Synthesis and anti-tubercular evaluation of some novel pyrazolo[3,4-d]pyrimidine derivatives

A series of phenothiazine clubbed pyrazolo[3,4-d]pyrimidines have been synthesized by using the Biginelli multi-component cyclocondensation reaction and their ability to inhibit growth of Mycobacterium tuberculosis in vitro have been determined. The results show that compounds 4b, 4d, and 4f exhibited excellent anti-tubercular activity with percentage inhibition of 93, 91, and 96, respectively, at a minimum inhibitory concentration (MIC) of <6.25?μg/ml, whereas compounds 4a, 4c, 4e, 4g, and 4h exhibited moderate to good anti-tubercular activity with percentage inhibition of 75, 68, 74, 54, and 63, respectively at a MIC of >6.25?μg/ml.