title: Transglucosidation of methyl and ethyl D-glucofuranosides by alcoholysis.
abstract: The acid catalyzed ethanolysis of methyl 5-O-methyl-alpha- and -beta-D-glucofuranoside and the analogous methanolysis of ethyl 5-O-methyl-alpha- and -beta-D-glucofuranoside have been investigated. For all four reactions, the primarily formed transglycosylation product was a single glycoside that had the opposite anomeric configuration to the starting material. This strongly indicates that a D-glucose methyl ethyl acetal is first formed and is then ring closed by a nucleophilic attack by HO-4, giving either the starting material or a transglycosylation product with the opposite anomeric configuration. Low percentages of the methyl ethyl acetals and of dimethyl acetals were also observed in the reaction product during the methanolysis reactions.
authors.affiliation: Department of Chemistry, Linkoping University, Sweden.
authors.forename: K J
authors.initials: KJ
authors.lastname: Johansson
authors.forename: P
authors.initials: P
authors.lastname: Konradsson
authors.forename: Z
authors.initials: Z
authors.lastname: Trumpakaj
mesh_terms: D000431:Ethanol / Q000737:chemistry; D005663:Furans / Q000737:chemistry*; D005947:Glucose / Q000031:analogs & derivatives*; D005960:Glucosides / Q000737:chemistry*; D006031:Glycosylation; D000432:Methanol / Q000737:chemistry; D013237:Stereoisomerism
chemical_list: D005663:Furans; D005960:Glucosides; D000431:Ethanol; D005947:Glucose; D000432:Methanol