A novel, two-step synthesis of 4-pyridone-3-carboxamides from 2-cyano-4-pyrones

Reactions of 2-cyano-6-(trifluoromethyl)-4-pyrone, 2-cyano-4-pyrone, and 2-cyano-6-methyl-4-pyrone with aliphatic and aromatic amines in ethanol at −20 °C for 2-21 days gave 5-amino-3-oxopent-4-enamides in 28-78% yields, which were cyclized with DMF-DMA in toluene under ambient conditions to afford 4-pyridone-3-carboxamides in 31-70% yields.