13C- and 1H-nuclear magnetic resonance spectroscopy of permethylated disaccharides

Abstract

The 13C-N.m.r. spectra of permethylated disaccharides composed of D-glucose, or D-galactose, or both residues are analyzed and discussed. Peaks were assigned by correlation of the spectra of the disaccharide derivatives with those of the constituent permethylated monomers. Large shift-increments for skeletal and methoxyl carbons, with respect to the resonance positions of corresponding atoms of the monomers, are explained in terms of steric or proximity effects. The configuration of glycosidic linkages can be deduced from the chemical shifts of the anomeric carbons and from the 1H-n.m.r. data of the attached protons.