| abstract |
A method for the synthesis of an α,β-unsaturated ketone useful for making substituted 1,4-dihydropyridines is described by reacting an aldehyde with pyrrolidine and then adding a ketone followed by trifluoroacetic acid at low temperature. The synthesis is used in a process for making substituted 1,4-dihydropyridines wherein a vinylogous amide is prepared by reacting a 1,3-cyclohexanedione with a phenylethylamine. The α,β-unsaturated ketone can be reacted with a vinylogous amide to form a 1,5-diketone which can be converted to a substituted 1,4-dihydropyridine. |