[Heterocyclic compounds with potential anti-inflammatory activity containing a 4-aminophenylalkanoic acid residue. V. Derivatives of 2,4-dihydro-3H-pyrazole-3-one].

The synthesis and pharmacological study of some derivatives of 2,4-dihydro-3H-pyrazol-3-one of general formula (I) are described. The compound in which R = C6H5 and R' = CH3 [2-(4- carboxymethylphenyl )-4-phenyl-5-methyl-2,4- dihydropyrazol -3-one] (MG 18949) proved to have antipyretic activity equal to that of ibuprofen and aminopyrine.