evidence for the presence of slow post-irradiation processes when sugar solutions are irradiated in oxygen and under vacuum. When D-glucose solutions are irradiated under vacuum, the absorption at 265 mp increases steadily and attains a maximum at 20-30 hr. after irradiation has ceased.186 Similarly, for D-fructose solutions irradiated in oxygen and under vacuum, the absorption maxima continue to increase for several days after irradiation has ceased. This process may be associated with the postirradiation decrease in concentration of hydrogen peroxide at a rate of 3 4 X lo'* molecules min.-l ml.-l in irradiated ~-fructosel~~ and D-glucose13b solutions. The occurrence of post-irradiation reactions is further demonstrated in these systems by a liberation of gas for 2 6 3 0 hr. after irradiation is terminated.186 Further detailed examination of these interesting reactions is necessary, before it will be possible to speculate about their association with several important post-irradiation processes encountered when biological systems are irradiated.'* 5. Self-decomposition of Cl4-hbeledCarbohydrates

When carbon-14 tracer techniques are applied to chemical problems, it is important that the C14-labeled compounds used should be chemically pure. However, it has frequently been assumed that such compounds are virtually stable when stored prior to use. Evidence is now accumulating that this assumption is unwarranted, and that a considerable degree of degradation occurs in CWabeled amino acids, amino alcohols, purine derivatives, calcium glycolate, cholesterol, thyroxine, and succinic acid during st0rage.1~7J~ As noted previously, rnethan01-C~~ undergoes decomposition under the action of its own radiation.60 Wagner and GuinnlE2studied the self-decomposition of methyl-C14 iodide and, from the limited literature on this s u b j e ~ t , l it ~ ~would J ~ ~ appear that various groups of C14-labeled compounds have widely differing susceptibilities to radiation self-decomposition. A reference to the self-decomposition of carbohydrates appeared in 1956,1h when it was discovered that ~-glucose-C~~ solution requires (162) C. D. Wagner and V. P. Guinn, J . Am. Chem. SOC.,76, 4861 (1963). (183) See, in addition to the cited references, B. M. Tolbert and R. M. Lemmon, Radiation Research, 3, 62 (1956). (164) W. G . Dauben and P. H. Paycot, J . Am. Chem. SOC.,78,6667 (1966). (l64a) P. J. Allen and J. S. D. Bacon, Biochem. J . , 65,200 (1966).

RADIATION CHEMISTRY OF CARBOHYDRATES

55

purification, as 2 % of its activity migrates (during paper chromatography) in the disaccharide region. Although this effect was not attributed to selfdecomposition, this explanation now appears likely. Clearly, it is of supreme importance that the user of C14-labeled carbohydrates for tracer studies be aware of the phenomenon of self-decomposition, since the products resulting can otherwise lead to erroneous interpretation of the results of experiments. It is also important that the method of storage that will cause minimal degradation should be ascertained and the products be recognized, so that purification methods may be devised. Therefore, although but little published material is available166J66 a t the time of writing, the author has compiled this Section (consisting of preliminary information) in order that this important aspect of the radiation chemistry of carbohydrates may be included. The author is indebted to Professor E. J. Bourne, Dr. H. Weigel, and Dr. R. Bayly for making their complete results available prior to publication. The decomposition of a compound labeled with a radioactive isotope can be due to one or more of four effects,lg as follows. (1) A primary (internal) radiation effect, wherein the decomposition of the molecules arises as a result of the disintegration of their unstable atomic nuclei. (2) A primary (external) radiation effect, in which decomposition occurs by interaction of the molecule with a nuclear particle. (3) A secondary radiation effect, where decomposition arises from reaction with a reactive species produced by the radiation. An example would be that of free radicals produced by the radiolysis of residual water in freeze-dried carbohydrate samples. (4)A chemical effect, whereby decomposition arises from chemical reactions which are not connected with radiation. For C14-labeled carbohydrates stored as freeze-dried samples under vacuum at room temperature, self-decomposition arises mainly by the primary (external) radiation effect and the secondary radiation effect. However, it has been observed that the alkalinity of normally washed, Pyrex glass is detrimental to the stability of C14-labeled carbohydrate sirups, and it is desirable to store the samples at as low a temperature as possible in order to reduce the rate of such unavoidable chemical reactions. Table I1 shows the extent of self-decomposition of initially pure samples of sucrose-C14 and ~-glucose-C14which had been stored as uniform films on Whatman No. 3 paper or as freeze-dried samples in Pyrex tubes (which had been filled with water and autoclaved for 2 hr. at 151 lb./sq. in. to remove surface alkalinity). The tubes of samples which were stored under vacuum were evacuated to a pressure of 0.01 mm. Hg for several hours before being sealed (to reduce the moisture content to a minimum). (165) N. Baker, A. P. Gibbons and R. A. Shipley, Biochim. et Biophys. Acta, 28, 68 (1958). (166) A. Walton and H. Weigel, Nature, 189, 981 (1959).

a.

56

0 . PHILLIPS

It would appear that, for the freeze-dried samples of D-glucose (tubes 749, secondary-radiation effects play a major role in the decomposition, due probably to retention of non-bonded water by the D-glucose. Sucroae, TABLE I1 Sel decompositim1~of Swro8e-C14 and ~-Orlucoee-C~~

-

-

Slorags conditions

compoumi

Pub8 no.

-

TyP., Prar-

Form

C.

sure

freaadried room froow-dried --Boo on paper room --Boo on PSW room on psper

Mo.

1

a a 4 6 0

-

Im-

,i:s, %

-

on paper

--Boo

atm. atm.

16.4 16.1 16.7 4.9

WO.

a.4

VIM.

1.8

VBO.

7 8

room

atm.

--Boo

atm.

9

room -80'

-0.

room -80'

-0.

10 11

ia

-

vao.

18.9 0.0 13.1 3.0 1.a 0.7

- -VIM.

I-

I-I-

0.071

0.36

0.086

0.96

0.0dB

o.oao

0.010

-

-

0.007 -0.77 0.13 0.61 o.1~ 0.044 0.024

o.a o.a o.a 0.1

-a1 a1 ai

ai

-

-

16 16 0.3 0.3 0.3

4.0 4.a a34 68 33

0.8

16

10 10 10 10

79 a3 63 14 900

- 47 0.m - 47 0.05 6!26 * To calculate G(-M),

The weight of the Whatman No.3. pa er waa 18 m om-'. it is necessary to estimate the fraotion of the tot8energy liberated (during the decomposing period) that is absorbed by the sugar or su ar sirup. For a pure 0emitter distributed over a relatively large area in a layer 1 o f even thickness (in om.), this fraction F, is given by:

(8)

0

F

-

+

1 ~ 1 0 . 5 log, r/pO1/2r where p is the density (me. om.-#) and r is the mean range of the particles expressed in m om.* units. Alternatively, the fraction of the energy absorbed by the sugar may t e calculated by Besumin that the compound and the paper absorb all the radiation in the ratio of their weigtts. 0 Defined aa the number of molecules permanently altered or decomposed per 100 0.v. absorbed by the sugar or sugar sirup. * Each sucrose tube contained 600 pc in 1.16 mg. of sucrose (149 mc. per m. mole; abundance of CI', 19.5p) and was stored for 88 weeks. Calculation shows that primary (internal) radiation ecompoaition contributed 0.06% to the observed impurity. Other experiments with s a m lea of freese-dried sucrose have shown that, a t -Ma, decomposition is considera%l increaaed if the sugar is stored under atmospheric pressure instead of being sealedrunder vacuum. The difference is even greater with samples held at room temperature. Each tube of D- lucose contained 100 pc in 0.43 mg. of D-gluoose (42 mc. perm. mole; abundance of &4,11.0%) and waa stored for 34 weeks. Calculation shows that primary (internal) radiation decomposition contributed 0.006% to the observed impurity.

on the other hand, can, with efficient freeze-drying, be obtained anhydrous, and the extents of decomposition for tubes 1 and 2 suggest that this small, constant amount of degradation is attributable to primary-radiation effects. This may be inferred from the very small difference in the extent of decomposition of freeze-dried aucroee at room temperature and at -80'. For D-glucose, a much greater temperature-dependence is shown, due, pre-

RADIATION CHEMISTRY OF CARBOHMRATES

57

sumably, to a reduction in the mobility of radicals formed by secondary effects. Radicals would, therefore, appear not to play an important part in the decomposition of freeze-dried sucrose samples. When sugars are distributed on paper (tubes 3-6, 11, and 12), the decomposition is more marked, presumably because of increased secondary effects arising from the moisture in the paper. The importance of secondary-radiation effects may be seen from the decomposition of dextran-CI4sulfate containing about 20 D-glucose residues per molecule, observed by Bayly and Weigel.1g7JB8 It had the relatively low specific radioactivity of 22.4 mC. per g.-atom of carbon (about 3 mC/ millimole of dextran sulfate). After three weeks in the freeze-dried form, it had charred and become a total loss. The decomposition was presumably attributable to a secondary-radiation effect arising from a prior liberation of sulfuric acid, which then released more sulfuric acid to destroy the material. Arising from the decomposition of C14-labeled carbohydrates are an enormous variety of products. For example, when a sample of ~-glucose-C'~ (about 6 mg., having a specific activity of about 14.44 mC. per millimole) was stored as a freeze-dried sample in the dark for 26 months, a 14.5% decomposition of the D-glucose occurred and, by use of two-dimensional paper chromatography-paper electrophoresis, the presence of 37 constituents was revealed.la The greater complexity of this system in comparison with that of +radiated solutions of ~-glucose185supports the view that direct-action effects supplement the decomposition caused by secondaryradiation effects, which are entirely responsible for the decomposition when dilute solutions are irradiated. Two methods for reducing the magnitude of decomposition from primary (external) radiation are (a) dispersion over a large area and (b) dilution. These methods also reduce decomposition caused by secondaryradiation effects'"; this is borne out by experimental results obtained168 with ~-mannose-C'~.Aliquots (5 ml.) of pure ~-mannose-C'~ (about 100 pC.) in water (100 ml.) were stored under vacuum. By isotope-dilution analysis, it was estimated that the rate of decomposition in the freeze-dried state was 7 % a year and, in the frozen state, 1 % a, year. The frozen state would, therefore, appear to be the most satisfactory method of storage over long periods of time.

Note Added in Proof Since this review was prepared, an important development has been reported by Dr. F. C. Leavitt at the 3rd. Cellulose Conference, Syracuse, (167) R. J. Bayly and H. Weigel, Nature, 188, 384 (1960). (108) E. J. Bourne, D. H. Hudson and H . Weigel, J . Chem. Soc., 5153 (1960). (169) G. 0. Phillips and W. J. Criddle (unpublished reaults).

58

Q. 0. PHILLIPS

N. Y. (October, 1960). High-energy radiation unexpectedly produces crosslinking in some cellulose compounds. An important factor which determines whether cross-linking or degradation predominates is the viscosity of the system. Highly viscous solutions give limited freedom of motion to polymer chains, and high-energy radiation degrades these systems until the fall in viscosity permits free, bimolecular coupliig-reactions, At this point, the system immediately gels. There is evidence that the cross-linking process involves an indirect effect of radiation, occurring through the agency of free radicals.

APPLICATIONS OF TFUFLUOROACETIC ANHYDRIDE IN CARBOHYDRATE CHEMISTRY

BY T. G. BONNER Department of Chemistry, Royal Holloway College, University of London, Engle$eld Green, Surrey, England

.......................... n with Trifluoroacetic Anh 1. 0-Trifluoroacetylation.

...................... ............ ......................

59

60

2 . N-Trifluoroacetylation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 62 I11 The Trifluoroacetyl Group &B a Blocking Group .......................... 63 1 The Synthesis of 2- and 3-0-Substituted D-GIucoses .................... 63 2 . The Synthesis of 2,4.Di.O.methyl.~.rhamnose ......................... 64 3 . Other Synthetic Uses of Trifluoroacetyl Derivatives . . . . . . . . . . . . . . . . . . . 65 IV. 1. Acylation with Carboxylic Acid-Trifluoroacetic Anhydride Mixtures 67 . . . . . . ............ 67 Acylation of Hydroxy Compounds.. . . . . . . . . . . . . . . . . .

.

.

V. Selective Ring-opening of Cyclic Acetals with Carboxylic Acid-Trifluoroacetic Anhydride Mixtures, . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1. Methylene Acetals of D-Glucitol.. . . . . . . . . . ............ 2. Methylene Acetals of D-Mannitol.. . . . . . . . . . . ........... 3. Other Acetals.. ............................. ............ VI. The Synthesis of Linear Polymeric Esters from C and DibMic Carboxylic Acids. ....................... .............. VII. The Mechanism of Acylation by Acyl Trifluor 1. The Formation of Acyl Trifluoroacetates.. . ................

69 69 75 76 77

79 2. The Reaction of Acyl Trifluoroacetates with Hydroxy Compounds.. .... 81 3. Other Acylation Reactions of Acyl Trifluoroacetates.. . . . . . . . . . . . . . . . . . 83

I. INTRODUCTION Trifluoroacetic anhydride was first obtained by Swarts by dehydration of the acid, and his initial studies of organic compounds containing the trifluoroacetyl group began with an examination of ethyl trifluoroacetate, synthesized by esterification of ethyl alcohol with trifluoroacetic acid in the presence of concentrated sulfuric acid.1 A few other organic trifluoroacetates were later prepared in the same way, but the potential use of the anhydride of tritluoroacetic acid as a preparative agent in general organic chemistry, and , in particular, in carbohydrate chemistry was not realized until recently.2J The importance of this reagent became apparent with (1) F. Swarts, Bull. clasae sci., Acad. roy. Belg., 8, 343 (1922). (2) E. J. Bourne, M. Stacey, J. C. Tatlow and J. M. Tedder, Nature, 164,705 (1949). (3) J. M. Tedder, Chem. Revs., 66, 787 (1956).

59

60

T. 0. BONNER

the discovery that, apart from its use as a direct trifluoroacetylating agent, its addition to a carboxylic acid in slight excess of the equimolecular proportion provided a powerful acylating solution for the conversion of a suitable substrate to the acyl derivative of the carboxylic acid.4 The original investigation which revealed this latter property of trifluoroacetic anhydride was concerned with an attempt to prepare cellulose trifluoroacetates by direct treatment of cellulose with the anhydride. No reaction was apparent, but, when the cellulose was pretreated with acetic acid, it subsequently dissolved slowly in trifluoroacetic anhydride, with the formation of a chloroform-soluble product containing no fluorine and having the properties of cellulose acetate. This novel use of trifluoroacetic anhydride has since been widely extended. At the same time, the more conventional function of introducing the trifiuoroacetate group into hydroxy compounds is of considerable interest and will be briefly dealt with first. Trifluoroacetic anhydride is conveniently prepared in high yield by distillation of trifluoroacetic acid over phosphorus pentaoxide.le4 An alternative procedure, for which a high yield is also claimed, utilizes sulfur trioxide to convert trifluoroacetic acid into trifluoroacetylsulfuric acid which, on further treatment with trifluoroacetic acid, affords trifluoroacetic anhydride.' Although highly volatile (b.p. 34-40'), trifluoroacetic anhydride is much more convenient to handles than the acyl chloride (b.p. -27") or the acyl bromide (b.p. -5").

11. TRIFLUOROACETYLATION WITH TRIFLUOROACETIC ANHYDRIDE 1. 0-Trifluoroacetylatirm

The replacement of the hydrogen atom in a hydroxyl group by the trifluoroacetyl group is effected by the usual acylation procedure of warming the hydroxy compound with trifluoroacetic anhydride in the presence of dry sodium trifluoroacetate under anhydrous conditions.? The recovery of the ester requires, however, a modified procedure, since the usual method of destroying the excess acid anhydride by means of aqueous sodium bicarbonate simultaneously brings about hydrolysis of the alkali-labile trifluoroacetate group. In order to remove excess trifluoroacetic anhydride and the trifluoroacetic acid present under anhydrous conditions, the reaction mixture is distilled several times with dry carbon tetrachloride and (4) E. J. Bourne, M. Stacey, J. C. Tatlow and J. M. Tedder, J . Chem. Soc., 2976 (1949). (6) J. F. Dowdall, U. S. Pat. 2,628,263 (1963); Chem. Abstracts, 48, 1426 (1964). 66,389 (1943). (6) J. H. Simons and E. 0. Ramler, J . Am. Chem. SOC., (7) E. J. Bourne, C. E. M. Tatlow and J. C. Tatlow, J . Chenc. Soc., 13G7 (1960).

APPLICATIONS OF TRIFLUOROACETIC ANHYDRIDE

61

the ester is finally removed from the residual sodium trifluoroacetate by extraction with the same solvent or dry hexane. Original experiments resulted in good yields, from the appropriate sugar derivatives, of D-mannitol hexakis(trifluoroacetate)and methyl 4,6-O-benzylidene-2,3-di-O-(trifluoroacetyl)-cy-D-glucoside,both of which are crystalline, and methyl 2,3,4,6tetra-0-(trifiuoroacetyl)-a-D-glucosideand 1 ,2-0-isopropylidene-3,5,6-tri0-(trifiuoroacety1)-D-glucose, isolated as pure liquids. The method was later applied successfully to a wide variety of hydroxy compounds, both aliphatic and phenolic, and additional procedures were adopted for the isolation of the product? The trifluoroacetates are reasonably stable when pure and dry, but, in the presence of water, they are hydrolyzed readily (apparently autocatalytically, through the trifluoroacetic acid liberated). The hydrolysis is very rapid with esters of polyhydroxy compounds, indicating a unique lability of trifluoroacetyl groups when they are adjacent to each other in the same molecule. An alternative method of removing the trifluoroacetyl groups is provided by the use of dry methanol; in this solvent at 17",the observed rotation of a dry methanolic solution of the product fell to 70% of its original value in 1 hour and to zero overnight. Both detrifluoroacetylation procedures produce the parent hydroxy compound without occurrence of an accompanying Walden inversion or formation of an anhydro ring. The above method of trifluoroacetylation was utilized to convert benzyl @-D-glucosideinto its 2,3,4,6-tetrakis(trifluoroacetate), with the intention of using this product in the synthesis of D-glucosyl ester^.^ It was hoped that the benzyl group could be removed by catalytic hydrogenation, and then position C-1 could be esterified with a carboxylic acid in the presence of trifluoroacetic anhydride, and the product detrifluoroacetylated with dry methanol; conditions could not, however, be found for the effective removal of the benzyl group from the trifluoroacetyl derivative. Swarts used a mixture of trifiuoroacetic acid and concentrated sulfuric acid for esterifying monohydroxy compounds and, although the method has subsequently been used successfully, other workers have found that either trifiuoroacetic acidlo or its anhydride aloneu J* are often effective esterifying media. Another method employs silver trifluoroacetate for (8) E. J. Bourne, M. Stacey, J. C. Tatlow and R. Worrall, J . Chem. SOC.,3268 (19%). (9) F. Weygand and E. Rauch, Chem. Ber., 87, 211 (1954). (10) A. Kalusayner, S. Reuter and E. D. Bergmann, J . Am. Chem. SOC.,77, 4164 (1955). (11) H. W. Coover and J. B. Dickey, U.S. Pat. 2,759,912 (1956); Chem. Abslracls, 61, 2327 (1957). (12) R. F. Clark and J. H. Simons, J . A m . Chem. SOC.,76, 6305 (1953). (13) V. T. Oliverio and E. Sawioki, J . Org. Chem., 20,363 (1956).

62

T. 0. BONNER

converting sn alkyl iodide into the corresponding alkyl trifluoroacetate in high yield.I4 A detailed study has been made of the action of pure trifluoroacetic acid on cellulose and cellobiose (and their acetates) .l6 Dissolution of cellulose occurs, and swelling takes place with rupture of hydrogen bonds and with micellar dispersion; esterscation takes place without occurrence of degradation, the cellulose being fully recovered on hydrolysis of the trifluoroacetylated product. It appears that there is a more rapid rate of trifluoroacetylation of primary than of secondary alcohol groups. Although pyridine has been reported to be an unsuitable medium for trifluoroacetylation (as it reacts with trifluoroacetic anhydride),? this solvent has been successfully employed in the trifluoroacetylation of 1l-epicorticosteronel6; in aqueous pyridine a t 20°, the trifluoroacetyl group introduced was found to undergo slow hydrolysis without further aid. 2. N - T r i J u o r ~ t y l a t i o n

An interesting contrast is provided by the methods of synthesizing 0trifluoroacetyl and N-trifluoroacetyl derivatives. The latter are very readily formed by the direct action of trifluoroacetic anhydride on primary or secondary amines, and are stable to prolonged boiling with dry methanol.” Since O-trifluoroacetylation usually requires the presence of sodium trifluoroacetate, selective trifluoroacetylation of amino groups is possible ; any adventitious introduction of O-trifluoroacetyl groups can be dealt with by subsequent treatment with methanol (to remove these groups selectively). Investigations of N-trifluoroacetylation have been mainly confined to amino acids, for which, excellent yields (70-95%) are obtained by the use of tritluoroacetic anhydride in anhydrous trifluoroacetic acid .u The presence of the strong acid prevents ionization of the carboxylic acid group of the amino acid and ensures nonformation of a mixed anhydride. This medium has also been found to trifluoroacetylate the amino group of a peptide linkage.lg Excellent yields of the N-trifluoroacetyl derivatives of amino acids and peptides, usually without occurrence of racemiaation, have been obtained20 by heating with phenyl trifluoroacetate in phenol at 1 2 0 - 1 5 0 O . A novel N-trifluoroacetylating reagent which has been used for (14) R. Filler, J. F. O’Brien, I. V. Fenner and M. Hauptechein, J . Am. Chern. SOC., 76, 966 (1963). (16) A. L. Geddee, J . Polymsr Sci., II,31 (1966). (16) A. Lardon and T. Reichatein, Helu. Chim. Acta, 87,388 (1964). (17) E. J. Bourne, 8.H. Henry, C. E. M. Tatlow and J. C. Tatlow, J . Chem. Soc., 4014 (1962). (18) F. Weygand and R. Geiger, Chem. Ber., 89,047 (1966). (19) F. Weygand, R. Geiger and V. Gloakler, Chem. Ber., 89,1643 (1966). (20)F. Weygand and A. Rapech, Chem. Ber., 81,2095 (1959).

APPLICATIONS OF TRIFLUOROACETIC ANHYDRIDE

63

amino acid anions in aqueous solutionz1is S-ethyl trifluorothioacetate CF3COSEt; the product was found to be stable in aqueous acid, but, in solutions of pH > 10, the trifluoroacylamide bond underwent rapid hydrolysis.

111. THETRIFLUOROACETYL GROUPAS

A

BLOCKING GROUP

1. The Synthesis of 2- and 3-0-SubstitutedD-Glucoses

The ease of hydrolysis of the trifluoroacetyl group, without occurrence of complicating side-effects, has obvious synthetic possibilities through the provision of a readily removable blocking group. Removal of the group has been achieved under extremely mild conditions at room temperature with (a) anhydrous methanol,7*22(b) aqueous acetone, when an autocatalytic acid hydrolysis appears to accompany the release of trifluoroacetic and (c) aqueous pyridine.I6 The first examination of this use of the trifluoroacetyl group in carbohydrate studies was concerned with the conversion of methyl 4,6-0-benzylidene-2,3-di-0-(trifhoroacety1)-cr-~-glucoside (1) into 2- and 3-substituted D-glucoses.22The compound (1) , although losing both trifluoroacetyl groups readily in methanolic solution on prolonged standing (18 hr.), can undergo partial de-esterification to the monotrifluoroacetyl derivative (2), either by suitable treatment with dry methanol-carbon tetrachloride or by use of a concentrated solution of the bis(trifluor0acetate) in methanol, when the mono ester gradually separates. In establishing the location of the surviving trifluoroacetyl group, it was found that, apart from its lability and ease of replacement, this group may migrate under alkaline conditions. Methylation of the mono ester (2) with methyl iodide and silver oxide was inconclusive, the sole product being the 2,3-dimethyl ether; this replacement of trifluoroacetyl groups by methyl groups during methylation, which had been noted previously, is variable and appears to depend on such factors as the purity of the reagents.' The reactions of the mono ester which indicated the position of the trifluoroacetyl group and its propensity to migrate were (a) acetylation with an acetic acid-trifluoroacetic anhydride mixture, (b) acetylation with acetic

L!2)oM.

''L

(1); R = R' CFsCO (2); R = CFsCO, R' = H (3); R = R' = H

OR

R'

(4); R CFsCO, R' = BZ (5); R = Bz,R' = H

anhydride in pyridine, and (c) tosylation in pyridine. I n each case, the (21) E. E. Schallenberg and M. Calvin, J . Am. Chem. Soc., 77, 2779 (1955). (22) E. J. Bourne, M. Stacey, C. E. M. Tatlow and J. C. Tatlow, J . Chem. Sac., 826 (1951). (23) E. J. Bourne, A. J. Huggard and J. C. Tatlow, J . Chem. Soc., 735 (1953).

64

T. 0. BONNBR

free hydroxyl group was substituted, the trifluoroacetyl group being retained. On removal of the latter group, the products were found to be the following derivatives of methyl 4,6-O-benzylidene-cu-~-glucoside (3): from reaction (a), the 2-acetate; from (b), the 3-acetate; and from (c), the 2-0tosyl derivative. Since migration of acyl groups is favored by alkaline conditions, it was concluded that migration of the trifluoroacetyl group occurs during the aeetylation in pyridine solution, but not in the aeetylation under acid conditions nor in the p-tolylsulfonation. The displacement can be regarded as a process similar to the removal of the trifluoroacetyl group in methanolysis, since both processes involve transfer of the group from one alkoxy oxygen atom to another. It is known that, whereas p-tolylsulfonylation of (3) proceeds preferentially a t the C-2 hydroxyl group, the 3-acetate of (3) is more stable than the 2-acetate. The trifluoroacetyl group appears, therefore, to be readily displaced when, by this occurrence, the incoming group is enabled to take up its most favorable position. The mono(trifluoroacetate) (2) is, therefore, the 3-ester. This conclusion has been confirmed by a study of the benzoylation of this isomer.a* A monobenzoate (4) was obtained which gave, either on acid hydrolysis or on alcoholysis, a product which, on p-tolylsulfonylation, formed the 2-0benzoyl-3-0-tosyl derivative of (3). Attempted removal, by dilute alkaline hydrolysis, of the trifluoroacetyl group from the monobenzoyl derivative (4) led to simultaneous migration of the benzoyl group from the C-2- to the C-3-hydroxyl group, to give methyl 3-0-benzoyl-4,6-O-benzylidenea-D-glucopyranoside (5) ; this migration also occurs when the 2-benzoate (4) is treated with dilute alkali. 2. The Synthesis of d ,4-Di-O-methyl-~-rhamnose Although the 2 ,&dimethyl and 3 ,Cdimethyl ethers of L-rhamnose were known, the 2,4-dimethyl ether had not been synthesized prior to its preparation through a trifluoroacetyl intermediate.2412sThe synthesis started from methyl 2,3-O-isopropylideneiu-~-rhamnopyranoside; this was methylated and the acetal group removed, to give methyl 4-O-methyl-cu-~rhamnopyranoside (6). Conversion to the 2,3-bis(trifluoroacetate) (7) was readily achieved with trifluoroacetic anhydride in the presence of sodium trifluoroacetate. As expected, the trifluoroacetate (7) was completely deacylated by treatment with alcohol, regenerating (6) ; this process was complete after 25 min. a t room temperature. The procedure for selective de-esterification was based on the observation that, if excess carbon tetrachloride (6 vol.) is present, very little methanolysis occurs. By use of a mixed methanol-carbon tetrachloride solvent (65: 35 vol./vol.), the meth(24) K. Butler, P. F. Lloyd and M. Stacey, Chem. & Ind. (London), 107 (1954). (26) K. Butler, P. F. Lloyd and M. Stacey, J . Chem. Soc., 1631 (1966).

65

APPLICATIONS OF TRIFLUOROACETIC ANHYDRIDE

anolysis was allowed to proceed to the point of maximum optical rotation, and the de-esterification was then effectively stopped by pouring the solution into a large volume of carbon tetrachloride. On evaporation of the solvent, a sirup was obtained having the methoxyl content of a mono(trifluoroacetate). On acetylation with pyridine and acetic anhydride, followed by methanolysis to remove the remaining trifluoroacetyl group, methyl 3-0-acetyl-4-0-methyl-cu-~-rhamnopyranoside (8) was obtained. This was converted to its 2-methyl ether (9), with silver oxide and methyl iodide; and then subjected to deacetylation and acid hydrolysis to give, predominantly, 2,4-di-O-methyl-~-rhamnose, together with a small pro(6); R = R' = H MeO,I.&po,eyMe

W I

OR

I

OR'

(7): R R' = CFSCO (8); R = Ac, R' = H (9); R = Ac, R' = Me (10); R = CFsCO, R' = H

portion of the 3,4-dimethyl ether. The reaction sequence employed is similar to that used with the D-glucose analogs above, and, although not established so conclusively, it was assumed that methanolysis of the bis(trifluoroacetate) proceeds more rapidly at the C-2- than at the C-3-hydroxyl group. Methanolysis of the di-ester was found to be much faster than that of the residual mono(trifluoroacetate), confirming the unique lability noted previously in trifluoroacetyl groups adjacent to each other in the =me molecule. The mono(trifluoroacetate) obtained by selective methanolysis of the diester is, therefore, regarded as having the structure (10) and the formation of the monoacetate (8) must involve migration of an acyl group at some stage. As in the analogous reaction in the previous Section, it is considered most likely that transference of the trifluoroacetyl group from the C-3- to the C-2-hydroxyl group occurs during the acetylation of (10) in pyridine. 3. Other Synthetic Uses of Trijiuoroacetyl Derivatives

Use has been made of the trifluoroacetyl derivatives of 1,3: 2,4-di-0ethylidene-D-glucitol (11) in the synthesis of some 5- and 6-substituted R = R' = H Ac, R' CFsCO (12); R (13); R = Ac, R' = H (14); R = Me, R' = Ac (16); R = Me, R' = H

(11);

p

66

T. Q. BONNER

D-glucitols.26 The 5,6-bis(trifluoroacetate) of (11) was obtained by the usual procedure, and controlled alcoholysis with isopentyl alcohol removed one trifluoroacetyl residue. In contrast to the results obtained with methyl 4,6-0-benzylidene-cu-~-glucoside, acetylation of the free hydroxyl group with either acetic anhydride and pyridine or acetic acid-trifluoroacetic anhydride gave the same 5-0-acetyl-6-0-trifluoroacetyl derivative (12), both acylations proceeding without accompanying migration of the trifluoroacetyl group. Alcoholysis of (12) with methanol gave the 5-acetate (13), and treatment of this product (13) or of its precursor (12) with methyl iodide-silver oxide gave the same 6-0-acetyl-5-0-methyl derivative (14). The trifluoroacetyl group in (12) is removed in the methylation reaction, and there is an accompanying migration of the acetyl group from C-5 to C-6. The migration also occurs in the 5-acetate (13) and is known to be common during methylations with Purdie's reagents?' Deacetylation of (14) yields the 5-methyl ether (15). An interesting application of the use of trifluoroacetic anhydride to provide blocking groups has been reported in the synthesis of D-glucosides and D-glucosiduronic acids of phenolic amino acids.28 Tetra-0-acetyl-a+glucopyranosyl bromide (or methyl tri-0-acetyl-1-bromo-1-deoxy-D-glucuronate) is coupled with the ethyl ester of the N-(trifluoroacety1)amino acid, and the N-(trifluoroacetyl) group is readily removed by treatment with 0.2 N sodium hydroxide or 0.2 N barium hydroxide; this procedure does not affect the D-glucosidic (or D-ghcosiduronic) linkage. For diiodotyrosine, this is a much more useful method of blocking the amino group than the more usual benayloxycarbonyl substitution, since the catalytic hydrogenation procedure employed for removing the latter group can also cause de-iodination. Trifluoroacetylation of a hydroxyl group (in order to prevent reaction at this group) has also found application in steroid synthesis; for example, methyl 3/3-hydroxy-5-etiocholenate has been converted to 1l-epi-corticosterone by way of its trifluoroacetyl ester.'* A possible application of the blocking effect of trifluoroacetyl groups, making use of the difference in reactivity of the N-(trifluoroacetyl) and 0-(trifluoroacetyl) groups toward hydrolytic attack, would be for conversion of a hexosamine into its tetra-0-acetyl derivative containing the free amino group. The procedure for this synthesis would require the conversion of the hexosamine to its pentakis(trifluoroacetate), the selective removal of the 0-(trifluoroacetyl) groups with dry methanol, followed by (26) E. J. Bourne, C. E. M. Tatlow, J. C. Tatlow and R. Worrall, J . Chem. SOC., 3946 (1968). (27) J. M. Sugihara, Advances in Carbohydrate Chem., 8,l (1963). (28) A. Taurog, 8.Abraham and I. L. Chaikoff, J . Am. Chem. Soc., 76,3476 (1953).

APPLICATIONS OF TRIFLUOROACETIC ANHYDRIDE

67

acetylation of the free hydroxyl groups and hydrolysis of the N-(trifluoroacetyl) group by mild treatment with alkali.

