Thiosugars, in which the ring oxygen of the monosaccharide is replaced with a sulfur atom, have been utilized in the synthesis of bioactive oligosaccharides as excellent analogs of monosaccharides because of their tolerant reactivity with glycosidases. 1 Naturally occurring thiosugar derivatives, as well as synthesized derivatives, show inhibitory activity against glycosidases, for example, salacinol isolated from Salacia reticulata is a potent inhibitor of ...