Chemical modification of some methyl (3,4-di-O-acetyl-2-deoxy-2-hydroxyimino-α-d-arabino-hexopyranosid)uronates

Methyl [ethyl 3,4-di-O-acetyl-2-deoxy-2-(Z)-hydroxyimino-α-d-arabino-hexopyranosid]-uronate (1) and N-tert-butoxycarbonyl-O-[methyl 3,4-di-O-acetyl-2-deoxy-2-(Z)-hydroxyimino-α-d-arabino-hexo-pyranosyluronate]-l-serine methyl ester (2) were modified at C-2 and C-3. They have been transformed into the corresponding methyl (2,3,4-tri-O-acetyl-α-d-glycopyranosid)uronates by the sequence of reactions 2-CNOH → 2-CO → 2-COH → 2-COAc. Reaction of 1 and 2 with sodium azide gave the corresponding methyl [ethyl 4-O-acetyl-3-azido-2,3-dideoxy-2-(Z)-hydroxyimino-α-d-glycopyranosid]uronates and N-tert-butoxycarbonyl-O-[methyl 4-O-acetyl-3-azido-2,3-dideoxy-2-(Z)-hydroxyimino-α-d-glycopyranosyluronate]-l-serine methyl esters.