title: Controlled reduction of acarbose: conformational analysis of acarbose and the resulting saturated products.
abstract: Saturation of the double bond in the non-reducing terminal unit of the tetrasaccharide amylase inhibitor, acarbose (1), with Raney nickel as the catalyst and at pH 8, gave 57% of a approximately 1:1 mixture of the 5a-carba-gluco (2) and -ido (3) isomers together with cleavage products including 26% of the trisaccharide 6-deoxy-alpha-D-Glcp4N-(1----4)-alpha-D-Glcp-(1----4)-D-Glc (4). The saturated compounds were isolated and characterised using 1H- and 13C-n.m.r. spectroscopy. The preferred conformations of 1 and 2 were dependent on the state of ionisation of the bridging nitrogen atom. The inhibition by 1-4 of the hydrolysis of methyl beta-maltoside by glucoamylase has been investigated; 1 and 2 were strong inhibitors.
authors.affiliation: Department of Chemistry, Carlsberg Laboratory, Valby, Denmark.
authors.forename: K
authors.initials: K
authors.lastname: Bock
authors.forename: M
authors.initials: M
authors.lastname: Meldal
authors.forename: S
authors.initials: S
authors.lastname: Refn
mesh_terms: D020909:Acarbose; D002236:Carbohydrate Conformation; D002240:Carbohydrate Sequence; D002247:Carbon Isotopes; D002384:Catalysis; D065089:Glycoside Hydrolase Inhibitors; D006026:Glycoside Hydrolases / Q000037:antagonists & inhibitors; D007004:Hypoglycemic Agents / Q000737:chemistry; D009682:Magnetic Resonance Spectroscopy; D008969:Molecular Sequence Data; D010084:Oxidation-Reduction; D010165:Palladium; D014312:Trisaccharides / Q000737:chemistry*
chemical_list: D002247:Carbon Isotopes; D065089:Glycoside Hydrolase Inhibitors; D007004:Hypoglycemic Agents; D014312:Trisaccharides; D010165:Palladium; D006026:Glycoside Hydrolases; D020909:Acarbose