Synthesis of galactose-containing analogues of (1→6)-branched (1→3)-glucohexaose and its lauryl glycoside Original Research Article

Coupling of the trisaccharide acceptor either 2,4,6-tri-O-acetyl-β-D-glucopyranosyl-(1→3)-[2,3,4,6-tetra-O-benzoyl-β-D-glucopyranosyl-(1→6)]-5-O-acetyl-1,2-O-isopropylidene-α-D-glucofuranose (13) or lauryl 2,4,6-tri-O-acetyl-β-D-glucopyranosyl-(1→3)-[2,3,4,6-tetra-O-benzoyl-β-D-glucopyranosyl-(1→6)]-2,5-di-O-acetyl-α-D-glucopyranoside (15) with the trisaccharide donor 2,3,4,6-tetra-O-benzoyl-β-D-glucopyranosyl-(1→3)-[2,3,4,6-tetra-O-benzoyl-β-D-glucopyranosyl-(1→6)]-2,4-di-O-acetyl-α-D-galactopyranosyl trichloroacetimidate (12) gave α-linked hexasaccharides 14 and 16, respectively, while coupling of either 13 or 15 with trisaccharide donor 2,3,4,6-tetra-O-benzoyl-β-D-galactopyranosyl-(1→3)-[2,3,4,6-tetra-O-benzoyl-β-D-galactopyranosyl-(1→6)]-2,4-di-O-acetyl-α-D-galactopyranosyl trichloroacetimidate 17 did not afford any hexasaccarides. The analogues of the immunomodulator β-D-Glcp-(1→3)-[β-D-Glcp-(1→6)]-α-D-Glcp-(1→3)-β-D-Glcp-β-(1→3)-[β-D-Glcp-(1→6)]-β-D-Glcp (1) was obtained by deprotection of 14 and 16.