Stereochemical Aspects of Proton Chemical Shifts. IX. Influence of O-Alkyl Groups on the Chemical Shift of the Glycosidic Proton in Pyranoid Systems

The 1H NMR parameters of some alkyl β-D-xylopyranosides (alkyl = Me, Et, n.Pr, i.Pr and t.Bu) have been measured in D2O and DMSO-d6 solution at 300 and 360 MHz. A rationale is checked to explain the influence of the 0-alkyl groups on the chemical shift of the glycosidic proton. It is found, as reported previously for other cases1, 2, that γ-increments in full carbon-skeleton are very similar to those in a H-C-O-C-C skeleton.