thioglucoside

Thioglucoside is a type of glycoside in which the anomeric carbon of a glucose unit is bound to a sulfur atom of the aglycone, forming an S-glycosidic bond. This contrasts with the more common O-glycosidic linkage in ordinary glucosides. The term can also refer to compounds in which a thioglucose moiety—beta-D-thioglucose—is linked to a non-sugar moiety via sulfur.

In natural products, thioglucosides occur as part of glucosinolates, a class of sulfur-containing glucosides produced by plants in the Brassicales order. Upon enzymatic hydrolysis, glucosinolates release glucose and a sulfur-containing aglycone that can be converted to bioactive isothiocyanates and related compounds. The thioglucoside unit is central to the biochemical behavior of these molecules.

In synthetic chemistry, thioglucosides are prepared and used as glycosyl donors (S-linked glycosides) because sulfur-glycosidic bonds have distinct stability and reactivity compared with oxygen linkages. They are typically formed by S-glycosylation of thiols with suitably protected glycosyl donors, or by installing a thiol at the anomeric position of glucose (a glycosyl thiol) followed by attachment to the desired aglycone. These strategies allow selective activation under specific conditions to construct more complex glycosidic architectures.

Properties and significance: S-glycosides exhibit different hydrolysis kinetics and enzyme recognition compared with O-glycosides. Their relative stability and controllable reactivity make them valuable tools in carbohydrate synthesis and in studies of glycoside metabolism.