The synthesis of diosgenyl 2-amino-2-deoxy-beta-D-glucopyranoside hydrochloride

The N-trifluoroacetyl- and N-tetrachlorophthaloyl-protected bromide of D-gl ucosamine has been used for the first time as a glycosyl donor for the glyc osylation of diosgenin [(25R)-spirost-5-en-3 beta-ol]. Both 1,3,4,6-tetra-O -acetyl-2-deoxy-2-trifluoroacetamido-beta-D-glucopyranoside and 1,3,4,6-tet ra-O-acetyl-2-deoxy-2-tetrachlorophthalimido-alpha,beta-D-glucopyranoside w ere transformed into the appropriate glycosyl bromides. These reacted with diosgenin under mild conditions, using silver triflate as a promoter, and g ave the corresponding protected diosgenyl glycosides. Each was deprotected to give diosgenyl 2-amino-2-deoxy-beta-D-glucopyranoside hydrochloride. The structures of the new glycosides were established by H-1 NMR spectroscopy. (C) 2000 Elsevier Science Ltd. All rights reserved.