Carbohydrate Chemistry provides review coverage of all publications relevant to the chemistry of monosaccharides and oligosaccharides in a given year. The amount of research in this field appearing in the organic chemical literature is increasing because of the enhanced importance of the subject, especially in areas of medicinal chemistry and biology. In no part of the field is this more apparent than in the synthesis of oligosaccharides required by scientists working in glycobiology. Clycomedicinal chemistry and its reliance on carbohydrate synthesis is now very well established, for example, by the preparation of specific carbohydrate- based antigens, especially cancer-specific oligosaccharides and glycoconjugates. Coverage of topics such as nucleosides, amino-sugars, alditols and cyclitols also covers much research of relevance to biological and medicinal chemistry. Each volume of the series brings together references to all published work in given areas of the subject and serves as a comprehensive database for the active research chemist Specialist Periodical Reports provide systematic and detailed review coverage in major areas of chemical research. Compiled by teams of leading authorities in the relevant subject areas, the series creates a unique service for the active research chemist, with regular, in-depth accounts of progress in particular fields of chemistry. Subject coverage within different volumes of a given title is similar and publication is on an annual or biennial basis.
Carbohydrate Chemistry Volume 28
A Review of the Literature Published during 1994
By R. J. FerrierThe Royal Society of Chemistry
Copyright © 1996 The Royal Society of Chemistry
All rights reserved.
ISBN: 978-0-85404-208-1Contents
Chapter 1 Introduction and General Aspects, 1,
Chapter 2 Free Sugars, 3,
Chapter 3 Glycosides, 19,
Chapter 4 Oligosaccharides, 64,
Chapter 5 Ethers and Anhydro-sugars, 85,
Chapter 6 Acetals, 94,
Chapter 7 Esters, 100,
Chapter 8 Halogeno-sugars, 115,
Chapter 9 Amino-sugars, 120,
Chapter 10 Miscellaneous Nitrogen Derivatives, 137,
Chapter 11 Thio- and Seleno-sugars, 158,
Chapter 12 Deoxy-sugars, 165,
Chapter 13 Unsaturated Derivatives, 170,
Chapter 14 Branched-chain Sugars, 181,
Chapter 15 Aldosuloses and Other Dicarbonyl Compounds, 197,
Chapter 16 Sugar Acids and Lactones, 199,
Chapter 17 Inorganic Derivatives, 214,
Chapter 18 Alditols and Cyclitols, 219,
Chapter 19 Antibiotics, 251,
Chapter 20 Nucleosides, 263,
Chapter 21 N.M.R. Spectroscopy and Conformational Features, 307,
Chapter 22 Other Physical Methods, 318,
Chapter 23 Separatory and Analytical Methods, 333,
Chapter 24 Synthesis of Enantiomerically Pure Non-carbohydrate Compounds, 345,
Author Index, 380,
CHAPTER 1
Introduction and General Aspects
A description of the pioneering work of Emil Fischer in the period around 1890, especially relating to his elucidation of the molecular configuration of glucose and aspects of his philosophical view of chemistry, has appeared. Lemieux and Spohr have looked in detail at how Fischer was led to the "lock and key" concept for enzyme specificity. An animated 386-based PC program with VGA graphics has been produced to assist visualization of the relationship between Fischer and Haworth projections of monosaccharides.
An ACS symposium was held in 1993 on the anomeric effect and associated stereoelectronic effects, and as part of it J. T. Edward reviewed the influence of the anomeric effect in carbohydrates covering the origin of its postulation. Several calculations relevant to carbohydrates have been reported. Ab initio M.O. methods have been applied to the axial and equatorial conformations of 2-methoxytetrahydropyrans, and also 2-chloro- and 2-fluoro-tetrahydropyrans, the energy values obtained being found to be dependent on solvent. Force fields have been calculated for monosaccharides and (1 -> 4)-linked polysaccharides, and a review has been written on path energy minimization (PEM), a novel method for generating a reaction path linking two known conformations of molecules. A test example considered the change in pucker angle of α-D-threo-pentulofuranose. The method can identify transition state structures and energy barriers. A major review covering structural and conformational analysis of oligosaccharides of glycoproteins deals with n.m.r., mass spectrometric and molecular modelling methods.
