Oxidation of aldose oximes. Formation and structure of hydroxydiazene oxide acetals and preparation of hydroximolactones. X-Ray crystal structure of 2,3:5,6-di-O-isopropylidene-α-D-mannofuranosyl-ONN-azoxy 2,3:5,6-di-O-isopropylidene-α-D-mannofuranoside
Abstract
Oxidation of the glucopyranosylamine (1) with peracid gave, in low yield, either the stable 1-deoxy-1-nitrocompound (2) or the dimer (3), depending on the reaction conditions. Oxidation of the oximes (4), (9), (13), and (17) with periodate at low pH gave the hydroxiolactones (5), (10), (14), and (18), respectively, and, in the case of the oxime (17), the dimer (20) also [at higher pH]. The structure of compound (20) was determined by X-ray analysis. The structures of the hydroximolactones were deduced from spectroscopic data and chemical transformations; they were obtained in high yield from the aforementioned oximes by oxidation with periodate at higher pH.