title: Stereoselective total synthesis of glycopeptides bearing the dimeric and trimeric sialosyl-Tn epitope.
abstract: The dimeric and trimeric sialosyl-Tn epitopes, [alpha-D-Neup5Ac-(2----6)-alpha-D-GalpNAc-(1----3)-L-Ser]n-L-Val (n = 2 and 3), which represent part of a clustered carbohydrate region of glycophorin A, a human erythrocyte glycoprotein, have been synthesised stereoselectively. 2-Azido-3-O-benzyl-4,6-O-benzylidene-2-deoxy-D-galactopyranosyl fluoride (GalpNAc unit), Fmoc-L-serine phenacyl ester (Ser unit), and benzyl 5-acetamido-4,7,8,9-tetra-O-benzyl-5-deoxy-3-S-phenyl-3-thio-D-erythro-L - gluco-2-nonulopyranosylonate bromide (Neup5Ac unit) were the key intermediates for stereoselective glycosylation. 2-Ethoxy-1-ethoxycarbonyl-1,2-dihydroquinoline-promoted elongation of the peptide chain and then hydrogenolysis afforded the title compounds.
authors.affiliation: RIKEN Institute of Physical and Chemical Research, Saitama, Japan.
authors.forename: Y
authors.initials: Y
authors.lastname: Nakahara
authors.forename: H
authors.initials: H
authors.lastname: Iijima
authors.forename: S
authors.initials: S
authors.lastname: Shibayama
authors.forename: T
authors.initials: T
authors.lastname: Ogawa
mesh_terms: D000595:Amino Acid Sequence; D000951:Antigens, Neoplasm / Q000737:chemistry*; D015295:Antigens, Tumor-Associated, Carbohydrate; D002240:Carbohydrate Sequence; D004187:Disaccharides / Q000138:chemical synthesis / Q000737:chemistry / Q000276:immunology; D000939:Epitopes / Q000737:chemistry; D006801:Humans; D008766:Methylmannosides / Q000138:chemical synthesis* / Q000276:immunology; D008969:Molecular Sequence Data; D015394:Molecular Structure; D009077:Mucins / Q000276:immunology; D012795:Sialoglycoproteins / Q000138:chemical synthesis* / Q000737:chemistry / Q000276:immunology*; D013237:Stereoisomerism; D014312:Trisaccharides / Q000138:chemical synthesis / Q000737:chemistry / Q000276:immunology
chemical_list: D000951:Antigens, Neoplasm; D015295:Antigens, Tumor-Associated, Carbohydrate; D004187:Disaccharides; D000939:Epitopes; D008766:Methylmannosides; D009077:Mucins; D012795:Sialoglycoproteins; D014312:Trisaccharides; C055491:sialosyl-Tn antigen; C073378:methyl 2-acetamido-2-deoxy-beta-D-mannopyranoside