No abstract

Recent studies showed that 1,4-dihydropyridine-3,5-dicarbamoyl derivatives with lipophilic groups have significant antitubercular activity. In this study, we have synthesized new derivatives of 1,4-dihydropyridines bearing carbmethoxy and carbethoxy group at C-3 and C-5 of the 1,4-dihydropyridine ring. In addition, 1H-pyrazole ring is substituted at C-4 position. These analogues were synthesized by multi-component Hantzsch reaction. The in vitro antitubercular activity of compounds against Mycobacterium tuberculosis H(37) Rv was evaluated. The lowest minimum inhibitory concentration value, 0.02 μg/mL and SI > 500, was found for dimethyl 1,4-dihydro-4-(3-(4-nitrophenyl)-1-phenyl-1H-pyrazol-4-yl)-2,6-dimethylpyridine-3,5-dicarboxylate 3f, diethyl 1,4-dihydro-4-(3-(4-fluorophenyl)-1-phenyl-1H-pyrazol-4-yl)-2,6-dimethylpyridine-3,5-dicarboxylate 4c and diethyl 1,4-dihydro-4-(3-(4-bromophenyl)-1-phenyl-1H-pyrazol-4-yl)-2,6-dimethyl pyridine-3,5-dicarboxylate 4e, making them more potent than first-line antitubercular drug isoniazid. In addition, these compounds exhibited relatively low cytotoxicity.

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 lg/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 lg/ml.

The present article describes a facile one-pot synthesis of a series of eight pyrazolo[3,4-d]pyrimidines 4a-h which were evaluated for their in-vitro antibacterial activity against Mycobacterium tuberculosis H37Rv using the Alamar-Blue susceptibility test and the activity expressed as the minimum inhibitory concentration (MIC) in mg/mL. The compounds 4b, 4c, 4d, and 4g exhibited the best results (1.2 microg/mL) when compared with first-line drugs such as isoniazid (INH) and rifampicin (RIP). Therefore, this class of compounds could be a good starting point to develop new lead compounds in the treatment of multidrug-resistant tuberculosis.

In the present investigation ethyl 2-(4-carboxyphenylazo)acetoacetate 1 on condensation with various aromatic aldehydes in ethanolic NaOH solution yielded the corresponding chalcones 2a-j. These chalcones were further reacted with urea in the presence of base in ethanol, which led to the formation of pyrimidine derivatives 3a-j. The newly synthesized heterocyles were characterized on the basis of their chemical properties and spectroscopic data. All newly synthesized compounds were evaluated for their antimycobacterial activities against Mycobacterium tuberculosis H 37 Rv.