Antibacterial and antitubercular evaluation of dihydronaphthalenone‐indole hybrid analogs

A new series of indole appended dihydronaphthalenone hybrid analogs ( 5a–t ) have been synthesized through the Lewis acid catalyzed Michael addition of indoles to the arylidene/hetero arylidene ketones. All the synthesized derivatives are well characterized through the ¹H‐NMR, ¹³C‐NMR, HRMS spectroscopic techniques, compound 5r was further confirmed through single crystal X‐ray analysis and screened for antibacterial and antitubercular activities. Among the synthesized compounds, the minimum inhibition concentration of 5l (against Escherichia coli) and 5o & 5p (against E. coli & Staphylococcus aureus) was found to be as low as 3.12 μg/ml as compared to the standard antibacterial drug ciprofloxacin 2.5 μg/ml. In antitubercular activity, compounds 5o and 5p with minimum inhibition concentration 6.25 μg/ml were found to be comparable with that of the drugs Pyrazinamide 5 μg/ml and Streptomycin 5 μg/ml. Compounds 5i , 5j , 5m , 5n , 5q , and 5r also showed promising activity against group of organisms tested.