title: Efficient synthesis of a heptasaccharide, the repeating unit of the O-chain lipopolysaccharide produced by Xanthomonas campestris strain 642.
abstract: 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.
authors.affiliation: Research Center for Eco-Environmental Sciences, Academia Sinica, P.O. Box 2871, Beijing 100085, China.
authors.forename: Jianjun
authors.initials: J
authors.lastname: Zhang
authors.forename: Jun
authors.initials: J
authors.lastname: Ning
authors.forename: Fanzuo
authors.initials: F
authors.lastname: Kong
mesh_terms: 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*
chemical_list: D008070:Lipopolysaccharides; D019081:O Antigens; D009844:Oligosaccharides; D012210:Rhamnose