Microwave-assisted Synthesis of Novel 3,4-Bis-chalcone-N-arylpyrazoles and Their Anti-inflammatory Activity

A series of 3,4-bis-chalcone-N-arylpyrazoles 3a-h was prepared conveniently from diacetyl pyrazoles 2a,b. All reactions were carried out under conventional thermal heating and/or microwave irradiation. The structure of the latter functionally pyrazoles was confirmed under the bases of their IR, mass, H-1 NMR and C-13 NMR. The X-ray diffraction of compound 3e not only confirmed the chemical structure of 3a-h, but also showed the E configuration of their chalcone moieties. Treatment of compound 3e with phenyl hydrazine in presence of acetic acid afforded the tri-pyrazle 4. The anti-inflammatory activity of the newly synthesized compounds was investigated. Some of these compounds showed a moderate activity when compared with indomethacin as a reference drug. The combination between chalcone and pyrazole moieties revealed a variable effect in anti-inflammatory activity.