IV. ACYLATION WITH CARBOXYLIC ACID-TRIFLUOROACETIC ANHYDRIDE MIXTURES 1. Acyhtion of Hydroxy Compounds

The selective acylating action of a mixed anhydride of two carboxylic acids was first correctly diagnosed by B6ha1,2e who showed that, in the acylation of an alcohol by a mixed anhydride, there preponderates (in the product) the ester formed from the acid having the smaller number of carbon atoms. The formation, from a mixture of acetic anhydride and either mono-, di-, or tri-chloroacetic acid, of an acetylating agent sufficiently powerful to effect p-acetylation of anisole was later demonstrated by Unger?e* Trifluoroacetic acid was first used in this connection by Newman,aowho found that a mixture of this acid with acetic anhydride converted anisole into 4'-methoxyacetophenone in 63 % yield (with recovery of 31 % of the anisole) at a much lower temperature than that previously employed with chloroacetic acids. The modified technique adopted by Bourne and co. workers, which has now been extensively applied to acylation reactions,'~~~ consists in treating the hydroxy compound with a slight excesa of an equimolar mixture of the requisite carboxylic acid in the presence of trifluoroacetic anhydride; the reaction mixture is poured into aqueous sodium bicarbonate, and the ester is isolated. Esterification by the lower fatty acids usually proceeds spontaneously and exothermally, and is sometimes complete by the time the temperature has returned to room temperature. For benzoylation, warming of the reaction mixture is necessary and it is recommended that, in general, any carboxylic acid should first be heated gently with trifluoroacetic anhydride before adding the hydroxy compound. The mild conditions of this acylating technique enable acyl derivatives of acidlabile glycosides to be prepared in good yield, as illustrated by the resulting yields of the tetraacetate (55 %) and the tetrapropionate (77 %) of methyl a-D-glucoside and the octaacetate of ap-trehalose (68 %). Sucrose, which is extremely sensitive to acid, affords its octaacetate in 67 %yield. Both cellulose and amylose gradually dissolve at 50-60" in a mixture of acetic acid and trifluoroacetic anhydride, with the formation of chloroform-soluble, fibrous (29) A. BBhal, Compt. rend., 128, 1460 (1899); Ann. chim.phys., [7] 20, 417 (1900). (2Qa) F. Unger, Ann., 604,267 (1933). (30) M. S . Newman, J . Am. Chem. sbc., 67,345 (1945). (31) E. J. Bourne, M. Stacey and J. C. Tatlow, British Pat. 684,754; Chem. Ab8 h C l 8 , 48, 2095 (1954).

68

T. 0. BONNER

acetates having acetyl contents greater than 40 %, with no evidence of extensive degradation of the polysaccharide chains. Conversion of cellulose to its benzoate was similarly achieved. 2. Composition of the Acylating Medium The role of trifluoroacetic anhydride in these acylations was indicated by the diminished yield of acylation product obtained when the ratio of trifluoroacetic anhydride to hydroxy compound lay below unity, optimum conditions requiring a slight excess of this reagent. A catalytic function was, therefore, excluded, and the view was advanced that trifluoroacetic anhydride serves the purpose of converting the added carboxylic acid into the corresponding acyl trifluoroacetate. Later work on the nature of the equilibria between acyl anhydrides and acids in the presence of trifluoroacetic anhydride showed that the acylating capacity of a mixture of a carboxylic acid and trifluoroacetic anhydride is enhanced by the trifluoroacetic acid liberated when the unsymmetrical anhydride is formed.= Further, cryoscopic studies on solutions in acetic acid of the pure, unsymmetrical anhydride, acetyl trifluoroacetate, have shown that, contrary to an earlier conclusion that acetic anhydride is not formed to any appreciable extent,as acetyl trifluoroacetate is, in fact, almost completely converted into acetic anhydride in excess acetic acid.84In carrying out an acylation with trifluoroacetic anhydride and a carboxylic acid, it is, therefore, important to avoid an excess of the acid, so that the maximum concentration of the unsymmetrical anhydride is present in the equilibrium system. Extensive studies made on the action of acyl trifluoroacetates on hydroxy compounds under different conditions, with the simultaneous formation of the acyl and trifluoroacetyl derivatives, will be discussed later. The rate of acetylation of 0-(hydroxymethy1)cellulose (and other hydroxy compounds) by mixtures of carboxylic acids and their anhydrides has been found to increase greatly in the presence of trifluoroacetic acid. The acceleration is very much less with mono- and tri-chloroacetic acids, presumably because they form unsymmetrical anhydrides which are less effective acylating agents than acyl trifluoroacetates.*6The exceptional acylating power of the latter anhydrides is shown by their use in the synthesis of alkyl aryl ketones from polyalkylbenzenes, phenyl ethers, furan, and thiophene under mild The principle has been extended to include acids (32) (1964). (33) (34) (36) (3G) (1951).

E. J. Bourne, M. Stacey, J. C. Tatlow and R. Worrall, J . Chem. Soe., 2006 P. W. Morgan, J . A m . Chem. SOL, 75,860 (1961). E. J. Bourne, J. C. Tatlow and R. Worral1;J. Chem. SOC.,316 (1967). P. W. Morgan, U. s. Pat. 2,629,716 (1963); Chem. Abstracts, 48, 716 (1954). E. J. Bourne, M. Stacey, J. C. Tatlow and J. M. Tedder, J . Chem. SOC.,718

APPLICATIONS OF TRIFLUOROACETIC ANHYDRIDE

69

other than those of the carboxylic type; for example, a mixture of p-toluenesulfonic acid and trifhoroacetic anhydride forms sulfones by reaction with suitably activated aromatic compounds. By the same technique, the hexanitrate esters of D-mannitol and D-glucitol were obtained" by use of solutions of fuming nitric acid in trifluoroacetic anhydride at 0". The probable reaction mechanisms of these and other examples of the conversion of oxy acids into reactive entities have been briefly considered." Similar use has been made of trifluoroacetic anhydride in the preparation of the cyclic 2,3-phosphate of adenosine from adenosine 2-phosphate ; the latter appears to be converted into the unsymmetrical anhydride, which then acts as an internal phosphorylating agent toward the C-3-hydroxyl group.89Treatment of the product with ethanolic ammonia removed the

HO-

B

-0-COCFS

trifluoroacetyl groups present. In the field of nucleotides, many similar preparations have been effected, all of which appear to proceed through the unsymmetrical phosphoryl trifluoroacetic anhydride~.~O-e

V. SELECTIVE RING-OPENING OF CYCLIC ACETALS WITH CARBOXYLIC ACID-TRIFLUOROACETIC ANHYDRIDE MIXTURES 1. Methylene Acetals of D-Gluca*tol

The use of an acylating medium for effecting scission of the acetal ring of a cyclic acetal of a sugar was first demonstrated in the conversion of methyl 4,6-O-ethylidene-&~-glucosideinto methyl 4 - 0 4 1-acetoxyethy1)6-O-acetyl-~-~-glucoside.~ The reagent employed was a 0.1 % (vol./vol.) solution of concentrated sulfuric acid in acetic anhydride at room tempera(37) E. J. Bourne, M. Stacey, J. C. Tatlow and J. M. Tedder, J . Chem. SOC.,1695 (1952). (38) E. J. Bourne, J. E. B. Randles, M. Stacey, J. C. Tatlow and J. M. Tedder, J . Am. Chem. SOC., 76, 3206 (1954). (39) D. M. Brown, D. I. Magrath and A. R. Todd, J . Chem. SOC.,2708 (1952). (40) S. M. H. Christie, D. T. Elmore, G . W. Kenner, A. R. Todd and F. J. Weymouth, J . Chem. Soc., 2947 (1963). (41) L. Schuster, N. 0. Kaplan and F. E. Stoleenbach, J . Biol. Chem., 216, 195 (1955). (42) C. Deluca and N. 0. Kaplan, J . Biol. Chem., 228,569 (1956). (43) H. H. Schlubach, W. Rauchenberger and A. Schultse, Ber., 66, 1248 (1933).

70

T. a. BONNER

ture. In a slightly modified form,"-'e this procedure has been extensively employed for the selective ring-scission of cyclic acetals of polyhydric alcohols at 0". When the ring-opening reaction occurs with a cyclic methylene acetal, the product contains an 0-acetyl group attached to one and an 0-(acetoxymethyl) group to the other of the two oxygen atoms originally forming the methylenedioxy ring. The acetylating entity attacking the ring is presumed to be the acetylium ion, CHaCO', or the conjugate acid of acetic anhydride, (CHaCO)20H' ; the formation of either species requires the presence of a strong acid. Since a mixture of a carboxylic acid and trifluoroacetic anhydride also gives rise to a strongly acylating entity, it was evident that this reagent could react similarly with a cyclic methylene acetal. Assuming that, in this case, the acylating species originates in the unsymmetrical anhydride, that is, the acyl trifluoroacetate, the product of the ring-opening reaction might be expected to contain an 0-(trifluoroacetoxymethyl) group, in addition to the 0-acyl group. The procedure was tested4' by treating 1,6di-O-benzoyl-2,4:3,5-di-O-methylene-~-glucitol(16) with a nine-fold excess (necessary for effecting complete dissolution) of an equimolar mixture of acetic acid and trifluoroacetic anhydride at 25". After 3 hours, the optical rotation had become constant, and the product was a fluorine-containing sirup which decomposed, on exposure to air, with evolution of formaldehyde and trifluoroacetic acid. Treatment of the product with dry methanol (to remove any 0-trifluoroacetyl groups) gave an 0-acetyl-1 ,6-di-O-benzoyl2,4-O-methylene-~-glucitol. Assignment of the acetoxyl group to C-5 (17) was indicated by the formation of a product identical with compound (17) 6-di-0by controlled, acid hydrolysis of 3-0-(acetoxymethyl)-5-0-acetyl-l, benzoyl-2,4-O-methy~ene-~-glucitol to remove the acetoxymethyl group. Confirmation was provided" by the further employment of trifluoroacetic anhydride in conjunction with benzoic acid to open the 1,3-acetal ring of 5-0-acetyl-6-O-benzoyl-l ,3 :2,4-di-O-methylene-~-glucitol (18) and produce, after removal of the trifluoroacetoxymethyl group by methanolysis, compound (17); attack by the benzoylating agent had clearly taken place a t C-1, and the subsequent ring-scission was followed by the appearance of a trifluoroacetoxymethyl group at C-3. The attempted benzoylation of the free hydroxyl group in (17) revealed some interesting stereochemical features (of this and similar molecules) which determine the reactivity to further attack by different reagents. Although acetylation of the C-3-hydroxyl group with acetic anhydride in A. T. Ness, R. M. Hann and C. 8. Hudson, J . A m . Chem. Soc., 66,2216 (1943). R. M. Hann and C. S. Hudson, J . Am. Chem. Soc., 66, 1906 (1944). A. T. Ness, R. M. Hann and C. S. Hudson, J . A m . Chem. SOC.,70,766 (1948). E. J. Bourne, J. Burdon and J. C. Tatlow, J . Chem. SOC.,1274 (19%). (48)E. J. Bourne, J. Burdoa and J. C. Tatlow, J . Chem. rSoc., 1864 (1969). (44) (46) (46) (47)

APPLICATIONS OF TRIFLUOROACETIC ANHYDRIDE

CHzOR

71

CHZOBZ

I

I

I

~H~OR' (16); R = R' = Bz (23); R = R' = Ac (29); R = R' = Pr

(17); R (19);R (20); R (21);R

= H, R' = Ac

= Bz, R' = kc = H, R' = Bz = Ac, R' = Bz

CHzOR

HbOA

HAOJ HAOR!' AHzOR"'

(24) (18); R = Ac, R' = Bz (22); R = R' = Ac

(25); R = R"' = Ac, R' = R" = H (26);R = R' = R" = R'" = Ac (27); R = R"' = Pr, R' = R" = H (28); R = R'" = Pr, R' = R" = Ac

pyridine a t room temperature is quite successful, benzoyl chloride in the same medium is much less effective. Benzoic acid and trifluoroacetic anhydride at 60°, on the other hand, achieve a good yield of the 3-benzoate (19). It might appear that, since the C-3-hydroxyl group under attack is axial with respect to the acetal ring, an effect operates that is similar to that recognized with axial hydroxyl groups in cyclohexane derivatives. These hydroxyl groups are difficult to esterify because of the steric hindrance offered by the two &hydrogen atoms; the corresponding @-positionsin the cyclic acetal are, however, occupied by the ring-oxygen atoms. Models of (16) show that the three large groups attached to C-2 and C-5 hinder access of reagents to the C-3-hydroxyl group (see Fig. 1). This observation suggests that the successful acetylation in pyridine involves a less bulky reagent than benzoyl chloride in the same medium, and that the benzoylating agent in the benzoic acid-trifluoroacetic anhydride mixture is either of a size that makes it less easily obstructed or is a very powerful benzoylating species.

72

T.

a. BONNER

The relative inacceeaibility of the C-3-hydroxyl group is again indicated in which the Schotten-Baumann benzoylation of 2,4-O-methylene-~-glucitol, as that obtained gives the same tri-O-benzoyl-2,4-O-methy~ene-~-gluc~tol by aqueous hydrolysis of the product obtained from the reaction of 1,6di-O-benzoyl-2,4: 3,5-di-0 methylene-D-glucitol (16) with a nine-fold excess of an equimolar mixture of benzoic acid and trifiuoroacetic anhydride at 25" for 12 hours. The expected product in the latter reaction is the 1,5,6tribenzoate (20), by analogy with the similar reaction of acetic acid-trifluoroacetic anhydride with (16) to give (17), and this expectation was confirmed by acetylation to give a product different from the isomeric 5-0acetyl-1 ,3,6-tri-O-benzoyl derivative (19). The only possible alternative is the 3-O-acetyl-l , 5,6-tri-O-benzoyl derivative (21).

$

FIG. 1.4onformation of (16). (+ = Favorable route for RCO'; .-+ able route for RCO".)

unfsvor-

The stability of the 2,4-ring in the above acylating media was further demonstrated by the failure of prolonged action (24 hr. at 25') of acetic acid and trifluoroacetic anhydride on the parent compound (2 ,CO-methylene-D-glucitol) to produce any appreciable ring-scission. This acetal ring is a BC-ring, which is known to possess much greater stability than other types of ring formed in these cyclic acetals of hexitol~~~~50; in accordance with the views of Mills,K1the stability is attributed to the fact that the large benzoyloxymethyl group occupies an equatorial position in the 2,4-ring, whereas, in contrast, the axial position of this group with respect to the 3,B-ring @T) makes the latter relatively unstable and labile to attack. Although it is not unexpected, therefore, that the dibengoate (16) undergoes ring scission a t the 3,5414 only, it is significant that this scission occurs solely in one direction, that is, the acylating species attacks uniquely at the C-5 position. The explanation offered is that the most "favored" conforma(49) 8.A. Barker and E. J. Bourne, Aduancee in Carbohydrate Chem., 7,137 (1962). (60)S.A. Barker, E. J. Bourne and D. H. Whiffen, J . Chem. Soc., 3866 (1962). (61) J. A. Mills, Aduancee in Carbohydrate Chem., 10.2 (1966).

APPLICATIONS OF TRIFLUOROACETIC ANHYDRIDE

73

tion of (16), which is analogous to cis-decalin, allows attack of the acylating agent in an equatorial direction a t the Cd-oxygen atom to be the least hindered (see Fig. 1).Approach of the reagent in an equatorial direction at the C-3-oxygen atom is hindered by non-bonded interaction with the benzoyloxymethyl group attached to (3-2, and attack in axial directions either at position 3 or 5 is ruled out for the usual conformational reasons. Molecular models confirm that an oxonium complex is possible at the C-5-oxygen atom, but not at that a t C-3. It was found" that, when a 1O:l molar ratio of acetic acid to trifluoroacetic anhydride was caused to react with (16), the product (after 12 hr. at 25") was 3-0-(acetoxymet hyl)-5-0-acet yl- 1,6-di-O-benzoyl-2,4-0-met hylene-D-glucitol, formed in 90% yield. Since this is the product which would be obtained in the Hudson acetolysis reaction, its formation suggests that, in the presence of excess acetic acid, trifluoroacetic anhydride does not afford acetyl trifluoroacetate (as in the equimolecular mixture), but is converted into trifluoroacetic acid, with acetic anhydride as the accompanying product; the mixture would then be similar to that used in acetolysis, that is, acetic anhydride in acetic acid in the presence of a strong acid. This result emphasizes the advantage of using the 1:1molar ratio for selective scissions of cyclic acetals, since the trifluoroacetoxy groups which result from the ring opening with this mixture are readily removed by methanol, without effect on other groups, whereas the removal of acetoxy groups requires a more vigorous, hydrolytic procedure, with a concomitant low yield of product. Further examples of selective ring-opening in cyclic acetals by an equimolecular mixture of a carboxylic acid and trifluoroacetic anhydride have been provided by 8- and a-methylene derivatives of D-glucitol where the initial attack appears to occur a t the primary carbon atom of these two types of ring. With acetic, benzoic, and propionic acids, the product obtained, after ring opening and removal of the trifluoroacetoxymethyl groups, contains the 0-acyl group a t the primary carbon atom, with free hydroxyl groups at the secondary position; for example, treatment of 5,6-di-O-acetyl1,3:2,4-di-O-methylene-~-glucitol (22) with a mixture of acetic acid (3 moles) and trifluoroacetic anhydride (3 moles) for 7 hr. at 25" yielded, after mild hydrolysis with sodium bicarbonate solution, a crystalline tri-0-acetyl2,4-0-methylene-~-glucitol identical with that obtained by the similar treatment of 1,6-di-O-acety1-2,4:3,5-di-0-methylene-~-glucitol (23). As it had been established that the 3,5-ring in the latter is selectively opened and the center of attack is at the C-5-oxygen atom, it is clear that the product is 1,5,6-tri-0-acetyl-2,4-O-methylene-~-glucitol. Hence, in the diacetal (22), the 1,3-ring @) is broken by attack of the acylating reagent at the C-1-oxygen atom, leaving the 2,4-ring intact. Studies of acid hydrolysis, acetolysis, and ease of formation of cyclic

74

T. 0. BONNER

acetals of hexit0ls4~*4~-6~ show that an a-ring is likely to be more labile than a &ring. It follows that interaction of 1,3:2,4:5,6-tri-O-methylene-~glucitol (24) with the acetic acid-trifluoroacetic anhydride mixture should result in scission of the 1,3-ring and the 5,6-ring (a), with the formation, after mild hydrolysis of the product, of l ,6-di-O-acetyl-2,CO-methylene-D-glucitol (25). The reaction yielded a sirup which had the correct analytical values and which could be acetylated to the known 1,3,5,6tetra-O-acetyl-2,4-0-methylene-~-glucitol (26), but attempts to prepare other derivatives by substitution at the two free hydroxyl groups failed. However, similar treatment of the tri-O-methylene-D-glucitol with an equimolecular mixture of propionic acid and trifluoroacetic anhydride gave the

(a)

H

' H

FIG.2.-Conformation of a 1,3:2,4-Diacetal of D-Glucitol. (4= Favorable route for RCO';

--+

= unfavorable route for RCO'.)

expected 2 ,4-O-methylene-.L,6-di-O-propionyl-~-glucitol(27), whose structure was shown by its hydrolysis to 2,4-0-methylene-~-glucito1 and by its acetylation to the 3,8diacetate (28). The structure of the diacetate was proved by its synthesis by an alternative route, which involved treatment of 2,4:3,5-di-0-methylene-l,6-di-O-propionyl-~-glucitol (29) with acetic acid-trifluoroacetic anhydride, followed by mild hydrolysis and acylation of the free hydroxyl group at C-3. Examination of the probably most stable conformation of a 1,3:2,4-diacetal of D-glucitol (see Fig. 2) shows that an axial approach to either oxygen atom of the 1,3-ring is improbable, because of non-bonded interactions analogous to the 1,&diaxial interactions of cyclohexane.@The same type of interaction would impede an equatorial approach to the C-3-oxygen atom, and the most probable attack of the acylating agent is, therefore, through an equatorial approach to the C-l-oxygen atom, to give the l-ester

APPLICATIONS OF TRIFLUOROACETIC ANHYDRIDE

75

of the 2 ,4-acetal. In the 5 ,6-ring of the tri-o-methylene-D-glucitol (24), the more accessible oxygen atom is a t C-6, with the result that, after reaction, the acyl group is found attached a t this position in the product. 2. Methylene Acetals of D - M a n n i t o l Some significant experiments have been carried out with 1 ,3 :2,5 :4 ,6tri-0-methylene-D-mannitol(1 mole) with acetic acid (4.5 moles) and trifluoroacetic anhydride (4.5 moles) at room t e m p e r a t ~ r e An . ~ ~initial, rapid increase in optical rotation was observed, culminating in a sharp maximum after 2 hr., with a subsequent slow fall in rotation spread over several days. This suggested that fission of the 1,3(@)-and 4,6@)-rings had occurred rapidly (since these rings are opened preferentially in the Hudson acetolysis procedureu), and that this was followed by a slower attack on the 2,5(yT)ring. By use of a solvent (to moderate the reaction), it was found that dilution of the reaction mixture with chloroform completely prevented ring scission, tri-0-methylene-D-mannitolbeing recovered in 93 % yield. In pure nitromethane, however, and in a mixture of this solvent with chloroform ( 1 : l by vol.), the initial, rapid change in optical rotation was again observed, but without the appearance of a sharp maximum rotation; samples of the reaction mixture taken within one hour of the start of the reaction were found to contain appreciable proportions (about 50%) of a mixture of an O-(acetoxymethy1)-O-acetyl-1, 3 :2,5-di-O-methylene-~-mannitol (30) and a di-O-(acetoxymethyl)-di-O-acetyl-2,5-O-methylene-~-mannitol (31). This result is quite different from that obtained with tri-o-methyleneD-glucitol, since the product of partial ring-scission of the latter gave no evidence of the presence of an O-(acetoxymethyl) group. It is probable that the 1 ,3- and 4,6-rings in tri-0-methylene-D-mannitol are opened in the expected way, to give O-acetyl-O-(trifluoroacetoxymethyl)derivatives, but that the latter group undergoes replacement by the acetoxymethyl group as a result of further attack by the acylating agent. Why this reaction occurs only for tri-0-methylene-D-mannitol and not for tri-0-methylene-D-glucitol is not clear, but the behavior is probably related to the different conformations of the two systems. Further experiments have established that, when tri-0-methylene-D-mannitol is treated with a larger proportion of the reagent, the 2 ,Bring does not remain intact, although it is evidently the most resistant to attack. Tri-O-methylene-D-mannitol(1 mole), on treatment with the 10: 1 mixture, that is, acetic acid (45 moles) and trifluoroacetic anhydride (4.5 moles), showed a similar differentiation in reactivity of the acetal rings. The only product recoverable in the early stages of the reaction a t 50" was (30), with the further product (31) appearing much later. Higher temperatures were (62)

T.G . Bonner, E.J. Bourne and D. Lewis, unpublished work.

7G

T. 0. BONNER

necessary in order to bring about ring opening of the 2,5-ring in (31), although, even near 100°, prolonged treatment appears necessary in order to achieve substantial fission of this ring. 3. Other Acetals Acetolysis by the Hudson procedure is known to remove a benzylidene An equimolar mixture acetal ring, to give the corresponding diacetate.s8164 of acetic acid and trifluoroacetic anhydride reacts in the same way with both benzylidene and isopropylidene aceta1s.a Treatment of 3 ,4-di-0acetyl-l,2:5,6-di-0-isopropylidene-~-mannitol with this reagent for 2 hr. at 25' gave a small yield (21%) of D-mannitol hexaacetate. 1,3:2,5:4,6Tri-0-bensylidene-D-mannitol,treated similarly for 24 hr., gave the same product in 39 % yield, together with a 73 % yield of benzaldehyde; the expected bis(trifluor0acetate) of the benzylidene acetal could not be isolated. 1,3,5 ,6-Tetra-O-acetyl-2,4-0-benzylidene-~-glucitol gave a high yield (85%) of D-glucitol hexaacetate under the same conditions, so that, with a phenyl substituent a t the methylenic carbon atom, the 2,4(BC)-ring is easily opened. In these three experiments, considerable darkening of the reaction mixtures occurred, although the single substances, acetone, benzaldehyde, D-glucitol, and D-mannitol do not themselves undergo this color change under these conditions. The different mechanisms of reaction of benzylidene and isopropylidene acetals, compared with that of methylene acetals, have not yet been elucidated, but, assuming, in both cases, that the acetal ring is ruptured to give an acetyl substituent together with a trifluoroacetoxymethyl substituent, in place of the alkylidene or arylidene group, it is evident that, when either

4 I

-bOAc

-bOAo

-bO-&OCOCF, I 1

-bOAc

I

R or R' is a phenyl group or when both are methyl groups, the oxygen atom attached to the carbon chain of the hexitol is likely to be more nucleophilic than if an unsubstituted methylene group is present. Further attack by the electrophilic, acylating entity is, therefore, facilitated, and this could result in the replacement of the trifluoroacetoxymethyl substitutuent by an acetyl group. (53) W. T. Hsskins, R. M. H a m and C. S. Hudson, J . A m . Chem. Soc., 64, 132, 136, 1614 (1042). (64) J. K.Wolfe, R. M. Hann and C. 8. Hudson, J . A m . Chem. floe., 64,1493 (1942).

APPLICATIONS OF TRIFLUOROACETIC ANHYDRIDE

77

In spite of the ring-opening reactions which can occur, free hydroxyl groups in cyclic acetals can be acetylated in reasonable yield without accompanying ring-scission, provided that only a slight excess (1.2 mole per hydroxyl group) of the equimolecular mixture of acetic acid and trifluoroacetic anhydride is employed. By this means, 1,3:2,4-di-O-methylene-~glucitol, its ethylidene analog, and 2,4-0-benzylidene-~-glucitol, respectively, were converted into their fully acetylated derivatives in excellent yield. Isopropylidene acetals of D-glucitol and D-mannitol under the same conditions, however, gave only negligible amounts of the acetal acetates.@ VI. THESYNTHESIS OF LINEARPOLYMERIC ESTEFSFROM CYCLIC TRIMETHYLENE ACETALSAND DIBASICCARBOXYLIC ACIDS In the original investigation of the use of trifluoroacetic anhydride in promoting acylation of hydroxy compounds by carboxylic acids,' it was noted that long-chain polyesters might result either from the combination of a dihydric alcohol and a dibasic acid or from a hydroxy carboxylic acid. Treatment of p-hydroxybenzoic acid with trifluoroacetic anhydride for 15 min. at 75" did, in fact, produce a polyester having m.p. 360". With pure reactants, this poly-ester should take the form of a linear polymer, but the product obtained did not appear to have this characteristic property. The is selectively later discovery that 1 ,3:2,4:5,6-tri-0-methylene-~-glucitol attacked at only two of its three acetal rings by an equimolecular mixture of a carboxylic acid and trifluoroacetic anhydride a t room temperature pointed to an alternative route for the synthesis of linear polyesters by the substitution of a dibasic acid for acetic acid. Since the product obtained in the acetic acid reaction, after removal of excess reagent and mild hydrolysis with methanol, is 1,6-di-O-acetyl-2,4-O-methylene-~-glucitol, the polyester resulting from the use of a dicarboxylic acid would be expected to possess two free hydroxyl groups per D-glucitol unit in the polymer chain. The reaction sequence for a cyclic, methylene acetal containing two labile rings is shown in Fig. 3. The use of a cyclic acetal having more than two reactive centers would lead to branching in the poly-ester chain and, probably, to a cross-linked product. There is the possibility that an intramolecular reaction could occur, but, as the product would possess a large, unstable ring, this is unlikely. Benzylidene or isopropylidene acetal rings are destroyed by acetic acid and trifluoroacetic anhydride, with the appearance of two acetate residues per acetal ring; a dibasic acid in place of acetic acid could, therefore, give rise to a linear poly-ester, but the product would not provide free hydroxyl groups. The presence of free hydroxyl groups in a linear polymer is valuable for certain applications; for example, if the polymer has use as an artificial fiber, the free hydroxyl groups enable the fiber to absorb water and they facilitate uptake of dye.

T.

78

0. BONNER

The investigation of polyester formation has been carried out using equimolecular proportions of 1,3 :2,4 :5,6-tri-O-methylene-~-glucitol and adipic acid in excess trifluoroacetic anhydride, the latter serving as the solvent.b6 After 3 hr. at room temperature, the volatile constituents were removed, and the reaction mixture was treated with an aqueous sodium bicarbonate (CHJ4(COZH),

+ 2

(CF,CO),O

=(CHJ~(CO-OCOCFJa

+ 2 CF&OaH

where T = CF,CO,CH,.

Fro. 3.-Synthesis of a Polyester.

solution and kept for a few days. The insoluble product was a colorless, brittle solid, melting a t 130-150" to a viscous liquid which could be drawn into brittle threads. The solid became swollen in some solvents and dissolved completely in pyridine. Alkaline hydrolysis yielded 2 ,bO-methylene-~glucitol and adipic acid; the only other product detected by paper chromatography was IL trace of D-glucitol. The infrared absorption spectrum of the (56) T. G. Bonner, E. J. Bourne and N. M. Saville, J . Chem. Soc., 2914 (1980).

APPLIC ITIONB OF TRIFLUOROACETIC ANHYDRIDE

79

product showed the presence of aliphatic carboxylate ester (but not of trifluoroacetate) and cyclic ether groups. The carboxylate ion was also found, presumably as the end group in some of the molecules, and the carboxylic acid group appeared on treatment with acid. If the assumption is made that the absorption coefficients of the -COOR and -COOe groups have closely similar values, the ratio of the corresponding absorptions indicated the presence of about ten of the former groups to one of the latter. As the molecules may contain two, one, or no carboxylate end-groups, the average chain-length could not be calculated from these data. Viscosity measurements in pyridine indicated an average, molecular weight of about 5,000; if the product is a linear polymer having, as the repeating unit, a monomethylene-D-glucitoladipate residue, the polymer chains would contain an average of 16 units. The expected repeating-unit is shown in Fig. 4. The molecular weight of the poly-ester is too low to provide the basis for a useful fiber, but a modification of the experimental conditions and, possibly,

FIG.4.-Repeating Unit of the Polyester Obtained from Tri-0-methylene-nglucitol and Adipic Acid.

of the dibasic acid constituent could lead to the synthesis of a more suitable product by this method of polymer formation.

VII. THE MECHANISM OF ACYLATION BY A c n TRIFLUOROACETATES 1. The Formation of Acyl Trijeuoroacetates

When a carboxylic acid and trifluoroacetic anhydride are mixed, the following equilibria are assumed to be established.as-ba XOH

+ (CF,CO)nO * XOCOCFa + CF&OaH

XOCOCFS XlO

+ XOH S XeO + CFaCOzH

+ (CFsCO)*O+ 2 XOCOCFa

(1 1 (2)

(3)

whereX = RCO. It is frequently postulated that the unsymmetrical anhydride undergoes partial ionization to X' and CFFCO,~, but direct evidence for this further step is meager. The evidence for the formation of the unsymmetrical anhydride in similar systems is, however, well established from previous (66)E.J. Bourne, J. E. B. Randles, J. C. Tatlow and J. M. Tedder, Nature, 168, 942 (1961).

80

T.

0. BONNER

investigations on mixtures of carboxylic acids and other anhydrides, particularly as a result of infrared-absorption studies." The latter technique, applied to a mixture of acetic anhydride and trifluoroacetic anhydride in carbon tetrachloride, revealed the gradual development of a new absorption band at 1072 cm.-', with an accompanying diminution of the original bands due to the primary components; the new band almost certainly indicated the formation of acetyl trifluoroacetate. In cryoscopic studies initiated by Morganw on solutions (in acetic acid) of trifluoroacetic acid and of trifluoroacetic anhydride, van't Hoff factors of 1 and 2, respectively, were reported. This result indicated that trifluoroacetic anhydride does not react in accordance with equation 4 (which would result in an i factor of 3), but probably forms the unsymmetrical anhydride as shown in equation 6.

+ 2 CHaCOzH (CHaC0)rO + 2 CFsCOaH (CF&O)P + CHaCOsH CHaCO4COCFS + CFaCO9H (CF&O)*O

+

(4) (6)

However, further infrared investigations,@based on comparisons of these systems with pure acetyl trifluoroacetate, although confirming the formation of the latter in 95 % yield from an equimolecular mixture of trifluoroacetic anhydride and acetic acid as represented in equation 6, showed that, in an equimolecular mixture of acetyl trifluoroacetate and acetic acid, acetic anhydride is formed to the extent of 60%. This result suggested that, in a large excess of acetic acid (as used in the cryoscopic studies), acetyl trifluoroacetate (and, hence, trifluoroacetic anhydride) should be largely converted into acetic anhydride, as represented by equation 4. New cryoscopic studies in acetic acida4showed an initial depression of freezing point corresponding to the formation of 2.5 particles per molecule of trifluoroacetic anhydride, but the freezing point was found to increase with time, the final result being an i factor of 2. The difficulties were attributed to ingress of atmospheric moisture, and, by use of (a) a special apparatus designed to avoid this ingress and (b) a more reliable cryoscopic constant for acetic acid, the cryoscopic behavior of trifluoroacetic anhydride was found to correspond to equation 4, and of acetyl trifluoroacetate, to equation 6. Probably, the original investigation,= although apparently providing evidence for the formation of acetyl trifluoroacetate, gave an erroneous result through interference by atmospheric moisture. CHaCO4COCFa

+ CHaCOnH

(CH&O)(O

+ CFsCOzH

(6)

In a detailed study of the electrical conductivities of the ternary system (CFaCO)~O-H&(CHaGO)nO, it was found that a dilute solution of trifluoroacetic anhydride in acetia acid has a small but definite conductivity which is slightly greater than twice that of a solution of trifluoroacetic acid (57) L.Brown and I. F.Trotter, J . Chem. floc., 87 (1961).

