Efficient regioselective synthesis of 6-amino-5-benzoyl-1-substituted 2(1H)-pyridinones.
[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.
Schirok
Hartmut
H
Bayer HealthCare AG, Pharma Research, D-42096 Wuppertal, Germany. hartmut.schirok@bayerhealthcare.com
Alonso-Alija
Cristina
C
Benet-Buchholz
Jordi
J
Göller
Andreas H
AH
Grosser
Rolf
R
Michels
Martin
M
Paulsen
Holger
H
D008956:Models, Chemical; D008968:Molecular Conformation; D015394:Molecular Structure; D011728:Pyridones / Q000138:chemical synthesis*; D013237:Stereoisomerism
D011728:Pyridones