Synthesis of a pentasaccharide hapten related to a monoantennary glycan chain of human chorionic gonadotropin.

A stereocontrolled synthesis of a pentasaccharide hapten, namely, 8-ethoxy-carbonyloctyl O-beta-D-galactopyranosyl-(1----4)-O-(2-acetamido-2-deoxy-beta-D-gluc opy ranosyl) -(1----2)-O-alpha-D-mannopyranosyl-(1----3)-O-[alpha-D-mannopyranosyl- (1----6)]-alpha-D-mannopyranoside, is described employing a trihexosyl glycosyl-donor, O-(2,3,4,6-tetra-O-acetyl-beta-D-galactopyranosyl)-(1----4)-O-(2-acet amido-3,6- di-O-acetyl-2-deoxy-beta- D-glucopyranosyl)-(1----2)-3,4,6-tri-O-benzyl-alpha-D-mannopyranosyl trichloroacetimidate, and a mannobiosyl glycosyl-acceptor, 8-ethoxycarbonyl-octyl O-(2,3,4,6-tetra-O-benzyl-alpha-D-mannopyranosyl)-(1----6)-2,4-di-O-benz yl-beta - D-mannopyranoside, as the key intermediates.