Synthesis and antitubercular evaluation of novel substituted aryl and thiophenyl tethered dihydro-6H-quinolin-5-ones.

A series of novel aryl and thiophenyl tethered dihydro-6H-quinolin-5-ones have been synthesized in very good yields through CeCl(3)·7H(2)O-NaI catalyzed one-pot condensation of β-enaminones derived from the respective methyl ketones; 1,3-cyclohexanedione & 5,5-dimethyl-1,3-cyclohexanedione and ammonium acetate refluxing in 2-propanol. Dihydro-6H-quinolin-5-ones 3a-f was further derivatized to the respective hydroxymethyl analogs using proline as an organocatalyst in aqueous media. Among the all 18 compounds screened for in vitro antimycobacterial activity against Mycobacterium tuberculosis H(37)Rv (MTB), dihydro-6H-quinolin-5-ones 4e and 4f were found to be most active with MIC 3.13 μg/mL.