Synthesis of 2-Acetamido-2,5-dideoxy-5-phosphoryl-D-glucopyranose Derivatives: New Phospha-sugar Analogs of N-Acetyl-D-glucosamine

Starting with N-acetyl-D-glucosamine, methyl 2-acetamido-3,6-di-O-benzyl-2-deoxy-beta-D-xylo-hexofuranosid-5-ulose (18) was prepared in 7 steps. The addition reaction of dimethyl phosphonate to 18, followed by deoxygenation of its 5-hydroxy group, provided the 5-deoxy-5-dimethoxyphosphoryl-D-glucofuranoside derivative (21a). The hydride reduction of 21a, followed by the action of hydrochloric acid and then hydrogen peroxide, afforded the first D-glucosamine analog (23) having a phosphoryl group in the hemiacetal ring. This was converted into the per-O-acetylated N-acetyl-D-glucosamine phospha-sugar (25), while the same treatment of the 5-deoxy-5-dimethoxyphosphoryl-L-idose dimethyl acetal derivative (13b) afforded the N-acetyl-L-idosamine phospha-sugar (29).