Large Scale Synthesis of A Derivative of An α-Galactosyl Trisaccharide Epitope Involved in the Hyperacute Rejection of Xenotransplantation

Abstract

ABSTRACT A derivative of an α-galactosyl trisaccharide xenoactive antigen, (2,3,4,6-tetra-O-benzyl-α-D-galactopyranosyl)-(1→3)-(2,4,6-tri-O-acetyl-β-D-galactopyranosyl)-(1→4)-2,3,6-tri-O-acetyl-β-D-glucopyranosyl azide (5), was synthesized on a large scale (50 gram). The synthesis involved a high yielding and highly stereoselective (α/β>20:1) glycosylation reaction utilizing a thiogalactoside as the donor and a selectively protected lactose azide as the acceptor. This derivative serves as a versatile intermediate that can be transformed into a variety of α-Gal containing glycoconjugates highly desired in xenotransplantation research and pharmaceutical development.