title: C-linked disaccharide analogue of the Thomsen-Friedenreich (T)-epitope alpha-O-conjugated to L-serine.
abstract: Condensation of a silylated beta-D-galactopyranosylaldehyde (3) with isolevoglucosenone (4) in the presence of Et(2)AlI provided bicyclic enone 5. Subsequent addition of BnNHOMe gave adduct 6, which was converted into 4-O-acetyl-1,6-anhydro-3-C-[(1 R)-1,3,4,5,7-penta-O-acetyl-2,6-anhydro-D-glycero-L-manno-heptitol-1-C-yl]-2-azido-2,3-dideoxy-beta-D-galacto-hexopyranose after liberation of the 2-amino group, its transformation into a 2-azido moiety, desilylation, and peracetylation. Ring-opening of the 1,6-anhydro galactopyranosyl unit and O-glycosidation with Fmoc-Ser-O-tBu afforded a 5:1 mixture of alpha- and beta-galactosides. Treatment with CH(3)COSH gave pure N-[(9H-fluoren-9-ylmethoxy)carbonyl]-{4,6-di-O-acetyl-3-C-[(1 R)-2,6-anhydro 1,3,4,5,7-penta-O-acetyl-D-glycero-L-manno-heptitol-1-C-yl]-2-[(N-acetyl)amino]-2,3-dideoxy-alpha-D-galactopyranosyl}-l-serine tert-butyl ester (2), a protected form of a C-disaccharide analogue of the Thomsen-Friedenreich (or T) epitope (beta-D-Galp-(1-->3)-alpha-D-GalNAcp) alpha-O-conjugated to L-serine.
authors.affiliation: Laboratory of Glycochemistry and Asymmetric Synthesis, Ecole Polytechnique Federale de Lausanne (EPFL), Switzerland.
authors.forename: Loay
authors.initials: L
authors.lastname: Awad
authors.forename: Jens
authors.initials: J
authors.lastname: Riedner
authors.forename: Pierre
authors.initials: P
authors.lastname: Vogel
mesh_terms: D000447:Aldehydes / Q000138:chemical synthesis* / Q000737:chemistry; D019086:Bridged Bicyclo Compounds, Heterocyclic; D002240:Carbohydrate Sequence; D004187:Disaccharides / Q000138:chemical synthesis* / Q000737:chemistry; D005685:Galactans; D008968:Molecular Conformation; D008969:Molecular Sequence Data; D012694:Serine / Q000737:chemistry*
chemical_list: C476164:1,6-anhydro-2,3-dideoxyhex-3-enopyran-4-ulose; D000447:Aldehydes; D019086:Bridged Bicyclo Compounds, Heterocyclic; D004187:Disaccharides; D005685:Galactans; C443716:galactosyll(1,3)-N-acetylgalactosamine; D012694:Serine