A microwave-assisted, facile, regioselective Friedländer synthesis and antitubercular evaluation of 2,9-diaryl-2,3-dihydrothieno-[3,2-b]quinolines

A series of 2,9-diaryl-2,3-dihydrothieno[3,2-b]quinolines have been synthesized regioselectively by Friedländer annulation of 5-aryldihydro-3(2H)-thiophenones and 2-aminobenzophenones in the presence of trifluoroacetic acid in good yields under microwave irradiation at 100 °C. The 2,9-diaryl-2,3-dihydrothieno[3,2-b]quinolines were screened for in vitro antimycobacterial activity against Mycobacterium tuberculosis H37Rv (MTB) and multi-drug resistant M. tuberculosis (MDR-TB). Among the 17 compounds screened, 7-chloro-2-(2,4-dichlorophenyl)-9-phenyl-2,3-dihydrothieno-[3,2-b]quinoline and 7-chloro-2-(3-nitrophenyl)-9-phenyl-2,3-dihydrothieno[3,2-b]quinoline display maximum activity with MIC of 0.90 and 0.95 μM against MTB and MDR-TB respectively.

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