New quinoline derivatives: Synthesis and investigation of antibacterial and antituberculosis properties

Four new series of quinoline derivatives were synthesized starting from 2-trifluoromethyl aniline through multi-step reactions. In the reaction sequence, substituted aniline was cyclized to 4-hydroxy quinoline 1, which was then transformed to 4-chloro-2,8-bis(trifluoromethyl)quinoline 2. The key scaffold 4-hydrazinyl-2,8-bis(trifluoromethyl)quinoline 3, obtained from the compound 2, was successfully converted to target quinoline derivatives, viz. hydrazones 4a–t, ureas 5a–e, thioureas 6a–c and pyrazoles 7a–d, in good yields. The newly synthesized title compounds were evaluated for their in vitro antibacterial activity against Escherichia coli, Staphylococcus aureus, Pseudomonas aeruginosa and Klebsiella pneumoniae (recultured) and antituberculosis activity against Mycobacterium tuberculosis H37Rv and MDR-TB. Preliminary results indicated that most of the hydrazone derivatives demonstrated very good antibacterial and antituberculosis activities while other derivatives showed moderate activity.

Graphical abstractFour new series of quinoline derivatives have been synthesized from 2-trifluoromethyl aniline and evaluated for antibacterial and antituberculosis studies. Majority of them showed moderate to good antimicrobial activity.Figure optionsDownload full-size imageDownload as PowerPoint slide