Abstract
The nuclear magnetic resonance spectra of methyl amino-hexopyranosides in the forms of free base, hydrochloride and N-acetate were measured in deuterium oxide and, in part, in pyridine. The spectrum of the free base showed a multiplet at higher field than 7 p.p.m., caused by weakly deshielding of an amino group. The analysis of this signal was shown to offer information in the vicinity of an amino group. The spectrum of the hydrochloride showed long-range deshielding of an anomeric proton along with other ring protons, possibly induced by the electric field of an ammonium cation. The long-range deshielding due to an acetamido group was weaker than an ammonium group. It was observed in a variety of the derivatives that H2 of α-glucopyranoses resonated at lower field with greater J1, 2 values than those of α-mannopyranoses. The differences presented ready distinction between the two isomers.
