Synthesis and antibacterial activity of a series of 2-trifluoromethylbenzimidazole-thiazolidinone derivatives

A series of 2-phenyl-3-(2-(trifluoromethyl)-1H-benzoimidazol-6-yl)thiazolidin-4-one derivatives were synthesized from p-nitro-o-phenylenediamine in a three-step reaction. Their structures were elucidated by NMR and mass spectral data. The synthesized compounds showed excellent antibacterial activity ranging from 3-fold, to greater than 100-fold higher than the standard antibiotics, ciprofloxacin and levofloxacin. Compounds 3d (2′-Br), 3j (4′-Br), and 3l (4′-NO₂) displayed a broad spectrum of activity against the strains tested (0.14–38.33 μM). The brominated derivatives 3d and 3j showed excellent activity against the Gram-positive bacterial strains (MBC between 0.12 and 35.46 μM), while the nitro derivative 3l showed excellent activity against all four Gram-negative strains tested (MBC between 0.15 and 9.58 μM).