Abstract
Condensation of acetoacetamide (1) with acetone in polyphosphoric acid (PPA) gave 4, 6-dimethyl-2 (1H)-pyridone (2a) in 32% yield. Similarly, the amide 1 was condensed with 2-butanone, 2-pentanone, 3-pentanone, cyclopentanone, cyclohexanone, cycloheptanone, acetophenone, and propiophenone to give the corresponding pyridone derivatives (2b-i) in 13-76% yields. Condensation of the amide 1 with acetylacetone and ethyl acetoacetate gave 3-acetyl-4, 6-dimethyl-2 (1H)-pyridone (5) and ethyl 4, 6-dimethyl-2 (1H)-pyridone-5-carboxylate (6), respectively. Self-condensation of the amide 1 in PPA gave 3-acetyl-4-hydroxy-6-methyl-2 (1H)-pyridone (7).
