The chemistry of maltose. Part II. Chemical modifications at the reducing unit

Abstract

Chemical transformations of the reducing unit of maltose have been accomplished by routes starting from the known 1,2,2′,3′,4′,6,6′-hepta-acetate. In particular, the syntheses of 3-chloro-3-deoxy-, 3-azido-3-deoxy-, 2,3-anhydro-, 3,6-anhydro-, and 3-oxo-α-1,4-linked disaccharides are described. The 2,3-anhydride, which has the allo-configuration in the reducing ring, reacted with hydrogen bromide to give the 3-bromo-3-deoxy-maltose derivative by specific diequatorial ring opening. Methyl 4-O-(α-D-glucopyranosyl)-β-D-ribo-hex-3-ulopyranoside hexa-acetate underwent ready epimerisation to give the 2-axial epimer.