Conformational dependence of 13C nuclear magnetic resonance chemical shifts in oligosaccharides

Abstract

It is shown that ¹³C n.m.r. chemical shifts of the anomeric and aglycone carbon atoms can be correlated with one of the glycoside torsion angles (ψ) which are involved in determining the conformation of oligosaccharides. The correlation is shown to be valid for oligosaccharides having an α-D-glucopyranosyl or α-D-galactopyranosyl unit at the non-reducing end of the molecule. Calculation of the minimum-energy conformation of the oligosaccharides is made on the basis of hard-spheres exo-anomeric (HSEA) effect calculations.