title: Convergent synthesis of an elusive hexasaccharide corresponding to the cell-wall polysaccharide of the beta-hemolytic Streptococcus group A.
abstract: A convergent synthesis of a hexasaccharide corresponding to the cell-wall polysaccharide of the beta-hemolytic Streptococcus Group A is described. The strategy relies on the preparation of a key linear trisaccharide unit beta-D-GlcpNAc-(1-->3)-alpha-L-Rhap-(1-->2)-alpha-L-Rhap which has previously resisted our efforts. The trisaccharide functions both as a glycosyl acceptor and donor to give an elusive hexasaccharide. This fully functionalized unit can serve, in turn, as a glycosyl acceptor or donor for the synthesis of higher-order structures. Deprotection gives a hitherto unknown hexasaccharide for use as a hapten in immunochemical studies. The characterization of all compounds by high-resolution 1H and 13C NMR spectroscopy is also described.
authors.affiliation: Department of Chemistry, Simon Fraser University, Burnaby, British Columbia, Canada.
authors.forename: J R
authors.initials: JR
authors.lastname: Marino-Albernas
authors.forename: S L
authors.initials: SL
authors.lastname: Harris
authors.forename: V
authors.initials: V
authors.lastname: Varma
authors.forename: B M
authors.initials: BM
authors.lastname: Pinto
mesh_terms: D002236:Carbohydrate Conformation; D002240:Carbohydrate Sequence; D007202:Indicators and Reagents; D009682:Magnetic Resonance Spectroscopy; D008969:Molecular Sequence Data; D015394:Molecular Structure; D009844:Oligosaccharides / Q000138:chemical synthesis* / Q000737:chemistry; D009904:Optical Rotation; D011135:Polysaccharides, Bacterial / Q000737:chemistry*; D013297:Streptococcus pyogenes / Q000737:chemistry / Q000276:immunology*
chemical_list: D007202:Indicators and Reagents; D009844:Oligosaccharides; D011135:Polysaccharides, Bacterial