title: [Synthesis of a tetrasaccharide unit of the capsular polysaccharide of Streptococcus pneumoniae type 9V].
abstract: In the synthesis of 8-methoxycarbonyloctyl O-(alpha-D-galactopyranosyl)-(1----3)-O-(2-acetamido-2-deoxy-beta-D- mannopyranosyl)-(1----4)-O-(beta-D-glucopyranosyl)-(1----4)-alpha-D- glucopyranoside, which represents a component of the capsular polysaccharide of Streptococcus pneumoniae type 9V, the key step was the coupling of alpha-D-Galp-(1----3)-beta-D-ManpNAc-(1----4)-D-Glc as glycosyl donor with 8-ethoxy-carbonyloctyl 6-O-acetyl-2,3-di-O-benzyl-alpha-D-glucopyranoside as glycosyl acceptor by use of the imidate method. Only the beta-imidate of the trisaccharide could be employed in this glycosidation reaction to give stereoselectively the tetrasaccharide in high yield. The alpha-imidate of the trisaccharide led to hydrolysis of the imidate group.
authors.affiliation: Institut für Organische Chemie der Universität Hamburg, Bundesrepublik Deutschland.
authors.forename: H
authors.initials: H
authors.lastname: Paulsen
authors.forename: B
authors.initials: B
authors.lastname: Helpap
mesh_terms: D002236:Carbohydrate Conformation; D002240:Carbohydrate Sequence; D055598:Chemical Phenomena; D002621:Chemistry; D007096:Imidoesters; D008969:Molecular Sequence Data; D009844:Oligosaccharides / Q000138:chemical synthesis*; D011135:Polysaccharides, Bacterial; D013296:Streptococcus pneumoniae
chemical_list: D007096:Imidoesters; D009844:Oligosaccharides; D011135:Polysaccharides, Bacterial
vernacular_title: Synthese Einer Tetrasaccharideinheit Des Kapselpolysaccharides Von Streptococcus pneumoniae TYP 9V.