Crystal structures of analogues of D-galactose. I. 2,3-Di-O-acetyl-1,6-anhydro-β-D-galactopyranose (DAG)

Abstract

The structure of DAG has been determined from three-dimensional diffractometer data by direct methods with the tangent formula. The space group is P21 with a = 11.3328 (17), b=6.1197 (4), c-8-2568 (11)/~, fl= 103.44 (1) °. The molecule has an anhydro bridge across the galactose moiety forming a five-membered ring which has an envelope conformation while the pyranose ring has a strained chair conformation. An intermolecular hydrogen bond (2.864 A) occurs between the hydroxyl group and the O atom of the bridge.