STEREOCHEMICAL STUDY OF THE CD SPECTRAL DIFFERENCES BETWEEN ANOMERS OF ALKYL GLUCOPYRANOSIDES

Slightly different chair conformation geometries were demonstrated to be the origin of the CD spectral differences observed in anomers of al kyl glucopyranosides. The study, using methyl glucopyranoside derivati ves as model compounds, showed excellent agreement between CD data, H- 1 NMR data, and semiempirical calculations, and the geometries found e xplained satisfactorily the higher amplitudes observed for the beta-an omers of tetrachromophorically substituted alkyl glucopyranosides. The pairwise interactions involving the chromophore at C2,the 2/3, 2/4 an d 2/6, were the most dependent on the anomeric configuration, the 2/4 interaction even showing opposite CD signs for the anomers. In additio n, the 2/3 pairwise interaction was revealed to be independent of the structural nature of the aglycon. (C) 1998 Elsevier Science Ltd. All r ights reserved.