Base-catalyzed Degradations of Carbohydrates. VII. Alkaline Degradation of 3,6-Di-O-substituted Hexoses

Abstract

6-O-β-D-Glucopyranosyl-3-O-methyl-D-glucose (4) has been synthesized as a model com pound for regions of branching in polysaccharides. Alkaline degradation of the disaccharide affords an epimeric pair of O-glycosyl metasaccharinic acids which have been characterized by reduction to 3-deoxy-6-O-β-D-glucopyranosyl-D-ribo-hexose (6) and 3-deoxy-6-O-β-D-glucopyranosyl-D-arabino-hexose (7). Alkaline degradation of the branched β-D-glucan from Sclerotiumrolfsii followed by reduction of the derived metasaccharinic acids furnishes 3-deoxy-D-ribo-hexose (8), 3-deoxy-D-arabino-hexose (9), and the two disaccharides (6 and 7).