As a result of the reaction between 3,4-dichloro-2-butene-1-ones and semicarbazide hydrochloride with natrium hydrocarbonate, the hydrazones of ketones are produced. When boiled with the pyridine within surrounding of the dioxan, they are heterocyclized into 3-R-1-carbamoil-5-chloromethylpyrazoles. When the latter is influenced with binary amines and potassium phenolate, produced are 3-R-1-carbamoil-5-dialkylamino- and 3-R-1-carbamoil-5-phenoxymethylpyrazoles.