APPLICATIONS OF TRIFLUOROACETIC ANHYDRIDE

81

of the same molar concentration in the same solvent.@Also, in anhydrous mixtures of acetic anhydride and trifluoroacetic anhydride, a maximum conductivity appears near the equimolecular composition. These facts are interpreted as evidence for the formation of acetyl trifluoroacetate, and its partial ionization according to equation 7. CHICO~-COCFI

CHsCOe

+ CFpCOie

(7)

The production of these ions is assumed to occur more readily from the unsymmetrical anhydride than from the symmetrical anhydrides, resulting in the higher conductivities observed. The preparation of pure acetyl trifluoroacetate for the infrared studies referred to above was achieved by (a) fractional distillation of an equimolecular mixture of acetic anhydride and trifluoroacetic anhydride, or (b) the addition of pyridine to a mixture of acetic acid and trifluoroacetic anhydride, and fractional distillation of the fi1trate.a Acetyl trifluoroacetate is a colorless liquid, b.p. 95", which gradually becomes colored on ~tanding.6~ In solution in carbon tetrachloride or other inert solvent, no coloration occurs and the solutions are stable. Similar methods of preparation have been used by other workers, and several different acyl trifluoroacetates have been reported.60A different procedure for the preparation of acyl trifluoroacetates is the addition of the appropriate acyl chloride to a solution of silver trifluoroacetate in ether.61 The unsymmetrical anhydrides were found to be stable during the subsequent distillation, but disproportionation occurs in the presence of silver trifluoroacetate. 2. The Reactions of Acgl Tm'jeuoroacetateswith Hydroxy Compounds

The f i s t quantitative analyses of the products obtained by treating alcohols and phenols with an acyl trifluoroacetate showed that the anhydride can act simultaneously as an acylating and a trifluoroacetylating agent."*l-Butanol and acetyl trifluoroacetate in ether solution at 20" give a much greater yield of butyl trifluoroacetate than of butyl acetate; in the presence of trifluoroacetic acid, the proportions are reversed. In the absence of trifluoroacetic acid, sec-butyl alcohol gives about twice as much of the acetate as of the trifluoroacetate, and tert-butyl alcohol gives the acetate almost exclusively. It was confirmed with other hydroxy compounds that, when the acetylation predominates, the yield of product is much the same if the acetyl trifluoroacetate is replaced by an equimolecular mixture of (68) J. E. B. Randles, J. C. Tatlow and J. M. Tedder, J . Chem. Soc., 436 (1954). (69) J. M. Tedder, J . Chem. Soc., 2646 (1954). (60) W. D. Emmons, K. S. McCallum and A. F. Ferris, J . Am. Chem. Soc., 76, 6047 (1953). (61) A. F. Ferris and W. D. Emmons, J . Am. Chem. Soc., 76,232 (1953).

82

T.

a.

BONNER

acetic anhydride and trifluoroacetic anhydride. It was tentatively suggested that an acyl trifluoroacetate operates as a trifluoroacetylating agent in its molecular form, whereas the alternative acylation proceeds through the acylium ion (RCO@),the formation of which is enhanced by the addition of trifluoroacetic acid. The latter is always present in the acylating medium when a mixture of a carboxylic acid and trifluoroacetic anhydride is used in accordance with equation 1. More extensive studies* on a variety of hydroxy compounds, together with some rate measurements based on infrared analysis, appear to provide general support for the original interpretation of the mechanism of these reactions, although indicating many features which need further investigation. In these studies, the hydroxy compound was treated at 20" with a 30 per cent molar excess of acetyl trifluoroacetate in different environments which included the pure reactants only and the pure reactants with addition of trifluoroacetic acid, carbon tetrachloride, and sodium trifluoroacetate. The persistent formation of a high proportion of acetate in certain cases, under non-polar conditions in the presence of sodium trifluoroacetate (which would be expected to suppress formation of acetylium ions according to equation 7), clearly indicated that acetylation may also occur through the molecular form of acetyl trifluoroacetate. Possibly, this function only appears when a relatively less accessible hydroxyl group is present, to which the approach of the (larger) trifluoroacetyl group is more hindered than that of the acetyl group, as previously postulated62in acylation reactions of anhydrides of the chloroacetic acids. This steric factor is probably an important factor in the predominance of acylated derivatives when carbohydrates are treated with acetyl trifluoroacetate. Acylation of hydroxyl groups through acylium-ion attack, when a mixture of the acid anhydride and trifluoroacetic anhydride is employed, is probably preceded by formation of such acylium-ion derivatives as RC02H2@,(RCO)aOH@,and RCOOCOCFa:H@,which may, in themselves, act as acylating species. The function of trifluoroacetic acid in catalyzed acylations is not fully understood. The dielectric constant of trifluoroacetic acid (€20" = 8.4) does not suggest a strongly ionizing medium, but the capacity of the acid to solvate its own negative ions may be important, since such solvation could facilitate heterolysis of the unsymmetrical anhydride to acylium and trifluoroacetate ions.68Another mechanism was observed to operate with tert-butyl alcohol treated with acetyl trifluoroacetate, both in the absence of a solvent or in the presence of trifluoroacetic acid? The major product was tert-butyl trifluoroacetate, a 90 % yield being (62) A. R. Emery and V. Gold, J . Chem. Soc., 1443,1447,1466 (1960).

(63) J. J. Throssell, S. P. Sood, M. Szwarc and V. Stannett, J . Am. Chem. Soc., 78, lln (1966).

APPLICATIONS OF TRIFLUOROACETIC ANHYDRIDE

83

obtained with trifluoroacetic acid present. Since both the acetate and the alcohol were converted by trifluoroacetic acid alone into the trifluoroacetate, it is likely that alcohols of this type are first protonated by the acid, to give a conjugate acid, one molecule of which loses a molecule of water and then reacts with a trifluoroacetate anion. This mechanism of alkyl-oxygen fission is only likely to operate when there are structural factors tending to stabilize the carbonium ion formed. Measurements of rate of reaction of butano1 and sec-butyl alcohol showed that trifluoroacetate esters are formed much more rapidly with acetyl trifluoroacetate than with trifluoroacetic acid, so, in these cases, direct trifluoroacetylation by the acid is of minor importance. 3. Other Acylation Reactions of Acyl Tri$uoroacetates Other acylation reactions brought about by acyl trifluoroacetates and suggesting the operation of an acylium-ion mechanism are the acylation of aromatic compoundsPo~6 and the ring-opening reaction of cyclic acetals (see Sections V and VI). Successful acylations have been carried out on anisole, phenetole, mesitylene, thiophene, and furan, by use of trifluoroacetic anhydride in conjunction with acetic acid, benzoic acid, and cinnamic acid. Acetyl trifluoroacetate has been used directly for the acetylation of phenetole and thiophene, and benzoyl trifluoroacetate for the conversion of anisole to 4-methoxybenzophenone82;with both reagents, yields appear to be higher than with the carboxylic acid-trifluoroacetic anhydride mixtures. Although there is every likelihood that acylation of the aromatic ring proceeds through electrophilic attack by an acylium ion, the alternative mechanism of nucleophilic attack of aromatic compound on unsymmetrical anhydride (whether in the form of an ion-pair or of a highly polar molecule) is equally acceptable. In the reactions of acyl trifluoroacetates with cyclic acetals, selective attack of the reagent at certain sites of the acetal is interpreted by conformational analysis as discussed above. This interpretation represents the reaction as proceeding through attack of the acylium ion, with the implication that only this entity is capable of penetrating to the appropriate oxygen center. Conformational analysis, however, establishes which sites are most accessible to attack, without regard to the nature of the reagent. It is quite possible that a highly polar molecule could be the reacting agent and that this only undergoes heterolysis when within bond-forming distance of the reaction site. Such a species could not be acetyl trifluoroacetate alone, since this reagent has no capacity for opening any cyclic acetal rings under the usual conditions in the absence of trifluoroacetic acid.& There is thus a (64)P. H. Gore, Chem. Revs., 66, 229 (1955).

T.

84

Q. BONNER

strong likelihood that the conjugate acid of acetyl trifluoroacetate (or a species derived from it) is the acetylating agent when the acid is present. The difficulty of deciding between alternative reaction-intermediates with this type of reagent is evident from the analogous study of the cryoscopic behavior of acetic anhydride in anhydrous sulfuric acid. The discovery66 that the depression of freezing point corresponds to the formation of nearly four particles per mole of acetic anhydride led to an acceptable representation of the ionization as shown in equation 8. (CH&O)rO

+ 2 His04 + CHICO" + CHaCOOHa" + 2 HSO"

(8)

However, the results of other studies on this system suggested that quite different species are formed, and it has now been confirmed, by further that equation 8 is erroneous cryoscopic and conductivity and that the interaction taking place between acetic anhydride and sulfuric acid is that shown in equation 9. (CH&0)20

+ 3 HsSOI + 2 CHICOOH~"+ HSnOie + HSOP

(9)

Although this result does not constitute evidence against the occurrence of the acetyl ion as a reaction intermediate (since thie could be present in trace amounts in this and other acylating systems), it does transfer the onus of demonstrating the existence of this species in acetylation reactions to other, more sensitive, techniques. The method most likely to provide information concerning the nature of the reaction intermediates is that of detailed, kinetic analysis under a variety of carefully controlled conditions. It is evident that, in the application of this method, there is an extensive field of investigation to be surveyed, not only of the action of acyl trifluoroacetates on hydroxylic compounds under the infiuence of different media and catalysts, but also of the peculiar differences between the ring-opening reactions of cyclic acetals with this type of reagent and with that which is employed in the Hudson acetolysis procedure. (66) R. J. GiIlespie, J . Chem. 8m., 2997 (1960). (66) R. J. Gillespie and J. A. Leisten, Quart. Revs. (London), 8,40 (1964). (67) J. A. Leisten, J . Chem. ~ o c . 298 , (19%). (68) R. Flowers, R. J. Gilleepie and 9. Wasif, J . Chem. Soc., 607 (1966).

GLYCOSYL FLUORIDES AND AZIDES

BY FRITZMICHEELAND ALMUTHKLEMER* Organisch-Chemisches Institut der Universitdt, Milnater ,WestfaZen, Gemzany I. Introduction ............................................................ 11. Preparation of the Glycosyl Fluorides.. ................................. 111. Reactions of the Glycosyl Fluorides.. ................................... 1. Reactions Involving Participation. ................................... 2. Reactions Not Involving Participation. ............................... 3. Structure of the D-Fructose Moiety in Sucrose.. ...................... 4. Other Reactions.. .................................................... IV. The w-Fluoro Carbohydrates. ........................................... V. The Aldosyl &idea. .................................................... VI. Tables of Properties of Glycosyl Fluoride Derivatives ...................

85 88 88 89 92 93 93 95 95 97

I. INTRODUCTION In an earlier review’ of the glycosyl halides and their derivatives, the discussion of the fluoro compounds was necessarily limited by the restricted knowledge of these interesting compounds. Recent investigations have provided sufficient information to permit correlation of this rapidly expanding area of carbohydrate chemistry. The glycosyl fluorides and their derivatives occupy an exceptional position a~the result of the very high bond-energy of the carbon-fluorine linkage. Although the energy of the aliphatic carbon-fluorine bond is more than 50 % greater than that of any of the other aliphatic carbon-halogen bonds? the magnitudes of the bond energies for the various glycosyl halides are unknown. Certainly, the same relative order would be expected, but all the values should be lower. The experimental evidence so far obtained supports these expectations. Although the major portion of this review is concerned with the glycosyl fluorides and their derivatives, short Sections on the closely related glycosyl azides and on carbohydrates containing fluorine at non-glycosidic carbon atoms have been included. *The original German manuscript waa translated by Dr. Walter von Bebenburg and then revised by Mr. Alan Chaney of the Department of Chemistry of The Ohio State University, Columbus, Ohio. (1) L. J. Haynes and F. H. Newth, Advances i n Carbohydrate Chem.,10,207 (1965). (2) L. Pauling, “The Nature of the Chemical Bond,” Cornell University Press, Ithaca, N. Y., 2nd Edition, 1940, p. 53. 85

86

F. MICHEEL AND A . KLEMER

11. PREPARATION OF THE GLYCOSYL FLUORIDES The first acetylated glycosyl fluoride derivative was prepared by BraunsS in 1923 and, in subsequent papers, he explored the synthesis of a number of poly-0-acetylglycosyl fluoride^.^-^ I n addition, Brauns prepared the other poly-0-acetylglycosyl halides of the same carbohydrates and investigated the proportionality relations which exist between their optical rotations and the diameters of the respective halogen atoms.lO The method of synthesis employed in this early work involved the action of anhydrous, liquid hydrogen fluoride on the fully acetylated carbohydrate. In recent years, the process has been simplified by the usell of the anhydrous hydrogen fluoride commercially available, and by substitution1* of polyethylene equipment for the platinum vessels used earlier.8 This process should be capable of extension to carbohydrates with functions other than acetyl blocking the hydroxyl groups. However, only various partially methylated substances and the nitrogen-substituted (methyl, acctyl, and p-tolylsulfonyl) derivatives of 3,4,G-tri-O-acetyl-2-amino-2deoxy-D-glucose have been subjected to the reaction. Although reaction of the acetylated carbohydrates with hydrogen fluoride normally effects the desired replacement without complications, prolonged treatment sometimes causes deep-seated structural changes. Thus, octa-0-acetylcellobiose, after a reaction time of thirty minutes, gives a moderate yield of hepta-O-acet,ylcbellobiouyl fluoride,*,' but, after five hours, the major product is 3,6-di-0acetyl-4-0-(2,3,4,6-tetra-O-acetyl-P-D-glucosyl) -a-D-mannosyl fluoride.6 Prolonged treatment of penta-0-acetyl-P-D-fructopyranose with liquid hyfluoride.# drogen fluoride afforded 3,4,5-tri-0-acetyl-~-~-fructopyranosyl In the first example, both inversion and acetyl removal occurred a t the carbon atom adjacent to the potential reducing center, whereas, in the latter, only acetyl removal at the primary hydroxyl group was effected. The compounds prepared by this method are listed in the Tables. Examples of the newer methodsl'JY of synthesis will now be described. Hydrofluoric arid (50 ml., from a tank) is added to 20 g. of 1,2,3,4,6-penta-Oacetyl-a(or P-)-D-glucose cooled to -15" in a polyethylene flask. Thc acetatc dis(3) D. H . Brauns, J . A m . Chem. SOC.,46,833 (1923). (4) D. H. Brauns, J . A m . Chem. Soc., 46, 2381 (1923). (5) D. H. Brauns, J . A m . Chem. SOC.,46. 1484 (1924). (6) D. H. Brauns, J . A m . Chem. SOC.,48.2776 (1926). (7) D. H. Brauns, J . Am. Chem. Soc., 49, 3170 (1927). (8) D. H. Brauns, J . A m . Chem. Soc., 61, 1820 (1929). (9) D. H. Brauns and H. L. Frush, Bur. Standards J . Research, 6,449 (1931). (10) D. H. Brauns, Rec. Irau. chim., 69, 1175 (1950). (11) F. Micheel, A. Klemer, M. Nolte, H. Nordiek, L. Tork and H. Westermann, Chem. Ber., 90, 1612 (1957). (12) F. Micheel and H . Wulff, Chem. Ber., 89, 1521 (1956).

87

GLYCOSYL FLUORIDES AND AZIDES

solves in 2 to 3 min., and, after 20 min. at this temperature, the solution is kept a t room temperature for 10 min. The reaction mixture is then poured into a mixture of ice, water, and chloroform, and the organic layer is extracted with water several times. After drying the solution and evaporating the solvent, the product usually crystallizes. Recrystallization from hot ethanol gives pure 2,3,4,6-tetra-O-acetyla-D-glUCOSY1 fluoride (62%).

Most of the acetylated monosaccharides afford the more stable anomeric fluoride in this process.s However, the action" of a solution of hydrogen triacetate fluoride in acetic anhydride on 1,6-anhydro-p-~-glucopyranose (1) gave tetra-0-acetyl-P-D-glucopyranosyl fluoride (3). This result is prob-

ii

F

CHI-0-C-CH:

I

I

OAC

6AC

OAC

ably dependent on attack of the active species, acetyl fluoride, a t the anhydro-ring oxygen atom, as indicated. The intermediate structure [(2)] is hypothetical. The normal method of preparation of the less stable anomers of the acetylated glycosyl fluorides involves the action of silver fluoride on the acetylated glycosyl halide (bromide or chloride) of the opposite configuration a t the glycosidic carbon atom.13 Thus,'3 ti 50-g. sample of tetra-0-acetyl-a-D-glucosyl bromide in 150 ml. of dry acetonitrile containing 50 g. of anhydrous silver fluoride is shaken for 1 hr. The mixture is filtered and the filtrate is evaporated under diminished pressure a t a bath temperature of 3 5 O , with precautions to exclude moisture. The residue is dissolved in ether and cooled. Subsequently, crystallization is completed by the addition of petroleum ether. A 50 % yield of tetra-0-acetyl-P-D-glucopyranosyl fluoride is obtained.

Similar methods have been employed for the synthesis of the fluoride anomers of a number of variously substituted carbohydrate derivatives (see Tables), However, treatment of tri-0-acetyl-a-D-xylopyranosyl bro(13) B. Helferich and R. Gootz, Ber., 61, 2505 (1929). (14)F. Micheel, A. Klerner and R. Flitsch, Chem. Ber., 91, 663 (1958).

88

F. MICHEEL AND A. KLEMER

mide" and tri-0-acetyl-8-u-arabinopyranosyl bromide16 gave the acetylated glycosyl fluorides of the same configuration at the glycosidic carbon atom as that of the original bromides. Apparently, the unstable anomers, which are presumably formed a t first, readily isomerize to the more stable anomers. Unlike any of the other atetylated glycosyl halides, the fluorides may be deacetylated without loss or isomerization of the halide function. This unique reaction can be effected either with alcoholic ammonia17J8 or with a catalytic amount of sodium methoxide in alcoh01.~7J~ In some instances, however, depending on the concentration of base and on the configuration and type of substitution at the carbon atom next to the glycosidic center, side-reactions occur that lead to glycoside or anhydride structures.12.'4'1*'20

111. REACTIONS OF THE GLYCOSYL ~~'LUORIDES It R i of interest to note that, historically, the first chemical synthesis17 of a disaccharide, gentiobiose, involved the condensation of tetra-o-acetyla-D-glucopyranosyl bromide with 2,3,4-tri-O-benzoyl-a-~-glucopyranosyl fluoride. The resulting 8-0-(tetra-O-acetyl-8-D-glucopyraiiosyl)-tri-O-benzoyl-a-D-glucopyranosyl fluoride was saponified with methanolic ammonia, and the fluorine was removed by boiling with an aqueous suspension of calcium carbonate, to yield the free disaccharide (characterized as the 8-octaacetate). The procesees used in this synthesis are further discussed under the appropriate headings. When the halogen is fluorine, the usual methods' for the preparation of glycosides and oligosaccharides from the acetylated glycosyl halides (by reaction with hydroxylic compounds) are only successful in certain cases. The formation of a,/3-trehalosez1 may be cited as one of the few successful syntheses. However, with metal alkoxides, glycosides may be obtained having either the same or the opposite configuration at the glycosidic carhon atom. Frequently, internal glycosidation or anhydro-ring formatioii occur8 as a competing reaction; high concentrations of alkali favor this competition. In any event, the type of substitution Ltt the carbon atom adjacent to the carbon atom bearing the fluorine atom, and the Rputial relations of the groups involved, play dominant roles in the reactions of the glycosyl fluorides,12J4J*~20 The reactions may be divided into two types. (15) (16) (17) (18) (1960). (19) (20) (21)

H . Nordiek, Diplomarbeit, Miinster, 1964. A. Klemer and J. Ridder, Diplomarbeit, Muneter, 1958. B. Helferich, K . Bauerlein and F. Wiegand, Ann., 447, 27 (1926). F. Micheel and L. Tork, Diplomarbeit, Munster, 19M; Chem. Ber., 93. 1013 F. Micheel and A. Klemer, Chem. Ber., 86, 187 (195"). F. Micheel and E. Michaelis, C k m . Ber., 91, 188 (1958). V. E. Sharp and M. Stacey, J . Chem. Soc., 285 (1951).

89

QLYCOSYL FLUORIDES AND AZIDES

The first kind of reaction occurs when the substituent adjacent to the fluorine atom exists in a configurationally cis relation to it or contains no acidic hydrogen atom. The second and much faster type of reaction requires that the neighboring substituent exist in a configurationally trans relation to the fluorine atom and that it bear a removable hydrogen atom. In this latter circumstance, the reactions are believed to proceed through intermediates very similar to Brigl's anhydride,22 tri-O-acetyl-l , 2-anhydroa-D-glucopyranose, although such compounds have never actually been isolated from the reactions. Thus, the two types of reaction are those in which neighboring-group participation plays a role and those in which no participation can occur. 1. Reactions Involving Participation

If a hydroxyl group is situated trans to the glycosidic fluorine atom, a rapid reaction with sodium methoxide occurs, with elimination of hydrogen fluoride, as shown for the reaction14of 8-D-glucopyranosyl fluoride (4).The , was not isolated, depends on the confate of the intermediate [ ( 5 ) ] which centration of alkoxide. In dilute solution, methyl P-D-glucopyranoside (6) is formed, whereas, in concentrated solution, the product is 1,6-anhydroP-D-glucopyranose (7). If the C-6-hydroxyl group has been blocked with the triphenylmethyl group, methyl P-D-glucopyranoside is the sole product. NaOM in MeOH

bH (4)

a Coned. NaOMe

no

Ho

6H (6) (22) P. Brigl, 2.phy8iOl. Chem., 122,245 (1922).

90

F. MICHEEL AND A. KLEMER

Similar reactions have been observed with 8-D-galactopyranosyl fluoride2* and a-D-mannopyranosyl flu0ride.2~In this latter example, the epoxide ring in the supposed intermediate [(S)] would not be favorably located for internal-glycoside formation with the C-6-hydroxyl group ; the oiily observed product is methyl a-D-mannopyranoside (9).

0 CHzOH

HO OH

CC 8 11

(9) Depending on the alkoxide concentration, either the methyl 8-D-glucoside (12) or the anhydride (13) arises from 2-deoxy-2-p-toluenesulfonamidop-D-glucopyranosyl fluoride ( 10).l2,*O The presumed intermediate imine [(Il)] has not been isolated.

0

HO

HNT8

( 10)

Dilutr

HNT1

NoOMe MeOH in

-

FAT8

HO

“II)]

Concd.

HIITS

(13) (12) When the methanolic alkoxide is replaced by an aqueous solution of an inorganic base (preferably barium hydroxide), completely analogous reac(23) F. Micheel, A . Klemer, G . Baum, P. RistiE and F. Zumbulte, Chem. Ber., 88, 475 (1955). (24) F. Micheel and D. Borrmann, Dissertation, Miinster, 1960; Chem. Ber., 98, 1143 (1960).

91

GLYCOSYL FLUORIDES AND AZIDES

tions 0ccur.l9,*~ In dilute base, the free aldoses are formed preponderantly and, at higher concentrations, the anhydro glycosides result unless the C-6-hydroxyl group is blocked or is situated cis to the potential epoxide. Where internal-glycoside formation is possible, high yields of these compounds can be obtained by employing strongly basic ion-exchange resins.26 The action of aqueous base on a-D-mannopyranosyl fluoride (14) does since the epoxide internot afford any 1,6-anhydr0-/3-~-mannopyranoside, mediate (15) would be unfavorably situated with respect to the C-6-hydroxyl group. two disaccharides of the trehalose type are formed

1

Alkdi

CH2OH

obviously by reaction of the epoxide (15) with the anomeric I)-maniioses, (16) and (17), produced by hydrolysis. The disaccharides (18) and (19) are accompanied by polymeric D-mannans. The main products obtained, however, are nonreducing oligo- and poly-saccharides which, on the basis of their degradation with periodic acid, contain essentially linear (1 -+ 6)linkages. These linkages obviously arise by reaction of (15) with (18) and

(25) F. Micheel and

G. Baum, Chem. Ber., 88, 479 (1955).

92

F. MICHEEL AND A. KLEMElt

(191,

[a]+124"

(19). In a similar way, raffinose is transformed by (15) to oligo- and poly-

saccharide^.^^ 2. Reactions Not Involving Participation For the glycosyl fluorides, those reactions which do not involve participation are normally much slower than those which may proceed through cyclic intermediates (5, 8, 11, and 15). Two situations may force the glycosyl fluorides t,o react with bases without participation of the neighboring group. The C-2 function may be cis to the fluorine atom at C-1 or, if the relation is trans, may bear no removable proton. In the first case, typical reactions are the formation of the methyl 8-Dglucoside from a-D-glucopyranosyl fluorideI4 and of its 2-amino-2-deoxy on treatderivative from 2-amino-2-deoxy-cr-~-glucopyranosyl ment with sodium methoxide in methanol. The products from the reaction of aqueous bases with the glycosyl fluorides depend on the concentration of alkali. At low concentrations, the normal hydrolysis products are f ~ r m e d At . ~higher ~ ~ ~ concentrations ~ of base, if the proper (trans) steric relation exists between C-6 and the fluorine atom at C-1, anhydro compounds are formed,2a,za-za as in (21) from (20).

6)+ q CHg-0

HO

H

(20)

(21)

R = OH, NHTs or OMe and R ' = OH or R = R ' = OMe

In the second case, as with the 8-fluorides of 2-O-methyl-~-glucopyranose~4 and 2-deoxy-N-methyl-2-p-toluenesulfonamido-~-glucopyranose,26 the less readily obtainable methyl a-D-glycosides are produced, as in (23) from (22). (26) E. Michaelie, Diesertution, Miinster, 1959. (27) F. Micheel, A. Klemer and R. Flitsch, Chem. Ber., 91, 194 (1958). (28) C. Holthrtus, Diplomurbeit, Miinster, 1957.

QLYCOSYL FLUORIDES AND AZIDES

R = OMe

OT

93

CH~NTS

3. Structure of the D-Fructose Moiety in Sucrosc. Although the structure of the D-glucose moiety of sucrose had been established as a-~-gl~copyranosy1,2~ the only evidence for the structure of " the 1)-fructose moiety had been of a hiochemical n a t ~ r e . ~However, direct chemical proof31for the 0-wfructofuranosyl structure was obtained in 1958. The behaviorla of the anomeric 1-0-methyl-D-fructopyranosyl fluorides toward methoxide ion provides an independent proof of this structure. Thus, 1-0-methyl-p-D-fructopyranosyl fluoride (24), treated with methoxide ion (slow reaction) and then acetylated, affords methyl 3,4,5-tri-O-acetyl-l-O-methyl-a-u-fructopyranoside(25). Deacetylation with sodium methoxide results in the formation of methyl 1-0-methyl-a-ufructopyranoside (26).This slow replacement of fluorine by the methoxyl group requires that the fluorine be cis to the C-3-hydroxyl. In accord with this, 1-0-methyl-a-u-fructopyranosyl fluoride (27),having a trans situation, has been found to undergo a fast reaction with methoxide, affording the same methyl glycoside (26)on isolation through its acetate (25).These reactionsl8 establish the anomer (0-D) of negative rotation as (24),having the cis relation of the C-3-hydroxyl group to the fluorine atom; the other anomer (27)must be CY-Dand possess the trans relationship. Since the optical rotations of the D-fructopyranoses differ from those of the D-fructofuranoses in magnitude only (and never in sign), the anomeric configurations of the D-fructofuranoses are established. The /3 configuration derived in this way for the D-fructose moiety in sucrose coincides with the results of previous investigat~rs.~'JJ'

4. Other Reactions The aldosyl fluorides can react with pyridine to give pyridinium compounds.16The degree of reactivity depends on the steric arrangement of the glycosidic fluorine atom and on the nature of the substituent a t the ad(29) M. L. Wolfrom and F. Shafizadeh, J . O T ~Chem., . 21.88 (1956). (30) C. S. Hudson and C. B. Purves, J . Am. Chem. SOC.,69, 49 (1937). (31) R. U. Lemieux and J. P. Barrette, J . Am. Chem. SOC.,80,2243 (1958).

94

F. MICHEEL AND A. KLEMER

(-47

Ho I OH

(241,

OH

[&I -llOo

[a]+12.6"

(27X

r(G$Y] OH

dH

(261,

t34.1"

jacent carbon atom. Insufficient data have been accumulated to permit a general theoretical treatment. Pyridine containing pyridinium chloride reacts in the cold with @-D-glucopyranosylfluoride to give D-glucopyranosylpyridinium chloride (29, R = H, [CY]D+49.5"), but the same product results from the CY-Danomer on heating only. Both of the snomers of 2-0methyl-D-glucopyranosyl fluoride require heating with this reagent i n order to afford (2-0-methyl-~-glucopyranosyl)pyridinium chloride (29, R = Me, [CY]D +39.7").

(291, R =

H

or Me

GLYCOSYL FLUORIDES AND AZIDES

95

The lower reactivity of a-D-glucopyranosyl fluoride permits its etherification with triphenylmethyl chloride in pyridine without formation of the quaternary compound; the product is 6-O-trityl-cr-~-glucopyranosylfluoride." A similar process, leading, however, to the @-D anomer, can be carried out if a sterically hindered base, 2, 6-dimethylpyridine1 is used instead of the pyridine." Benzylidene acetals of the aldosyl fluorides can be prepared" by treatment with benzaldehyde-zinc chloride, if two suitably situated hydroxyl groups are present in the sugar derivative. This method has afforded 4,6-0benzylidene-P-D-glucopyranosyl fluoride.

IV. THEW-FLUORO CARBOHYDRATES and of 5-deoxy-5Several derivatives of 6-deoxy-6-fluoro-~-glucose~~ f l u o r o - ~ - r i b o s ehave ~ ~ * ~been ~ prepared (see Table 111). Because of the high strength of the carbon-fluorine bond12no displacement reactions of the fluorine atoms in these compounds are known. However, it has been reis strongly reported32that methyl 6-deoxy-6-fluoro-@-~-glucopyranoside ducing toward Fehling solution, in contrast with the behavior of the respective 6-chloro and 6-bromo compounds. The reaction of almond emulsin with a series of glycosides of 6-deoxy-6-fluoro-~-glucosehas been thoroughly inve~tigated.~~ The usual method for the synthesis of the u-fluoro aldoses is based on the displacement of a methylsulfonyloxy group by fluorine (supplied by either potassium fluoride or calcium fluoride). The reaction may be accomplished in aqueous methanol,32 ethylene or N , N-dimethylf ~ r m a m i d e employing ,~~ carbohydrate derivatives that have all the hydroxyl groups, except that to be replaced, blocked by groups stable to bases. The following example illustrates the synthetic meth0d.~2 Esterification of 3 ,5-O-benzylidene-l , 2-O-isopropylidene-c~-~-glucofuranose with pyridine and methanesulfonyl chloride in pyridine affords the 6-0-methylsulfonyl ester, which is treated with potassium fluoride (dihydrate) in methanol a t 100". Cleavage of the two acetal groups, with sulfuric acid in aqueous methanol, yields 6-deoxy-6-fluoro-~-glucose,which can be purified as the acetate. V. THEALDOSYL AZIDES The aldosyl azides resemble the aldosyl halides, especially the fluorides; this is to be expected from the similarities of hydrazoic acid and the halogen (32) B. Helferich and A. Gniichtel, Ber., 74, 1035 (1941). (33) N . F. Taylor and P. W. Kent, J . Chem. SOC.,872 (1958); P. W. Kent, A. Morris and N. F. Taylor, ibid., 298 (1960). (34) H. M. Kissmann and M. J. Weiss, J . A m . Chem. SOC.,80, 5559 (1959). (35) B. Helferich. S. Grunler and A. Gnuchtel, 2.physiol. Chem., 248,85 (1937).

96

F. MICHEEL AND A. KLEMER

acids. The aldosyl azides can be prepared easily by treating the readily available poly-0-acetylaldosyl halides with sodium azide or silver azide, the resulting displacement react ion usually produring an inverted configuration a t the glycosidic carbon atom. The first poly-0-acetylaldosyl azide was synthesized by I 3 ~ r t h ohy ~~ treating tetra-0-acetyl-a-u-glucopyranosylbromide with a metal azide. I n addition to the aldosyl azide derivatives that are k n o w (see Table IV), derivatives of 2-aniin0-2-deoxy-~-glucosylazide have been prepared" ,x7 (see Table V ) . If the trans hydroxyl group a t C-2 is not ncetylated, an iutermediate epoxide of the type suggested for the aldosyl fluorides call form, and the azide obtained has the same anonieric coilfiguration as thc original halide, as shown by the formulas. The acetylated azides, like the

cT - cko-T r CH,OAc

AgN,

ACO

AcO

WOH

H

acetylated fluorides, can be saponified withou 1 loss of the azide function.12* 2 3 , 3 8 3 8 The aldosyl azides obtained are much more stable thari the aldosyl fluorides and have not as yet been converted to glycosides. With conceritrated alkali, aldosyl azides having the proper steric arrangement (the C-2-hydroxyl group trans to both the azide group and the C-G group) react ' (like the corresponding fluorides) to produce the stable anhydro dcmvat i ~ e s . 2The ~ conversion of 8-D-glucopyranosylazide (30) to 1,6-anhydro-P-uglucopyranose (7) is illustrated.

