Antibacterial and Antifungal Evaluation of 5-Aryl-4-(1H-pyrazol-1-yl)pyrazolidin-3-one Derivatives

Pyrazole derivatives have attracted considerable attention because of their diverse chemotherapeutic potential. In the present research work, some 5-phenyl-4-(1H-pyrazol-1-yl)pyrazolidin-3-one derivatives (4a-f) were synthesized and evaluated for their in vitro antibacterial activities against Gram-positive Staphylococcus aureus, Bacillus subtilis, and Gram-negative Escherichia coli, Pseudomonas aeruginosa strains and antifungal activities against Aspergillus niger and Candida albicansstrains. The synthesized derivatives were characterized by infrared, nuclear magnetic resonance (¹H-NMR and¹³C-NMR), and mass spectrometry. The result showed that the compounds 5-(4-methoxyphenyl)-4-(1H-pyrazol-1-yl)pyrazolidin-3-one (4d), 5-(4-chlorophenyl)-4-(1H-pyrazol-1-yl)pyrazolidin-3-one (4e), and 5-(4-nitrophenyl)-4-(1H-pyrazol-1-yl)pyrazolidin-3-one (4f) showed significant antimicrobial activities when compared to standard drugs (streptomycin as antibacterial drug and amphotericin-B as antifungal drug). Compound 4d was the most effective against both Gram-positive and Gram-negative bacteria while compounds 4e and 4f showed the most effective antifungal activity.