Synthesis of 3-O-[6-O-(α-D-galactopyranosyl)-β-D-galactopyranosyl]-1,2-di-O-stearoyl-L-glycerol, a ‘digalactosyl diglyceride’

Abstract

2,3,4,-Tri-O-benzyl-6-O-(but-2-enyl)-α-D-galactopyranosyl chloride was condensed with 1,2-O-isopropylidene-3-O-(2,3,4-tri-O-benzyl-β-D-galactopyranosyl)-L-glycerol, under conditions shown previously to lead to 1,2-cis-glycosides, to give crystalline 1,2-O-isopropylidene-3-O-[2,3,4-tri-O-benzyl-6-O-(2,3,4-tri-O-benzyl-6-O-but-2-enyl-α-D-galactopyranosyl)-β-D-galactopyranosyl]-D-glycerol. Removal of the but-2-enyl group, by the action of potassium t-butoxide in dimethyl sulphoxide, gave the corresponding crystalline alcohol. The alcohol was benzylated and the isopropylidene group was removed by hydrolysis; subsequent acylation with stearoyl chloride and hydrogenolytic removal of the benzyl groups gave the title compound.