title: Synthesis of ketopyranosyl glycosides and determination of their anomeric configuration on the basis of the three-bond carbon-proton couplings.
abstract: Anomeric pairs of ketopyranosyl glycosides with various substituents at C(alpha), C(beta) and C(gamma) were synthesized from the corresponding thioglycosides, and the influence of the C(alpha)-C(beta)-C(gamma)-H(gamma) torsion angle and substituent effects on the three-bond carbon-proton couplings was studied. The cis coupling constants range from 1 to 2Hz. The trans couplings are generally as small as 2.3-2.6Hz; however, for compounds bearing an unsubstituted gamma-carbon, a relatively large trans coupling was measured (4.8Hz). An S-ethyl group at the beta-position increases the cis coupling (up to 3.2Hz) compared to the corresponding O-glycosides.
authors.affiliation: Research Group for Carbohydrates of the Hungarian Academy of Sciences, PO Box 94, Debrecen H-4010, Hungary.
authors.forename: Gábor
authors.initials: G
authors.lastname: Májer
authors.forename: Anikó
authors.initials: A
authors.lastname: Borbás
authors.forename: Tünde Zita
authors.initials: TZ
authors.lastname: Illyés
authors.forename: László
authors.initials: L
authors.lastname: Szilágyi
authors.forename: Attila Csaba
authors.initials: AC
authors.lastname: Bényei
authors.forename: András
authors.initials: A
authors.lastname: Lipták
mesh_terms: D002236:Carbohydrate Conformation; D002244:Carbon / Q000737:chemistry*; D004187:Disaccharides / Q000138:chemical synthesis; D006027:Glycosides / Q000138:chemical synthesis* / Q000737:chemistry; D011522:Protons; D013237:Stereoisomerism; D013865:Thioglycosides / Q000138:chemical synthesis
chemical_list: D004187:Disaccharides; D006027:Glycosides; D011522:Protons; D013865:Thioglycosides; D002244:Carbon