..%y' - HgAq .I;;;

__c

H

(30)

CC511

(71

Reduction of the acetylated aldosyl azides afford~"~-~O the corresponding acetylated aldosylamines, as exemplified by the preparation*' of t ri-0acetyl-2-amino-2-deoxy-~-~-g~ucopyranosy~am~ne (31 -+ 33). A. Bertho (with H. Nussel), Ber., 88, 836 (1930). A. Bertho and A. RBvBss, Ann., 681, 161 (1953). A. Bertho (with M. Bentler), Ann., 661, 229 (1949). A. Bertho and J. Maier, Ann., 498, 50 (1932). (40) A. Bertho and D. Aures, Ann., 692, 54 (1955). (36) (37) (38) (39)

GLYCOSYL FLUORIDES AND AZIDES

97

Analogous to the reaction of other azides with acetylene and its derivatives to produce trinzoles, tetra-O-acet,yl-p-u-glucopyranosyl azide (34) reacts with phenylacetyle~ie.~~ Although the linear azide group might, permit addition in two ways to give either the 4-or the 5-phenyltriazole ring, only a single product, results. On the basis of theoretical con~iderations,~~ the preferred structure for this substance is 4-phenyl-1- (tetra-O-acetyl-p-r,glucopyranosyl) triazole (35).

OAC

(34)

Ac

(35)

VI. TABLES OF PROPERTIES OF GLYCOSYL FLUORIDE DERIVATIVES The five tables record the properties of the glycosyl fluoride derivatives. The refererice~~?-6~ not given in the text,, but cited in the Tables, are collected here. (41) (42) (43) (44) (45) (46) (47) (48) (49) (50) (51)

F. Micheel and G. Baum, Chem. Ber., 90, 1595 (1957). F. Micheel and J. Reinbold, Dissertation, Munster, 1960. F. Micheel and H. Westermann, Dissertation, Munster, 1958. B. Helferich and H. Bredereck, Ber., 60, 1995 (1927). F. Micheel and H. Kochling, Dissertation, Munster, 1960. F. Micheel and El Baya, unpublished work. F. Micheel and D. Bartling, Diplomarbeit, Munster, 1953. F. Micheel and G. Baum, Dissertation, Munster, 1956. B. Helferich and M. Vock, Ber., 74, 1807 (1941). B. Helferich and 0. Peters, Ann., 494, 101 (1932). D. H. Brauns, Bur. Standards J . Research, 7, 573 (1931).

TABLEI Properties of Some Gl ycos yl Fluoride Derivatives

W

00

Fluoride 8-D-Arabinopyranosyl t ri -0-acet yl 8-L-Arabinopyranosyl, tri4-acetyla-Cellobiosyl, hepta4-acetyl8-Cellobiosyl hepta-0 -acetyla-D-Fructopyranosyl 1-0-methyltri -0-acet yl 8-~-Fructopyranosyl 14-methyltri-0-acetyltetra-0-acetyl3,4,5-tri-O-acetyltri-0-acetyl-34-methylB-D-Galactopyranosyl tetra-0-acetyla-Gentiobiosyl hepta-0-acetyl2',3', 4',6'-tetra-O-acetyl2,3,4-tri-O-benzoyla-D-Glucopyranosyl 6-bromo-6-deoxytri -0-acet yl 6-chloro-6-deoxytri-0-aeetyl2,3-di-O-methyldi-0-acetyl-

ROrorion sdneni

Melting point, "C.

EtOH EtOH HzO EtOH (amorph.) CHClr/Et 00 amorph . EtOH EtOH EtOH Et &/Pe t .* EtOH-EtzO EttO ?

EtOH EtzO MeOH MeOH EtOH MeOH/Et20 EtOH MeZCHOH MeOH/Et 20 CHCla/Pet EtOH/Et 2 0 .O

95-96 (dee.) 115 117-118 187

-182 -140 +138.2 +30.6

+7 173

-4

20 20

m

20

H2 0 CHCli CHCla CHCl: MeOH CHClg

References

16 16 5

3,6

23

23

ctl

?:

54-56

110-119 (dec.) 102-109 (dec.) 94 112 134-135 113-114 110-118 (dec.) 98-99 215-220 (dec.) 168-169 195-196 118-125 (dec.) 131 (dec.) 149 138 (dec.) 151-152 105-108 b.p. 114-116 (0.oOPmm.)

-12.6 +52.9 -119 -110 -116 -90.4

-128.8 -88.7

+a +n

+33.5

+43.8 +I5 +96.7 +82 +I04 +88.8

+107 +94

+60

20 20 20 20 20 19 18 20 20 23 18

20 20 20 20

HzO CHCla HIO HtO CHCla

ma: CHCla CHClr H20 MeOH HIO CHCl,

18 18 11 18 9 4, 9 9 9 23 23 17 7

CHClr H to HtO CHClr HR CHC13 0 H2

17 17, 50

EtOH

27

11 11

44 44 27

i;

B M

P 9 1:

W

9

PM k2 P

~

2-0-methyltri-0-acetyltetra-0-acetyltetra-0-benzoyl2,3,6-tri-C-methyl4-0-acetyl6-0-trityltri-0-acetyltri-0-bensoyl6-D-Glucopyranosyl 4,6-0-benzylidene6-bromo-6-deoxytri-0-acetyl2,3-di-0-benzyldi-0-acetyl2-0-methyltri-0-acetyltetra-o-acetyl6-0-trityltri-0-acetyla-D-Mannopyranosyl tetra-o-acetyla-D-Xylopyranosyl tri-0-acetyl4-0- (6-D-Glucopyranosyl)a-D-mannosyl hepta-o-acetyl3,6,2’,3’,4‘,6’-hexa-O-acetyl a-Lactosyl a-Ma1tosyl, hepta-o-acetyla -Melibiosyl , hepta -0-acet ylPet. = petroleum ether.

EtOH EtOH EtOH E t zO/Pet.a Etz0 Pet MetCO/Pet .a EtOH (amorph.) EtOH/Et 2 0 EtzO EtOH MeZCHOH EtzO/Pet.‘ (sirup) EtOH/Et SO EtrO EttO CHC1a/Pet.a MesCHOH EtOH

115 (dec.) 77-79 108 110-1 12 56- 57 42 135-140 (dec.) 147-148 99-102 (dec.) 156 (dec.) 11CL112 (dec.) 99 112-114

EtzO MezCHOH EtOH

108-112 (dec.) 73-75 98 70-80 123 96-97 114 (dec.) 68-69 105 (dec.) 87

MeOH MeOH HzO/MeOH EtOH MeOH/H20

155-156 145 180-195 (dec.) 174-175 135

+99.7 +I16 +W.l +110 +70.5 +77.2 +58.4 +119.6 75 +25 -74.5 -36 +35 +36 +8.6 +I1

I

+

20 20

20

+25

22 21 18

+58 +21.9 +17.9 +17.9 +16.1 +21.5 +76 +67.2

22 14 20 18 22 20

20

Hz 0 CHCla CHCla CsHsN CHCla CHCla CIH~N C sH sN CsHsN H ZO CsHsN dioxane H9 0 CHC13 CHCla CHCla H SO CHCla CHC13 CsHsN CsHsN

28 28 3 17 46 46 17 17 17 13, 19 11 11 11

11 42 42 14 14 13, 21 11 43

cc

d

4 l? crl

F

2

Ee3

P

z

tr P

I

H SO CHClr EtOH CHCla

24 51 11 3

CHCla CHCla CHCl a CHCI, CHCla

6 6 13 8 8

E c

e3

I

+13.6

20

+20.8

20 16 20 20

+83.2 +111.1 +149.7

co co

TABLE I1 Properties of Some i-Amino-d-deozr-D-alucosul Flwn'des Melling point, "C.

2-Amino-~-deoxy-a-~-~ucopyrsnosyl N-acetyl-

t ri -0-acet yl N-tosylM -methylt ri -0-acetyltri-0-acetyltri-0-acetyl-N-benzoyl2-~ino-2-deoxy-~-~-glucopyranosyl N-methyl-N-tosyltri-0-acetyltri-0-acetyl-N-tosyl-

' a ] D , degrees

Rolatimr SOlVd

Refcrnrcw

?

z

i;

z

Me&HOH/EttO EtOAc HtO Me&O/C6H MeOH MeOH MeOH MeOH MeOH EtOAc/Pet.

6

161.5-162 (dec.)

+96

186-187 (dec.) 136 (dec.) 83 117-118 146-147 lG4

+54.4 +55.5 +56 +62.8 +66 +lo7

148-150 147-118 147-148

-6.2 +6.9 +2

EtOH/dioxane CHClr MeOH MeOH CHClr CHCl 8 CHCla MeOH CHCls CHCla

12,47

12,47 20 20 20

m

45

20 20 12

m

m

20 ?

Pm z

m

::

TABLE I11 Properties of Some w-Fluoro Alddse Derivatives Compound

Crystallization SOlFent

Potation temp., "C.

Mdting point, "C.

Rotation solvent

Referentes

-

6-Deoxy-6-fluoroa-D-galactopyranose 1,2:3,4-di-O-isopropylidene-

MeOH/Et 2O

methyl pyranoside 6-Deoxy-6-fluoroa-D-glucofuranose, 1,20-isopropylidene acetal 3,5-O-benzylidene 3,5-di-O-acetyl3,5-di-O-mesyl6-Deoxy-6-fluoroa-D-glucopyranose methyl glycoside 2,3,4-tri-O-mesylG-Deoxy-G-fluoro-8-n-glucopyranoside phenyl triacetate vanillyl triacetate Tetra-0-acetyl-6-deoxy-6-fluoro-D-glucopyranose Tri-0-acetyl-6-deoxy-6-fluoroa-D-glucopyranosyl bromide 5-Deoxy-5-fluoro-p-~-ribofuranose methyl glycoside, 2,3-O-isopropylidene acetal tri-0-acetyl-

hfe2CO/Et20

-135 +7i lG0 b.p. 7&72O (0.015 -51.4 mm.) 139 +I94 -+

20 20

H2 0 CHCl3

33 33

20

H2 0

33

MeOH MeOH/H20 EtOH EtOH CHCla/Pet. MeOH

104- 105 112 109 155 109-110 133-131

+I4 +23 -24.5 -86 -+ +4i +43 +93

21 20 20 19 21 22

C6H6 CHClr CHCla 0 H2 H2 0 C 5H 5N

32,33 49 49 32, 49 33 32

H2 0 EtOH H2 0 EtOH EtOH

148-119 167-168 181-182 1%-167 125-126

-79 -82

21 19 19 20 19

H $0 CHClr CsHSN CHCla CsHjN

32 32 32 32 32

CHCIa/Pet.

127-1 28

+234

21

CHCls

32

b.p. 32O (0.025 mm.)

-92

20

CHCl3

33, 34

100-101 (subl.)

-26.8

25

CHCli

34

EtzO

-48.6 -35.7 +20

TABLEIV Properties of Some Glycosyl Azides Melting point, "C.

a-L-Arabinopyranosyl, tri-0-acetyl&Cellobiosyl, hepta-o-acetyl6-D-Galactopyranosyl tet ro-0-acetyla-D-Glucopyranosyl tetra-0-acetyl3,4,6-tri-O-acetyl2-0- (trichloroacetyl) @-D-Glucopyranosyl tetra-0-acetyl3,4,6-tri-O-acetyltri-O-acetyl-6-bromo-6-deoxy8-Maltosyl, hepta-o-acetyl8-D-Xylopyranosyl, tri-0-acetyl-

MeOH/H *O MeOH MeOH EttO/Pet. Et,O/Pet. Me&O/EtOH n-C sH 1i0H EtOH/MeOH EteO/Pet. MeOH MeOH/HsO MeOH/HzO

[CI~D,

degrees

"C.

88-89 182-182.5 152 96

-11.0 -30.9

106.5 66 139.5 89 129 (dec.)

+I80 +223.1 +145.7 -29.6 -33.0 -13.7 -15.2

155 137-138 (dec.) 91 87.5

'2o.ktion temp.,

20 16

+8.5

-16.2

+53

-79.3

20 18 19.5 19 20 19 18 23

18 16

Rotation solvent

References

'tl

5

CHCla CHCla HZ0 CHCla

38 38

c1

48

F

CHClt CHClz CHCla HeO CHCla CHCla CHC13 CHCli CHCI,

40 40 40 23,36 36 40 36 38 38

39

z

M

m

*2: tr

?

P

E

3

TABLE V Properties of Some 2-Amino-2-deozy-8-D-glucopyranosyl Azides 2-A mino-2-deoxy-B-D-glzopyranosyl az&

Unsubstituted N -acetylN 4sopropylidene3,4,6-tri-O-acetylN-acetylN-anisylideneN -p-nitrobenzylideneN -salicylidene-

crystallizalion

solvent

amorph. EtOH/Et 2 0 Me 2CO/H 2O EtOH EtOAc/Pet. MeOH MeOH MeOH

Mdting point, "c.

142 166-167 123 160-161 (dec.) 134 102 95

1

[a]D,degrees

-58.6 -30 -53 -11.5

-43

1 1 ygLy Rotation te;?,

20 20 20 20 20

-

Hz0 HzO H20 CHClr CHCla

-

References

12 12 12 37 12 37 37 37

k.

This Page Intentionally Left Blank

THE “DIALDEHYDES” FROM THE PERIODATE OXIDATION OF CARBOHYDRATES

BY R. D. GUTHRIE Shirley Instilute, Manchester, England* . . . . . . .................... ............ I. Introduction . . . . . . . . . . . . . . . . 11. Nomenclature . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 111. General Properties of the Oxidation Products, . . . . . . . . . . . . . . . . . . . . , . . . . IV. Oxidation Products from Monosaccharide Derivatives and Related Compounds . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1. Introduction.. . . . . . . , . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2. Oxidation Products Forming Hemialdals , , . . . . . . . . . . . . . . , . . . . . , , . . . . 3. Oxidation Products Forming Internal Hemiacetals. . . . . . . . . . . . . . . . . . . 4. Reactions of Non-carbohydrate Analogs., . , . . . . . . . . . . . . . . . . . . . . . . . . . V. Oxidation Productasfrom Di-, Tri-, and Oligo-saccharides . . . . . . . . , , . . . . 1. Introduction.. . . , . , , , . . . . . . . . . . . . . , , . . . . . . , . . . . . . . . . . . . . . . . . . . . , . . . . 2. From Sucrose.. . . . . . 3. From Other Disacch heir Derivatives.. . . . . . . . . . . . , . , . . . . ......................... 4. From Tri- and OligoVI. Oxidation Products ......................... 1. Introduction.. . . . . . . . . . . . 2. From Starch . . . . . . _ _ _. ... . . . . . . . _, _ ., . , . . _ ., . . . . . . . . . . . . . . . . . . . . 3. From Cellulose. . 4. From Xylan. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5. From Other Polysaccharides . . . . . . . . . . . . . . . VII. Alkaline Degradation of Periodate-oxidized Carbohydrates VIII. Uses of Periodate-oxidized Carbohydrates.. , . , . . . . . . . . . . . . . . . . . . . . . . . . .

105 106 108 108 108 109 123 132 134 134 134 135 137 137 137 140 146 152 153 153 157

I. INTRODUCTION The splitting of a-glycol groups by periodate was discovered by Malapradcl-*in 1928, and the reaction has since found wide application. Icrom a n acyclic glycol, the products of the reaction are two carbonyl compounds; an a ,w-dicarhonyl compound results from a cyclic glycol. The Rl RLoH

I

It’

R1

(5

R =O RC=O

I

R*

* Present address: Cheniistry Department, The University, Leicesler, England. (1) L. Malaprade, Compt. rend., 186,382 (1928). (2) L. Malaprade, Bull. soc. china. (France), 43, 683 (1928).

105

106

R. D. GUTHRIE

carbonyl compounds are usually aldehydes, because carbohydrate oxidations generally involve secondary hydroxyl groups (R = H). Periodate will also cleave an a-amino alcohol group, to give the same product as thc corresponding a-diol; as the former group does not occur widely in carhohydrate chemistry, the products discussed are nearly all derived from a-diols. Periodate oxidation has found its main use as an analytical tool for the detection of a-glycol groups, especially in polysaccharide chemistry. Only in the last decade has any real study been made of the reaction products. This situation is probably attributable to several factors: (a) the alleged instability of the products, (b) the use by Jackson and Hudson in the late 1930’s of the acids prepared by further oxidation (see later for detailed references), and (c) the lack of knowledge of aliphatic and other dialdehydes, of which no systematic study has yet been made. Other aspects of the reaction, such as experimental conditions, stereochemical effects, mechanism, and analytical applications, will not be discussed, as these have been reviewed elsewhere.*-6The structure and reactions of the oxidation products have been reviewed previously, but only The application of the formazan reaction to periodate-oxidized carbohydrate derivatives has been reviewed.’ Throughout this review, “oxidation product(s) ” refers to that from periodate oxidation, unless otherwise stated. This review will be limited to a discussion of the structures and reactions of the aldehydes obtained from oxidation of cyclic carbohydrate derivatives. Such products as that from the oxidation of 1,2-O-isopropylideneu-glucofuranose, which is a monoaldehyde, will not be dealt with. A monosaccharide derivative will normally give rise to a dialdchyde, a disaccharide derivative to two dialdehyde units linked together (or a tetra-aldehyde) , and a polysaccharide will give a dialdehyde polymer (a polyaldehyde). All of these classes of compounds will be discussed. The same aldehydic products may be obtained, in some cases, by oxidation with lead tetraacetak? although this procedure has not been so widcly used as periodate oxidation in carbohydrate chemistry. 11. NOMENCLATURE

A hemialdal group9 is formed by the addition of the elements of a molecule of water across two aldehyde groups; these groups are usually, but (3) E. L. Jackson, Org. Reactions, 2, 341 (1944). (4) J. R. Dyer, Methods of Biochem. Anal., 3, 111 (1956). (5) J. M. Bobbitt, Advances in Carbohydrate Chem., 11, 1 (1956). (6) I(. Takiura and K. Koizumi, Yakugaku Kenkyu, 30, 809 (1958). (7) L. Meeter, Advances i n Carbohydrate Chem., 13, 105 (1958). (8) A. S. Perlin, Advances in Carbohydrate Chem., 14, 1 (1959). (9) V. C. Barry and P. W. D. Mitchell, J . Chem. Soc., 3631 (1953).

PERIODATE-OXIDIZED CARBOHYDRATES

107

H

rc=o

+Ha0

Lc=0 H

-n,o

rCHOH

\

I

0 I LCifoH

Hemialdal

not necessarily, in the same molecule. The hemialdal and the dialdehyde will be in equilibrium in water. In this review, the term dialdehyde methanolale1° will define the group resulting from the addition of a molecule of methanol across two aldehyde groups in the same molecule. These forms will be in equilibrium as above. The name dialdehyde methanolate does H p = 0 I I L C = 0 H

+ MeOH

A

or

P

- MeOH

Dialdehyde methanolate

not imply methanol of crystallizat,ion. Similar dialdehyde alcoholates could be made with other alcohols. The oxidation products and their derivatives, which generally exist in cyclic forms, cannot be named by the usual rules of carbohydrate nomenclature. For example, the cyclic form of the oxidation product (I) from

CH,OH--

(2)

( 1)

methyl 4 ,6-O-benzylidene-a-~-glucoside is namedl0 7,O-dihydroxy-kmethoxy-2-phenyl-trans-m-dioxano-[5,4-e][ 1,4]-dioxepan; the oxidation product (2)from methyl a-L-rhamnoside is named” 3,5-dihydroxy-2-~”methoxy-6-~”-methyldioxane. I n view of the difficulty for the reader to become familiar with new nomenclatures, the oxidation products will be referred to as “the oxidation product from. .,” or “the polyaldehyde from . . .,” and so on. The original paper may give the systematic name for any particular oxidation product. However, where the unoxidized compound is described by one trivial name (for example, sucrose; or cellulose), the

.

(10)R. D.Guthrie and J. Honeyman, J . Chem. Soc., 2441 (1959). (11) I. J. Goldstein, B. A. Lewis and F. Smith, J . A m . Chem. Soc., 80,939 (1958).

108

R. D. QUTIIRIE

periodate-oxidation product will bc denoted by using the prefix (‘oxy,’’ as in oxysucrose and oxycellulose. Should the compound be oxidized by some oxidant other than periodatc, that oxidant will precede thc namc, as in sodium dichromate oxycellulosc.

111. GENERALPROPERTIES OF THE OXIDATION 1’RODUCTS No product from the oxidation of a cyclic carbohydrate derivative has yet been isolated directly as the free dialdehyde, all being found as hemialdals or as internal hemiacetals, although the dialdehydes or their derivatives may be obtained from the oxidation products. Some of the oxidation products are crystalline, although many are sirups. The infrarcd absorption spectra of niost oxidation products show little or no carbonyl absorptiori, even those in which (from chemical react,ions) there is apparently a frw aldehyde group. Other physical methods yield similar results. Because the oxidation products exist in complex, cyclic forms, they display mutarotation in such solvents as water, pyridine, and alcohols1*;these mutarotation8 suggest that, in solution, equilibria occur between various forms. Early workers often sought one definite structure for a particular product, and results from different reactions gave different answers. The formation of cyclic forms of the oxidation products is interesting conformatZionally, although few authors have considered the products from this point of view. The main reactions studied have been oxidation to the corresponding acids, reduction to the corresponding polyhydric alcohol, or partial reduction to an intermediate “aldehyde-alcohol” ; reaction with nitrogenous bases has been studied, and also the reaction of the products wit,h alkylating and acylating reagents. Many of the oxidation products are extremcly labile to alkali, and this has been a wide field of study, particularly with the oxidation products from polysaccharides. The oxidation products will be divided into classes, and dealt with compound by compound, except for the reaction with alkali, which will be discussed separately. IV. OXIDATIONPRODUCT^ FROM MONOSACCHARIDE DERIVATIVES AND RELATED COMPOUNDS 1. Introduction

T o yield a “dialdehyde” on periodate oxidation, a monosaccharide derivative must be held in a ring form by suitable substituents. The oxidation products can be divided into two classes: those which generally do not contain hydroxyl groups elsewhere in the molecule, and form hemialdals, for example (3), and those which can form internal hemiacetals with a hydroxyl group elsewhere in the molecule, for example (4);the latter class (12) I. J. Coldstein, B. A. Lewis and F. Smith, Chem. & Ind. (London), 596 (1958).

PERIODATE-OXIDIZED CARBOHYDRATES

109

(3)

F)oMe k,))

O=CH

O=CH

e

O=CH

CH,OH Me

may, of course, form hemialdals as well. These two classes of products will be dealt with separately. Oxidation destroys the asymmetry of the sugar molecule and, consequently, the same oxidation products may be obtained from the same derivative of several diflerent sugars. For example, oxidation of any methyl a-D-pentopyranoside would yield (3) as the product.

2. Oxidation Products Forming Hemialdals a. From N ,N’-Dibenzoylstreptamine ( 5 )P-In structural work on streptomycin, the streptamine derivative ( 5 ) was oxidized with periodate and yielded a crystalline “dialdehyde monohydrate,” which gave a triacetate. The cyclic hemialdal structure (6b) was, hence, proposed for this oxidation product which, on oxidation with bromine water, gave the di(benzamid0)hydroxyglutaric acid (7), derived from the dialdehyde (6a). This was the first instance of a hemialdal structure’s being proposed for an oxidattion product of this type. b. From Methyl 6-Deoxyaldohexopyranosides.-Jackson and HudsonI4 noted that the crystalline oxidation product from methyl a-L-rhamnopyranoside has an analysis corresponding to that calculated for a dialdehyde monohydrate. Later work16 showed that several methyl 6-deoxyaldohexopyranosides give crystalline dialdehyde monohydrates. It was noted that the products could be sublimed a t 65” in vacuo over Anhydrone, without (13) H. E. Carter, R. K. Clark, Jr., S. R. Dickman, Y. H . Loo, P. S. Skell and W. A. Strong, Science, 103, 540 (1946). (14) E. L. Jackson and C. S. Hudson, J . A m . Chem. SOC.,69, 994 (1937). (15) W. D. Maclay, R. M. Hann and C. S. Hudson, J . Am. Chem. SOC.,61, 1660 (1939).

R. D. CiUTHRIE

110

=:OT HO

OH NHBZ

]H,O

O=

H

NHBz

OH

*

triacetate

COJi

loss of water; the water was, therefore, assigned as water of constitution although no structure was proposed for the products. The dialdehyde monohydrate from methyl cu-L-rhamnopyranoside has been shownll to possess the hemialdal structure (8) since it forms a di-pnitrobenzoate, and methylation with methyl iodide and silver oxide introduces two more methoxyl groups. Also, the dialdehyde monohydrate, and its enantiornorph,l6 show no infrared carbonyl absorption, but show hyMe

Me0 (8 )

(9)

droxyl absorption. The conformation shown in (8) has been suggested for this oxidation product,11which is not reduced by hydrogen in the presence of a palladium-charcoal catalyst, behavior characteristic of the hemialdal group.17J8It is, however, reduced, either with hydrogen and a Raney nickel catalyst or with sodium borohydride, to the corresponding diprimary al(16) D. Walters, J. D. Dutcher and 0. Wintersteiner, J . A m . Chem. Soc., 79, 5076 (1957). (17) J. E. Cadotte, G . G . S. Dutton, I. J . Goldstein, B. A. Lewis, J. W. Van Cleve and F. Smith, Abslracts Papers Am. Chem. sbc., 119, 5D (1956). (18) J. E. Cadotte, G . G . S. Dutton, I. J. Goldstein, B. A. Lewis, F. Smith and J. W. Van Cleve, J . A m . Chem. SOC.,79, 691 (1957).

111

PERIODATE-OXIDIZED CARBOHYDRATES

coho1 (9).I8 Oxidation of the periodate-oxidized methyl 6-deoxyaldohexopyranosides gave the corresponding dicarboxylic acids, isolated as their strontium or barium ~a1ts.I~ c. From Methyl 4 ,6-O-Alkylidene- and -Arylidene-D-g1ycosides.-The most completely studied compound in the group of, compounds forming hemialdals is the crystalline oxidation product from methyl 4,6-O-benzylidene-a-D-glucoside. This has been shown to be a dialdehyde dihydrate,10J2. 20-B for which the hydrated dialdehyde structure (10) was proposed,20 as there is hydroxyl absorption but no carbonyl absorption in its infrared spectrum. Recrystallization of the dialdehyde dihydrate from nitromethane10*22 or from dimethyl sulfoxide12 showed that one molecule of water was water of constitution, and the other, of hydration. One molecule of Reaction of water per molecule was also removed by drying in u(1cu0.~~ either the dialdehyde mono- or di-hydrate with acetic anhydride in pyridinelo gave the Same diacetate, showing that the original compounds sz2

PrCH2 \

PhCH0(-')OMe CH ,C,H Hd 'OH HO OH

(10)

0-CH,

ph(

(t)

0

/

CH I OH

\:Me

I

OH

(11)

were a hemialdal (11) and its hydrate; similar results were obtained by use of other acylating or alkylating reagents.10J2*22s28Attempts to prepare sulfonates of (11) gave only unchanged compound.1° Sublimation of the hemialdal hydrate in vucuo gave the crystalline, free dialdehyde, which had intense carbonyl absorptionI2; exposure to a moist atmosphere regenerated the hemialdal hydrate. The latter compound reduces Fehling solution, but does not restore the color to Schiff reagent,"Je22showing that a hemialdal group is chemically similar to a hemiacetal. The formation of the hemialdal (11) has been presumed to occur by hydration of one aldehyde group followed by ring closure,"Js22 as follows. Such a system allows for the possible formation of four isomers, although (19) M. Abdel-Akher, J. E. Cadotte, R. Montgomery, F. Smith, J. W. Van Cleve and B . A. Lewis, Nature, 171, 474 (1953). (20) J. W. Rowen, F . H. Forziatti and R . E. Reeves, J . A m . Chem. SOC.,73,4484 (1951). (21) J. Baddiley, J. G. Buchanan and L. Szabo, J . Chem. Soc., 3826 (1954). (22) R. D. Guthrie and J. Honeyman, Chem. & Znd. (London), 388 (1958). (23) I. J. Goldstein, B . A. Lewis and F. Smith, Abstracts Papers A m . Chem. Soc., 131, 17D (1957).

112

--

\

&CH

--

R. D. QUTHRIE ,

/ HC=O

\/OH/

&O

HC

HC=O

\OH

\ A ,’ CH

b

I

--‘a

\Ho\

/’

CH Le-O=CH ,,CH bH HO’

(11)

the crystalline product will presumably have that conformation having the two hydroxyl groups in the plane of the ring; also, the above scheme shows the free dialdehyde in equilibrium with the hemialdal in solution. The hemialdal and its hydrate showed complex mutarotation in pyridine.1° ,2z Dissolution of the hemialdal (11) or its hydrate in hot methanol, concentration, and cooling gtive a different derivative, whose analysis correRponded to that calculated for a dialdehyde methanolate.10~~ This derivative gave the @me methylation product as that from the hemialdal, but acetylation introduced only one ester group. Recrystallization of the methanolate from water gave the hemialdal hydrate, in contrast to the behavior of the fully methylated derivative, which was quite stable to boiling water. O-CHz

pl,cQ\) 0

c
\ CH,OH

CH

H d \OH

H/f&

HPoH

(148)G.Jayme, M.Siitre and 9. Maria, Nalum'ssenschaften, 29, 768 (1941). (149)G.F. Davidson, J . Tcztile Inst., 31, T81 (1940). (150)F.S. H.Head, Nature, 166,236 (1960);J . Textile Inst., 44, T209 (1953). (151)T.P.Nevell, J . Teztile Inet., 47, T287 (1956). (152) I. N . Ermolenko, R. C. Zhbandkov, V. I. Ivanov, I. Y. Lenshina and V. 8. Ivanova, Zzvest. Akad. Nauk S.S.S.R.Oldel. Khim. Nauk, 249 (1958);Chem. Abstracls, 62, 11408 (1958).

PERIODATE-OXIDIZED CARBOHYDRATES

147

at the primary alcohol group was cited,l= although no mention of it was made in later work.166It was claimed166that a band at 10.99~was connected with a hemiacetal group, and that its intensity was proportional to the D.O. The most thorough studies have been those of Higgins and McKenzielMand Spedding.lS6Both groups of workers showed that the intensity of the 5 . 7 8 ~(carbonyl) band was dependent on the D.O. and on the moisture content of the sample; this band increased from a weak shoulder at low D.O. to a distinct peak a t high D.O. Drying of oxycellulose filmsls6 caused a large increase in carbonyl intensity, first, with a decrease in the adsorbed water band, and, later, with this band at a minimum. This behavior was largely reversible and suggested the presence of two different sorts of dehydratable groups. The hydroxyl-group absorption had an intensity in the oxycellulose spectra lower than that of the cellulose spectra. This evidence led to the that oxycellulose contained about 70 % of its aldehyde groups as hemialdals and the remainder as hemiacetals or hydrated aldehydes. Higgins and M ~ K e n z i eshowed l ~ ~ that a band assigned to the primary alcohol group (at 9 . 5 2 ~ )disappears at very high D.O.; this was attributed to cycliation or oxidation. No clear evidence was found for the presence of hemiacetal groups. It was also shown’” that no band appeared at 5 . 8 ~until a D.O. of 20% was reached; since it was thought that all the aldehyde groups were masked, this absorption was assigned to carboxyl groups. I n view of the work described above, this conclusion is most unlikely. It has been shown, from x-ray ~tudies,~O~ that periodate attacks both the amorphous and the crystalline regions. Oxycelluloses are more hygroscopic than c e l l u l ~ s e . ~ ~ ~ J ~ ~ The reaction of oxycelluloses with hydroxylamine hydrochloride and determination of the freed acid, or of the nitrogen content of the product, has been used as a measure of the aldehyde content.’28Other methods for this determination are reduction with sodium borohydridelMor oxidation with chlorous Strole160has compared the hydroxylamine and borohydride methods and has shown that they give similar results. Oxidation with alkaline hypoiodite is not reliable for aldehyde-content determinations be(153) R. T. O’Connor, E. F. DuPr6 and D. Mitcham, Textile Research J . , 28, 382 (1958). (154) H. G . Higgins and A. W. McKensie, Australian J . Appl. Sci.,9, 167 (1958). (155) H. Spedding, J . Chem. Soc., 3147 (1900). (156) R. G. Zhbandkov, Optika i Spektroskopiya, 4, 318 (1968); Chem. Abstracls, 62, 11570 (1958). (157) A. Meller, Tappi, 36, 72 (1952). (158) B. Lindberg and 0. Theander, Svensk Papperstidn., 67,83 (1954). (159) G. M. Nabar and C. V. Padmanabhan, J . SOC.Dyers Colourisls, 69, 295 (1953). (160) U. Strole, Makromol. Chem., 20, 19 (1956).

