TRITERPENE GLYCOSIDES OF Astragalus AND THEIR GENINS.LXXII.X-RAY CRYSTAL STRUCTURE OF CYCLOORBICOSIDE D

摘要

The structure of the new cycloartane glycoside cycloorbicoside D (1),which was isolated from Astragalus orbiculatus Ledeb.(Leguminosae),was determined based on chemical transformations and spectral data as 23xi,24xi-cycloartan-3beta,6 alpha,16beta,23,24,25-hexaol 3-O-beta-D-xylopyranoside [1].The methods used previously [1] were not capable of resolving the issue of the stereochemistry of asymmetric C-23 and C-24 in the glycoside.The present communication addresses this problem.