Synthesis of an Immunologically Active Heptamannoside of Mycobacterium tuberculosis by the [Au]/[Ag]-Catalyzed Activation of Ethynylcyclohexyl Glycosyl Carbonate Donor

Abstract

Tuberculosis (TB) is one of the most dreadful diseases, killing more than 3 million humans annually. M. tuberculosis (MTb) is the causative agent for TB and has a thick and waxy cell wall, making it an attractive target for immunological studies. In this study, a heptamannopyranoside containing 1 → 2 and 1 → 6 α-mannopyranosidic linkages has been explored for the immunological evaluations. The conjugation-ready heptamannopyranoside was synthesized by exploiting the salient features of recently discovered [Au]/[Ag]-glycosidation of ethynylcyclohexyl glycosyl carbonate donors. The glycan was conjugated to the ESAT6, an early secreted protein of MTb for further characterization as a potential subunit vaccine candidate.

Total Synthesis of Conjugation-Ready Hyperbranched Pentasaccharide of Clavibacter phaseoli VKM Ac-2641T by [Au]/[Ag] Catalysis

“…In other words, the monomer ( 1 ) can be visualized as a hyperbranched ribofuranose unit attached to two mannopyranosides at the C2 and C3 positions, and the C1 position is glycosylated to a digalactofuranoside. As part of our interest in the application of our silver-assisted gold-catalyzed glycosidations using glycosyl ethynylcyclohexyl carbonate donors for the synthesis of sterically demanding and highly branched saccharides, we have attempted to synthesize the pentasaccharide 1 …”