Synthesis of four structural elements of xylose-containing carbohydrate chains from N-glycoproteins
| Autor: | András Lipták, Johannes F.G. Vliegenthart, Jan B. Bouwstra, János Kerékgyártó, Johannis P. Kamerling |
|---|---|
| Rok vydání: | 1989 |
| Předmět: |
chemistry.chemical_classification
Magnetic Resonance Spectroscopy Xylose Trimethylsilyl Stereochemistry Organic Chemistry Disaccharide Regioselectivity Oligosaccharides General Medicine Biochemistry Analytical Chemistry chemistry.chemical_compound chemistry Carbohydrate Sequence Bromide Mannosylation Carbohydrate Conformation Stereoselectivity Indicators and Reagents Trisaccharide Trifluoromethanesulfonate Glycoproteins |
| Zdroj: | Carbohydrate research. 186(1) |
| ISSN: | 0008-6215 |
| Popis: | The synthesis of the oligosaccharides beta-D-Xylp-(1----2)-beta-D-Manp-OMe (12), beta-D-Xylp-(1----2)-[alpha-D-Manp-(1----6)]-beta-D-Manp+ ++-OMe (17), beta-D-Xylp-(1----2)-[alpha-D-Manp-(1----3)]-beta-D-Manp+ ++-OMe (21), and beta-D-Xylp-(1----2)-[alpha-D-Manp-(1----3)] [alpha-D-Manp-(1----6)]-beta-D-Manp-OMe (25) is described. Methyl 3-O-benzyl-4,6-O-isopropylidene-beta-D-mannopyranoside (6) was prepared from the corresponding glucoepimer (4) by oxidation, followed by stereoselective reduction. Condensation of 6 with 2,3,4-tri-O-acetyl-alpha-D-xylopyranosyl bromide in the presence of mercuric cyanide gave a 1:9 mixture of methyl 3-O-benzyl-4,6-O-isopropylidene-2-O-(2,3,4- tri-O-acetyl-alpha- (7a) and -beta-D-xylopyranosyl)-beta-D-mannopyranoside (7), and then 7 was converted into the acetylated disaccharide-glycoside 11. Regioselective mannosylation, with 2,3,4,6-tetra-O-acetyl-alpha-D-mannopyranosyl bromide, at position 6 of deisopropylidenated 7 (8), using mercuric bromide as a promoter, afforded the trisaccharide-glycoside derivative 13, which was transformed into the acetylated trisaccharide-glycoside 16. The disaccharide derivative 10, obtained from 8, and the trisaccharide derivative 15, obtained from 13, were glycosylated at position 3 with O-(2,3,4,6-tetra-O-acetyl-alpha-D-mannopyranosyl)trichloroacetimidate (19), using trimethylsilyl triflate as a promoter, giving rise to acetylated tri- (20) and tetra-saccharide (24) derivatives, respectively. O-Deacetylation of 11, 16, 20, and 24 gave 12, 17, 21, and 25, respectively. |
| Databáze: | OpenAIRE |
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