Sugar mercaptals

The Action of Lead Tetraacetate on Sugar mercaptals, E. J. Boume, W. M. Corbett, M. Stacey, and... 

As a result of these considerations, a rejuvenescence of interest in sulfonic esters of acyclic-sugar derivatives, e.g., of sugar mercaptals, is to be expected, since they afford a route to the synthesis not only of compounds having one or more methylene groups at desired positions in the sugar chain (of which 2-deoxy-D- ribose, or 2-deoxy-D-eryother groupings, e.g., double bonds, at selected positions in the chain. 

Various sugar mercaptals have been converted to the disulfones by the action of organic per-acids 257). Thus, D-glucose diethyl mercaptal penta-acetate is oxidized by perphthalic acid to D-ara5o-3,4,5,6-tetraacetoxy-... 

Hydrogen peroxide/ammonium molybdate Oxidation of sugar mercaptals... 

Kent39 demonstrated that mercaptanolysis of desoxyribonucleic acids resulted in the liberation of the sugar, which was isolated as the dibenzyl mercaptal. 

A different type of sulfur-containing. sugar derivative had been obtained by Fischer many years earlier by the interaction of various aldoses with mercaptans. The sugars react, as aldehydes, with two moles of mercaptan and the mercaptal or thioacetal is formed. (These compounds will not be reviewed herein in detail.) In 1916 Schneider and Sepp made the important observation that these mercaptals would... 

Preparation. The preparation of 2-deoxy-D-erythro-pentose by hydrolysis of the natural deoxypentosenucleic acids is tedious and the yields are low. The nucleic acids first are hydrolyzed enzymatically to deoxyribonucleo-sides (V-deoxyribofuranosyl purines and pyrimidines). Further mild acidic hydrolysis then liberates the sugar from the purine bases 57). The sugar-pyrimidine linkage, however, is more stable and its hydrolysis by stronger acid is accompanied by destruction of the deoxypentose to levulinic acid. Direct mercaptanolysis of deoxyribosenucleic acids has been employed to obtain the dibenzyl mercaptal of the deoxysugar 58). 

A method of degradation with excellent preparative possibilities has been devised by MacDonald and Fischer (200), The higher-carbon sugar first is condensed with ethyl mercaptan to form the bis(ethylthio)acetal (mercaptal) (I) (Chapter IV). Oxidation of the mercaptal with perpro-pionic acid then leads to the bis(ethylsulfonyl) compound (II), which is smoothly degraded by aqueous ammonia to the next lower aldose and bis(ethylsulfonyl)methane. 

The use of boric acid has been suggested by Brigl for the preparation of partially 0-benzoylated sugars (41, 44)- Unimolar 0-benzoylation of glycosides and mercaptals results usually in preferential esterification of the primary hydroxyl (45). 

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