The reaction of β-aminocrotonamide (V) with ketene afforded α-acetyl-β-aminocrotonamide (VII). When the reaction was carried out in the presence of triethylamine or pyridine, α-acetyl-β-acetylaminocrotonamide (VIII) was obtained. Heating of the diacetyl compound (VIII) with sodium hydroxide gave 5-acetyl-2, 6-dimethyl-4 (1H)-pyrimidone (IX) in good yield. Similarly, the reaction of β-amino-N-methylcrotonamide (XII) with ketene afforded α-acetyl-β-acetylamino-N-methylcrotonamide (XV) and 5-acetyl-2, 3, 6-trimethyl-4 (1H)-pyrimidone (XIV). On the other hand, the treatment of β-amino-N, N-dimethylcrotonamide (XIII) with ketene resulted in the formation of a resinous product. The reaction of V or XII with diketene yielded 3-acetyl-4-hydroxy-6-methyl-2 (1H)-pyridone derivatives. The reaction of XIII with diketene gave only nitrogen free compounds.