Synthesis of 2,3,5,6-tetrasubstituted pyridines from enamines derived from N,N-dimethylformamide dimethyl acetal

Article abstract of DOI:10.1055/s-1995-3954

Reactions of 1,3-dicarbonyl compounds with N,N-dimethylformamide dimethyl acetal, followed by cyanothioacetamide or cyanoacetamide and sodium hydride, then acidification, give 5,6-disubstituted 3-cyanopyridine-2(1H)-thiones or 5,6-disubstituted 3-cyanopyridin-2(1H)-ones 4. Analogous reactions with the malononitrile dimer give 5,6-disubstituted 3-cyano-2-(dicyanomethylene)-1,2-dihydropyridines 9.