Nuclear magnetic resonance studies of 1,6-linked disaccharides
The signals in the 13C n.m.r. spectra of all anomeric forms of the methyl glycosides of D-Glcp-(1→6)-D-Glcp and D-Glcp-(1→6)-D-Galp in water have been assigned. The chemical-shift differences obtained by comparison with relevant monosaccharide derivatives were used to calculate 13C n.m.r. spectra of oligo- and poly-saccharides containing 1,6-linkages. Good agreement between calculated and experimental spectra were obtained for raffinose, stachyose, dextran, and pustulan. The importance of comparing spectra determined at the same temperature is emphasized. Temperature shifts may, in favourable cases, be used for assignment of signals.