Abstract The reactivity of the enamino compounds 4-amino-3-phenylamino (thio) carbonyl-3- penten-2-one 1 and 2 and ethyl 3-amino-2-phenylamino (thio) carbonyl-2-butyrate 7 and 8 was studied using the reaction with hydrazine hydrate and hydrazine hydrochloride to evaluate the 1, 3 electrophilic center of the compounds by the formation of the pyrazole rings. The pyrazoles 3, 4, 5, 9, 11 and 13 were obtained depending on the reaction ...