Abstract
The reaction of diketene with ketene acetals (Ia-f) has been studied on cycloaddition reaction to form 4-pyrone derivatives (II and III). Cyanoketene diethylacetal reacted with diketene to give 3-cyano-4-ethoxy-6-methy1-2-pyrone besides the formation of IIIf. IIa, b and IIIa, b, c, d, f were converted in good yields to corresponding 2-ethoxy-6-methyl-3-substituted-4-pyridone (V), respectively, whereas VI was converted to VIII and IX by treatment with ammonia.
