title: A convenient new pathway for stereospecific epimerization of monosaccharide moieties in disaccharides.
abstract: The disaccharides benzyl 4,6-O-benzylidene-2-O-alpha-D-mannopyranosyl-beta- D-glucopyranoside (2), 6-O-beta-D-galactopyranosyl-1,2:3,4-di-O-isopropylidene-alpha-D- galactopyranose (4), and phenyl 4-O-beta-D-galactopyranosyl-1-thio-beta-D-glucopyranoside (7) were selectively acetalated with chloral-dicyclohexylcarbodiimide in a nonclassical pathway. During acetalation, the D-mannopyranosyl moiety of the disaccharide 2 and the unprotected beta-D-galactopyranosyl moieties of 4 and 7 were epimerized at their 3-positions, generating D-altro- and D-gulo-pyranosyl moieties, respectively.
authors.affiliation: Fachbereich Chemie, Universität Rostock, Germany.
authors.forename: R
authors.initials: R
authors.lastname: Miethchen
authors.forename: D
authors.initials: D
authors.lastname: Rentsch
authors.forename: M
authors.initials: M
authors.lastname: Frank
authors.forename: A
authors.initials: A
authors.lastname: Lipták
mesh_terms: D002236:Carbohydrate Conformation; D002240:Carbohydrate Sequence; D004024:Dicyclohexylcarbodiimide / Q000378:metabolism; D004187:Disaccharides / Q000378:metabolism*; D004952:Esters / Q000378:metabolism; D005697:Galactosides / Q000378:metabolism; D005960:Glucosides / Q000378:metabolism; D009682:Magnetic Resonance Spectroscopy; D008968:Molecular Conformation; D008969:Molecular Sequence Data; D015394:Molecular Structure; D009005:Monosaccharides / Q000378:metabolism*
chemical_list: D004187:Disaccharides; D004952:Esters; D005697:Galactosides; D005960:Glucosides; D009005:Monosaccharides; D004024:Dicyclohexylcarbodiimide