Synthesis and characterisation of methyl 2- O-(β- d-glucopyranosyl)-6- O-(α- l-rhamnopyranosyl)-α- d-glucopyranoside

The branched trisaccharide, 2-O-(beta-D-glucopyranosyl)-6-O-(alpha-L-rhamnopyranosyl)-D-glucopyranos e (2), is regarded as the sugar moiety of an anthocyanin pigment isolated from the fruits and flowers of certain Begonia, Clivia, Rubus, Prunus, and Ribis species. The cyanidin-3-glycoside of 1 has been identified as one of the major pigments of Montmorency cherries (Prunus cerasus). It has also been isolated as quercetin and kaempherol glycosides from the flowers of potato (Solanum tuberosum). Synthesis of the methyl glycoside of 1, methyl 2-O-(beta-D-glucopyranosyl)-6-O-(alpha-L-rhamnopyranosyl)-alpha-D-glucop yranoside (2) is reported.