Synthesis and NMR analysis of 13C-labeled oligosaccharides corresponding to the major glycolipid from Mycobacterium leprae.

Abstract An improved synthesis of propyl 4- O -(3,6-di- O -methyl- β - d -glucopyranosyl)-2,3-di- O -methyl- α - l -rhamnopyranoside, a disaccharide corresponding to the phenolic glycolipid of Mycobacterium leprae using a trichloroacetimidate as a glycosyl donor is described. The synthetic strategy is also applied to the preparation of three corresponding disaccharide analogues containing 13 C-labeled methyl groups. The preparation of the trisaccharide, propyl 2- O -[4- O -(3,6-di- O -methyl- β - d -glucopyranosyl)-2,3-di- O -methyl- α - l -rhamnopyranosyl]-3- O -methyl- α - l -rhamnopyranoside is also reported. The di- and tri-saccharides were characterized by 1 H and 13 C NMR spectroscopy.