Cyclisation at very high temperature. Thermal transformations of N-alkyl and N,N-dialkyl cinnamic amides into pyrrolidin-2-ones under FVT conditions

Novel cyclisations of N-alkyl and N,N-dialkyl cinnamic amides to the corresponding pyrrolidin-2-ones under the conditions of flash vacuum thermolysis, are described. It was found that this reaction proceeds at 950–1000 °C affording a mixture of isomeric pyrrolidin-2-ones in various yields. Two possible mechanisms are proposed for the process.