Synthesis of a spacer-armed disulfated tetrasaccharide of SB1a, a carbohydrate hapten associated with human hepatocellular carcinoma Original Research Article

A disulfated tetrasaccharide fragment with a spacer arm of human hepatocellular carcinoma carbohydrate antigen SB1a, namely, 2-aminoethyl 3-O-sulfo-β-d-galactopyranosyl-(1→3)-2-acetamido-2-deoxy-β-d-galactopyranosyl-(1→4)-3-O-sulfo-β-d-galactopyranosyl-(1→4)-β-d-glucopyranoside was synthesized via a [2+1+1] block building mode. In the last coupling step toward the trisaccharide acceptor 8, benzoyl protected galactosyl bromide donor 14 was found to be much more reactive than the acetyl-protected donors.