Synthesis of a 6V-sulfated mannopentasaccharide analogue related to PI-88 Original Research Article

An efficient and convergent synthesis of a regioselectively 6V-sulfated mannopentasaccharide derivative 1c, octyl 6-O-sulfo-α-d-mannopyranosyl-(1 → 3)-α-d-mannopyranosyl-(1 → 3)-α-d-mannopyranosyl-(1 → 3)-α-d–mannopyranosyl-(1 → 2)-α-d-mannopyranoside, was achieved by a ‘3 + 2’ strategy. The target was designed to mimic the promising anticancer agent PI-88 and was obtained from the building blocks, octyl 3,4,6-tri-O-benzoyl-α-d-mannopyranoside (3), allyl 2,4,6-tri-O-benzoyl-3-O-(4-methoxybenzyl)-α-d-mannopyranoside (6), and 6-O-acetyl-2,3,4-tri-O-benzoyl-α-d-mannopyranosyl trichloroacetimidate (11), under TMSOTf-catalyzed glycosylation conditions. Compound 1c displays a mild anti-angiogenic activity based on a chorioallantoic membrane (CAM) model study.