Monosaccharide derivatives and

Considerable effort has heen directed towards the synthesis of monosaccharide derivatives, and, in particular, C-glycosyl compounds, from Diels-Alder adducts offuran. Just and his group investigated the reaction of furan with a number of dienophiles, and described many interesting transformations of the adducts obtained from... 

IV. Oxidation Products from Monosaccharide Derivatives and Related Compounds. 108... 

The Bacterial Cell Wall A Medical Perspective Monosaccharide Derivatives and Heteropolysaccharides of Medical Interest Summary Key Terms... 

C Chemical Shifts of Monosaccharides, Derivatives, and Analogous Compounds (Numbered formulae are on pp. 296-299)... 

Figure 4.2.17 Special natural monosaccharide derivative and cyclitol analogs.

Condensation of syn- or anti-27 with hydrazine afforded new pyrazole derivatives 28 with a stereodefined and protected amino diol side chain [64]. The preparation of push-pull substituted unsaturated monosaccharide derivatives and their use in the synthesis of nucleoside analogs have been reviewed [65]. Thus, the 2-formyl pentose glycals were transformed to the corresponding acyclo-C-nucleosides 29 [66]. Similarly, the benzy-lated 2-formylglycals reacted with hydrazine derivatives to afford the substituted l,2,4-tri-0-benzyl-lC-(lH-pyrazol-4-yl)-D-tetritols the deprotection of which was achieved with Pd/H2 to yield the lC-( 1-methyl-lH-pyrazol-4-yl)-D-tetritols [67]. 3-0-Benzyl-6-deoxy-l,2-0-isopropylidene-o -D-xylo-hept-5-ulofuranurono-nitrile was reacted with f, N-dimethylformamide dimethyl-acetal in THF to furnish the (E)-3-0-benzyl-6-deoxy-6-dimethyl-aminometh-ylene-l,2-0-isopropylidene-Q -D-xylo-hept-5-ulofuranurono-nitrile as a major product, and on treatment with carbon disulfide and methyl iodide under basic conditions afforded 3-0-benzyl-6-deoxy-l,2-0-isopropylidene-6-[bis(methylsulfanyl)methylene]-a-D-xylo-hept-5-ulofuranurono-nitrile. Further reaction with hydrazines yielded the reversed pyrazole-C-nucleoside analogs [68]. 

Streptomyces strain capable of incorporating the cyclohexyl substituent at C25 from a source that is added to the fermentation medium. Selamectin [34, 35] is a new experimental antiparasitic drug introduced by Pfizer. It is a semisynthetic avermectin-monosaccharide derivative, and it is produced from doramectin by chemical synthesis. 

With 2,3-[isopropylidenebis(oxy)]propanal the facial selectivity of the allylstannane generated from tin(II) chloride, the disodium salt of diethyl 2,3-dihydroxybutanoatc, and 3-bromo-1-propene (see preceding section) is overwhelmed by the facial selectivity of the substrate97. Some selectivity was observed in coupling monosaccharide derived allylstannanes with monosaccharide aldehydes99. 

The generic term carbohydrate includes monosaccharides, oligosaccharides and polysaccharides as well as substances derived from monosaccharides by reduction... 

This section relates to the introduction of a double or triple bond between two contiguous carbon atoms of the backbone chain of a monosaccharide derivative. A double bond between a carbon atom of the backbone chain and an atom outside that chain, or a double or triple bond between two carbon atoms outside the backbone chain, will be treated according to the normal rules of organic nomenclature [13,14],... 

Note 1. The term glycal is a non-preferred, trivial name for cyclic enol ether derivatives of sugars having a double bond between carbon atoms 1 and 2 of the ring. It should not be used or modified as a class name for monosaccharide derivatives having a double bond in any other position. 

Monosaccharide derivatives having a triple bond or cumulative double bonds in the backbone chain are named by the methods of 2-Carb-17.2, with the infix n-yn for a triple bond and infixes such as ij-dien for cumulative double bonds. 

Symbols for the common monosaccharide residues and derivatives are listed in Table 2. They are generally derived from the corresponding trivial names. Abbreviations for substituents (see 2-Carb-1.16.2), preceded by locants, follow the monosaccharide abbreviations directly. 

Table 2. Symbols for monosaccharide residues and derivatives in oligosaccharide chains...

The first observations on the stereochemical dependence of spin-lattice relaxation-rates of carbohydrate molecules, beginning in " 1972, provided a general survey of the nonselective relaxation-rates of the anomeric protons of monosaccharide derivatives, oligosaccharides, and some polysaccharides. 

Comparison of Sweetness between Trehalose Derivatives and the Corresponding Monosaccharide Analogs by Paired Comparison Test d... 

The most well known and most widely used compounds mentioned in the chapter are the doubly protected monosaccharide derivatives (cf. Schemes 16-18 and 27-29), which serve as building blocks for the regio- and stereospecific synthesis of a host of more complex carbohydrates. A number of newly discovered alkaloids contain fused 5 6 6-triheterocyclic systems these compounds may come from not only traditional (plant) sources, for example, compounds 96, 292-294, 446, and 447, but also insects (compounds 531-533), marine animals of various kinds, for example, sponges (compounds 58 R = H or OH) and ascidians (compound 289), and amphibians (compound 535). Although the majority of these alkaloids are known to be toxic in sufficient quantity, any possible therapeutic applications have apparently not yet been disclosed. 

By treatment of chitin with alkali the acetyl groups can be removed and a polyglucosamine formed. This compound, chitosan, appears to be broken down with nitrous acid even under mild conditions, the sole product being a monosaccharide derivative. 

TABLE A.5. The Masses of Some Monosaccharide Residues and Their Derivatives... 

Reaction of nitromethane and monosaccharide-derived dialdehydes is a useful tool that has been broadly used for the preparation of nitro and amino sugars, and carbocycles.30 Dialdehydes can easily be obtained by oxidative cleavage of conveniently protected monosaccharides with sodium periodate. Their subsequent Henry reaction with a nitroalkene, commonly nitromethane, usually gives isomeric mixtures that require the isolation of the major isomer.31 Thus, treatment of the D-ribose derivative 27 with sodium periodate gave dialdehyde 28, which was subjected to a Henry reaction with nitromethane, to afford nitrosugar 29 as an epimeric mixture (Scheme 11).32... 

In such cases, it is practical to apply the following considerations. The analysis usually provides data that can be expressed as numbers of moles of each monosaccharide derivative per mole of sample. The expression [NS] - [DS] - 2 [TS] - 3 [TeS] (where NS = nonsubsti-tuted (terminal), DS = disubstituted (branched), TS = trisubstituted, and TeS = tetrasubstituted sugars) should theoretically give a value of unity. If values far below unity are encountered, several sources of analytical error must be considered. Undermethylation must be considered, as well as erroneously low values for terminal sugars caused by the volatility of their methylated derivatives. Nonglycosidic substituents, such as sulfate,56 phosphate, and acetal groups must also be considered.48... 

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