Synthesis of trifluoromethyl derivatives of pyrazolidine- and 2-pyrazoline-1-carboxamides and pyrazolidine- and 1-pyrazoline-carbothioamides

The reactions of enones containing trifluoromethyl groups with semicarbazide in basic media proceed unequivocally to give pyrazolidine-1-carboxamides. The direction of the reactions of these enones with thiosemicarbazide depends on their structure; the reaction products are pyrazolidine- and 2-pyrazoline-1-carbothioamides. An enone containing a CF3 group and an ethoxy group capable of replacement reacts with semicarbazide to give 2-pyrazoline-1-carboxamide and with thiosemicarbazide to give the double addition product, 5-(1-thiosemicarbazido)-2-pyrazoline-1-carbothiamide. ©1998 Plenum Publishing Corporation.