Synthesis of chlorodeoxy trisaccharides related to the Shigella flexneri Y polysaccharide.
Chloromethoxylation of di-O-acetyl-L-rhamnal has been employed as a convenient route to methyl 3,4-di-O-acetyl-2-chloro-2-deoxy-alpha-L-rhamnopyranoside 7, which was converted into an ethyl thioglycoside 10, suitable for use as a glycosyl donor. It and a disaccharide analogue 20 were effective donors in N-iodosuccinimide-triflic acid promoted glycosylations of a 2-acetamido-2-deoxy-D-glucopyranoside acceptor 22. Chlorodeoxy saccharides have previously been shown to be suitable derivatives to probe oligosaccharide-protein interactions, and this synthetic strategy provided three monochlorodeoxy trisaccharide congeners of the native Shigella flexneri epitope 2, alpha-L-Rhap-(1-->3)-alpha-L-Rhap-(1-->3)-beta-D-GlcNAcp+ ++-(1-->O)-Me.
Auzanneau
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FI
Institute for Biological Sciences, National Research Council of Canada, Ottawa, Ontario.
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D002236:Carbohydrate Conformation; D002240:Carbohydrate Sequence; D002713:Chlorine; D007202:Indicators and Reagents; D009682:Magnetic Resonance Spectroscopy; D008969:Molecular Sequence Data; D015394:Molecular Structure; D019081:O Antigens; D009904:Optical Rotation; D011135:Polysaccharides, Bacterial / Q000737:chemistry*; D012763:Shigella flexneri / Q000276:immunology*; D014312:Trisaccharides / Q000138:chemical synthesis*
D007202:Indicators and Reagents; D019081:O Antigens; D011135:Polysaccharides, Bacterial; D014312:Trisaccharides; D002713:Chlorine