Synthesis of Ethylene Tethered Isatin‐Coumarin Hybrids and Evaluation of Their in vitro Antimycobacterial Activities

A series of novel isatin‐coumarin derivatives tethered through ethylene were designed, synthesized, and evaluated for their in vitro antimycobacterial activities against Mycobacterium tuberculosis (MTB) H37Rv and multidrug‐resistant tuberculosis (MDR‐TB). All hybrids exhibited potential antimycobacterial activities against MTB H37Rv and MDR‐TB with minimum inhibitory concentration (MIC) ranging from 32 to 256 μg/mL. In particular, the hybrid 4h (MIC: 50 and 32 μg/mL) was most active against MTB H₃₇Rv and MDR‐TB strains, which was 2 and >4 folds more potent than the first‐line antitubercular agents rifampicin (MIC: 64 μg/mL) and isoniazid (MIC: >128 μg/mL) against MDR‐TB, warrant further optimization.