Synthesis, antimicrobial and cytotoxic activity of pyrazole derivatives of pyridyloxadiazoles

In the present communication, a series of novel 1-(2-(3-(4-methoxyphenyl)-1-phenyl-1H-pyrazol-4-yl)-5-(pyridin-4yl)-1,3,4-oxadiazol-3(2H)-yl)-3-(aryl)prop-2-en-1-ones 5a-o have been efficiently synthesized and evaluated for their in vitro antimicrobial and cytotoxic activities. The results of antimicrobial study reveal the compounds 5f, 5g and 5k-m to be among the most potent antimicrobial agents compared to the standard drugs chloramphenicol and griseofulvin. From the standpoint of SAR studies, it is observed that presence of electron donating groups remarkably enhanced the antimicrobial activity of newly synthesized compounds. Further, the results of preliminary MTT cytotoxicity studies on HeLa cells suggest that the potent antimicrobial activity of 5f, 5g and 5k-m is accompanied by low cytotoxicity. All the newly synthesized analogues have been characterized by IR, H and C NMR and mass spectroscopic techniques.