Synthesis and antiinflammatory activity of some imidazolinylpyrazole derivatives

Some new imidazolinyl-pyrazoles (4) were synthesized by condensation of 2-imidazolylhydrazine hydroiodid (1a) with beta-ketoesters to afford the intermediate 3 that, as free base, ring closes only to 4. The attempt to obtain the imidazo-triazepinone 5, starting from 2-imidazolinyl-2-methylhydrazine, was accomplished, in low yield, only in reacting with ethyl acetoacetate. The pharmacological evaluation of antiinflammatory and analgesic activities of pyrazoles 4a-f revealed an appreciable antiinflammatory activity.