Synthesis of glycolipids containing disaccharides and two longer alkyl chains and their applications as enzyme modifiers

The aminolysis between p-(aminomethyl)benzoic acid and lactobiono-1,5-lactone was carried out in Me2SO in quantitative yield. The amide formed thus was used directly for the final reaction without isolation of the intermediate from the reaction mixture. This simple one-pot procedure finished a convenient and useful synthesis of the target N-[p-(dialkyl-l-glutamatecarbonyl)-benzyl]lactobionamides. The phase-transition temperature of glycolipids was shown to greatly depend on the structure between the hydrophilic moiety and the hydrophobic segment of the glycolipids. The yield of proteins of lipases coated with the glycolipids containing disaccharides remarkably increased with alkyl-chain length, which was higher than that with glycolipids containing monosaccharides. The yields were also closely correlated to the origin of the lipases. The enzymatic reactivity of lipid-coated lipase PS was seldom affected by the hydrophobic segment of lipids, but its enantioselectivity was mainly affected by the hydrophilic moiety of lipids.