title: Chemical synthesis of the pyruvic acetal-containing trisaccharide unit of the species-specific glycopeptidolipid from Mycobacterium avium serovariant 8.
abstract: The functionalized, pyruvic acetal-containing haptenic trisaccharide, p-trifluoroacetamidophenyl 6-deoxy-2-O-(3-O-[4,6-O-(S)-(1-methoxycarbonylethylidene)-3-O-meth yl- beta-D-glucopyranosyl]-alpha-L-rhamnopyranosyl)-alpha-L-talopyranosid e (19), a component of the glycolipid from Mycobacterium avium serovar 8 was synthesized. For the preparation of the terminal pyruvic acetal-containing unit, benzyl 2-O-benzyl-3-O-methyl-beta-D-glucopyranoside (6) was condensed with methyl 2,2-di(ethylthio)propionate (1) in the presence of SO2Cl2-CF3SO3H catalyst to yield benzyl 2-O-benzyl-4,6-O-(S)-(1-methoxycarbonylethylidene)-3-O-methyl-beta -D- glucopyranoside (7S), which was then converted into the suitably substituted glycosyl donor 2-O-acetyl-4,6-O-(S)-(1-methoxycarbonylethylidene)-3-O-methyl-alph a-D- glucopyranosyl trichloroacetimidate (11). The disaccharide glycosyl acceptor p-nitrophenyl endo-3,4-O-benzylidene-6-deoxy-2-O-(2,4-di-O-benzyl-alpha-L-rhamnopyrano syl)- alpha-L-talopyranoside (15) was glycosylated with 11 in the presence of trimethyl trifluoromethanesulfonate to furnish the protected trisaccharide p-nitrophenyl 2-O-(3-O-[2-O-acetyl-4,6-O-(S)-(1-methoxycarbonylethylidene)-3-O-m ethyl-beta- D-glucopyranosyl]-2,4-di-O-benzyl-alpha-L-rhamnopyranosyl)-endo-3,4- O-benzylidene-6-deoxy-alpha-L-talopyranoside (16). After deprotection, this gave the spacer-armed unprotected haptenic trisaccharide 19.
authors.affiliation: Institute of Biochemistry, Lajos Kossuth University, Debrecen, Hungary.
authors.forename: I
authors.initials: I
authors.lastname: Bajza
authors.forename: J
authors.initials: J
authors.lastname: Kerékgyártó
authors.forename: J
authors.initials: J
authors.lastname: Hajkó
authors.forename: L
authors.initials: L
authors.lastname: Szilágyi
authors.forename: A
authors.initials: A
authors.lastname: Lipták
mesh_terms: D002236:Carbohydrate Conformation; D002240:Carbohydrate Sequence; D006001:Glycoconjugates / Q000737:chemistry*; D007202:Indicators and Reagents; D008969:Molecular Sequence Data; D015394:Molecular Structure; D009162:Mycobacterium avium / Q000737:chemistry* / Q000145:classification; D009904:Optical Rotation; D012703:Serotyping; D014312:Trisaccharides / Q000138:chemical synthesis* / Q000737:chemistry
chemical_list: D006001:Glycoconjugates; D007202:Indicators and Reagents; D014312:Trisaccharides