Synthesis of the tetrasaccharide repeating unit of the K-antigen from Klebsiella type 57.
Starting from D-galactose and D-mannose two disaccharide blocks, namely 2-(trimethylsilyl)-ethyl 2,3,4,6-tetra-O-benzyl-alpha-D-mannopyranosyl-(1-->4)-6-O-(4-methoxybenz yl)- beta-D-galactopyranoside and ethyl 2,3,4,6-tetra-O-benzyl-alpha-D-mannopyranosyl-(1-->3)-4-O-acetyl- 2,6-di-O-benzoyl-1-thio-beta-D-galactopyranoside, were synthesized which were then allowed to react, in the presence of dimethyl(methylthio)sulfonium triflate to give a tetrasaccharide derivative. This compound was converted to 2-(trimethylsilyl)ethyl 2,3,4,6-tetra-O-benzyl-alpha-D- mannopyranosyl-(1-->3)-4-O-acetyl-2,6-di-O-benzoyl-beta-D-galactopyranos yl- (1-->3)-[2,3,4,6-tetra-O-benzyl-alpha-D-mannopyranosyl-(1-->4)]-tert-but yl (2-O-acetyl-beta-D-galactopyranosid)uronate which, on treatment with sodium methoxide followed by hydrogenolysis, afforded the methyl [2-(trimethylsilyl)ethyl glycosid]uronate of the tetrasaccharide repeating unit of the K-antigen from Klebsiella type 57.
Sarbajna
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S
Department of Biological Chemistry, Indian Association for the Cultivation of Science, Jadavpur, Calcutta, India.
Roy
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N
D000942:Antigens, Bacterial / Q000737:chemistry; D000954:Antigens, Surface / Q000737:chemistry*; D002236:Carbohydrate Conformation; D002240:Carbohydrate Sequence; D007709:Klebsiella / Q000276:immunology*; D009682:Magnetic Resonance Spectroscopy; D008969:Molecular Sequence Data; D009844:Oligosaccharides / Q000138:chemical synthesis*
D000942:Antigens, Bacterial; D000954:Antigens, Surface; C030659:K antigens; D009844:Oligosaccharides