Synthesis of glycopeptides from the carbohydrate-protein linkage region of proteoglycans

Abstract

2,3,4,6-Tetra- O-benzoyl-α- d-galactopyranosyl trichloroacetimidate was condensed with benzyl 2,3- O-isopropylidene-β- d-xylopyranoside to give the corresponding β-(1→4)-linked disaccharide derivative, which was transformed into 2,3-di- O-benzoyl-4- O-(2,3,4,6-tetra- O-benzoyl-β- d-galactopyranosyl)α- d-xylopyranosyl trichloroacetimidate. This glycosyl donor was condensed with a set of selectively C,N-protected l-seryl-glycine dipeptide units. Seletive deblocking at the C- or N-termini of the glycosylated or non-glycosylated dipeptide segments, and coupling using the mixed-anhydride procedure allowed the construction in high yield of partially or fully glycosylated oligopeptides from the carbohydrate-protein linkage region of proteoglycans.