Preparation of β-D-Glucopyranosyl Derivatives of 1,6:2,3- and 1,6:3,4-Dianhydro-β-D-hexopyranoses and Their 1 H and 13 C NMR Spectra
The corresponding acetylated and free 2-O- and 4-O-glucosyl derivatives of dianhydrohexoses Ib - VIIb and Ic - VIIc have been obtained by the reactions of 2,3,4,6-tetra-O-acetyl-α-D-glucopyranosyl bromide ( IX ) with 1,6:3,4- and 1,6:2,3-dianhydro-β-D-hexopyranoses ( Ia - VIIa ). Structure of the products and the effects of glycosylation upon chemical shifts and conformations of the disaccharides prepared have been studied using 1 H and 13 C NMR spectra.