Synthesis and antitubercular activity of novel pyrazole–quinazolinone hybrid analogs

A series of 2-(substituted-phenyl)-3-(((3-(pyridin-4-yl)-1-(p-tolyl)-1H-pyrazol-4-yl)methylene)amino)-quinazolin-4(3H)-ones have been synthesized. The structures of the synthesized compounds were assigned on the basis of IR, 1H NMR, 13C NMR, and mass spectral data, while their abilities to inhibit growth of Mycobacterium tuberculosis in vitro have been determined. The results show that compounds 5a, 5c, 5d, 5g, and 5k exhibited excellent antitubercular activity with percentage inhibition of 96, 90, 94, 93, and 92, respectively at a minimum inhibitory concentration (MIC) of <6.25 μg/mL, whereas compounds 5b, 5e, 5f, 5h, 5i, 5j, and 5l exhibited moderate- to- good antitubercular activity with percentage inhibition of 68, 70, 67, 64, 59, 73, and 67, respectively, at a MIC of >6.25 μg/mL. From the secondary screening, the actual MIC of compounds 5a, 5c, 5d, 5g, and 5k are <3.125.