Synthesis of Substituted Nicotinamides from Enamines Derived from N,N-Dimethylformamide Dimethyl Acetal

Abstract

Reactions of 1,3-dicarbonyl compounds with N,N-dimethylformamide dimethyl acetal followed by malonamide in the presence of sodium hydride give 5,6-disubstituted 1,2-dihydro-2-oxopyridine-3-carboxamides 3a-c, whereas reactions of the intermediate enamines with cyanothioacetamide or cyanoacetamide in the presence of piperidine give 4,5-disubstituted 1,2-dihydro-2-thioxopyridine-3-carboxamides 6a-c and 1,2-dihydro-2-oxopyridine-3-carboxamides 6d-h.