Efficient synthesis of a heptasaccharide, the repeating unit of the O-chain lipopolysaccharide produced by Xanthomonas campestris strain 642.
alpha-L-Rhap-(1-->3)-alpha-L-Rhap-(1-->2)-alpha-L-Rhap-(1-->3)-[beta-D-Xylp-(1-->2)-][beta-D-Xylp-(1-->4)-]alpha-L-Rhap-(1-->3)-alpha-L-Rhap, the repeating unit of the O-chain lipopolysaccharide produced by Xanthomonas campestris strain 642 was synthesized as its methyl glycoside via 3-O-selective glycosylation of methyl alpha-L-rhamnopyranosyl-(1-->3)-2,4-di-O-benzoyl-alpha-L-rhamnopyranoside (9) with 2,3,4-tri-O-benzoyl-alpha-L-rhamnopyranosyl-(1-->3)-2,4-di-O-benzoyl-alpha-L-rhamnopyranosyl-(1-->2)-3,4-di-O-benzoyl-alpha-L-rhamnopyranosyl trichloroacetimidate (8), followed by dixylosylation with 2,3,4-tri-O-benzoyl-alpha,beta-D-xylopyranosyl trichloroacetimidate (12) and subsequent deacylation.
Zhang
Jianjun
J
Research Center for Eco-Environmental Sciences, Academia Sinica, P.O. Box 2871, Beijing 100085, China.
Ning
Jun
J
Kong
Fanzuo
F
D002240:Carbohydrate Sequence; D008070:Lipopolysaccharides / Q000737:chemistry*; D008969:Molecular Sequence Data; D015394:Molecular Structure; D019081:O Antigens / Q000737:chemistry*; D009844:Oligosaccharides / Q000138:chemical synthesis* / Q000737:chemistry; D012210:Rhamnose / Q000737:chemistry; D016959:Xanthomonas campestris / Q000737:chemistry*
D008070:Lipopolysaccharides; D019081:O Antigens; D009844:Oligosaccharides; D012210:Rhamnose