13C- and 1H-N.M.R. spectroscopy of permethylated α- and β-D-galactopyranoses

Abstract

The complete assignment of the 13C- and 1H-n.m.r. spectra of the permethylated alpha- and beta-D-galactopyranoses was performed with the aid of specific trideuteriomethylation, heteronuclear spin-decoupling, and spectrum simulation. The n.m.r. data are discussed and compared with those of the permethylated glucopyranoses. Identification of partially methylated galactoses, e.g., as obtained in the methylation analysis of carbohydrates, can be carried out by conversion of the free hydroxyl functions into 2H- or 13C-labelled methoxyl groups, and comparison of the n.m.r. spectra of the resulting permethyl ethers with those of reference compounds.