3-acyl-1,2,3,4-tetrahydropyridine-2,4-diones: Synthesis and chemical properties

Abstract

N-Substituted 6-methyl-1,2,3,4-tetrahydropyridine-2,4-diones reacted with aliphatic carboxylic acid chlorides in the presence of pyridine or triethylamine to give the corresponding 4-O-acyl derivatives which underwent O,C-migration of the acyl group by the action of 2 equiv of triethylamine and a catalytic amount of 2-hydroxy-2-methylpropanenitrile. Reactions of 3-acyl-6-methyl-1,2,3,4-tetrahydropyridine-2,4-diones thus formed with aliphatic and aromatic amines gave the corresponding enamino derivatives at the side acyl group. Enamino derivatives at the C4 =O group were obtained by transformation of 3-acyl-1,2,3,4-tetrahydropyridine-2,4-diones into 3-acyl-4-methoxy-6-methyl-1,2-dihydropyridin-2-ones via alkylation with dimethyl sulfate and subsequent treatment with amines.