148

R. D. GUTHRIE

cause of the instability of oxycelluloses toward alkali.1E1a2The “copper number”168-168b of oxycelluloses gives an empirical measure of reducing power. which Oxycellulose and phenylhydrazine gave a yellow formed a diphenylformazan,lm showing that the oxycellulose had reacted in one of the two possible hemiacetal forms. Aminophenols and oxycellulose gave derivatives which coupled with diazonium compounds, enabling chemically colored fibers to be prepared.lE4Reduction of oxycellulose oxime with lithium aluminum hydride, sodium borohydride, or sodium amalgam gave an “amino-oxycellulose” (109) in which up to 25 % of the oxime groups had been reduced.lE6 CH,OH

(109)

The reaction of diazomethane with oxycelluloses has been studied166-16R as a possible means of reducing their alkali lability. Head’” has shown that diazomethane in ether does not react with oxycelluloses unless water is also present, presumably to increase accessibility. Oxycellulose (D.O. 93 %) reacted to give a product with only one methoxy group per dialdehyde unit, and yet the copper number was almost zero (showing that all the aldehyde groups had been blocked). Structures containing epoxide rings (diazomethane can react with aldehyde groups to give epoxides16D),for example (1lo), or methylated double hemiacetals derived from two adjacent dialdehyde units, such as (lll),were proposed in order to account for the above prop(161) E. Pacsu, Teztile Research J., 16, 106 (1946). (162) R. L. Colbran and T. P. Nevell, J. Teztile Znst., 49, T333 (1968). (163) C. G. Schwalbe, Bet., 40, 1347 (1907). (163a) T. F. Heyes, J. SOC.Chem. Znd. (London), 47, 90T (1928). (163b) Tappi Standard Methods, T 216 m-60 (1960). (184) 2. A. Rogovin, A. C.Yaehunskaya and B. M. Bogoslovski, J . Appl. Chem. U.S.S.R. (English Translation), 33, 666 (1960). (166) Y. S. Koalova and Z. A. Rogovin, Vysokomolekulyarnye Soedineniya Vsesoyuz. Khim. Obshchestvo im. D . Z. Mendeleeva, 3 , 614 (1960), Chem. Abstracts, 56, 6392 (1961). (166) R.E. Reeves, Ind. Eng. Chem., 36, 1281 (1943). (167) R. E. Reeves and F. Darby, Jr., Teztile Research J . , 20. 172 (1960). (168) F. S. H. Head, J . Teztile Zmt., 43, T1 (1962). (169) B. Eistert, “Newer Methods of Preparative Organic Chemistry,” Interscience Publishers, Inc., New York, N. Y., 1948, p. 613.

PERIODATE-OXIDIZEDCARBOHYDRATE8

(111)

149

(112)

erties; the presence of epoxide rings in the products was not tested for. Double hemiacetals within the same dialdehyde unit, for example (112), were not considered. The reaction of diazomethane with periodate-oxidized monosaccharide derivatives would make an interesting study. Sodium borohydride reduces oxycelluloses to the corresponding polyhydric alcohols,11bJ70-17* which are almost completely stable toward alka1i.l7OJr1 The influence of pH, temperature, and concentration of the reactants have been investigated.171 Hydrolysis of the reduced oxycellulose gave glycolaldehyde and erythrito1.l" Attempts were made to reduce oxycelluloses with aluminum isopropoxide, with zinc and acetic acid, and with hydrogen over a platinum oxide catalyst; none of the products showed any decrease in alkali sensitivity and so, presumably, no reaction had occurred.16' Jayme and Maris"' hydrogenated oxycellulose in the presence of h n e y nickel to give a product which was hydrolyzed to erythritol and glyoxal, suggesting that partial reduction of the hemiacetal form (103)had occurred. The hydrogenation mixture was made alkaline with barium hydroxide, so it is possible that some degradation of the oxycellulose occurred. (170) A. Meller, Chem. & Ind. (London), 1204 (1963). (171) F. 8.H. Head, J . Teztile Inst., 46, T400 (1966). (172) I. J. Goldatein, J. K. Hamilton, R. Montgomery snd F. Smith, J . Am. Chem. Sac., 79, 8469 (1967). (173) N. Virkola, Papen'ja Puu, 40,367 (1968). (174) G. Jayme and 8.Maria, Ber., TI, 383 (1944).

R. D. GUTHRIE

150

CHPOH

AH,OH

CH,OH

(113)

p

B

r

AJ

CO,H

~

CH,OH

~

H

HCOH HTOH CH,OH I

o

+

Hr H =O

,

~

The same workers17*oxidized oxycellulose with bromine water, to give a product which was hydrolyzed to D-erythronic acid and glyoxal, again suggesting that oxycellulose reacted preferentially in the hemiacetal form (113). This behavior is in contrast to Pacsu's findingsl7'; he isolated glyoxylic acid after hydrolysis of an oxycellulose which had been further oxidized with bromine in bicarbonate solution. Oxidation of oxycelluloses with chlorous acid showed that one aldehyde group was oxidized more rapidly than the 0ther.l7~The polydibasic acids from complete oxidation of oxycelluloses with the latter reagent have been prepared by several groups of workers.l761808 It was noted that oxidation greatly dimiihea the alkali instability of 0xycelluloses.~7~--'7~ Nitrogen dioxide oxidation of oxycellulose gave181 the polytribasic acid (114). Oxycelluloee was degraded by 10 % methanolic hydrogen chloride to give the same products as oxystarch.l* Reaction with 0.4% methanolic hydrogen chloride introduced up to 25% of methoxyl, but, with ethanolic hydrogen chloride, only 3 % of ethoxyl was formedz8;this behavior is probably attributable to the different sizes of the reagents. Oxycelluloses conlB0

(176)E.Pacsu, Testile Research J . , 16, 364 (1946). (176)G.F. Davidson and T.P. Nevell, J . Testile Inst., 46, T407 (1966). (177) H.A. Rutherford, F. W. Minor, A. R. Martin and M. Harris, J . Research Natl. Bur. Standards, 89, 131 (1942). (178) A. G. Yashunskaya, N. N. Shorygina and Z. A. Rogovin, Zhur. Pm'klad. Khim., 28, 1037 (1849); Chem. Abstracts, 46, 3692 (1961). (179) W. K.Wilson and A. A. Padgett, Tappi, 98,292 (1966). (180) G. M. Nabar and C. V. Padmanabhan, Proc. Indian Acad. Sci., S A , 212 (1960). (180a) B. T. Hofreiter, I. A. Wolff and C. L. Mehltretter, U. 5. Pat. 2,894,946 (1969);chem. Abstracts, M, 2794 (1960). (181)V. I. Ivanov, N. Y. Lenshina and V. S. Ivanova, Doklady Akad. Nauk 8.S. 8.R., 119,326 (1969); Chem. Abstracts, M, 8664 (1960).

PERIODATE-OXIDIZED CARBOHYDRATES

151

COZH

(114)

taining 2.1-2.6 % of methoxyl have been prepared by use of 1% methanolic hydrogen chlorideB2;the products showed a diminished solubility in acetone, suggesting that cross-linking had occurred. A small proportion of methanol was retained after oxycellulose was washed with this solvent and exhaustively dried.18*This retention was attributed to the formation of a “polydialdehyde methanolate,” similar to those obtained with simple monosaccharide derivatives. The proportion of methanol retained is shown TABLEI Reaction of Ozycelluloses with Methanol OaMn1

% ’

Moles of MeOH pn

Chain m i l s r&ing wiCh MeOH, %

5.1 10.7 22.2

23

100 chain-unils

18.2 48.6 92.7

22 24

in Table I; the constant percentage of reacted chain units suggests an equilibrium, under these conditions, between about 25% of hemialdal groups and 75 % of other groups, probably hemiacetals. Nitrogen dioxide oxycellulose of a high D.O. also showed this phenomen0n.~~J8* Davidson”JgJ~~prepared nitrate esters from oxycellulose and noticed that, above about 2 % D.O., the products were insoluble in acetone; this observation has been confirrned.l8* The explanation put forwardlE2to account for the diminished solubility was that formation of hemiacetal cross-links occurred in the presence of anhydrous, strong acids. An alternative explanation is that the cross-links were already present in the oxycellulose and that J

~

~

-

~

~

~

(la) Z. A. Rogovin, A. G. Yashunskaya and N. N. Shorygina, Zhur. Priklad. Khim., 22, 866 (1949);Chem. Abstracts, 44, 835 (1960). (183)T.P.Nevell, Chem. & Ind. (London), 389 (1958). (184)T.P.Nevell, J . Feztile Inat., 42, T91 (1951). (185)H.Haas, E.Battenberg and D. Teves, Tappi, 36, 116 (1952). (186)Z. A. Rogovin, A. G. Yashunskaya and N. N. Shorygina, Zhur. Pn’klad. Khim., 22, 857 (1949);Chem. Abstracts, 44, 835 (1950). (187)B. Anthoni, Paperi j a Puu, 38, 504 (1956); Dissertation, Meden, Helsinki (1958).

152

R. D. QUTHRIEl

nitration stabilized them.l@ The physical properties of nitrated oxycelluloses have been studied in some Acetylation of oxycellulose gave a triacetate that, again, appeared to be cross-linked, and for which structure (115) was suggestedU* structures (116) and (117) would also be possible for the triacetate.

45-b $yP\Q\ EC CIi,OAc

CHOAc Acd%AC (115)

CHOAC

dAc

A C A C (116)

(117)

4. From Xylun Xyhn was oxidbed by Jayme and his coworkers1@,'88J8@ in a buffered solution; hydrolysis1"*W-1@0 of the product gave glyceroae (67 %) (as pyruThe devaldehydem) and glyoxal(62 %), as the bis(phenylhydraz0ne).l@J8@ gree of oxidation of the oxyxylan was calculated from the nitrogen content of the orange-yellow phenylhydrazine derivative, which was assumed to be the poly[bis(phenylhydrazone)l.'sg It has been recorded,@6however, that oxyxylan reacted with less than one molecule of phenylhydrazine per dialdehyde unit. Degradation of oxyxylan with phenylhydrazine-acetic acid gave glyoxal bis(phenylhydrazone),glycerosazone,and D-xylosazone.@6 I t has been averred that the oxyxylan-phenylhydrazine derivative formed a poly(diphenylforma~an)~*o; this olaim has been criticized'@'on the grounds that, unlike oxycellulose or oxystarch, oxyxylan could not form a hemiacetal, and, hence, there should be no free aldehyde groups to form true phenylhydrazones that would yield formazans. Hydrogenation of oxyxylan in the presence of Raney nickel, followed by hydrolysis, gave glycerol and glycolaldehydel@,lE2 Jg8; alternate reduction and hydrolysis gave glycerol and ethylene g1yco1.1"J@8Oxidation of oxyxylan with bromine water, followed by hydrolysis, gave D-glyceronic acid (isolated as the barium or brucine salts).'" #lea (188) G. Jayme and M. Btre, Ber., 76, 1840 (1942). (189) G. Jayme and M. &itre, Ber., 77,242 (1944). (190) M. Hamada and K. Maekawa, J . Fac. Agr. Kyuehu Uniu., 9, 311 (1950); Chem. Abstracte, 48,2602 (1964). (191) V. C. Barry and P. W. D. Mitchell, Chem. & Ind. (London), 1046 (1967). (192) I. Ehrenthal, R. Montgomery and F. Smith, J . Am. Chem. Soc., 76, 5609 (1964). (193) G. Jayme and M. Btre, Ber., 77,248 (1944).

PERIODATE-OXIDIZED CARBOHYDRATES

153

5. From Other Polysaccha&es

Oxyinulin has been hydrolyzed to yield glycerose. Oxidation of oxyinulin followed by hydrolysis gave glyceronic acid; reduction and hydrolysis gave g l y c e r i t ~ l Oxyinulin .~~~ and phenylhydrazine gave a yellow product which contained one phenylhydrazine group per dialdehyde unit,g6and which formed a formazan.l’O Isonicotinoylhydrazineg and paminobenzaldehyde thiosemicarbazonelsgalso reacted, to give products with one basic group per dialdehyde unit. Alginic acid was oxidized in the course of proof of its structure.l96 Hydrolysis of oxyalginic acid gave glyoxal, and, after further oxidation, it gave erythraric acid.l96 Oxyalginic acid reacted with isonicotinoylhydrazineg and p-aminobenzaldehyde thiosemicarbazonelsgto give products with one basic group per dialdehyde unit. The former compound was hydrolyzed with 50 % acetic acid to the corresponding glyoxal bis(hydrazone), but hydrolysis in the presence of phenylhydrazine or cyclohexylamine gave the glyoxal derivative of the added baseg; (compare oxystarch, p. 145). Oxydextran showed no carbonyl absorption in the infrared or ultraviolet spectra; hydration of the aldehyde groups was assumed.lg6Many other polysaccharides have been oxidized with periodate,6 but only in purely structural work; and no reactions have been studied (other than hydrolysis of the oxypolysaccharide or its oxidation or reduction products). OF PERIODATE-OXIDIZED CARBOHYDRATES VII. ALKALINE DEGRADATION The degradation by alkali of oxycelluloses containing carbonyl groups is of great importance in industries based on cellulose (for example, textiles and paper). A great deal of work has been carried out on periodate-oxidized cellulose as a typical example of these carbonyl oxycelluloses.196aThe majority of the work on periodate-oxidized monosaccharide derivatives has been carried out as a model for the oxycellulose system. The alkali lability of oxycelluloses was first observed by D a ~ i ds o n ,l O~J 4who ~J ~noted that, with as low as 2 % D.O., there was great alkali sensitivity. The characteristic feature of the degradation is the production of acidic fragments.lW Oxidized methyl a-L-rhamnopyranoside (118) undergoes a Cannizzaro

(194) K. Maekawa and T.Nakajima, Nippon Ndgei-kagaku Kaishi, 28,357 (1954); Chem. Abstracts, 48, 10078 (1954). (196) H. J. Lucas and W. T.Stewart, J . A m . Chem. SOC.,62, 1792 (1940). (196) J. W.Sloan, B. H. Alexander, R. L. Lohmar, I. A. Wolff and C. E. Rist, J . Am. Chem. SOC.,76, 4429 (1954). (196a) W. M. Corbett in ‘‘Recent Advances in the Chemistry of Cellulose and Starch,” J. Honeyman, ed., Heywood & Co., Ltd., London, 1969, p. 106. (197) G . F. Davidson, J . Testile Inst., I D , T196 (1938). (198) G . F. Davidson and T.P. Nevell, J . Testile Inst., 99, T102 (1948).

154

R. D. GUTHRIE

Me

(118)

Me

(119)

reaction in alkali, with the formation of a mixture of monobasic acids (119),’9nso it is possible that such a reaction might occur with oxycelluloses. Several theories have been proposed for the alkaline degradation of oxycelluloses; of these theories, two have predominated. Pacsu176 considered oxycellulose to be a hydroxyketene acetal(l20) ;degradation of such a compound would give glycolic acid and D-erythrose as the primary products. CHpOH

( 120)

However, Head200showed that glyoxal is produced by the treatment of both oxycellulose and periodate-oxidized methyl B-cellobioside (121) with alkali. The other theory was that of Haskins and Hogshead,2O1 based on the j3alkoxycarbonyl elimination mechanism of Isbell2O2for the formation of saccharinic acids on treatment of sugars with alkali. They suggested that fission of the C5-0 bond would yield glyoxal and D-erythrose. Recent work has indicated that the degradation is, indeed, based on a 8-alkoxycarbonyl elimination, but the products are different from those postulated above. Headloo showed that, whereas periodate-oxidized methyl j3-cellobioside (121) is quite labile to alkali and gives glyoxal, periodate-oxidized methyl j3-D-glucoside (122) reacts only slowly with alkali to produce acidic products,

j=oy

o

=

~

~

a CcH

HC=O ~

(199) E.M. Fry, E. J. Wileon and C. S. Hudson, J . Am. Chem. Soc., 64,872 (1942). (Zoo) F. S. H. Head, J . Teztile Znst., 88, T389 (1947). (201) J. F. Haskins and M. J. Hogsheed, J . Org.Chem., 16, 1204 (1950). (202) H. S. Isbell, J . Research Natl. Bur. Standards, 81, 46 (1944).

c

155

PERIODATE-OXIDIZED CARBOHYDRATES

presumably by a Cannizzaro reaction. Inspection of the formulas (121)and (122) reveals that the former contains both a- and /3-alkoxycarbonyl systems, whereas the latter has only an a-system. Alkaline degradation of periodate-oxidized methyl 4,6-O-benzylidene-aD-glucoside (123) with lime-water gave equal amounts of glycolic acid and 4-formyl-2-phenyl-2H,6H-1,3-dioxin (124), as well as a mixture of acids

7e~o~----(~hp

ph 6. 6 . Hydrolytic, Synthetic, and Transfer Reactions

The glycosidases are known to catalyze hydrolytic as well as transfer reactions, that is, the sugar residue forming the glycon part of the substrate molecule may be transferred to water or to some other hydroxylic acceptor (such as another sugar or an alcohol). With P-galactosidases from various sources, this phenomenon was studied by Aronson, Ballio, Pazur, ,54-60 The synthesis of glycosides from Wallenfels and their co~orkers.~g free sugars and alcohols has also been shown to be catalyzed by these enzymes. Whether all three reactions are catalyzed by the same or by different enzyme proteins has long been a topic of discussion. With a crystalline p-galactosidase, Wallenfels and coworkers2' have shown that one and the same enzyme is responsible for these three reactions insofar as galactosyl transfer is concerned. To date, this is the only example in which it has been definitely established that these reactions are catalyzed by the same enzyme. In fact, an interesting relationship has been observed among these reactions. Of the various isomeric galactosylglucoses, the isomer most readily hydrolyzed is also that produced with the greatest speed by transfer and synthetic reactions (compare Fig. 5A, for L-arabinose transfer). The order of decreasing velocity of hydrolysis is (1 6 ) > (1 + 4) > (1 --+ 3) (see Table V), whereas the order for synthesisR1is (1 + 6) > (1 + 4) 2 (1 -+ 3). With purified, calf-intestine enzyme, this order is reversed, both for the hydrolytic and the transfer reactions.'6 On longer incubation, all of the products are hydrolyzed. These observations are readily explained if it is assumed that the aglycon and the acceptor occupy the same position on the enzyme molecule. The products of transfer can be detected in even lcss than 1 minute after the start of the reaction. Thc galactosyl transfer cannot be due to hydrolysis followed by synthesis, becausc this would involve synthesis a t exceedingly low D-galactosc concentrations, a phenorncnon which could not be ---f

(53) R. G . Young and F. J. Reithel, Biochim. el Biophys. Acla, 9, 283 (1952). (54) I28,31), 265(31), 266(31, 43), 267(31), 268(31), 269(31), 270(31), 271(31), 272(31), 273(82b), 274(78), 280(28,85), 281(89), 282(16), 283(16), 284(15), 286(15), 288(28, 93) Walters, D., llO(16) Walton, A., 65(166) Walton, W. W., 183(202) Waly, A., 33(119) Ward, J. O., 19(39) Ward, R. B., 30(103), 31(104,106), 32(104, l06), 38(146), 43(106), 45(104, 105), 53(146), 54(146) Warkentin, B. P., 363(89a) Wasif, S., 84(68) Watanabe, N., 233(104) Watkins, O., 172(81) Watson, P. R., 141(117), 157(117), 158 (218) Watters, A. J., 200 Webb, B. H., 194(300) Weber, L. G., 291(116) Webley, D. M., 351(87), 362(87), 354(100) Weeks, B. M., 19(39), 29(101) Weidenhagen, R., 291(122), 297(150) Weidmann, S., 234(107) Weigel, H., 55(166, 167), 57(167, 168) Weisberg, H., 157(211) Weisbuch, F., 204(396) Weiser, R. S., 234 Weiss, D. W., 237 Weiss, J., 16(21), 18, 19(38), 25(68), 26(77, 78), 27(86, 87, 88, 89), 28(90, 91, 93, 94, 95, 97), 29(97), 46(67) Weim, M. J., 95(34), lOl(34) Weiss, W., 49(152) Wellm, J., 203(386) Wells, 1’. A., 157(213, 14) Werner, J., 198(344) Werner, W., 206(407) Wertheim, M., 299(1) Westermann, H., 86(11), 87(11), 95(11), 97(43), 98(ll), QQ(l1,43) Westphal, o., 233(99) Weygand, F., 61(9), 62(18, 19, 20) Weymouth, F. J., 69(40) Wheeler, C. M., 27, 28(90) Whelan, W. J., 188(232) Wherry, E. T., 203(380)

16

Whiffen, D. H., 31(104), 32(104), 45(104), 72(50), 74(50) Whistler, R . L., 156(205, 2054, 300(5), 304, 323(36), 338(22), 339(22), 340 (22) ,341 (22,29), 342(22), 343(22), 349 (22), 350(22), 352(22), 353(22) White, A. A., 172(80) White, J. C. D., 167(38) White, R. A., 231 White, R. G., 230,235(123), 236 Whitefield, P. R., 156(209) Whitehouse, M. W., 171(67a), 362(89) Whittier, E. O., 169, 160(3), 167(3), 205 (431), 206(438, 439) Wickham, N., 233(98) Wickstrgim, A., 137(102, 104, 106), 184 (207), 190(260), 293(144), 294(142, 143, 144) Wiegand, F., 88(17), 95(17), 98(17), 99 (17) Wiegner, G., 205(432) Wieland, P., 206(411) Wigglesworth, V. B., 178(139) Wild, G. O., 290(109) Wilkinson, J. F., 180(167) Wilkinson, R. W., 28(96) Williams, D., 37(141), 38(141) Williams, T. F., 28(96) Wilson, E. J., 154(199) Wilson, G. L., 188(242), 204(242) Wilson, W. K., 150(179) Wimmer, E. L., 327,332 Winer, R. A., 241(17) Winkler, S., 290(111), 292(111) Winter, L. B., 172(82), 173(88) Wintersteiner, O . , 110(16), 162(27) Wise, C. S., 142(127) Wolf, A , , 198(346) Wolfe, J. K., 76(54) Wolfe, R. G., 242(32), 244(32), 240(32), 250(32), 251 (32) Wolff, H., 193(283) Wolff, I. A,, 141(122, 123, 126), 143(122), 144(122), 145(143, 144, 145), 150 ( M a ) , 153(196), 158(215) Wolfrom, M. L., 36(139), 37(141), 38(139, 141), 47(139), 49, 50, 51(157, 159), 52 (139), 63(139), 93(29), 188(230), 196 (317) Wood, H. G., 174(103, 105), 175(103, 107. 108,109), 176(111)

AUTHOR INDEX, VOLUME 16 Woods, B. M., 164(33), 186(213, 217), 188 (213, 234), 190(33) Worrall, R., 61(8), 66(26), 68(32, 34), 80 (32, 34), 81(32), 82(8), S(32)

Wright, J . , 50 Wright, L. M., 343(35, 36), 345(36), 346 (35), 347(36), 348(36), 353(35, 92)

Wulff, H., 86(12), 88(12), 90(12), 96(12), 100(12), 103(12)

Y Yamamura, Y., 231(91, 93), 232(91, 93) Yanovsky, E., 183(201), 203(201), 204 (201)

Yashunskaya, A. G., 148(164), 150(178), 151(182, 186), 152(182, 186), 156(178)

Yearian, H. J., 304(12) Yelland, W. C. E., 157(210) Yoshida, K., 180(161) Yoshida, R. K., 344(43) Yoshino, I., 168(224) Young, B., 290(10I)) Young, R. A., 310

377

Young, R. G., 196(328), 255(63) Z

Zaheer, S. H., 198(346) Zak, H., 194(293), 198(293) Zarnits, M. L., 241(27), 242(27), 246(27), 249(27), 250(27), 251(27), 252(27), 254(27), 255(27), 260(52), 264(27) Zartman, W. H., 188(237) Zechmeister, L., 292(136) Zellner, J., 194(293), 198(293) Zemplh, G., 162, 183(25), 193(25) Zerban, F. W., 206(436) Zervas, L., 200(358), 201(363) Zhbandkov, R. G., 146(152), 147(152, 156 Zief, M., 122(56), 123(56), 135(94) Zilliken, F., 167,168(47), 171(66,67a) Zimmer, K. G., 35(136) Zumbute, F., 90(23), 92(23), 96(23), 98 (23), 102(23) Zweifel, G., 338(25), 339(25), 342(25), 353(25)

Subject Index For Volume 16 A Acetaldehyde, effect on EtOH irradiation, 23 from ethanol irradiation, 25 Acetals, cyclic, reaction with acyl trifluoroacetates, 83 cyclic, ring opening of, 69 Acetic acid, anhydride with trifluoroacetic acid, 80,81 reaction with cellulose, 60 with trifluoroacetic anhydride, 60 -, trifluoro-, anhydride, 79, 80 anhydride, acylation by mixtures of carboxylic acids and anhydrides and, 67 carhohydrat,e eRterification by, 61 prepn. of, 8 reuction of, with acet,ic acid, cellulose and, Go with amines, 02 with amino acids, 62 with peptides, 62 anhydrides with carboxylic acids, 79, 81

acylation by, 83 reaction of, with cyclic acetitls, 83 with hydroxy compds., 81 anhydride with acetic acid, 80. 81 esters, hydrolysis of, 61, 63 prepn. of, 61 reaction with methanol, A1 ethyl ester, 59 phenyl ester, reaction with amino acids and peptides, 62 reaction with cellohiose and cellulose, 62 -, trifluorothio-, S-ethyl ester, reaction with amino acids, 63 Acetic anhydride, 68 Acetone, dihydroxy-. See a-Propanone, 1,I-dihydroxy-. Acetophenone, 4’-methoxy-, 67 Acids, 7-ray effect on solutions o f , 19 hydroxy, keto acids from, hy irradiation, 28-32

in starch fractionation, 326 of soil, organic, 337 Adenine, 9-B-D-glUCOpyranOSyl-, oxidn. product, and picrate, 128 Adenosine, 5-(benzyl H phosphate), alkali effect on oxidized, 151; cyclic 2,3-phosphate, 69 oxidn. product, 127, 128 2-phosphate, B9 5-phosphate, alkali effect on oxidized, 156 picrate, oxidn. product, 128 5-pyrophosphate, 177 5-triphosphate, 177 Adipic acid, polyester from 1,3:2,4:5,Dtri-0-methylene-~-glucitol and, 78 Aglycons, specificity of, in enzymic reactions, 261 Alanine, esters with sugars, 207 Alcohols, complexes of higher, wit,h amylose, 299 complexes with amylose, 325 irradiation of, 22-26 reaction with acyl trifluoroacetates, 81 in starch fractionation, 320, 325 Aldehydes, di-, (non-carbohydrate), 132133 Aldohexopyranosides, methyl, oxidn. products, 123 -, methyl 6-deoxy-, oxidn. products, 109,111 Aldopentofuranosides, methyl, oxidn. products, 123 Aldopentopyranosides, methyl, oxidn. products, 116118 Aldoses, w-fluoro derivs., 101 prepn. of, 95 Alkalis, in starch fractionation, 326 starch precipn. by, 327 Allolactose. See Glucose, G-O-fl-~-gdactopyranosyl-D-. Allosan, oxidn. product, 118 Alloside, methyl 4,6-0-benzylidene-3deoxy-3-phenylazo-~-,114 Alpha rays, effect on alcs., 22

378

SUBJECT INDEX, VOLUME

Altrosan, oxidn. product, 118 Altrose, 3-amino-l ,6-anhydro-3-deoxyD-, 118 -, 4-O-fl-~-galactopyranosyl-~-, 197 octaacetate, 197 Altroside, methyl 3-amino-4,6-O-benzylidene-3-deoxy-~-,oxidn. product, 115 Amines, reaction with trifluoroacetic anhydride, 62 Amino acids, from B-galactositlase, 252, 253 of mycoside C, 224 reaction with 8-ethyl trifluorothioacetate, 63 with phenyl trifluoroacetate, G3 with trifluoroacetic anhydride, 62 of soil, 343 of wax D, 220 Ammonium iodide, (hepta-O-acetyl-8lactosyl ) trimet hyl -, 199 Ammonium sulfate, st,arch fractionation by, 328 Amygdalin, 294 Amy1 alcohols, complexes of isomeric, with amylose, 305 in starch fractionation, primary, 326 Amylase, in soil, 349 “Amylodextrine,” 307 “Amylogeen,” 307 Amylopectin, 309, 318, 325 alkaline leaching of, 306 complexes, 303, 304 with alkaline-earth hydroxides, 327 fractionation of, 304 insolubilization of, 313 iodine adsorption by, 301, 303 from org.-solvent precipitation, 330 precipn. and recovery of, 316 precipn. of, 321, 324, 328, 329 by MeOH, 326, 327 temp. effect on, 319, 324 radiation, effect on, 35 from salt-fractionation process, 330, 331 sepn. from amylose, 308, 310, 313, 317, 326 structure of, 321 system: magnesium sulfate-water-, 318

16

379

water (cold) insoluble, 313, 316, 330, 331 soluble, 330, 331 Amylose, 299, 300,307, 308, 309, 310, 318, 319, 320, 325 acetates, 67 by aqueous leaching, 30B complexes, 303, 304, 319 with alcs., 325 with alkaline-earth hydroxides, 327 with 1-butanol, 304, 306 with butanol, structure of, 303 with culcium hydroxide, 328 with chloral hydrate, 307 with iodine, struct,ure of, 303 with 2-methyl-l-butanol, 300, 317 with 2-1nethyl-2-butano1, 326 with pentanols, 304, 305 with 2-propanol, 321 crystalline, 300 fractionation of, 304, 315, 324 from fractionation with org. complesing agents, 329, 330 iodine adsorption by, 301, 302 particle size of precipd., 315 precipn. of, 312, 313, 310, 321-324, 320, 327, 328, 329 temp. effect on, 319 radiation effect on, 34, 35 recovery of precipd., 315 recrystallized, 309 retrograded, 323 from salt-fractionation process, 330 solubilization of, 323 solubility in water, 321 structure of, 321 system: magnesium sulfate-wster-, 318 water (cold) insoluble, 312, 330 soluble, 330 Arabinan, 328 Arabinofuranoside, methyl Q-D-, oxidn. product, 123 Arabinonic acid, 3-0-8-~-galactopyrarloSyl-D-, 184 Arabinopyranoside, o-nitrophenyl Q-I,-, hydrolysis of, 269 Arahinopyranosides, 8-L-,hydrolysis of, 292 Arabinopyranosyl bromide, tri-0-acetyl-fl-D-, 88

380

SUBJECT INDEX, VOLUME

Arabinose, L-, 284 D-, from D-glUCitOl irradiation, 48 D-, from D-glucose irradiation, 35 . D-, from glycolipids, 209 D-, from D-rnannitol irradiation, 47 D-, from D-mannose irradiation, 41-45 in polysaccharides from pathogenic bacteria, 352 of soil, 338, 342 D-, from starch irradiation, 35 D-, from sucrose irradiation, 51, 52 D-, from wax D, 219, 220 -, 3-0-8-~-galactopyrano~yl-~-, 162, 183, 195 hexaacetate, 200 Arubinoside, ethyl a-r.-, ensyrnic synthesis of, 257 -, methyl p-u(and @-L)-,oxidn. products, 118 -, o-nitrophenyl a-L-,hydrolysis of, 268-272 Arabinosides, a+-, 280 o-L-, hydrolysis of, by 8-D-galaCtOsidases, 256 Arabinosyl group, transfer of, by enzymes, 262, 263 a+, transfer of, 8-galactosidase in, 256 L-, 7-ray effect on, 30 radiation effect on, 46 Ascorbic acids, 52, 53

16

1-Butanol, 313 complex with amylose, 304, 306 in starch fractionation, 300 -, 2-methyl-, complex with ttinylosc, 306,317 in starch fraotionation, 311 2-Butanol, amethyl-, in starch fractionation, 326 Butyl alcohol. See 1-Butanol. Butyric acid, 3-hydroxy-, 28 C

Calcium hydroxide, complex wit,h stnrrh, 327 Cane sugar. See Sucrose. Carbohydrates, complexes of, in #oil, 352, 353 decornp. of, in soil, 349-351 effect on chemical processes in soil, 354 on microbial activity in Roil, 354 in emulsins, 254 esters, 209 formation by soil micro-organisms, 351 8-galactosidase sepn. from, 247-248 in glycolipids of acid-fast bacteria, 208, 209 labeled with C14,self-decompn. of, 54 oxidn. products, properties of, 108 oxygen effect on irradiation of, 38 radiation effect on, 30, 37 B in sedimentary rocks, 335 in soil, 337, 338, 347-348 Bacillua Pnegatherium, polysaccharides degradation of, 350 from, 352 detn. of, 344 Barium hydroxide, complex with starch, effect on plant nutrition, 354 327 source of, 348 Barry degradation, 139 Bensirnidazole, 1-(2-deoxy-~-“galacto- spectra of irradiated solutions of, 53 Carbon, isotope of mass 14, self-desyl”)-, oxidn. product, 130 compn. of compds. labeled with, Benzoic acid, p-hydroxy-, polyester, 77 54 Benzophenone, 4-methoxy-, 83 Cellobiose, as acceptor in transgalacBifidus factor, 165 tosylation, 262 “Blue value,” 308 oxidn. of, 184 2,3-Butanediol, from ethanol irradiaradiation effect on, 50 tion, 25, 26 reaction with trifluoroacetic acid, 62 Butanol, complex with amylose, struc- -, octa-0-acetyl-, reaction with HF, 86 ture of, 303 Cellobioside, methyl 8-, 136 in starch fractionation, 327 oxidized, alkali effect on, 154

