1H-1,2,3-triazole-tethered 8-OMe Ciprofloxacin and Isatin Hybrids: Design, Synthesis and in vitro Anti-mycobacterial Activities

A new class of 1H-1,2,3-triazole-tethered 8-OMe ciprofloxacin (8-OMe CPFX) isatin hybrids 5a-l was designed, synthesized and screened for their in vitro anti-mycobacterial activities against Mycobacterium tuberculosis H(37)Rv and multi-drug-resistant tuberculosis (MDR-TB). All targets (minimum inhibitory concentration (MIC): 0.20-8.0 mu g/mL) exhibited promising inhibitory activity against MTB H(37)Rv and MDR-TB. Among them, conjugate 5h (MIC: 0.20 mu g/mL), was 2-16 times more potent in vitro than the references CPFX (MIC: 3.12 mu g/mL), 8-OMe CPFX (MIC: 1.56 mu g/mL) and RIF (MIC: 0.39 mu g/mL) against MTB H(37)Rv. The most potent hybrid 5l (MIC: 0.25 mu g/mL) was 8-256 times more active than the three references (MIC: 2.0-64 mu g/mL) against MDR-TB. Both of them warrant further investigations.