Cyclisation at very high temperature. Thermal transformations of N-alkyl and N, N-dialkyl amides of α,β-unsaturated acids into mono- and bicyclic heterocycles under FVT conditions
摘要:
Cyclisations of N-alkyl and N,N-dialkyl cinnamic amides to the corresponding pyrrolidin-2-ones under the conditions of flash vacuum thermolysis (FVT), are described. It was found that these reactions proceed at 950-1000 degrees C affording in various yields the mixtures of isomeric mono and bicyclic gamma-lactams, which were separated chromatographically and analysed by means of NMR spectroscopy. Two alternative mechanisms for the title process are proposed. (C) 2009 Elsevier Ltd. All rights reserved.