SUBJECT INDEX, VOLUME

38 1

16

Cellobiosyl fluoride, hepta-0-acetyl-, 86 Cellulose, 138 acetates, 67 benzoatcs, 68 decompn. of labeled, in Roil, 351 hydroxyinethyl ether, 08 radiution effect 011, 33, 34, 58 reaction with trifliioacetic acid, 60,62 with trifluoroacetic anhydride, CAOi in soil, 349, 350 Chitin, in soil, 350, 352 Chloral hydrate, complex with amyloar, 307 Citric acid, 28 CIuyH, mononncchr~ride adsorption by, 338 Conformation, of glucose in lactose, 183 of hemialdala, 116, 117 of methyl cr-L-rhamnopyranoside oxidn. product, 110 Conformational analysis, of oxidized Me a-D-glucoside, 12(1 Cord factor, 207, 209 degradation of, 212, 213 effect on leucocytes, 231 enzyme inhibition by, 231 as hapten, 234 homologs (lower) of, 216217 isolation of, 210 occurrence of, 210 structure and activity of, 232 structure of, 210-212, 218 synthesis of, 212-216 toxicity of, 232-233 Critical concentration, the term, 302 Cyclohexanol, in starch fractionation, 301 Cytidine, oxidn. product, 128 picrnte, oxidn. product, 128 Cytosine, 3-8-n-glucopyranosyl-, picrate, oxidn. product, 128

Dextrins, from amylose irradiation, 34 from starch irradiation, 34, 35 Dialdehyde methanolate, the term, 107 Difuco-di-(lacto-N-tetraose), 171 Difuco-tri-(lscto-N-tetraoRe),171 Di- (Iacto-N-tctrttose), 171 p-Dioxane, 3,5-dihydroxy-2-~"-meth oxy-G-n"-methyl-, 107 m - Dioxano[6,4 -e][l,4]dioxepan, dihy droxy -0a- methoxy - 2 - phenyltrane-, 107 ni.-Dioxin-G-carboxaldehyde, 2-phenyl-, 155 Disaccharides, 91 structure of, 137 Dosimeters, 21

D

B

Dambonitol, oxidn. product,, 120 Delta rays, the term, 10 Dextrans, 7-ray effect on, 52 radiation effect 011, 35, 36 sulfate, labeled with C", 57

E Emulsins, carbohydrate8 in, 254 8-galactosidase in, 240 11-Epicorticosterone, 66 trifluoroacetylation of, 62 Epilactose. See Mannose, 4-0-8-n-galactopyranosyl-n -. Erythritol, 145, 149 from methanol-C14, 24 -, 1,2-di-O-rnethyl-, 122 -, 1-0-methyl-, 115 Erythronic acid, D-, 150 -, 2-O-8-D-galaCtOpyrarlOSyl-n-, 162 Erythrose, D-, 115, 142, 154 from D-glucose irradiation, 36 from hexose irradiation, 41 from n-mannose irradiation, 42, 43 phenylosazone, 142 -, 2-O-j3-~-galactopyranosyl-~-, 162, 163 -, 2-O-methyl-, 115 Ethanol, irradiation of, 23, 25 Ethyl alcohol. See Ethanol. Ethylene glycol, from methanol-Cl4, 24 from methanol irradiation, 24 5-Etiocholenic acid, 3@-hydroxy-,methyl ester, 66

Friictopyranose, 3-O-acetyl -l , 2 - 0 -is0 propylidene-n-, oxidn. product, 131 -, penta-0-acetyl-B-n-, reaction with HF, 86

382

SUBJECT INDEX, VOLUME

16

Fructopyranoside, methyl I,-0-methyl- -, methyl 6-O-rnethyl-a-~-, oxidn. product, 122 (I-D-, 93, 94 -, methyl 3,4,5-tri-0-acetyl-l-O-meth--, o-nitrophenyl (I-D-, 292, 293 yl-a-D-, 93, 94 -, o-nitrophenyl D-D-, in detn. of p-gaFructopyranosyl fluoride, 1-0-methyllactosidase activity, 241, 242 a-D(and &D)-, reaction with -, o(and p)-nitrophenyl P-D-, 260 NaOMe, 93, 94 -, nitrophenyl a-D-,29 -, 3,4,5-tri-O-acetyl-p-~-, 86 -, o-nitrophenyl I-thio-p-D-, effect on 8-galactosidase, 250 Fructose, D-, 294 D-, from dextran irradiation, 52 -, o(and p)-nitrophenyl I-thio-p-D-, 2CiO D-, effect on pectin irradiation, 34 -, phenyl a-D-,297 polysaccharides contg., formation by a-galactosidase standardization by, 292 bacteria, 351, 352 hydrolysis of, 293, 295, 298 I)-, radiation effect on, 38, 46, 47, 50, 54 of soil, 338, 343 -, propyl P-D-, enzymic synthesis of, 257 D-, structure of, moiety i n sucrose, 93 -, O-tOlyl (I-D-, 293 I)-, from sucrose irradiation, 51, 52 Galactopyranosides, P-D-, enzyme effect on, 260, 261 -, 3,0-anhydro-u-, osotriazole oxidn. 0-D-, hydrolysis of, 293, 294 product, 119 -, alkyl (Y-D-, 293 -, 3-0-8-D-galaCtOsyl-D-, 2G1 -, aryl (I-D-, 293 Fucose, D-, 262 from hydrolyzed bacterial cultures, Galactopyranosyl bromide, tetra-0-ace351, 352 tyl-a-D-, 165 of soil, 342, 347, 351, 352 Galactopyranosyl fluoride, 8-D-,90 Galactosamine. See Galactose, 2-amino-, 2-0-methyl-, 224 Fucosides, p-D-, 260 2-deoxy-. Fucosyl group, transfer of, by enzymes, Galactosan, oxidn. product, 118 Galactose, D-, 160, 161 262 Fulvic acids, of soil, 337 D-, a-galactosidase inhibition by, 298 2-Furfuraldehyde, 340 D-, p-galactosidase inhibition by, 280, G

284

-D-glucose interconversion, 179 Galactaric acid, 181 D-, incubation with melibiase, 297 Galactitol, from lactose, 187 D-, from isolactal, 200 Galactobiose, 297 D-, metabolism by yeasts, 179, 180 Galactofuranoside, ethyl B-D-,260 D-, mycolates, 212 -, o-nitrophenyl 6-D-,260 in polysaccharides from pathogenic Galactometasaccharinic acid, “(I”-D-. bacteria, 352 See Hexonic acid, 3 - d e o x y - ~ - of soil, 337, 338, 342 xylo-. D-, from wax D, 219, 220 Galactonic acid, D-, 182 -, 2-amino-2-deoxy-~-,of soil, 343, 3-47, D-, 1,4-lactone, 298 352 L-, 1,4-lactone, radiation effect on, 52 from wax D, 220 Galactopyranose, (I-D-, radiation effect -, 1,6-anhydro-3,4-0-isopropylideneon, 38 8-D-, 199 -, 1,2:3,4-di-O-isopropylidene-~-, 198 -, 6-deoxy-. See Fucose. Galactopyranoside, ethyl (I-D-, 293 -, 6-O-@-lactosyl-~-,198 -, ethyl 0-D-,enzymic synthesis of, 257 -, 2(and 6)-O-mycoloyl-~-,232 -, methyl WD-, 293 -, 2,3,4, 6-tetra-0-methyl-D-, 161 hydrolysis of, 295 Galactosidases, (I-, 239, 290 -, methyl P-D-, 161 p-, 239 D-,

SUBJECT INDEX, VOLUME a-,acceptor specificity in presence of,

294 8-, amino acids from, 253 8-, in animals, 240 8-, in a-L-arabinosyl group transfer, 256 8-, binding sites of, 281 p - , from caIf intestine, 246-248 8-, carbohydrate sepn. from, 247-248 &, chem. composition of, 252, 253 8-, detn. of activity of, 241-242 8-, from Escherichia coli, 242-246 8-, in galactosyl group transfer, 255, 263 a-,hydrolysis by, 293, 294 P-D-, hydrolysis of a-L-arabinosides by, 256 8-, hydrolysis of glycosides by, 258,259 8-, imidazolium group of, 266 a-,inactivation of, 298 8-, inhibition of, 273-280, 283, 284, 297 B-, kinetics of, 262, 264, 282 8-, manganese ion in activation of, 242 8-, mechanism of action, 285-289 o-, metals in, 252, 277 8-, in micro-organisms, 240 p - , mol. wt. of, 249 a-,occurrence of, 291 & D - , occurrence of, 178 a-,pH effect on, 297 8-, pH effect on, 254, 265 b-, in plants, 240 a-,properties of, 292 8-, properties of, from different sources, 248-249 &, specificity of, 260 8-, sulfhydryl group of, 273 D-D-, synthesis of, 179 a-,synthesis (induced) of, 298 8-, synthesis (induced) of, 290 8-, temp. effect on, 254 8-, ultraviolet spectrum of, 251 8-, units of enzyme activity of, 242 Galactoside, ethyl P-D-, in 8-galactosidase detn., 241 -, methyl a-D-,oxidn. product, 123 -, methyl 8-u-, oxidn. product, 123 -, methyl 4,G-o-benzylidene-8-~-, oxidn. product, 115 -, o-nitrophenyl 8 - ~ -257, , 275, 280, 284 hydrolysis of, 268-272, 277, 287

16

383

hydrolysis with 8-galactosidase, kinetics of, 262, 264, 283 p H effect on, 264-266 -, p-nitrophenyl P-D-, hydrolysis of, 268-272 -, o-nitrophenyl I-thio-@-D-,280, 281, 282,284 -, p-nitrophenyl I-thio-fl-D-, 282 -, phenethyl l-thio-p-D-, 271, 281 --, phenyl &D-, 280 in 8-galactosidase detn., 241 hydrolysis of, 290 -, phenyl I-thio-D-D-, 280 Galactosides, P-D-, 261 @- D- , 8-galactosidase inhibition by, 280 -, I-thio-D-D-, hydrolysis of, 285 Galactosyl group, transfer by enzymes, 255, 262, 263, 294 Galactosyl phosphate, D-, 176 --, a-D-, 177, 179 Galactotriaose, 297 Galactowaldenase, 177 Gamma rays, effect on acid solns., 19 effect on L-ascorbic acid, 30 Gentianose, 137 Gentiobiose, 88 Glucans, a- and b-, fractionation, 311 Glucaric acid, D-, 181 of soil, 343 Glucitol, D-, acetals, 73 D-, derivs., 65, 66 D-, 1,3:2,4-diacetals, 74 D-, hexanitrate ester, 69 D-, isopropylidene acetals, 77 D- , from lactose, 187, 188 D-, radiation effect on, 38, 45, 47, 48-50 -, 3-0-(acetoxymethyl)-5-0-acetyl-l,6di-O-benzoyl-2,4-0-methylene D-, 70, 73 -, 5-0-acetyl-6-O-benzoyl-l ,3: 2,4-di-Omethylene-n-, 70 -, 5-O-acetyl-l , 6-di-0 -benzoyl-2,4-0methylene-D-, 70 -, 5-O-acetyl-l , 3: 2,4-di -0-ethylideneD-, 66 -, 6-O-acetyl-l , 3: 2,4-di-O-ethylidene5-O-methyl-~-,66 -, 5-O-acetyl-l , 3: 2,4-di-O-ethylidene6-O-trifluoroacetyl-D-, BG -, 3-O-acetyl-l,5,6-tri-O-benzoyl-2,40-methylene-D-, 72

384

SUBJECT INDEX, VOLUME

-, 5-O-acetyl-l , 3,6-tri -0-benaoyl-2 ,4-

16

D-,from D-glucose irradiation, 35, 45 D-,lactone, 54 0-methylene-D-, 71, 72 -, 2,5-anhydro-1,6-di-O-benzoyl-~-, D-,1,4-lactoneJ radiation effect on, 52 D-, from starch irradiation, 35 oxidn. product, 122 -, I ,5-anhydro-4-0-@-~-galactopyrano- D-, from sucrose irradiation, 51, 52 -, 2-keto-. See Hexulosonic acid, DSyl-0-, 199 arabino-. -, 2,4-0-benzylidene-o-, 77 -, tetra-O-methyl-D-, 1,4-lactjoue, 162 -, 1,6-di-O-acetyl-2,4:3,5-di-O-methylGlucopyranose, WD-, radiation effect ene-D-, 73 -, 5,6-di-O-acetyl-l,3:2,4-di-O-methylon, 38 -, 1,6-anhydro-8-~-,88, 96, 199 ene-D-, 73 -, l16-di-O-acetyl-2,4-O-methylene-~-, triacetate, reaction with H F , 87 -, 1,6-anhydr0-2-deoxy-2-p-toluene74, 77 sulfonamido-@-D-,90 -, 3,5-di-O-acetyl-2,4-0-met hylene-l,6-, 0-a-L-fucopyranosyl-(1-4) -0-B-D-gadi -0-propion yl -D-, 74 lactopyranosyl-(1+4)-~-,168 -, 1,6-di-O-benzoyl-2,4:3,5-di-O-nieth-, 0-a-L-fucopyranosyl - (1 -4)-0-@ - Dylene-n-, 70, 71, 72 galactopyranosyl- (1 +3) -0- (2-, 1 , 3:2,4-di-O-ethylidene-~-,77 acetamido -2-deoxy -@ - D-gluco derivs., 65 pyranoeyl)-(l-3)-0-@-~-galac-, 1,3: 2,4 - di - 0 - ethylidene8,6 - di -0topyranosyl- (1+4) -D-,169, 170 (trifluoroacetyl) -D-,66 -0-@-D-ga-, 1,3:2,4-di-O-ethylidene-5-0-methyl--, O-~-~-fucopyranosyl-(l-+2) lactopyranosyl- (1-4) -0- [a- L D-,66 f ucopyranosyl- (1+3) -1-D-, 169 -, 1 , 3:2,4-di-O-methylene-~-,77 -, 2,4:3,5-di-O-methyIene-l,6-di-O-pro-, 4-0-~-~-galactopyranosyl-n-. See pionyl-D-, 74 Lactose. -, 4-O-@-~-galactopyranosyl-~ -. See -, 0-@-D-galactopyranosyl-(1-3) -0-(2acetamido-2-deoxy-8-D-gluceLactitol. pyranosyl)-(l-+3)-0-B-~-galac-, hexa-0-acetyl-, D-, 76 topyranosyl-(l+4)-~-, 169 -, 2,4-0-methylene-~-,72, 74, 78 -, 2,4-0-methylene-l,6-di -0-propionyl- -, 0-~-~-galactopyranosyl-(1+3)-O-[~L-fucopyranosyl-(1-4))-0- (2D-,74 acetamido - 2 - deoxy -8 - D-gluco -, 1,3,5,6-tetra-O-acetyI-2,4-0-benzylipyranosyl)-(l-+3)-0-@-1~-gnlac dene-D-, 76 topyranosyl-(1+4)-~-,170 -, 1,3,5,6-tetra-O-acetyI-2,4-O-meth-, 1,2,3,4-tetra-O-acetyl-@-u-, 198 ylene-D-, 74 -, l15,6-tri-0-acetyl-2,4-O-niethylcnc - -, tri-0-acetyl-1,Z-anhydro-a-I>-,80 Glucopyranoside, a - D - glucopyrarionyl D-, 73 a-D-.See Trehalose. -, 1,5,6-tri-0-benzoyl-2,4-0-methyl-, methyl WD-, 295 ene-n-, 72 -, 1,3: 2,4: 5,6-tri-O-methylene-u-, 74, oxidn. product, 123-127 radiation effect on, 51 75, 77, 79 -, methyl @-D-,88 polyester from adipic acid and, 78 Glucofuranose, 3,5-0-benzylidene-l,2- -, methyl 3-0-beneoyl-4,6-0-benzylidene-a-D-, 63, 64 0-isopropylidene-6 -0- (methyl -, methyl 6-deoxy-6-fluoro-@-~-, 95 sulfonyl)-a-D-, 95 -, 3,5-O-benaylidene-l , 2-04 sopropyli- -, methyl 2-deoxy-2-(N-methyl-p-toluenesulfonamido)-wD-,93 dene-a-n-, 95 -, methyl 2-deoxy-2-p-toluenesulfonaGluconic acid, D-,161, 182 D-,from dextran irradiation, 36, 52 mido-@-D-,90 D-,from D-glucitol irradiation, 40 -, methyl 2-0-methyl-a+, 93

SUBJECT INDEX, VOLUME

-, methyl 6-O-trityl-a-~-,oxic'n. prod-

16

385

-n-galactose interconversion, 179 uct, 122 8-galactosidase inhibition by, 280, Glucopyranosylamine, 3,4,6-tri-O-ace284 tyl-2-amino-2-deoxy-p-~-, 96, 97 from D-glUCitOl irradiation, 48 Glucopyranosyl azide, &D-, 96 from glycolipids, 209 -, 2-amino-2-deoxy-p-n-, derivs., 96, as lactoee precursor, 174 103 from methyl a-u-glucopyranoside -, tetra-0-acetyl-pa-, 97 irradiation, 51 -, 3,4,6-tri-O-acetyl-2-amino-2-deoxy- mycolates, 212 B-D-, 97 oxidn. of, 182 Glucopyranosyl bromide, tetra-0-aceradiation effect on, 32, 35, 38, 39, tyl-ff-D-,66, 88, 96 42, 44, 45, 47, 54 -, 3,4 ,G-tri-O-acetyl-2-amino-2-deoxy- from starch irradiation, 35 ff-D-, 97 structure of, moiety in sucrose, 93 Gliicopyranosyl fluoride, CY-D-, 95 from sucrose irradiation, 51, 52 8-D-, 94 polysaccharides containing, formation CY-D-,reaction with NaOMe, 92 by soil bacteria, 351, 352 0-D-,reaction with NaOMe, 89 D-, oi soil, 337, 338, 342, 352 -, 2-amino-2-deoxy-a-~-,reaction with -, 2-acetamido-2-deoxy-o-, oligosacchaNaOMe, 92 rides contg., 168 -, 4,6-0-benzylidene-~-~-, 95 of soil, 343 -, 2-deoxy-2-(N-niethyl-p-toluenesul--, 2-ncetamido-2-deoxy-3(4, and 6 ) - 0 fonamido)-p-u-, reaction with @-u-galactoSyl-I>-, 261 NaOMe, 93 -, 2-amino-2-deoxy-, of soil, 343, 347, -, 2-deoxy-2-p-toluenesulfonamido-p352 D-, reaction with NaOMe, 90 -, 2-amino-2-deoxy-i)-,294 -, 2-O-methyl-n-, anomers, 94 mycolates, 212 -, 2-o-methyl-p-~-, reaction with from wax D, 220 NaOMe, 93 -, 3-amino-3-deoxy-~-,derivs., 114 -, tetra-0-acetyl-a-n-, 87 -, 2-amino-2-deoxy-2(and 6)-0-myco-, tetra-0-acetyl-p-D-, 87 lOyl-D-, 232 -, 2,3,4-tri -O-benzoyl-a-~-,88 -, 2,3,4-tri-0-benzoyl-6-0-(tetra-0-ace--, 1,2-anhydr0-4-0-p-~-galactopyrnnoSyl-D-, 199 acetyl-@-D-glucopyranosyl)-aD-, 88 -, 1,G-nnhydro-4-O-~-~-galactopyra1io-, G-O-trityl-cu-D(andp-D)-, 95 Syl-b-D-, 199 Glucosamine. See Glucose, 2-amino-2- -, 3(4, and 6)-0-a-~-arabi11osy1-D-, 256 deoxy-. -, 6-deoxy-6-fluoro-D-, 95 -, N-acetyl-. See Glncose, 2-acetamidoderivs., 95, 101 2-deoxy-. -, 2,3: 5,6-di-O-isopropylidene-~-, di Glucose, D-, 161 ethyl acetal, 165 D-, from amylose irradiation 34 -, 1,2-0-ethylene-4-0-p-~-galactopyD-, conformation in lactose, 183 ranosyl-D-, 198 D-, from cord factor, 211, 212 -, &O-&u-galactopyranosyl-D-, 168, 2GO decomp. of labeled, in soil, 351 -, 3-O-p-~-galactosyl-o-, 8-galactosidase D-, from dextran irradiation, 36, 52 in prepn. of, 257 D-, effect on pectin irradiation, 34 hydrolysis of, 255, 256 D-, esters, labeled with CI4 in lactose -, 3(and 4)-O-p-D-gttlaCtOSyl-D-, 261 biosynthesis, 174 -, 4(and 6)-O-p-D-galaCtOSyl-D-,phenylD-, ethyl acetoacetate condensation osazones, 261 product, oxidized deriv., 121

386

SUBJECT INDEX, VOLUME

-,

16

methyl 4,6-0-benzylidene-2-O-p-tolylBUlfOnyl-a-D-, 64 -, methyl 4,6-0-benzylidene-3-O-triBuoroacetyl-a-D-, 63 -, O-u-D-galaCtOSyl-(lj6)-~-a-D-galaCmethylation of, G3 tOSyI-(l+G)-D-, 294 -, 4-0-8-~-glucopyranosyl-~-. See Cello- -, methyl 4,6-O-o-bromobenzylidenea - ~ -oxidn. , product, 115 biose. -, 1,2- 0 -isopropylidene -3,5,6 - tri - 0 - -, methyl 4,6-0-o(and p)-chlorobenzylidene-a+-, oxidn. product, 115 (trifluoroacetyl) -D -, 61 -, methyl 4,6(and 5,G)-di-O-methyl-a-, 6-O-@-laCtoSyl-D-,198 D-, oxidn. product, 122 -, 2(and 6)-O-mycoloyl-o-, 232 -, 1,2,3,4,6 -penta - 0 - acetyl -CI (or 8) - -, methyl 4,6-0-ethylidene-a-~-,oxidn. product, 115 D-, reaction with HF, 87 -, 3,4,6-tri-O-acetyl-2-amino-2-deoxy--, methyl 4,6-0-ethylidene-B-~-,69 -, methyl tetra-0-acetyl-a-w, 67 D-, derivs., 80 -, 2,3,4-tri-O-methyl-n-, from cord -, methyl tetra-0-propionyl-a+, 67 -, methyl 2,3,4,G-tetra-O-(trifluorofactor, 212 acetyl)-a-D-, 61 -, 2,3,G-tri-o-methyl-~-,161 Glucose-C14, D-, self-decompn. of, 54, 55, Glucosone, D-, 161 from dextran irradiation, 52 56, 57 from D-fructose irradiation, 46 Glucose oxidase, in soil, 349 from D-glUCOSe irradiation, 46 GlucoBide, benzyl 2,3,4 ,0-tetra-0-(trifrom D-mannose irradiation, 43, 44 fluoroacetyl)-P-D-, 61 from sucrose irradiation, 51, 52 -, methyl WD-, oxidn. product, 123 Glucosyl bromide, tetra-0-acetyl-a+, -, methyl P - D - , 92, 294 reaction with silver fluoride, 87 oxidn. product, 123 Glucosyl phosphate, D-, 176, 177 oxidized, alkali reaction with, 154 a-D-,177 -, methyl 4-0- (1-acetoxyethyl)-6-0Glucuronic acid, D-, from dextran irradiacetyl-p-D-, 69 ation, 36 -, methyl 2(and 3)-0-acetyl-4,6-0D-, from D-glucose irradiation, 35 benzylidene-a-D-, 64 from starch irradiation, 35 -, methyl 3-amino-4,6-0-benzylidene- D-, D-,from sucrose irradiation, 51,52 ~-3-dcoxy-D-,114 -, tri - 0 - acetyl - 1- bromo - 1- deoxy - I), -, methyl 2-arnino-2-deoxy-8-1~-,92 methyl ester, 66 -, methyl 2-0-benzoyl-4,6-0-benzyli- Glyceritol, 295 dene-a-o-, 63, 64 from methanol-Cl4, 24 -, methyl 2-0-benzoyl-4,6-0-benzyli- 1 (and 2)-phosphates, x-ray effect on, dene-3-O-p-tolylsulfongl-a-~-, 28 64 -, 2-0-@-~-galactopyranosyl-, 164 -, methyl 4,6- 0 - benzylidene - CY - D - , -, 1-0-methyl-&, 122, 126, 127 oxidn. product, 107, 111-115, -, 1-0-methyl-L-, 122, 126 121 Glyceritol-l,S-Cs14, in lactose biosynoxidn. product, alkaline degradation thesis, 175 of, 155 Glycerol. See Glyceritol. -, methyl 4,6-O-benzylidene-@-~-,Glycerose, phenylosazone, 152 oxidn. product, 115 -, 3-O-~-arabinofuranosyl-, phenylosa-, methyl 4,6-0-benzylidene-3-deoxyzone, 139 3-phenylazo-a-~-,114 Glycine, N-lactosyl-, 194 -, methyl 4,6-0-benzylidene-2,3-di-Glycolic acid, radiation effect on, 30-31, 0-(trifluoroacetyl)-a-D-, 61, 63 32

-, 6-0-8-D-galaCtoSyl-D-, 8-galrtctosidase i n prepn. of, 257 hydrolysis of, 255, 256

SUBJECT INDEX, VOLUME

Glyc01ic-C~~ acid, calcium salt, 32 Glycolipids, of acid-faat bacteria, 209 biological activities of, 230 carbohydrates of, 208, 209 glycosidic, 223 peptido-, 218 Glycols, a-, reaction with periodates, 105, 106 Glycopeptides, 222 Glycosidases, 261 reactions of, 255 Glycosides, 207 6-deoxyB-fluoro-, reaction with almond emulsin, 95 enzymic synthesis of, 257 hydrolysis of, by &galactosidases, 258, 259 inositol, 207 phenolic, of soil, 339, 344 phosphatidyl-inositol, 228 prepn. of, 88 -, methyl 4,6-0-alkylidene-, oxidn. products, 111 Glycosiduronic acids, of soil, 346 Glycosylamines, rearrangements of, 194 Glycosylation, trans-, glycosidase catalyzed, 255 Glyco~ylazides, 102 Glyco~ylfluorides, properties of, 98 -, 2-amino-2-deoxy-~-,properties of, 100 Guanosine, oxidn. product, 128 Guloheptulosan, L-. See Heptulopyranose, 2,7-anhydro-p-t-gulo-. Gulonic acid, L-, from D-glucitol irradiation, 49 D- (and L)-, 1,4-lttctones, radiation effect on, 52 Gulosan, oxidn. product, 118 Gulose, L-, from D-glUCitOl irradiation, 48 -, 3-amino-l,6-anhydro-3-deoxy-~-, 118 Guloside, methyl WD-, oxidn. product, 123 -, methyl 4,6-0-benzylidene-p-~-, oxidn. product, 115 Gynolactose, 168 G value, detn. of, 18 the term, 18

H Hemiacetals, 108 Hemialdal group, 106, 110

16

387

Hemialdals, 108, 109 conformation of, 116, 117 Hemicelluloses, decomp. of labeled, in soil, 351 fractionation of, 311 in soil, 349 Heptonic acid, 4-O-~-~-galactopyranoSyl -D-glyCt?rO-D-gUb,195 Heptopyranose, 1,7-anhydro-~-glycero8-o-gulo-, oxidn. product, 129 Heptopyranosi de, phen yl D-glycero -a-D galacto-, 292 Heptoses, 0-methyl-, of soil, 342 Heptulopyranose, 2,7-anhydro-p-~altro-, oxidn. product, 129 -, 2,7-anhydro-&~-gulo-,oxidn. product, 129 -, 2,7-anhydro-p-~-ido-,oxidn. product, 129 1-Hexene, effect on EtOH irradiation, 23 Hexitols, cyclic acetals, 72, 74 derivs., 76 radiation effect on, 47 Hexokinase, 254 Hexonic acid, 3-deoxy-~-zylo-,189 -, 2-0x0-D-arabino-. See Hexulosonic acid, D-arabino-. Hexosamines, 66 Hexose, 3,6-anhydro-~-arabino-, phenylosazone, 191 -, 3,6-anhydro-~-ribo-,phenylosazone, 191 phenylosotriaxole, 192 -, 3,6-anhydro-4-0-~-~-galactopyrttnosyl-D-ribo-, phenylosazone, 192 phenylosotriazole, 192 -, D-arabino-, phenylosazone, 190, 191 -, 2-deoxy-~-lyxo-,262 -, 3-deoxy-~-xylo-,262 -, 4,5 -di -0- acetyl -3,G -anhydro - D arabino-, phenylosazone, 191 -, 3,6-dideoxy-o-zylo-, 262 -, D-lyzo, phenylosazone, 201 -, 2-oxo-~-arabino-.See Glucosone, D-. Hexoses, deoxy-0-methyl-, of glycolipids, 209, 223 G-deoxy-, of soils, 347 0-methyl-, of soils, 342 radiation effect on, 36 of soil, detn. of, 344 Hexosides, 8-deoxy-~-xylo-,2GO

388

SUBJECT INDEX, VOLUME

16

Hexosulose, D-arabino-. See Glucosone, by amylose, 301, 302 by starch, 301 D-. Hexulose, 1,6-anhydro-~-efylhro-,2,3complex with amylose, structure of, 303 phenylosazone, 201 -, 1,5-anhydro-4-0-8-~-galactopyrano-Ionization, by radiation, 14, 15 syl-D-arahino-, 201 Isoglucal, D-,and pentaacetate, 200 -, 1,5-anhydro-4-0-j3-~-galactopyranoIsolactal, 200 syl - D - erylhro - , 2,3 - phenyl- Isomaltose, from dextran irradiation, 36 Isomaltotriose, from dextran irradiation, osazone, 201 -, 5,6-dideoxy-~-threo-,131 36 -, 4-0-8-~-galactopyranosyl-~-arabino-. Isosaccharinic acid, “@’-D-, 189 iia , I -D-, calcium salt, 163 See Lactulose. -, D-lyzo-. See Tagatose, D-. ‘ W ’ - D -lactone, , 188, 189 Hexulosonic acid, D-arabino-, 354 K from D-fructose irradiation, 46 from D-mannOSe irradiation, 43 Ketone, isobutyl methyl. See 2-Pentafrom sucrose irradiation, 51, 52 none, 4-methyl-. -, 4-O-8-D-galaCtOpyranOSyl-D-aTabinO-,Ketones, alkyl aryl, 68 183 Ketoses, 1-amino-1-deoxy-, 194 5-Hexulosonic acid, D - ~ ~ / z o47- , Koenigs-Knorr reaction, 197, 198 Hibbert, Harold, obituary of, 1 1 Humic acids, 353 Lactal, 200 of soil, 337, 346 hydroxylation of, 200 Humus, 336, 337, 348 -, hexa-0-acetyl-, 165 Hyaluronic acid, radiation effect on, 33 ozonolysis of, 200 Hydrogen, formation in irradiation of prepn. of, 199 water, 16-19 reaction with alkali, 200 Hydrogen peroxide, formation in irradiarearrangement of, 200 tion of water, 17, 18 Hydrolysis, of 0-arabinosylglucoses, 256 Lactaminic acid. See Neuraminic acid, N -acetyl-. of glyco~idesby 8-galactosidases, 258, Lactase. See Galactosidme, P-D-. 259 Lactic acid, 28 of trifluoroacetates, 61, 63 Hydroxyl (radical), formation in irradia- Lactitol, 187, 188 IAaclobacil~u8 bijidus, 166, 107 tion of water, 16, 19 var. pennsylvanicus, 167 I Lactobionic acid, 161, 180, 182 I dohep t ulosan , u -.See Hcpt ulopy ranose , calcium salt, 183 oxidn. of, 183 2,7-anhydro-&-~-ido-. Idose, 3-amino-l,6-anhydro-3-deoxy-~-, 1,5-lactone, 162 118 -, 2-keto-. See Hexulosonic acid, 4-0-8Inositol, derivs., 228 D -galactopyranosyl -D -arabino-. glycosides, 207 -, octa-0-methyl-, 162 hexaacetate, 2% Lacto-N-difucohexaose, 168, 170 myo-, and phosphates, 227 Lactodif ucotetraose. See Glucopyranosc, and phosphates, of soil, 343 0-a-L-fucopyranosyl-(1-12) -0myo-, from phospholipids, 225 8-n-galactopyranosyl - (1+4) -0myu-, radiation effect on, 38 [a-~,-fucopyranosyl-(1+3)J-o-. Invertase, in soil, 349 Lacto-N-fucopentaose I. See GlucopyraIodine, adsorption, by amylopectin, 301, nose, 0-a-L-fucopyranosyl(1+2)-0-8-~-galactopyranosyl 303

SUBJECT INDEX, VOLUME

(1-+3)-0-(2-acetamido -2-deoxy 8 - D - glucopyranosyl) - (1-+3)-08-D-galactopyranosyl-(1-+4)-~-. Lacto-N-fucopentaose 11. See Glucopyranose, 0-8-~-galactopyranosyl(143) - 0 - [(Y- L - fucopyranosyl (1-+4)] - 0 -( 2 - a c e t a m i d o - 2 - d ~ oxy-8-u-glucopyranosyl) - (1-+3) O + - D -galactopyranosyl-(1-+4)D-.

