Analysis of the component aldehyde and alcohols in borohydride-reduced dialdehydes from hexosamine derivatives

Unlike the dialdehydes formed from neutral monosaccharide residues, the dialdehydes from hexosamine residues are resistant to acidified ethanethiol, leaving the hemiacetal bond intact. However, the borohydride-reduced dialdehydes are readily split into the component aldehyde and alcohols; gas Chromatographic analysis of their derivatives is useful for structural studies of hexosamine-containing carbohydrates. Investigation by these sequential derivatization reactions indicated that anomeric methyl 2-acetamido-2-deoxy-$\text{d}$-glucopyranosides were oxidized in normal Malapradian fashion, whereas 2-acetamido-2-deoxy-$\text{d}$-glucose was over-oxidized. The rate of oxidation of 2-acetamido-D-glucitol was very rapid; the oxidation product can also be analyzed by the direct dithioacetal method (mercaptalation followed by trimethylsilylation).