Calculation of NMR Chemical Shifts and Spin−Spin Coupling Constants in the Monosaccharide Methyl-β-d-xylopyranoside Using a Density Functional Theory Approach

Abstract

Density functional theory based approaches were used to calculate chemical shieldings and spin−spin coupling constants in a monosaccharide, methyl-β-d-xylopyranoside. Excellent agreement was found between the computed and experimental data for this monosaccharide both in solution and in solid state. The effect of torsion around the C1−O1 bond showed that chemical shifts of the anomeric proton, both ring and O1 oxygens as well as C1, C2, and the methyl carbons, strongly depend on the dihedral angle. Similarly, both one-bond and three-bond proton−carbon coupling constants among anomeric proton and anomeric and methyl carbons [(1JC1-H1) and (3JC(Me)-H1), respectively] showed a dependence on the torsion angle Φ.