Synthesis and antimicrobial activity of pyrazole nucleus containing 2-thioxothiazolidin-4-one derivatives

A series of novel compounds of type 3-(4-chlorophenyl)-5-((1-phenyl-3-aryl-1H-pyrazol-4-yl)methylene)-2-thioxothiazolidin-4-one (3a-h) have been synthesized from the 3-(4-chlorophenyl)-2-thioxothiazolidin-4-one (1) and 1-phenyl-3-(p-substituted phenyl)-1H-pyrazole-4-carbaldehyde (2a-h). The structures of all the synthesized compounds have been confirmed by elemental analyses, FT-IR, 1H NMR, 13C NMR and mass spectral data. These newly synthesized compounds were screened for in vitro antibacterial activity against Escherichia coli (MTCC 443), Pseudomonas aeruginosa (MTCC 1688), Staphylococcus aureus (MTCC 96), and Staphylococcus pyogenes (MTCC 442) using commercially available antibiotics ampicillin as a standard drug. Compound 3c was found as a potent compound against E. coli, compounds 3a, 3d and 3g were found as a potent against S. aureus, while 3d against S. pyogenes. For in vitro antifungal activity, these compounds were tested against Candida albicans (MTCC 227), Aspergillus niger (MTCC 282) and Aspergillus clavatus (MTCC 1323) using griseofulvin as a standard drug. Compounds 3b and 3d were found to have very good activity against C. albicans. Variable and modest activities were observed against the investigated strains of bacteria and fungi.