Lacto-N-pentaose, 171 Lactopyranoside, ethyl a-,and derivs., 195 -, ethyl hepta-0-acetyl-a-, 195 -, ethyl hepta-0-methyl-a-, 195 Lactosamine. See Lactose, 2-amino-2deoxy-. Lactose, alkali degradation of, 188-189 alkyl carbonates, 190 a-, 260, 261 a - and B-, 203-204 a-, hydrate, 203 anhydro derivs., 198-199 8-, 261 biosynthesis of, 173-178 in blood, 173 compd. with pyridine, 193 in chromatography, 205 crystalline forms of, 201-202 derive., 8-D-galactosidase hydrolysis of, 179 detn. of, 182 diethyl dithioacetal, 195 dithioacetals, 195 esters, 195-197 with fatty acids, 196 in 8-galactosidase activity detn., 241 8-galactosidase inhibition by, 280 in prepn. of, 257 D-glucose conformation in, 183 hydrogenolysis of, 188 hydrolysis of, 161, 181, 255, 256, 268271, 283 labeled with C", 174-175 metabolism of, 178-180 mutarotation of, 201, 203 nitrogen heterocyclic compda. from, 193, 194 occurrence of, 165 octanitrate ester, 196 octa(phenylurethan), 196

16

389

"over-oxidn.", 186 oxidn. of, 164, 180, 181-187 oxime, 183 phenylhydrazone, hydrogenation of, 192 phenylhydrazones, 192 phenylosazone, lG4, 189-192 heptaacetate, 191 oxidn. of, 190 physical properties of, 201-206 in plants, 173 reaction with NHa and amino compds., 193 with glycine, 194 with hydrazines, 189 with proteins, 194 redn. of, 187-188 electrolytic, 188 reversion of, 181 skin absorption of, 173 solubility of, 204 spectrum of, 205 structure of, 160-165 thermodynamic properties of, 205 unsatd. derivs., 199-200 in urine, 172-173 -, N-acetyl-0-acetylneuramino-, 171 -, N-acetylneuramino-, 171, 172 -, 2-amino-2-deoxy-, 192 -, anhydro-, phenylosazone, and its pentaacetate, 191 -, 0-fucosyl-, 168 -, hepta-0-acetyl-, 196 -, octa-0-acetyl-, 19F (Y anomer, 195,196 8 anomer, 195, 196, 197 -, octa-0-[p-(p-nitropheny1azo)benzoyll-a (and 8)-, 196 -, 1-thio-, 195 Lactose4 -C", reaction with proteins, 194 Lactoseen, hepta-0-acetyl-, 201 Lactoside, benzyl hepta-0-acetyl-8-, 198 -, (2-chloroethyl) hepta-0-acetyl-8-, 198 -, (3-chloropropyl) hepta-0-acetyl-8-, 198 -, cholesteryl hepta-0-acetyl-8-, 198 -, deoxycorticosterone hepta-0-acetyl8-, 198 -, (2-hydroxyethyl) hepta-0-acetyl-8-, 198 -, l-menthyl hepta-0-acetyl-8-, 198

390

-,

SUBJECT INDEX, VOLUME

methyl j3-, 136, 197

16

from starch irradiation, 35 radiation effect on, 50 Maltotriose, from amylose irradiation, 34 Mannans, 139 Lactosides, 197-198 D-, 91 of alkaloids, 194 in hexokinme, 254 Lactosone, 161, 192 in soil, stability of, 350 oxidn. of, 183 “Manninositose,” 225 Lactosuria, 172 Mannitol, D-,49, 295 Lactosylamine, derivs., 193 D-, hexanitrate, 69 derivs. of sulfa drugs, 194 D-, isopropylidene acetals, 77 -, N-octadecyl-, 193 D-, radiation effect on, 47 -, N-p-tolyl-, 194 of soil, 343 Lactosyl bromide, hepta-0-acetyl-a-, -, 0-(acetoxymethy1)-0-acetyl-l,3: 2,5196, 197, 198 di -0-met hylene-D -,75 hydrogen bromide removal from, 201 -, di-0-(acetoxyme thyl) -di-0-acetylreaction products with alkaloids, 194 2,5-0-methyIene-n-, 75, 76 with pyridine, 194 -, 3,4-di-0-acetyl-l,2:5,6-di-0-i~oproredn. of, 199 pylidene-D-, 76 Lactosyl chloride, hepta-0-acetyl-a-, -, hexa-0-acetyl-n-, 75 196, 197 -, hexa-O-(trifluoroacetyl) - D - , 61 Lactosyl fluoride, a-,197 -, 1,3:2,5: 4,6-tri -0-benzylidene-D-,76 Lactosyl iodide, hepta-0-acetyl-a-, 197 -, 1,3: 2,5:4,6-tri -O-methylene-~-,75 Lactosyl phosphate, 178 Mannobioside, phosphatidylinositol D-, a- and j3-, 196 227-228, 237 Lncto-N-tetraose. See Glucopyranose, Mannonic acid, D-, from D-mannose ir 0-8-D-galactopyranosyl- (1-+3)radiation, 39, 42, 43, 44 0 - (2-acetamido-2-deoxy-j3-~-Mannopyranose, 1,6-anhydro-2,3-0-isoglucopyranosy1)- (1+3) -0-j3-Dpropylidene-D-, 165 galactopyranosyl- (1-14) - D - . -, 6-0-a-~-mannopyranosyl-a-~-, 228 Lactotriaose, 179, 261 -, penta-0-acetyl-&D-, 47 Lactulose, 189 Mannopyranoside, a-D(and b-D)-manno-, 1-amino-1-deoxy-, 192 pyranosyl W D - , 91, 92 Levans, formation by soil micro-organ- -, methyl a - D -90 , isms, 351 -, methyl 3-amino-3-deoxy-a-~-,hydroLevoglucosan, diacid from, 129 chloride, 126 oxidn. product, 118 , 91 Mannopyranosyl fluoride, a - D -90, Levomannosan, oxidn. product, 118 Mannose, D-, compds. from irradiation LYXOSe, D-, 189 of, 40 D-, from D-mannose irradiation, 42 D-,from glycolipids, 209 D-, from n-mannitol irradiation, 47, 49 M D-,polymerization in irradiation of, 44 Magnesium sulfate, in starch fractionapolysaccharides contg., formation by tion, 328 soil bacteria, 351, 352 Magnesium sulfite, in starch fractionaD-, radiation effect on, 39-45, 47 tion, 314 of soil, 342 Malic acid, 28, 29 D-,from wax D, 219, 220 Maltose, aa acceptor in transgalactosyl- -, 4-0-~-~-galactopyranosyl-~-, 165, 200 ation, 262 -, tetra-O-acetyl-4-0-(tetra-O-acetyl-~from amylose irradiation, 34 D -galac t opyranosyl) -a+-,165 oxidn. of, 184 -, 2,3,4, B-tetra-O-rnethyl-~-,228

-, 2-naphthyl 1-thio-B-, 199 -, phenyl 8-, 199 -, phenyl 1-thio-8-, 198

SUBJECT INDEX, VOLUME

16

391

-, 2,3,4-tri-O-methyl-~-,228 8-galactosidase inhibition by, 283 Mannose-04, D-, self-decompn. of, 57 oxidn. products, 108 Mannose-I-C", D-, radiation effect on, 41 of soil, 337 Mannoside, methyl a-D-,294 in soil, stability of, 350 oxidn. product, 123 -, 1,6-anhydro-, oxidn. products, 118 -, methyl B-D-, oxidn. product, 123 -, 3,6-anhydro-, osotriazoles, 119 -, methyl 4,6-0-benzylidene-a-~-, Mor, 336, 348 oxidn. product, 115 Mucic acid. See Galactaric acid. -, methyl 4-0-8-D-galaCtOpyranOSyl-a- Mull, 336, 348 D-,201 Muramic acid, 220 Mannosyl fluoride, 3,6-di-O-acety1-4- Mutarotation, of osazones, 190 0 - (2,3,4,6-tetra-0-acetyl-8 - D - Mycocerosic acids, 224, 230 glUCOSyl)-a-D-, 86 Mycolanoic acid, 211 Mannotriaoside, phosphatidylinositol D-, -, 3,x-dihydroxy-, 218 238 -, 3-hydroxy-, 211 Mannuronic acid, D-, from D-mannitol -, 3-hydroxy-x-methoxy-, 218 irradiation, 47 [I-Test], 211 D-, from D-mannOSe irradiation, 39, 42, -, 3-hydroxy-x-oxo-, [3-BCG], 211 43, 45 Mycolic acids, 209, 211 Melezitose, 137 biological activity of, 230, 235 Melibiase. See Galactosidases, a - . from cord factor, 211 Melibiose, hydrolysis of, 290, 293, 294 esters with monosaccharides, 212 Methanol, amylopectin precipn. by, 226, as haptens, 234 227 nomenclature of, 211 irradiation of, 24 Mycoside A, 209, 223, 224 reaction with trifluoroacetates, 61 Mycoside B, 207, 209,223, 224 reaction with methyl 4-0-methyl-2,3- Mycoside C, 207, 223, B4-225, 226 di - 0 - (trifluoroacetyl) - (Y - L - Mycosides, 209, 223 rhamnopyranoside, 64,65 Methanol-04, self-decompn. of, 24, 54 N Michaelis constant, of hydrolysis of Neolactose. See Altrose, 4-0-8-~-galactoglycosides with 8-galactosidases, pyranos yl -D-. 258 -, a-chloroacetyl-, 197 Milk sugar. See Lactose. Neuraminic acid, 171 Monofuco-di-(lacto-N-tetraose),171 Monofuco-lacto-N-tetraose I. See Gluco- -, N-acetyl-, 171 Nitrogen, in soil, 337, 347 pyranose, 0-a-L-f ucopyranosylNucleic acids, phosphate from, after (1-2) -0-p- D-galactopyranosyl irradiation, 27 (1-3) -0-(2-acetamido-2-deoxyradiation effect on, 26-28 &D - glucopyranosyl) - (1+3) -0Nucleosides, oxidn. products, 127 8-~-galactopyranosyl-(l+4)-D-. Nucleotides, 15G Monofuco-lacto-N-tetraose 11. See Glupurine, radiation effect on, 28 copyranose, 0-8-D -galactopyrapyrimidine, radiation effect on, 28 nosyl - (143)- 0-[a- L - fucopyra nosyl- (1-4)]- 0-(2-acetamido-20 deoxy - 8 - D - glucopyranosyl) (1-3) - 0 - j3 - D - galactopyra - Obituary, of Harold Hibbert, 1 nosyl-(l+4)-~-. 1-Octanol, in amylose fractionation, 304 Monofuco-tri- (lacto-N-tetraose) , 171 2-Octanol, in starch fractionation, 301, Monosaccharides, adsorption by clays, 302 338 Octyl alcohol. See 1-Octanol.

392

SUBJECT INDEX, VOLUME

Oligosaccharides, as acceptow in glycosy1 transfers, 262 2 -acetamid0 - 2 - deoxy - u - glucose contg., 168 from cow’s milk, 171 a-D-galactose-contg., 290 lactose-contg., of milk, 165-171 nitrogen-contg., 168 nonreducing, 91 prepn. of, 88, 198 sialic acid-contg., 168 in soil, stability of, 350 by transglycosylation, 179 Osazones, anhydro derivs., 191 formation of, mechanism of, 192 mutarotation of, 190 Oxalacetic acid, 29 -, hydroxy-, 30 Oxyalginic acid, 153 derivs., 158 Oxyamygdalin, 136 Oxyamylopectin, 143, 145 Oxycellulose, 108, 137, 140 acetates, 152 alkaline degradation of, 153, 154, 156 cuprammonium fluidity of, l r i nitrates, 151 oxidn. of, 150 physical properties of, 146-147 prepn. of, 146 reaction with a h . , 150, 151 with N compds., 147-148 redn. of, 149 sodium dichromate, 108 stabilization towurd alkuli, 156 uties of, 158 -, amino-, 148 Oxydextran, 153 Oxyinulin, 153 derivs, 158 Oxyraffinose, 137 Oxystarch, 139 aldehyde content of, 141 derivs. as antitubercular s u bs tances, 158 hydrogenation of, 145 oxidn. of, 145 physical properties of, 141 prepn. of, 140 reactions of, 142

16

reaction with N H 3 , 143 with MeOH, 142 with N compds., 144-145 water-soluble, 158 uses of, 157-158 Oxysucrose, 108, 134-135 pheoylhydrazine deriv., 140 Oxytrehalose, 135, 136 Oxyxylan, 152

P Pectins, radiation effect on, 33, 34 in soil, stability of, 350 a-pentanone, 4-methyl-, in starch fractionation, 302 Pentasol. See Amy1 alcohols. Pentonic acid, 3-deoxy-2-C-(hydroxymethyl)-, 167 Pentopyranosides, methyl a - ~ -osidn. , products, 109 Pentoses, of soils, detn. of, 345 Peptides, reaction of, with phenyl trifluoroacetate, 62 with trifluoroacetic anhydride, 62 from wax D, 220 Periodates, oxidn. of a-glycols by, 105, 106 Phenols, reaction with acyl trifluoroacetates, 81 Phosphates, from nucleic acids after irradiation, 27 Phosphoglycolipids, 209, 225 biological activity of, 231, 234 Phospholipids, 225 antigenic effect of, 233 nitrogen-contg., 233 nitrogen-free, 225 Phosphoric acid, alkyl entcrri, rutlirtlion effect on, 28 Phthienoic acids, 230 as haptens, 234 Phytase, in soil, 349 “Pmko,” antigenic properties of, 234 effect on leucocytes, 231 hypersensitivity induction by, 234 immunizing activity of, 237 Polygalacturonase, in soil, 349 Polygalitol, oxidn. product, 130 Polymerization, in D-glucose irradiution. 45

SUBJECT INDEX, VOLUME

16

393

on pyrimidine nucleotides, 28 in D-mannose irradiation, 44 on water, 1 6 1 7 in sugar irradiation, 32 excitation and ionization of gases by, Polysaccharides, from Bacillus mega15 therium, 351, 352 excitation of molecules by, 15 effect on soil structure, 337, 353 hydrogen and hydrogen peroxide foresters, 218 mation in, of water, 17, 18 extraction from soil, 338-340 hydrogen and hydroxyl radical formaformation by soil micro-organisms, 351 tion in, of water, 16, 19 of Mycobaclerium tubercitlosis, m , 222 ionization by, 14, 15 mycolates, 219 measurement of, 21-22 nonreducing, 91 Raffinose, 7-ray effect on, 52 oxidized, 137-140 hydrolysis of, 293 from pathogenic bacteria, 352 Ramalin, 325 phospholipo-, 233 Reaction kinetics, of hydrolysis of glyradiation effect on, 33 cosides with 8-galactosidases, of soil, 338, 341, 342 258 from soil, attempted fractionntion of, Reductone, from D-fructose irradiation, 341 47 purification of, 340, 341 Rhamnopyranoside, methyl WL-, oxidn. i n soil, degradation of, 350 product, 109, 110 in sucrase, 254 oxidized, alkali effect on, 153 2-Propano1, complex with tmylosr, 321 -, methyl 3-0-acetyI-2,4-di-O-methyl2-Propanone, 1,3-dihydroxy-, from I)CU-L-, 65 fructose irradiation, 47 -, methyl 3-0-acetyl-4-0-methyl-~~-~-, phosphate, 28 65 Pseudolactal, 200 -, methyl 2,3-0-isopropylidene-a-~-, 64 -, penta-0-acetyl-, prepn. of, 200 -, methyl .l-O-methyl-a-~-,64 reaction with alkali, 200 Psicose, 3,6-anhydro-~-, osotriazolr -, methyl 4-0-methyl-2,3-di-O-(trifluoroacety1)-a-L-, 64 oxidn. product, 119 reaction with MeOH, 64,65 Pyritline, trifluoroacetylation in pres-, methyl 4-0-methyl-3-0-trifluoroaceence of, 62 tyl-a-L-, 65 Pyridinium chloride, l-I)-glucopyrnnoRhamnose, L-, 294 Ryl-, 94 polysaccharides contg., formation by -, l-(2-0-methy~-~-g~ucopyranosyl)-, 94 soil bacteria, 351, 352 hepta-O-acetyl-@-lactosyl Pyridinium of soil, 337, 342, 347 sulfate, 1-(hepta-0-acetyl-p-lac-, 2,4-di-O-methyl-, 64-65, 224 tosyl)-, 194 -, 3,4-di-O-methyl-, 224 Pyruvaldehyde, in soil, 350 -, 3,4-di-O-methyl-~-,65 Pyruvic acid, 28 -, 2-O-methyl-, 224

R Radiation, chemical changes by, 13 effect on a h . , 22-26 on alkyl phosphates, 28 on carbohydrates, 30, 32 on glycolic acid, 30-31, 32 on nucleic acids, 2 6 2 8 on purine nucleotides, 28

, Rhamnoside, methyl a - ~ -107 Rhamnosides, of soil, 344 Ribonucleic acids, of soil, 344 -, deoxy-, of soil, 344 Ribose, D-, 294 of soil, 338, 342 from hydrolyzed bacterial cultures, 351, 352 -, 5-deoxy-5-fluoro-o-, derivs., 95, 101

394

SUBJECT INDEX, VOLUME

Riboside, methyl 3-amino-3-deoxy-BD(and &L)-, 118

s Saccharic acid. See Glucaric acid. Saccharides, acidic, of milk, 171 from irradiation of amylose and starch, 34 Saccharinic acids, from lactose, 188 Sedoheptulosan. See Heptulopyranose, 2,7-anhydro-&~-altro-. Sialic acid, 171 oligosaccharides contg., 168 Sodium hydroxide, starch leaching by, 306 Sodium sulfate, starch fractionation by, 328 Solanine, 137 Sorbitol. See Glucitol, D-. Sorbose, L-, 294 Spurs, the term, 16 Stachyose, 137 Starch, complexes, 303 complexes with alkaline-earth hydroxides, 326 degradation and solubilization of, 323 degradation of, decrease in, by magnesium sulfite, 314 temp. and, 314 dialdehyde. See Oxyatarch. dissolution of, 326 fractionation of, 312, 314, 324, 325, 327 acids in, 326 alcs. in, 320 alkalis in, 326 1-butanol in, 300 chloral hydrate in, 307 -contg. raw materials, 329 2-methyl-1-butanol in, 311 2-methyl-2-butanol in, 326 salt solutions in, 310 by sulfates in, 328 fractionation of, of low molecular weight, 329 gelatinization temp. of, magnesium sulfate effect on, 313 hydrolysis products, fractionrttion of, 311

16

iodine adsorption by, 300, 301 leaching, by sodium hydroxide, 306 by water, 306 properties of fractions from potato, 331 radiation effect on, 34, 35 salting-out of, 312, 316 in soil, stability of, 350 solubilization temp., 313 solutions of, 310 system: magnesium sulfate-wuter-, 317 Streptamine, N,N'-dibenzoyl-, oxidn. products, 109, 110 Strontium hydroxide, complex with starch, 327 Styracitol, oxidn. product, 130 Succinic acid, 0x0-. See Oxalacetic acid. Sucrase, 254 Sucrose, as acceptor in transgalactosylation, 262 effect on pectin irradiation, 34 8-galactosidase inhibition by, 280 octaacetate, 67 radiation effect on, 32, 60,51, 52 structure of D-frllCtOSe moiety in, 93 of D-glucose moiety in, 93 Sucrose-C~4,self-decompn. of, 55, 50 Sugars, amino, of soil, 338, 343 detn. of, 346 effect on plant growth, 354 esters with alanine, 207 irradiation of, polymerization i n , 32 0-methyl-, of soil, 342 radiation effect on, 36, 39 reducing, in soil, 346 Sulfone, 8-D-glucopyranosyl phenyl, oxidn. product, 130 Sulfones, 69 Superlose, 325

T Tagatose,

D-,

189

-, 3,6-anhydro-~(and L)-, osotrinzole oxidn. products, 119 Takadiastase, 240 Talose, 6-deoxy-, 224 -, G-deoxy-3-O-methyl-, 224 Tartaric acid, 30, 31 Tetralactose, 198

SUBJECT INDEX, VOLUME

16

395

W “Theta temperature,” 325 Trehalose, 295 Water, hydrogen and hydrogen peroxide a#-, 88 formation from, by radiation, 17, from cord factor, 212 18 esters, 217, 232 hydrogen and hydroxyl radical forwith 2-eicosyl-3-hydroxytetracosamation in irradiation of, 16, 19 noic acid, 217 radiation effect on, 15-17 with fatty acids, 210 Wax C, 210 and esters, 209 adjuvant action of, 236 from glycolipids, 209 cord factor in, 210 octaacetate, 67 hypersensitivity induction by, 234 -, di-0-acetyl-6,6’-di-O-mycoloyl-, 214 Wax D, 207, 209, 210 -, 6,6‘-di-0-corynomycoloyl-,217, 233 adjuvant action of, 235-237 -, 2,2’-di-0-(3-hydroxy-x-methoxymy- antigenic properties of, 233 colanoy1)-, 215 biological activity of, 230, 231, 234, 235 -, 2,2’-di-O-mycoloyl-, 232 composition of, 218-222 -, 6,6’-di-O-mycoloyl-, 214, 215, 216, 232 cord factor in, 210 aa structure for cord factor, 212 properties of, 219 -, 6,6’-di-O-p-tolylsulfonyl-, 215, 216 structure of, 221 -, 2,3,4,2‘, 3‘,4‘-hexa-O-acetyl-6,6’-dideoxy-6,6’-diiodo-, 216 X -, 2,3,4,2’,3’, 4’-hexa-O-acety1-6 ,G’-di- X-rays, diffraction of, by amylose, 330 0-mycoloyl-, 215, 216 diffraction of, by butanol-amylose, 303 -, 2,3,4,2’,3’,4’-hexa-O-aeetyl-6,6’-di- by iodine-amylose, 303 0-p-tolylsulfonyl-, 215 effect of glyceritol l(and 2)-phos-, 6-O-mycoloyl-, 214, 232 phates, 28 -, 2,6,6’-tri -0-mycoloyl-, 214,232 Xylan, in soil, stability of, 350 lH-1,2,3-Triazole, 4-phenyl-l-(tetra-O- Xylitol, 1,4-anhydro-, oxidn. product, acetyl-p-D-glucopyrmosyl)-, 97 130 Xylopyranoside, methyl WD-, oxdn. prodU uct, 118 Uridine, 5-(D-galactosyl pyrophosphate), Xylopyranosyl bromide, tri-0-acetyl-aD-,87 180 Xylose, D - and L-, 294 5-(~-glucosylpyrophosphate), 17ti L-, from D-glucitol irradiation, 48 oxidn. product, 128 D-,phenylosazone, 152 5-pyrophosphate, 177 polysaccharides contg., formation by 5-triphosphate, 177 bacteria, 351,352 Uronic acids, polysaccharides contg., in soil, 337, 338, 342, 352 formation by soil bacteria, 351, Xyloside, methyl a-D-,oxidn. product. 352 117 of soil, 342, 346 -, methyl 8-D-,oxidn. product, 115 detn. of, 345 -, methyl 3-amino-3-deoxy-p-~-,118

CUMULATIVE AUTHOR INDEX FOR VOLUMES 1-16 BOBBITT,J. M., I’eriodate Oxidntioii of A Carbohydrates, 11, 1-41 ADAMS,MILDREI). See Culdwell, Mury L. B~ESEKEN, J., The Use of Boric Acid for ANDERSON, ERNEST,and SANDS,LILA, the Determination of the ConfiguraA Discussion of Methods of Value in tion of Carbohydrates, 4, 189-210 Research on Plant Polyuronides, 1, BONNER,T. G., Applications of Tri329-344. fluoroacetic Anhydride in CarboANDERSON,LAURENB. See Angyal, S. J . hydrate Chemistry, 16, 59-84 ANGYAL,8.J., and ANDERSON, LAURENS, BONNER, WILLIAMA., Friedel-Crafts and The Cyclitols, 14, 135-212 Grignard Processes in the CarboASPINALL,G. O., The Methyl Ethers of hydrate Series, 6, 251-289 Hexuronic Acids, 9, 131-148 E. J., and PEAT,STANLEY, The ASPINALL, G. O., The Methyl Ethers of BOURNE, Methyl Ethers of D-Glucose, 5, 145D-Mannose, 8, 217-230 190 ASPINALL, G . O . , Struct,ural Chemistry BOURNE, E. J. See also, Barker, S. A. of the Hemicclluloses, 14, 429-468 BOUVENG,H. O., and LINDBERO,B., R Methods in Structural Polysaccharide Chemistry, 15, 53-89 BALLOU,CLINTONE., Alkali-Jensitive BRAY, G., D-Glucuronic Acid in Glycosides, 2, 59-95 Metabolism, 8, 251-275 BARKER, G . R., Nucleic Acids, 111 285BRAY,H. G,, A N D STAcEY,M., Blood

-

333 Group Polysaccharides, 4, 37-55 BARKER,8. A . . nnd BOURNE,E. J.. Acetals nnd’Ketds of the Tetritok; C Pentitols and Hexitols, 7, 137-207 BARRETT,ELLIOTTP., Trendn in the CAESAR,GEORGEV., Starch Nitrato, 13, Development of Granular Adsorb331-345 CALDWELL, MARYL. and AIMMS, MILents for Sugar Refining, 6,205-230 JOHN, DRED, Action of Certain Alptin BARRY,C. P., and HONEYMAN, Fructose anti its Derivatives, 7, Amylaaes, 5, 229-268 CANTOR,SIDNEYM. See Miller, I t o h - t 53-98 BAYNE,S., and FEWBTER, J. A,, The Ellsworth. Osones, 11, 43-96 W. G . , ConCAPON,B., and OVEREND, B E ~ L I KANDREW, , Kojic Acid, 11,145-183 stitution and Physicochemical l’ropBELL, D. J., The Methyl Ethers of Derties of Carbohydrates, 15, 11-51 CARR,C. JELLEFF, and KRANTZ, JOHN Galactose, 6, 11-25 BEMILLER,J. N. See Whistler, Roy L. C., JP.,Metabolism of the Sugar RINKLEY, W. W., Column ChromatograAlcohol8 and Their DerivativeN, 1, phy of Sugars and Their Derivatives, 175-192 CLAMP,JOHN R., HOUGH,L., HICKRON, 10, 55-94 BINKLEY, W. W., and WOLFROM, M. L., JOHNL., and WHISTLER,ROY I,., Composition of Cane Juice and Cane Lactose, 16, 159-206 Final Molasses, 8, 291-314 COMPTON,JACK, The Molecular ConBLAIR, MARYGRACE,The 2-Hydroxystitution of Cellulose, 3, 185-228 CONCHIE), J., LEVVY,G. A., and MARSH, glycals, 9, 97-129

396

CUMULATIVE AUTHOR INDEX FOR VOLS.

1-16

397

C. A., Methyl and Phenyl Glycosides of the Common Sugars, 12, 157-187 CRUM,JAMES D., The Four-carbon Saccharinic Acids, 13, 169-188

Desulfurization by Raney Nickel, 5, 1-28 FLETCHER, HEWITT G., JR. See also, Jeanloz, Roger W. FORDYCE, CHARLESR., Cellulose Esters of Organic Acids, 1, 309-327 D FOSTER, A. B., Zone Electrophoresis of DAVIEY,D. A. L., Polysaccharides of Carbohydrates, 12, 81-115 Gram-negative Bacteria, 15, 271-340 FOSTER, A. B., A N D HORTON, D., Aspects DEAN,G. R., and GOTTFRIED, J. B., The of the Chemistry of the Amino Commercial Production of CrystalSugars, 14, 213-281 line Dextrose, 5, 127-143 FOSTER, A. B., and HUQQARD, A. J., The DEITZ,VICTORR. See Liggett, R. W. Chemistry of Heparin, 10, 335-368 DEUEL,H. See Mehta, N. C. FOSTER, A. B., A N D STACEY, M., The DEUEL,HARRYJ., JR., and MOREHOUSE, Chemistry of the 2-Amino Sugars MARGARET G., The Interrelation of (2-Amino-2-deoxy-sugars),7,247-288 Carbohydrate and F a t Metabolism, FOSTER, A. B., and WEBBER, J. M., 2, 119-160 Chitin, 15, 371-393 DEULOFEU,VENANCIO,The Acylated Fox, J. J., and WEMPEN,I., Pyrimidine Nitriles of Aldonic Acids and Their Nucleosides, 14, 283-380 Degradation, 4, 119-151 FRENCH, DEXTER,The Raffinose Family DIMLER, R . J., 1 ,&Anhydrohexofuof Oligosaccharides, 9, 149-184 ranoses, A New Class of HexosanB, FRENCH,DEXTER, The Schardinger 7, 37-52 Dextrins, 12, 189-260 DOUI)OROFF, M. See Hassid, W. Z. G DUBACH, P. See Mehta, N. C.

E ELDERYIELD, ROBERTC., The Carbohydrate Components of the Cardiac Glycosides, 1, 147-173 ELLIS,G . P., The Maillard Reaction, 14, 63-134

GARC~A G O N Z ~ L E F., Z , Reactions of Monosaccharides with bela-Ketonic Esters and Related Substances, 11, 97-143

GOEIJP,RUDOLPHMAXIMILIAN, J R . See Lohmar, Rolland. GOODMAN, IRVING, Glycosyl Ureides, 13,

215-236 ELLIS, G. P., and HONEYMAN, JOHN, GOTTFRIED, J. B. See Dean, G. R . Glycosylamines, 10, 95-168 GOTTSCHALK, ALFRED,Principles UndcrEVANH,TAYLOR H., and HIBBERT, lying Enzyme Specificity in the HAROLD, Bacterid I’olysaccharides, Domain of Carbohydrates, 5, 49-78 2, 203-233 W., The Halogen OxidaEVANS,w. I,., REYNOLDB, D. n., and GREEN,JOHN tion of Simple Carbohydrates, ExTALLEY, E. A., The Synthesis of cluding the Action of Periodic Acid, Oligosaccharides, 6, 27-81 3,129-184

F

GREENWOOD,C. T., Aspects of the Physical Chemistry of Starch, 11

FEWBTER, J . A . See Bayne, 8. 335-385 FLETCHER, HEWITT,G., JR., The Chem- GREENWOOD, C. T., The Size and Shape istry and Configuration of the Cycliof Some Polysaccharide Molecules, tols, 3, 45-77 7, 289-332; 11, 385-393 FLETCHER, HEWITTG., JR., and RICHT- GURIN,SAMUEL, Isotopic Tracers in the MYER, NELSONK., Applications in Study of Carbohydrate Metabolism, the Carbohydrate Field of Reductive 3,229-250

398

CUMULATIVE AUTHOR INDEX FOR VOLS.

GUTHRIE,R. D., The “Dialdehydes” from the Periodate 0xidat.ion of Carbohydrates, 16, 106-168

H HARRIS,ELWINE., Wood Saccharification, 4, 163-188 HASKINS, JOSEPHF., Cellulose Ethers of Industrial Significance, 2, 279-294 HASSID,W. Z., and DOUDOROFF, M., Enzymatic Synthesis of Sucrose and Other Disaccharides, 5, 29-48 HAYNES, L. J., and NEWTH,F. H., The Glycosyl Halides and Their Derivatives, 10, 207-258 J., The SubstitutedHEHRE,EDWARD sucrose Structure of Melezitose, 8, 277-290 HELFERICH, BURCKHARDT, The Glycals, 7, 209-245 HELFERICH, BURCKHARDT, Trityl Ethers of Carbohydrates, 3, 79-1 11 See Evans, Taylor H. HIBBERT, HAROLD. HICKSON, JOHNL. See Clamp, John R. HINDERT,MARJORIE.See Karabinos,

J. V. HIRST,E. L., [Obituary of] James Colquhoun Irvine, 8, xi-xvii HIRST, E. L., [Obituary of] Walter Norman Haworth, 6, 1-9 HIRST, E . I,., and JONES, J. K. N., The Chemistry of Pectic Materials, 2, 236-251 HIRST,E . L., and Ross, A. G., [Obituary of] Edmund George Vincent Percival, 10, xiii-xx HODGE,JOHNE., The Amadori Rearrangement, 10, 169-206 HONEYMAN, JOHN,and MORGAN,J. W. W., Sugar Nitrates, 12, 117-136 JOHN. See also, Barry, C. P. HONEYMAN, HONEYMAN, JOHN. See also, Ellis, G. P. HORTON, D., Tables of Properties of 2Amino-2-deoxy Sugars and Their Derivatives, 15, 169-200 HORTON, 1).See also, Foster, A. B. J. K. N., The HOUGH,L., and JONES, Biosynthesis of the Monosaccharides, 11, 186-262 HOUGH,L., PRIDDLE, J. E., and THEOBALD, R. S., The Carbonates and

1-16

Thiocarbonates of Carbohydrates, 15, 91-168 HOUGH,L. See also, Clamp, John R. HUDSON, C. S., Apiose and the Glycosides of the Parsley Plant, 4,67-74 HUDSON, C. S., The Fischer Cyanohydrin Synthesis and the Configurations of Higher-carbon Sugars and Alcohols, 1, 1-36 HUDSON,C. S., Historical Aspects of Emil Fischer’s Fundamental Conventions for Writing Stereo-formulas in a Plane, 3, 1-22 HUDSON, C. S., Melezitose and Turanose, 2, 1-36 HUGGARD, A. J. See Foster, A. B.

