Synthesis of Some Benzimidazolyl Pyrazole Derivatives Under Microwave Irradiation and their Antimicrobial Activities
A simple competent method has been developed for the synthesis of some pyrazole derivatives under microwave irradiation. The reaction of benzimidazolyl chalcone (1) with bromine in chloroform gave corresponding dibromochalcones (2), which when condensed with hydrazine hydrate afforded the title compounds 3-benzimidazolyl-5-aryl-2-pyrazoles (3). All the synthesized compounds were characterized by elemental analysis, IR, NMR and MS spectra. Microwave irradiation method provided improved product yield in a very short span of time. Newly synthesized pyrazoles were screened for their antimicrobial activity in vitro, some of them have exhibited impressive biological activity.