Crystal structures of O-acetylated 2-acylamino-2-deoxy- d-galactose derivatives

Abstract

The X-ray structures of 1,3,4,6-tetra- O-acetyl-2-deoxy-α- d-galactopyranoside derivatives with four different 2-(acylamino) substituents have been determined with Mo K α radiation at 123 K. The structure of the 2-acetylamino derivative and of its acyl-homologs with a 2-(propanoylamino)-, 2-(butanoylamino)-, and 2-(2-methyl-propanoylamino)-group crystallized in the monoclinic space group C2. The pyranose unit of all compounds has the usual 4 C 1 shape. The different orientations of the 6- O-acetyl-groups are discussed. Conformations of the acylamino-group are compared to those found in the crystal structure of N-acetyl-α- d-galactosamine.