J JEANLOZ, ROGERW., [Obituary of] Kurt Heinrich Meyer, 11, xiii-xviii ROGERW.,The Methyl Ethers of 2-Amino-2-deoxy Sugars, 13, 189214 JEANLOZ, ROGERW., and FLETCHER, HEWITTG., JR.,The Chemistry of Ribose, 6, 136-174 JONES, J. K. N., and SMITH,F., Plant Gums and Mucilages, 4, 243-291 JONES, J. K. N . Seealso, Hirst, E. L. JONES, J. K. N. See also, Hough, I,. JONSEN, J., and LALAND, S., Bacterial Nucleosides and Nucleotides, 15, 201-234 JEANLOZ,

K KARABINOS, J. V., Psicoae, Sorbose and Tagatose, 7, 99-136 MARKARABINOB, J. v., and HINDERT, JORIE, Carboxymethylcellulose, 9, 286-302 KENT,P. W. See Stacey, M. KERTESZ,2. I., and MCCOLLOCH, R. J., Enzymes Acting on Pectic Substances, 5, 79-102 KLEMER, ALMUTH.See Micheel, Fritz. KOWKABANY, GEORGEN., Paper Chromatography of Carbohydrates and Related Compounds, 9, 303-363 KRANTZ, JOHN C., JR.See Carr, C. Jelleff.

CUMULATIVE AUTHOR INDEX FOR VOLS.

L LAIDLAW, R . A., and PERCIVAL, E . G. V., The Methyl Ethers of the Aldopentoses and of Rhamnose and Fucose, 7, 1-36 LALAND, S. See Jonsen, J. LEDERER,E., Glycolipids of Acid-fast Bacteria, 16, 207-238 LEMIEUX,R . U., Some Implications in Carbohydrate Chemistry of Theories Relating to the Mechanisms of Replacement Reactions, 9, 1-57 LEMIEUX,R. U., and WOLFROM, M. L., The Chemistry of Streptomycin, 3, 337-384 LESPIEAU,R., Synthesis of Hexitols and Pentitols from Unsaturated Polyhydric Alcohols, 2, 107-118 LEVI, IRVING, and PURVES,CLIFFORD B., The Structure and Configuration of Sucrose (alpha-D-Glucopyranosyl beta-D-Fructofuranoside),4, 1-35 LEVVY, G. A., andMAmH, C. A., Preparation and Properties of 8-Glucuronidase, 14, 381-428 LEVVY,G. A. See also, Conchie, J. LIGQETT,R. W., and DEITZ,VICTORR., Color and Turbidity of Sugar Products, 9, 247-284 LINDBERQ, B. See Bouveng, H. 0. LOHMAR,ROLLAND,and GOEPP, R u DOLPH MAXIMILIAN, JR.,The Hexitols and Some of Their Derivatives, 4, 211-241

M MAHER,GEORGEG., The Methyl Ethers of the Aldopentoses and of Rhamnose and Fucose, 10, 257-272 MAHER,GEORGEG., The Methyl Ethers of &Galactose, 10, 273-282 MALHOTRA, OM PRAKASH. See Wallenfels, Kurt. MANNERS,D. J., The Molecular Structure of Glycogens, 12, 261-298 MARSH,C. A. See Conchie, J. MARSH,C. A. See Levvy, G. A. MCCLOSKEY, CHESTERM.,Benzyl Ethers of Sugars, 12, 137-156 MCCOLLOCH, R. J. See Kertesz, 2.I. MCDONALD, EMMAJ., The Polyfructo-

1-16

399

sans and Difructose Anhydrides, 2, 253-277 MEHLTRETTER,C. L., The Chemical Synthesis of D-Glucuronic Acid, 8, 231-249

MEHTA,N. C., DUBACH, P., and DEUEI,, H., Carbohydrates in the Soil, 16, 335-355 MESTER,L., The Formazan Reaction in Carbohydrate Research, 13, 105-167 MESTER,L., [Obituary of] G6za Zemplhn, 14, 1-8 MICHEEL,FRITZ, and KLEMER,ALMUTH, Glycosyl Fluorides and Azides, 16, 85-103 MILLER, ROBERT ELLSWORTH, and CANTOR, SIDNEYM., Aconitic Acid, a By-product in the Manufacture of Sugar, 6, 231-249 MILLS, J. A., The Stereochemistry of Cyclic Derivatives of Carbohydrates, 10, 1-53 MOREHOUSE, MARQARET G. See Deuel, Harry J., Jr. MORGAN, J. W. W. See Honeyman, John. MORI, T., Seaweed Polysaccharides, 8, 315-350 MUETQEERT,J., The Fractionation of Starch, 16, 299-333 MYRBACK,KARL, Products of the Enzymic Degradation of Starch and Glycogen, 3, 251-310

N NEELY,W. BROCK,Dextran: Structure and Synthesis, 15, 341-369 NEELY,W. BROCK,Infrared Spectra of Carbohydrates, 12, 13-33 NEUBERQ,CARL, Biochemical Reductions a t the Expense of Sugars, 4, 75-117 NEWTH,F. H., The Formation of Furan Compounds from Hexoses, 6, 83-106 NEWTH,F. H . See also, Haynes, L. J. NICKERSON, R . F., The Relative Crystallinity of Celluloses, 5, 103-126 NORD,F. F., [Obituary of] Carl Neuberg, 13, 1-7 0

OLSON,E. J. See Whistler, Roy L. OVEREND,W. G., and STACEY,M., The

400

CUMULATIVE AUTHOR INDEX FOR VOLS.

Chemistry of the 2-Desoxy-sugars, 8, 46-106 W. G . See also, Capon, B. OVEREND,

P PACSU, EUQENE,Carbohydrate Orthoesters, 1, 77-127 PEAT, STANLEY,The Chemistry of Anhydro Sugars, 2, 37-77 See also, Bourne, E. J. PEAT,STANLEY. PERCIVAL, E. G. V., The Structure and Reactivity of the Hydrasone and Osazone Derivatives of the Sugars, 3, 23-44

PERCIVAL, E. G . V. See also, Laidlaw, R. A. PERLIN,A. S., Action of Lead Tetraacetate on the Sugars, 14, 9-61 PHILLIPS, G . O., Radiation Chemistry of Carbohydrates, 16, 13-68 POLQLASE, W. J., Polysaccharides Associated with Wood Cellulose, 10, 283333 J . E. See Hough, L. PRIDDLE, I’URVES,CLIFFORD B. See Levi, Irving.

R RAYMOND, ALBERT L., Thio- and Selenosugars, 1, 129-146 REEVES,RICHARD E., CupranimoniumGlycoside Complexes, 6, 107-134 REYNOLDS, 1). D. See Evans, W. L. RICHTMYER, NELSONK., The Altrose Group of Substances, 1, 37-76 RICHTMYER, NELSONK., The 2-(aMoPolyhydrox yalkyl) benzimidazoles, 6, 176-203 RICHTMYER, NELSONK. See also, Fletcher, Hewitt G., Jr. Ross, A . G. See Hirst, E. L. S

SANDS,LILA.See Anderson, Ernest. SATTLER,LOUIS, Glutose and the Unfermentable Reducing Substances in Cane Molasses, 3, 113-128 SCAOCH, THOMAS JOHN, The Fractionation of Starch, l, 247-277 SHAFIZADEH, F., Branched-chitin Sugars of Natural Occurrence, 11, 263-283

1-16

SHAFIZADEH, F., Formation and Cleavage of the Oxygen Ring in Sugars, 13, 9-81 SMITH,F., Analogs of Ascorbic Acid, 2, 79-106 SMITH,F. See also, Jones, J. K. N. SOWDEN,JOHN C., The Nitromethane and 2-Nitroethanol Syntheses, 6, 291-318 SOWDEN,JOHNC., The Saccharinic Acids, 12, 36-79 SPECK,JOHN C., JR., The Lobry de Bruyn-Alberda van Ekenntein Transformation, 13, 63-103 D. B., The Biosynthesis of SI’RINSON, Aromatic Compounds from ii-Glucose, 15, 236-270 STACEY,M., The Chemistry of Mucopolysaccharides and Mucoproteinn, 2, 161-201 STACEY,M., and KENT, P. W., The Polysaccharides of Mycohncterirm tuberculosis, 3, 311-338 STACEY, M. See also, Bray, H. G. STACEY, M. See also, Foster, A. €3. STACEY, M. See also, Overend, W. G. STOLOBF, LEONARD, Polysaccharide Hydrocolloids of Commerce, 13,266-287 JAMES M., Relative ReacSU~IHARA, tivities of Hydroxyl Groups of Cnrbohydrates, 8, 1-44

T TALLEY, E. A. See Evans, W. L. TEAQUE, ROBERTS., The Conjugates of D-Glucuronic Acid of Animal Origin, 9,186-246 THEOBALD, R. S. See Hough, L. TIPSON,R. STUART,The Chemistry of the Nucleic Acids, 1, 193-246 TIPSON, R. STUART, [Obituary of] Harold Hibbert, 16, 1-11 TIPSON, R. Stuart, [Obituary of] Phoebus Aaron Theodor Levene, 12, 1-12 TIPSON, R. STUART,Sulfonic Esters of Carbohydrates, 8, 107-216

W WALLENFELS, KURT, and MALHOTRA, OM PRAKASH,Galactosidases, 16, 239-298

CUMULATIVEAUTHOR INDEX FOR VOLS.

WEBBER,J. M. See Foster, A. B. WEMPEN,I. See Fox, J. J. WHISTLER, ROY L., Preparation and Properties of Starch Esters, 1, 279307 WHISTLER,ROYL., Xylan, 5,269-290 WHISTLER, ROY L., and BEMILLER, J. N., Alkaline Degradation of Polysaccharides, 13, 289-329 WHISTLER,ROY L., and OLSON,E. J., The Biosynthesis of Hyaluronic Acid, 12, 299-319 WHISTLER, ROY L. See also, Clamp, John R . WHITEHOUSE,M. W. See Zilliken, F. WIQGINS, L. F., Anhydrides of the Pentitols and Hexitols, 5, 191-228

1-16

401

WIQQINS,L. F., The Utilization of Sucrose, 4, 293-336 WISE, LOUIS E., [Obituary of] Emil Heuser, 15, 1-9 WOLFROM, M. L., [Obituary of] Claude Silbert Hudson, 9, xiii-xviii WOLFROM, M. L., [Obituary of] Rudolph Maximilian Goepp, Jr., 3, xv-xxiii WOLFROM, M. L. Seealso, Binkley, W. W. Wolfrom, M. L. See also, Lemieux, R. U. Z

ZILLIKEN,F., and WHITEHOUSE, M . W., The Nonulosaminic Acids-Neuraminic Acids and Related Compounds (Sialic Acids), 13, 237-263

CUMULATIVE SUBJECT INDEX FOR VOLUMES 1-16 A

B

Acetals, of hexitols, pentitols, and tetritols, 7, 137-207 Acetic acid, trifluoro-, anhydride, applications of, in carbohydrate chemistry, 16, 59-84 Aconitic acid, 6, 231-249 Adsorbents, granular, for sugar refining, 6, 205-230 Alcohols, higher-carbon sugar, configurations of, 1, 1-36 unsaturated polyhydric, 2, 107-118 Aldonic acids, acylated nitriles of, 4, 119-151. Aldopentoses, methyl ethers of, 7, 1-36; 10, 257-272 Alkaline degradation, of polysaccharides, 13, 289-329 Altrose, group of compounds related to, 1,37-76 Amadori rearrangement, 10. 169-205 Amino sugars. See Sugars, 2-amino-2deoxy. Amylases, certain alpha, 6, 229-268 Anhydrides, difructose, 2, 253-277 of hexitols, 6, 191-228 of pentitols, 6, 191-228 Anhydro sugars. See Sugars, anhydro. Animals, conjugates of D-glucuronic acid originating in, B, 185-246 Apiose, 4, 57-74 Ascorbic acid, analogs of, 2, 79-106 Aromatic compounds, biosynthesis of, from D-glUCOSe, 16,

Bacteria, glycolipides of acid-fast, 16, 207-238 nucleosides and nucleotides of, 16,

235-270 402

201-234

polysaccharides from, 2, 203-233; 3, 311-336

polysaccharides of Gram-negative, 16. 271-340

Benzimidazoles, Z-(aZdo-polyhydroxyaIkyl)-,6. 175-203 Benzyl ethers, of sugars, 12, 137-156 Biochemical reductions, at the expense of sugars, 4, 75-117 Biosynthesis, of aromatic compounds from D - ~ I u cose, 16, 235-270 of hyaluronic acid, 12, 299-319 of the monosaccharides, 11, 185-262 Blood groups, polysaccharides of, 4, 37-55 Boric acid, for determining configuration of carbohydrates, 4, 189-210 Branched-chain sugars. See Sugars, branched-chain. C

Cane juice, composition of, 8, 291-314 Cane See Carbohydrates, applications of reductive desulfurization by Raney nickel, in the field of, 6, 1-28 applications of trifluoroacetic anhydride in chemistry of, 16, 59-84 aa components of cardiac glycosides, 1, 147-173

carbonates of, 16, 91-158 constitution of, 16, 11-51

CUMULATIVE SUBJECT INDEX FOR VOLS.

determination of configuration of, with boric acid, 4, 189-210 enzyme specificity in the domain of, 6, 49-78 formazan reaction, in research on, 13, 105-167 Friedel-Crafts and Grignard processes applied to, 6, 251-289 halogen oxidation of simple, 3, 129-184 infrared spectra of, 12, 13-33 mechanisms of replacement reactions in chemistry of, 9, 1-57 metabolism of, 2, 119-160; 3, 229-250 orthoesters of, 1, 77-127 periodate oxidation of, 11, 1 4 1 the “dialdehydes” from, 16, 105-158 physicochemical properties of, 16.11-51 radiation chemistry of, 16, 13-58 and related compounds, paper chromatography of, 9,303-353 relative reactivities of hydroxyl groups of, 8, 1-44 in the soil, 16, 335-355 stereochemistry of cyclic derivatives of, 10, 1-63 sulfonic esters of, 8, 107-215 thiocarbonates of, 16, 91-158 trityl ethers of, 3, 79-111 zone electrophoresis of, 12, 81-115 Carbonates, of carbohydrates, 16, 91-158 Carboxymet hyl ether, of cellulose, 9, ‘285-302 Cellulose, carboxymethyl-, 9, 285-302 eaters of, with organic acids, 1,309-327 ethers of, 2, 279-294 molecular constitution of, 3, 185-228 of wood, polysaccharides associated with, 10, 283-333 Celluloses, relative crystallinity of, 6, 103-126 Chemistry, of the amino sugars, 14, 213-281 of the 2-amino sugars, 7,247-288 of anhydro sugars, 2,37-77 of carbohydrates, applications of trifluoroacetic anhydride in, 16, 59-84 some implications of theories relat-

1-16

403

ing to the mechanisms of replacement reactions in, 9, 1-57 of the cyclitols, 3, 45-77 of the 2-deoxy sugars, 8. 45-105 of heparin, 10,335-368 of mucopolysaccharides and mucoproteins, 2, 161-201 of the nucleic acids, 1, 193-245 of pectic materials, 2, 235-251 of ribose, 6, 135-174 of streptomycin, 3, 337-384 physical, of carbohydrates, 16, 11-51 of starch, 11, 335-385 radiation, of carbohydrates, 16, 1358

stereo-, of cyclic derivatives of carliohydrates, 10. 1-53 structural, of the hemicelluloses, 14, 4w68 of polysaccharides, 16, 53-89 Chitin, 16, 371-393 Chromatography, column. See Column chromatography. paper. See Paper chromtttography. Color, of sugar products, 9. 247-284 Column chromatography, of sugars and their derivatives, 10, 65-94 Complexes, cuprammonium-glycoside, 6, 107-134 Configuration, of carbohydrates, determination of, 4, 189-210 of cyclitols, 3. 45-77 of higher-carbon sugar alcohols, 1,1-36 of sucrose, 4, 1-35 Conjugates, of D-glucuronic acid, 9, 185-246 Constitution, of carbohydrates, 16, 11-51 Crystallinity, relative, of celluloses, 6, 103-126 Cuprammonium-glycoside complexes, 6, 107-134 Cyanohydrin synthesis, Fischer, 1, 1-36 Cyclic derivatives, of carbohydrates, stereochemistry of, 10, 1-53

404

CUMULATIVE SUBJECT INDEX FOR VOLS. l-l(i

Cyclitols, 14, 135-212 chemistry and configuration of, 3, 45-77

D Degradation, of acylated nitriles of aldonic acids, 4, 119-151 enzymic, of glycogen and atarch, 3, 251-310 Deoxy sugars. flee Sugars, deoxy. Desulfurization, reductive, by Raney nickel, 6, 1-28 Dextran, structure and synthesis of, 16, 341-369 Dextrine, the Schardinger, 12, 189-260 Dextrom, commercial production of crystalline, 6, 127-143 ‘Dialdehydes,” from the periodate oxidation of carbohydrates, 16, 105-158 Difructose, anhydrides, 2, 253-277 Disacc harides, enzymic synthesis of, 6, 29-48

E Electrophoresis, zone, of carbohydrates, 1%81-115 Enzymes. See also, Amylases, Galactosidases, p-Glucuronidase. acting on pectic substances, 6, 79-102 degradition by, of starch and glycogen, 3, 261-310 specificity of, in the domain of carbohydrates, 6, 49-78 synthesis of sucrose and other disaccharides by, 6, 29-48 Esters, of cellulose, with organic acids, 1, 308-327 bela-ketonic (and related substances), reactions with monosaccharides, 11, 97-143 nitrate, of starch, 13, 331-345 of starch, preparation and properties of, 1, 279-307 sulfonic, of carbohydrates, 8, 107-215

Ethanol, 2-nitro-, syntheses with, 6, 291-318 Ethers, benzyl, of sugars, la, 137-156 carboxymethyl, of cellulose, 9, 285303 of cellulose, a, 27S29.1 methyl, of the aldopentoses, 7, 1-36; 10,257272 of 2-amino-2-deoxy sugars, 13, 189214 of fucose, 7, 1-36; 10, 257-272 of u-galactose, 6, 11-25; 10, 273-282 of D-glucose, 6, 145-190 of hexuronic acids, 9, 131-148 of D-mannose, 8, 217-230 of rhamnose, 7, 1-3G; 10, 257-274 t,rityl, of carbohydrates, 3, 79-111

F Fat, metabolism of, 2, 110-160 Formazltn reaction, in carbohydrate research, 13, 105-167 Formulas, stereo-, writing of, in a plane, 3, 1-22 Fractionation, of starch, 1, 247-277; 16, 299-333 Friedel-Crafts process, in the carbohydrate series, 6. 251-289 Fructans, 2, 253-277 Fructofuranoside, a-D-glucopyranosyl D-D-,4, 1-35 Fructosans, poly-. See Fructans. Fructose, and its derivatives, 7, 53-98 di-, anhydrides, 2, 253-277 Fucose, methyl ethers of, 7, 1-36; 10, 257-272 Furan compounds, formation from hexoses, 6, 83-10G G

Galactose, methyl ethers of D-, 6. 11-25; 10, 273232 Galactosidases, 16. 239-298

CUMULATIVE SUBJECT INDEX FOR VOLS.

Glucose. See also, Dextrose. biosynthesis of aromatic compounds from D-, 16. 235-270 methyl ethers of D-, 6, 145190 Clucuronic acid, D-, chemical synthesis of, 8,231-249 conjugates of, of animal origin, 9, 185-246 in metabolism, 8, 251-275 8-Clucuronidase, preparation and properties of, 14, 381428 Glutose, 3, 113-128 Glycals, 7, 209-245 -, 2-hydroxy-, 9, 97-129 Glycogens, enzymic degradation of, 3, 251-310 molecular structure of, 12, 261-298 Clycolipides, of acid-fast bacteria, 16, 207-238 Glycoside-cuprammonium complexes, 6, 107-134 Glycosides, alkali-sensitive, 9, 59-95 cardiac, 1, 147-173 methyl, of the common sugars, 12, 157-187 of the parsley plant, 4, 57-74 phenyl, of the common sugars, 12, 157187 Glycosiduronic acids, of animals, 9, 185-246 poly-, of plants, 1, 329-344 Glycosylamines, 10, 95-168 Glycosyl azides, 16, 85-103 Glycosyl fluorides, 16. 85-103 Glycosyl halides, and their derivatives, 10, 207-256 Goepp, Rudolph Maximilian , Jr., obituary of, 3, xv-xxiii Grignard process, in the carbohydrate series, 6. 251-289 Gums. See also, Hydrocolloids. commercial, 13, 265-287 of plants, 4, 243-291

H Halogen oxidation. See Oxidation, halogen . Haworth, Walter Norman, obituary of, 6, 1-9

1-16

405

Hemicelluloses, structural chemistry of, 14, 429468 Heparin, chemistry of, 10, 335-368 Heuser, Emil, obituary of, 16, 1-9 Hexitols, acetals of, 7, 137-207 nnhydrides of, 6, 191-228 and some of their derivatives, 4, 211241 synthesis of, 2, 107-114 Hexofuranoses, 1,6-anhydro-, 7, 37-52 Hexosans, 7, 37-52 Hexoses. See also, Hexofuranoses. formation of furan compounds from, 6, 83-106 Hexuronic acids, methyl ethers of, 9, 131-148 Hibbert, Harold, obituary of, 16, 1-11 Hudson, Claude Silbert, obituary of, 9, xiii-xviii Hyaluronic acid, biosynthesis of, 12, 299-319 Hydrazones, of sugars, 3, 23-44 Hydrocolloids, commercial, polysaccharidic, 13, 265287 Hydroxyl groups, relative reactivities of, 8, 1-44

I Infrared spectra, of carbohydrates, 12, 13-33 Irvine, James Colquhoun, obituary of, 8. xi-xvii Isotopic tracers. See Tracers, isotopic.

K Ketals. See Acetals. Kojic acid, 11, 145-183

L Lactose, 16, 159-206 Lead tetraacetate, action of, on the sugars, 14, 9-Gl Levene, Phoebus Aaron Theodor, obituary of, 12, 1-12

406

CUMULATIVE SUBJECT INDEX FOR VOLS.

Lobry de Bruyn-Alberda van Ekenstein transformation, 13, 63-103

M Maillard reaction, 14, 63-134 Mannose, methyl ethers of D-, 8. 217-230 Mechanism, of replacement reactions in carbohydrate chemistry, B, 1-57 Melezitose, 2, 1-36 structure of, 8, 277-290 Metabolism, of carbohydrates, 2, 119-160 use of isotopic tracers in studying, 3,229-250 of fat, 2, 119-160 of the sugar alcohols and their derivatives, 1, 175-192 D-glucuronic acid in, 8, 251-275 Methane, nitro-, syntheses with, 6, 291-318 Methods, in structural polysaccharide chemistry, 16, 63-89 Methyl ethers. See Ethers, methyl. Meyer, Kurt Heinrich, obituary of, 11. xiii-xviii Molasses, cane, 8, 113-128 cane final, composition of, 8, 291-314 Molecular structure, of glycogens, 12, 261-298 Monosaccharides, biosynthesis of, 11, 185-262 reactions of, with beta-ketonic esters and related substances, 11, 97-143 Mucilages. See also, Hydrocolloids. commercial, 13, 265-237 of plants, 4, 243-291 Mucopolysaccharides. See Polysaccharides, muco-. Mucoproteins. See Proteins, muco-. Mycobaclerium lubeTCUlO8i8, polysaccharides of, 3, 311-336

N Neuberg, Carl, obituary of, 13, 1-7

1-16

Neuraminic acids, and related compounds, 13, 237-263 Nickel, Raney. See Raney nickel. Nitrates, of starch, 13, 331-345 of sugars, 12, 117-135 Nitriles, acylated, of aldonic acids, 4, 119-151 Nonulosaminic acids, 13, 237-263 Nucleic acids, 1, 193-246; 11, 285-333 Nucleosides, bacterial, 16, 201-234 pyrimidine, 14, 283-380 Nucleotides, bacterial, 16, 201-234 0

Obituary, of Rudolph Maximilian Goepp, J r . , 3, xv-xxiii of Walter Norman Haworth, 6, 1-9 of Emil Heuser, 16, 1-9 of Harold Hibbert, 16, 1-11 of Claude Silbert Hudson, 9, xiii-xviii of James Colquhoun Irvine, 8, xi-xvii of Phoebus Aaron Theodor Levene, 12, 1-12 of Kurt Heinrich Meyer, 11, xiii-xviii of Carl Neuberg, 13, 1-7 of Edmund George Vincent Percivul, 10, xiii-xx of GBza ZemplBn, 14, 1-8 Oligosaccharides, the raffinose family of, 9, 149-184 synthesis of, 6, 27-81 Orthoesters, of carbohydrates, 1, 77-127 Osazones, of sugars, 3, 23-44 Oxones, 11, 43-96 Oxidations, halogen, of simple carbohydrates, 3, 129-148 lead tetraacetate, of sugars, 14, 9-61 periodate, of carbohydrates, 11, 1 4 1 the “dialdehydes” from, 16, 105-158 Oxygen ring, formation and cleavage of, in sugars, 13, 9-61

CUMULATIVE SUBJECT INDEX FOR VOLS.

P Paper chromatography, of carbohydrates and related compounds, B, 303-353 Parsley, glycosides of the plant, 4, 57-74 Pectic materials, chemistry of, 2, 235-251 enzymes acting on, 6, 79-102 Pentitols, acetals of, 7, 137-207 anhydrides of, 6, 191-228 synthesis of, 2, 107-118 Percival, Edmund George Vincent, obituary of, 10, xiii-xx Periodate oxidation. See Oxidation, periodate. Physical chemistry, of carbohydrates, 16, 11-51 of starch, 11, 335-385 Plants, glycosides of parsley, 4, 57-74 gums of, 4, 243-291 mucilages of, 4, 243-291 ' polyuronides of, 1, 329-344 Polyfru ctosans. See Fruc tans. Polyglycosiduronic acids. See Glycosiduronic acids, poly-. Polysaccharides. See also, Carbohydrates, Cellulose, Dextran, Dextrins, Fructans, Glycogen, Glycosiduronic acids (poly-), Pectic materials, Starch, and Xylan. alkaline degradation of, 13, 289-329 associated with wood cellulose, 10, 283-333 bacterial, 2, 203-233; 16, 271-340 blood group, 4, 37-55 hydrocolloidal, 13, 265-287 methods in structural chemistry of, 16, 53-89 muco-, chemistry of, 2, 161-201 of Gram-negative bacteria, 16,271-340 of Mycobacterium tuberculosis, 3, 311336 of seaweeds, 8. 315-350 shape and size of molecules of, 7, 289332;11, 385-393 Polyuronides, oi plants, i, 324-344

1-10

407

Preparation, of esters of starch, 1, 27!+307 of 8-glucuronidase, 14, 381-428 Properties, of 2-amino-2-deoxy sugars and their derivatives, 16, 159-200 of esters of starch, 1, 27!+307 of 8-glucuronidase, 14, 381428 physicochemical, of carbohydrates, 16, 11-51 Proteins, muco-, chemistry of, 2, 161-201 Psicose, 7, 99-136 Pyrimidines, nucleosides of, 14, 283-380

R Radiation, chemistry of carbohydrates, 16, 1358

Raffinose, family of oligosaccharides, B, 149-184 Raney nickel, reductive desulfurization by, 6. 1-28 Reaction, the formazan, in carbohydrate research, 13. 105-167 the Maillard, 14, 63-134 Reactivities, relative, of hydroxyl groups of carbohydrates, 8, 144 Rearrangement, the Amadori, 10, 169-205 Reductions, biochemical, at the expense of sugars, 4, 75-117 Replacement reactions, mechanisms of, in carbohydrate chemistry, 9, 1-57 Rhamnose, methyl ethers of, 7, 1-36; 10, 257-272 Ribose , chemistry of, 6, 135-174 S

Saccharification, of Wood, 4, 163-188 Saccharinic acids, 12, 3&79 four-carbon, 13. 169-188 Schardinger dextrins, 12, 189-260

408

CUMULATIVE SUDJECT INDEX FOR VOLS.

Seaweeds, polysaccharides of, 8, 315-350 Seleno sugars. See Sugars, seleno. Shape, of some polysaccharide molecules, 7, 289-332; 11, 385-393 Sialic acids, 13, 237-263 Size, of some polysaccharide molecules, 7, 289-332; 11, 385-393 Soil, carbohydrates in, 16, 335-355 Sorhose, 7, 99-136 Specificity, of enzymes, in the domain of carhohydrates, 6. 49-78 Spectra, infrared, of carbohydrates, 12, 13-33 Starch, enzymic degradation of, 3, 251-310 fractionat,ion of, 1, 247-277; 16, 299333 nitrates of, 13. 331-345 physical chemistry of, 11, 336-385 preparation and properties of esters of, 1, 279-307 Stereochemistry, of cyclic derivihves of carbohydrates, 10, 1-53 formulas, writing of, in a plane, 3, 1-22 Streptomycin , chemistry of, 3, 337-384 Structural chemistry, of the hemicelluloses, 14, 429-468 Structure, molecular, of dextran, 16, 341-369 of glycogens, 12, 261-298 of sucrose, 4, 1-35 Sucrose. See also, Sugar. enzymic synthesis of, 6, 2948 structure and configuration of, 4, 1-35 utilization of, 4, 293-336 Sugar, aconitic acid as by-product in manufacture of, 6, 231-249 Sugar alcohols, higher-carbon, configurations of, 1, 1-36 and their derivatives, metabolism of, 1. 175-192

1-16

Sugar products, color and turbidity of, 9, 247-284 Sugar refining, granular adsorbents for, 6, 205-230 Sugara, action of lead tetraacetate on, 14, 9-61 2-amino. See Sugars, 2-amino-2-deoxy. 2-amino-2-deoxyI 7, 247-288 aspects of the chemistry of, 14, 213281 methyl ethers of, 13, 189-214 properties of, 16, 159-200 anhydro, chemistry of, 2, 37-77 benzyl ethers of, 12, 137-150 biochemical reductions a t the expense of, 4, 75-117 branched-chain, of natural occurrcncc, 11, 263-283 2-deoxy, 8, 45-105 higher-carbon, configuration8 of, 1, 1-36 hydrazones of, 3, 23-44 methyl glycosides of the common, 12, 157-187 nitrates of, 12, 117-135 osazones of, 3, 23-44 oxygen ring in, formation and clenvage of, ia, 9-61 phenyl glycoaicles of the common, 12, 157-187 and their derivatives, column chronnrtography of, 10, 55-94 related to altrose, 1. 37-70 seleno, 1. 144-145 thio, 1, 129-144 Sulfonic esters, of carbohydrates, 8, 107-215 Syn t hesi 8, biochemical, of monosaccharides, 11, 185-202 chemical, of D-glucuronic acid, 8, 231249 of dextran, 16, 341-309 enzymic, of sucrose and other disaccharides, 6, 2948

T Tagatose, 7, 99-136 Tetritols, acatals of. 7. 137-207

CUMULATIVE SUBJECT INDEX FOR VOLS.

Thiocarbonates, of carbohydrates, 16, 91-158 Thio sugars. See Sugars, thio. Tracers, isotopic, 3, 229-250 Transformation, the Lobry de Bruyn-Alberda Ekenstein, 13, 63-103 Trityl ethers, of carbohydrates, 3, 79-111 Turanose, 2, 1-36 Turbidity, of sugar products, 9, 247-284

U Ureides, glycosyl, 13, 215-236

1-16

409

w Wood, polysaccharides associated with cellulose of, 10, 283-333 saccharification of, 4, 153-188 van

X Xylan, 6. 269-290 Z

ZemplBn, GBza, obituary of, 14, 1-8 Zone electrophoresis, of carbohydrates, 12, 81-115

ERRATA AND ADDENDA VOLUME12 read “l/d/Z.” Page 18, line 13 up. For ‘‘42” Page 29, lines 3, 7, and 0, and Reference 46. For “Coblenr” read “Coblentz.” Page 29, line 10. After “material,” insert “in saturated, aqueous solution.” Page 29, line 11. After “solutions,” insert “evaporated to sirups by gentle heating.’ Page 182, Table 111, entry 11, columns 2,3, and 5. Insert the following figures: 132133, -18.1, 142a; 131-133, -21, 142b; 130-131, -17.3, 142c. Page 182, line 3 up (of References). Insert (142a) H. G. Fletcher, Jr., and C. S. Hudson, J . Am. Chem. SOC.,72,4173 (1950). (142b) R. K. Ness and H. G. Fletcher, Jr., ibid., 78,4710 (1966). (142~)R. Bentley, ibid., 70, 1720 (1957).

VOLUME14 Page 227, lines 10 up, 13 up, and 14 up; and page 502. For “2-carboxy” read “l-carboxy.”

VOLUME15 Page 43, after Formula XXVII. ‘%H@”nieans “protonated solvent.” Page 113, line 2. For “carbohydrate” read “carbonate.” Page 160, column 3, entry 2 up. For ‘i-75.40” read “+75.4”.” Page 207, lines 2 up, 4 up, and 5 up; page 209, line 13; and page 294, line 14. For “2carboxyethyl” read “1-carboxyethyl,” Page 258, equations 11 and 12. For ‘IP”read “HP04B.” Page 262, equations. For “P” read “HPO,m,” Page 276, line 17. For ‘lane” read “and.” Page 420, line 5 under D. For “riductase” read “reductase.”

410