title: Competition between the beta-hydroxylation of a primary and a tertiary carbon atom in rats.
abstract: In order to study the effect of steric hindrance on competition between two kinds of beta-hydroxylation, a compound bearing on a pyrimidinetrione nucleus both a branched side chain with a tertiary carbon atom in position beta (isobutyl group) and a linear side chain (ethyl group), was selected and administered to rats. Urine and faeces were collected and extracted. Hydroxymetabolites and their derivatives were isolated and then identified. The beta-hydroxylation of the linear chain was more important than the beta-hydroxylation of the branched chain. Steric hindrance plays a decisive role in this regioselectivity.
authors.affiliation: Laboratoire de pharmacochimie, faculté de médecine et de pharmacie de Rouen, 22, boulevard Gambetta, 76183, Rouen, France.
authors.forename: S
authors.initials: S
authors.lastname: Chraibi-Ben Moubarik
authors.forename: S
authors.initials: S
authors.lastname: Menager
authors.forename: O
authors.initials: O
authors.lastname: Lafont
mesh_terms: D000818:Animals; D001463:Barbiturates / Q000737:chemistry / Q000493:pharmacokinetics* / Q000652:urine; D001667:Binding, Competitive; D001711:Biotransformation; D002244:Carbon / Q000378:metabolism*; D005243:Feces / Q000737:chemistry; D006900:Hydroxylation; D009682:Magnetic Resonance Spectroscopy; D008968:Molecular Conformation; D010084:Oxidation-Reduction; D011744:Pyrimidinones / Q000493:pharmacokinetics* / Q000652:urine; D051381:Rats; D017207:Rats, Sprague-Dawley; D013329:Structure-Activity Relationship
chemical_list: D001463:Barbiturates; D011744:Pyrimidinones; C409483:5-ethyl-5-isobutylbarbituric acid; D002244:Carbon