The effect of focused microwaves on the reaction of ethyl N-trichloroethylidenecarbamate with pyrazole derivatives

Under microwave irradiation vinylpyrazoles react with ethyl N-trichloroethy lidene carbamate 1 to give the addition to the imine system through the con jugated vinyl group. Likewise, compound 1 react with the NH group of pyrazo lylhydrazones, if present. To the best of our knowledge this reaction type has not been described before and only can be performed under microwave irr adiation. By classical heating, in the absence of microwaves, only dimeriza tion or decomposition of the pyrazole derivatives is observed in these reac tions. (C) 1999 Elsevier Science Ltd. All rights reserved.