Selective S-Deprotection of Thioglycoses

There are several methods for the selective S-deacetylation of thioglycoses one of the most successful of these is demercuration of phenylmercury thio-a- or -P-D-glycoses [22, 23]. Deprotection has also been achieved by use of sodium methoxide 

The same procedures can also be used to obtain compounds with the free thiol at the 2-, 3-, 4-, 5-, or 6- positions. Although these derivatives are very prone to forming disulfide linkages, this can be overcome by treatment of such compounds with DTE in aqueous solution thereby generating the free thiol [29], 

Both traditional and new approaches (often used in the preparation of O-glycosides) have been applied to the establishment of thio linkages. Here, the synthesis of thiodisaccharides and thiooligosaccharides is described with reference to linkage specificity and method of generation. 

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