title: Synthesis of tetra- and pentasaccharides corresponding to the capsular polysaccharide of Streptococcus pneumoniae type 9A&L, 9N and 9A.
abstract: Two tetrasaccharides, alpha-D-GlcAp-(1-->3)-alpha-D-Galp-(1-->3)-beta-D-ManpNAc-(1-->4)-beta-D-Glcp and alpha-D-GlcAp-(1-->3)-alpha-D-Glcp-(1-->3)-beta-D-ManpNAc-(1-->4)-beta-D-Glcp (protected form), and a pentasaccharide, alpha-D-Glcp-(1-->4)-alpha-D-GlcAp-(1-->3)-alpha-D-Galp-(1-->3)-beta-D-ManpNAc-(1-->4)-beta-D-Glcp have been synthesised from 2-aminoethyl glycoside trisaccharide acceptors in a linear approach via consecutive alpha-glycosylations. Ethyl thioglycosides were used as glycosyl donors and DMTST in Et(2)O or NIS/TfOH in CH(2)Cl(2) were employed as promoters.
authors.affiliation: Department of Organic Chemistry, Arrhenius Laboratory, Stockholm University, S-106 91 Stockholm, Sweden.
authors.forename: Mia
authors.initials: M
authors.lastname: Alpe
authors.forename: Stefan
authors.initials: S
authors.lastname: Oscarson
mesh_terms: D002240:Carbohydrate Sequence; D006001:Glycoconjugates / Q000737:chemistry; D008956:Models, Chemical; D008969:Molecular Sequence Data; D011134:Polysaccharides / Q000138:chemical synthesis*; D011135:Polysaccharides, Bacterial / Q000737:chemistry*; D013296:Streptococcus pneumoniae / Q000378:metabolism*; D013865:Thioglycosides / Q000737:chemistry; D014312:Trisaccharides / Q000737:chemistry
chemical_list: D006001:Glycoconjugates; D011134:Polysaccharides; D011135:Polysaccharides, Bacterial; D013865:Thioglycosides; D014312:Trisaccharides