earticle

영어

A great deal of effort has been devoted to the elucidation of the cell wall structure of Mycobacteriumtuberculosis, the causal agent of human tuberculosis, in recent years owing to the appearance of its multi-drug resistant strains. One of the major structural components of the cell wall of is the complex of mycolic acid, arabinogalactan (AB), and peptidoglycan, which plays a extremely important role for the survival and pathogenicity of M. tuberculosis. Novel cyclicgalactooligosaccharides 1, 2, and 3 were identified amongst the degradation products of AG by extracellular enzymes isolated from Cellulomonas sp. Herein we report the synthesis of cyclic tetra-, hexa- and octasaccharides 1, 2, and 3 including the alternating (1→5)-β-, and (1→6)-β- galactofuranosyl linkages by the intramolecular cycloglycosylation of corresponding linear sugars and by the cylclooligomerization of 1,5-linked and 1,6-linked disaccharides, 4 and 5. Notably, the cyclooligomerization of (1→6)-β-galactofuranosyl disaccharide 5 presented an effective way to secure all three cyclic sugars in one operation.