Synthesis of 6-O-octyl-β-D-galactopyranosyl-(1 → 5)-L-arabinose and comparative 1-deoxyglycitolation of Nα-Z-L-lysine with amphiphilic lipodisaccharides

A lipodisaccharide possessing a reactive aldopentose unit, 6-O-octyl-β-D-galactopyranosyl-(1 → 5)-L-arabinose 6, was obtained by glycoside synthesis. To avoid a possible intramolecular acyl transfer, benzoyl protecting groups and mild conditions of detritylation were used in the preparation of the furanosyl acceptor. The reductive alkylation of Nα-Z-L-lysine was then studied and compared to that of previously prepared liposaccharides. In this reaction, amphiphilic five-membered hemiacetals are generally more reactive than their six-membered analogues. The newly prepared disaccharide is the most reactive of the series and also the easiest to prepare. Therefore this reagent has been selected for a future study on the chemical modification of enzymes and the use in organic solvents of the biocatalysts obtained. Keywords: liposaccharides, reductive alkylation.