title: Efficient regioselective synthesis of 6-amino-5-benzoyl-1-substituted 2(1H)-pyridinones.
abstract: [Reaction: see text]. A regioselective and efficient approach toward 6-amino-5-benzoyl-1-substituted 2(1H)-pyridinones by reaction of acyclic ketene aminals with propiolic acid ester was developed. The effect of the solvent and temperature on the regioselectivity of the reaction and the compatibility of the target compounds to functional group manipulations was examined. Substrates with an ortho substituent build atropisomers due to the restricted rotation around the C-N bond. The enantiomers were separated, and the barrier of rotation was determined experimentally. Quantum chemical calculations allowed a ranking of the barrier heights, and a new mechanism of rotation by deformation of the central pyridinone moiety is proposed.
authors.affiliation: Bayer HealthCare AG, Pharma Research, D-42096 Wuppertal, Germany. hartmut.schirok@bayerhealthcare.com
authors.forename: Hartmut
authors.initials: H
authors.lastname: Schirok
authors.forename: Cristina
authors.initials: C
authors.lastname: Alonso-Alija
authors.forename: Jordi
authors.initials: J
authors.lastname: Benet-Buchholz
authors.forename: Andreas H
authors.initials: AH
authors.lastname: Göller
authors.forename: Rolf
authors.initials: R
authors.lastname: Grosser
authors.forename: Martin
authors.initials: M
authors.lastname: Michels
authors.forename: Holger
authors.initials: H
authors.lastname: Paulsen
mesh_terms: D008956:Models, Chemical; D008968:Molecular Conformation; D015394:Molecular Structure; D011728:Pyridones / Q000138:chemical synthesis*; D013237:Stereoisomerism
chemical_list: D011728:Pyridones