2(3H)-furanones and 2(3H)-pyrrolones: synthesis and antimycobacterial evaluation.

A series of 3-arylidene-5-(substituted phenyl)-2(3H)-furanones (3-10) and their nitrogen analogues, 3-arylidene-5-(substituted phenyl)-1-benzyl-2(3H)-pyrrolone (11-14), and 3-arylidene-5-(substituted phenyl)-2(3H)-pyrrolones (15-21) were synthesized. All the compounds were screened for their antimycobacterial activity in vitro against Mycobacterium tuberculosis H37Rv (ATCC 27294) in BACTEC medium using the Microplate Alamar Blue Assay (MABA). Among the synthesized compounds, compound 19, 3-(4-chlorobenzylidene)-5-(4-methylphenyl)-2(3H)-pyrrolone, emerged as a lead compound having the highest activity against Mycobacterium tuberculosis. The antimycobacterial activity was found to improve upon replacement of oxygen of furanone ring with nitrogen atom (pyrrolones), however, substitution with benzylamine moiety (1-benzylpyrrolones) markedly decreases the activity.