title: Synthesis of a series of ganglioside GM3 analogs containing a deoxy-N-acetylneuraminic acid residue.
abstract: Ganglioside GM3 analogs containing 4-, 7-, 8-, and 9-deoxy-N-acetylneuraminic acids in the place of N-acetylneuraminic acid (Neu5Ac) have been synthesized. Glycosylation of 2-(trimethylsilyl)ethyl O-(6-O-benzoyl-beta-D-galactopyranosyl)-(1----4)-2,6-di- O-benzoyl-beta-D-glucopyranoside with the methyl 2-thioglycoside derivatives of the respective deoxy-N-acetylneuraminic acids, using dimethyl(methylthio)sulfonium triflate as a promoter, gave the four required 2-(trimethylsilyl)ethyl alpha-sialosyl-(2----3b)-beta-lactosides. These were converted via O-acetylation, selective removal of the 2-(trimethylsilyl)ethyl group, and subsequent imidate formation, into the corresponding alpha-sialosyl-(2----3b)-alpha-lactose trichloroacetimidates 15, 17, 19, and 21. Glycosylation of (2S,3R,4E)-2-azido-3-O-benzoyl-4-octadecene-1,3-diol with 15, 17, 19, and 21 in the presence of boron trifluoride etherate afforded the expected beta glycosides, which were transformed in good yields, via selective reduction of the azido group, coupling with octadecanoic acid, O-deacylation, and de-esterification, into the target compounds.
authors.affiliation: Department of Applied Bioorganic Chemistry, Gifu University, Japan.
authors.forename: A
authors.initials: A
authors.lastname: Hasegawa
authors.forename: K
authors.initials: K
authors.lastname: Adachi
authors.forename: M
authors.initials: M
authors.lastname: Yoshida
authors.forename: M
authors.initials: M
authors.lastname: Kiso
mesh_terms: D002236:Carbohydrate Conformation; D002240:Carbohydrate Sequence; D005679:G(M3) Ganglioside / Q000031:analogs & derivatives* / Q000138:chemical synthesis* / Q000737:chemistry; D007202:Indicators and Reagents; D009682:Magnetic Resonance Spectroscopy / Q000379:methods; D008969:Molecular Sequence Data; D015394:Molecular Structure; D009844:Oligosaccharides / Q000138:chemical synthesis* / Q000737:chemistry; D012794:Sialic Acids
chemical_list: D005679:G(M3) Ganglioside; D007202:Indicators and Reagents; D009844:Oligosaccharides; D012794:Sialic Acids