A practical synthesis of β-d-GlcA-(1→3)-β-d-Gal-(1→3)-β-d-Gal-(1→4)-d-Xyl, a part of the common linkage region of a glycosaminoglycan Original Research Article

A practical synthesis of β-d-GlcA-(1→3)-β-d-Gal-(1→3)-β-d-Gal-(1→4)-β-d-Xyl-(1→OMe) was achieved by coupling of methyl 2,3,4-tri-O-acetyl-α-d-glucopyranosyluronate trichloroacetimidate with a trisaccharide acceptor. The trisaccharide acceptor was obtained by condensation of 3-O-allyl-2,4,6-tri-O-benzoyl-β-d-galactopyranosyl-(1→3)-2,4,6-tri-O-benzoyl-α-d-galactopyranosyl trichloroacetimidate with methyl 2,3-di-O-benzoyl-β-d-xylopyranoside, followed by deallylation. The β-(1→3)-linked disaccharide was prepared readily with p-methoxyphenyl 3-O-allyl-2,4,6-tri-O-benzoyl-β-d-galactopyranoside as the key synthon. The α-(1→3)-linkage was formed in considerable amount with galactose mono- and disaccharide trichloroacetimidate donors with C-2 neighboring group participation.