N-Thiocarbonyl Iminosugars: Synthesis and Evaluation of Castanospermine Analogues Bearing Oxazole-2(3H)-thione Moieties.

A straightforward and efficient synthetic route to a new class of glycosidase inhibitors containing an oxazole-2(3H)-thione moiety has been devised. The approach involves the formation of α-hydroxy ketones, which, after condensation with thiocyanic acid, leads to the formation of the heterocycle. By exploiting the ability of the nitrogen atom of oxazoline-2thione precursors to act as nucleophiles in intramolecular addition, castanospermine analogues could be readily prepared in good overall yields. Glycosidase inhibitory activity com