Considerable attention has been given in reviews to aspects of synthesis. The question of reactions which are promoted by water has been dealt with covering i) Diels Alder and hetero-Diels Alder reactions by which nionosaccharides may be synthesized; ii) sigmatropic rearrangements of aglycons which lead to asymmetric induction; iii) indium promotion of allylation of aldehydes or ketones and iv) reductive debrominations using soluble tin hydrides and AIBN. A further review has dealt with the hetero-Diels Alder reaction in asymmetric systems, and covered the use of carbohydrate chiral auxiliaries and the construction of pyranose rings from sugar butadien-1-yl ethers. The trichloroacetirnidate method for making glycosides which has become well established as of major importance has been reviewed by the developer, R. R. Schmidt, and the use of aldonolactones in synthesis has covered O-substitution and deoxygenation, reactions with various nucleophiles including chain elongating reagents, reductions and β-eliminations. Tetrapropylammoniwn perruthenate has become recognized as a soluble, non-volatile, stable oxidising agent for converting alcohols to ketones; used with sodium hyperchlorite it cleaves a-diols, and its chemistry has been reviewed.
New aspects of the synthesis of glycopeptides which contain glycosyl asparagine, serine and threonine has covered O- and N-glycosylations, and dealt with enzymic and solid phase procedures. A review of the use of enzymic methods in protecting group technology includes cover of examples relating to carbohydrates and nucleosides, and a further relates to chemoenzymic methods for preparing derivatives of D-ribose containing one or more 13c labels.
CHAPTER 2
Free Sugars
1 Theoretical Aspects
The relevant literature on lactose dissolution in water has been reviewed in a paper which describes a mathematical model for this process. Short time scale molecular dynamics simulations of sucrose in water and DMSO indicated that the conformations in both solvents are similar to that accepted in the crystalline state. Solid-liquid equilibria for aqueous sucrose have been studied by use of an UNIQUAC model. A comparison of GROMOS force field and Ha force field in molecular dynamics simulations of glucose crystals indicated superior performance by the latter method. Predicted crystal structures of β-D-glucose, β-D-galactose, β-D-allose, α-D-glucose, α-D-galactose, and α-D-talose matched or nearly matched the X-ray-derived data in four cases.
2 Synthesis
The synthesis of aldose derivatives by iterative, diastereofacially selective addition of 2-lithio-1,3-dithiane to O-protected chiral α-hydroxyaldehydes, starting from 1,2-O-cyclohexylidene-D-glyceraldehyde, has been reported. In a new modification of the aldolase-catalysed synthesis of ketose phosphates (see Vol. 27, Chapter 7, Ref. 71) the required dihydroxyacetone phosphate (DHAP) has been generated in situ from glycerol 1-phosphate by use of glycerol phosphate oxidase coupled with catalase. A large number of ketosugars, for example the new fluorinated [D]-fructose derivative 1, have been prepared by addition of the one-carbon nucleophile (benzyloxymethyl)lithium to suitably substituted and protected aldono-1,4-lactones. Acetyl-protected free pento-, hexo- and hepto-furanoses, such as compounds 2, have been obtained by reduction of the corresponding 1,4-aldonolactones with disiamylborane. An interesting new approach to chiral precursors of C-3 branched alditol and aldose derivatives involving bis-epoxidation of silylated ketenes is covered in Chapter 18, and the oxidative degradation of galactose, lactose, cellobiose and maltose to the next lower aldoses by hydrogen peroxide in the presence of borate ions is referred to in Section 5 of this Chapter (Ref 83).
2.1 Trioses to Hexoses. – Mixtures of erythro- and threo-3-pentulose have been obtained in the base-catalysed aldol condensation between unprotected DL-glycero-tetruose and formaldehyde, the product ratio depending on catalyst and solvent. In further studies on the aldolization of glycolaldehyde derivative 3, use of lithium hydroxide as catalyst furnished DL-galactose as the major trimerization product in 7.5% yield, in contrast to previous experiments with NaOH or KOH which had produced allose as the main hexose (see Vol. 25, Chapter 2, Ref. 12).
In the transketolase-catalysed condensation (see Vol. 27, Chapter 2, Refs. 6, 16) of...
