SYNTHESES OF O-PROTECTED 2-AMINO-2-DEOXY-GENTIOBIOSIDE HYDROHALIDES

The syntheses of ethyl 3,4-di-O-acyl(benzyl)-2-benzyloxycarbonylamino-2-deoxy-6-O-trityl-alpha-D-glucopyranosides (2-4) and methyl 3,4-di-O-acyl(benzyl)-2-deoxy-2-[(2',2'-dimethoxycarbonylvinyl)amino]-6-O-trityl-alpha-D-glucopyranosides (12-14) are reported. The partially protected D-glucosamine derivatives ethyl 3,4-di-O-benzyl- (5) and 3-benzyl-2-benzyloxycarbonylamino-2-deoxy-alpha-D-glucopyranoside (6), ethyl 3,4-di-O-benzoyl-2-benzyloxycarbonylamino-2-deoxy-alpha-D-glucopyranoside (9), methyl 3,4-di-O-acyl(benzyl)-2-deoxy-2-dimethoxycarbonylvinylamino-alpha-D-glucopyranosides (15-17) have been prepared or isolated as by-products. The preparation of ethyl 3,4-di-O-acetyl- (18), 3,4-di-O-benzoyl-(19), and 3,4-di-O-benzyl-2-benzyloxycarbonylamino-2-deoxy-6-O-(2,3,4,6-tetra-O-acetyl-beta-D-glucopyranosyl)-alpha-D-glucopyranosides (20), and methyl 3,4-di-O-acetyl- (21), 3,4-di-O-benzoyl-(22), and 3,4-di-O-benzyl-2-deoxy-2-dimethoxycarbonylamino-6-O-(2.3,4.6-tetra-O-acetyl-beta-D-glucopyranosyl)-alpha-D-glucopyranosides (23) through glycosylation reactions using 2, 3, 4, 12, 13, and 14 respectively as glycosyl acceptors and acetobromoglucose as glycosyl donor is described. The N-protecting group of 18, 19, and 21 was removed to give the alkyl hexa-O-acyl-2-amino-2-deoxy gentiobioside hydrohalides 24-26 respectively.