Synthesis of simple multivalent β-D-GalNAc-(1→4)-β-D-Gal oligomers as probes for investigating the interactions of P-aeruginosa pili with multivalent receptors

Five multivalent beta-D-GalNAc-(1-->4)-beta-D-Gal oligomers were selected and synthesized as probes for investigating the adhesin-receptor interactions of P. aeruginosa pill with multivalent receptors. They were synthesized by the amide coupling reactions of 8-(N-2-aminoethyl)carboxamidooctyl 4-O-(2-acetamido-2-deoxy-beta-D-galactopyranosyl)beta-D-galactopyranoside (7) with EDTA dianhydride, EDTA, Kemp's triacid and adipic acid with EDC, DIC and DCC combined with HOBt as coupling reagents and by the reaction of per-O-acetylated 7 with 1,3,5-benzenetricarbonyl trichloride followed by de-O-acetylation. These resulting multivalent compounds contain flexible C-9 spacer arms as linkers attached to either flexible hydrophilic moieties or rigid hydrophobic cores.