Synthesis and antitubercular activity of novel 3,5-diaryl-4,5-dihydro-1H-pyrazole derivatives.

Novel 3,5-diaryl-4,5-dihydro-1H-pyrazole derivatives were efficiently synthesized and evaluated for their in vitro antitubercular activity against Mycobacterium tuberculosis H37Rv (MTB). The chemical structures of the compound were elucidated by elemental analysis, FTIR, (1)H NMR, and mass spectral data. Most of the title compounds have exhibited significant antitubercular activity. Compounds 4g, 4h, 4l, 4n and 4o showed pronounced antitubercular activity comparable to the reference isoniazid, whereas, compounds 4a, 4c, 4j, 4k, and 4p displayed good antitubercular activity. 5-(4-chlorophenyl)-4,5-dihydro-3-p-tolylpyrazol-1-yl-(6-methylimidazo[2,1-b]thiazol-5-yl)methanone (4g) was found to be the most promising compound with MIC values of 0.39 µg/ml.