METHYL 3-NITRO- AND 3-AMINO-3-DEOXY-β-D-GALACTOPYRANOSIDE AND -MANNOPYRANOSIDE

The steric course of the nitromethane cyclization of L′-methoxy-D-hydroxymethyldiglycolic aldehyde was investigated. Methyl 3-nitro-3-deoxy-β-D-galactopyranoside was shown to arise as a second major reaction product in addition to the previously isolated principal stereoisomer, the gluco derivative. The corresponding manno stereoisomer is formed to a smaller extent. The configurations of the new methyl nitrodeoxyglycosides were established by conversion into the corresponding amino derivatives and hydrolysis of these latter to the known 3-amino-3-deoxy-D-galactose and -D-mannose hydrochlorides. All the products were obtained in a crystalline state. The reaction lends itself to a facile preparation of the nitrogenous galactose derivatives.