Design and synthesis of Novel 3,5-Diamino-4-(2′,3′,4′-Substituted Phenylazo)-1–2,5-dichlorphenylpyrazoles: Unveiling dual proficiency against inflammation and bacteria

Abstract

This study introduces a novel series of 3,5-diamino-4-(2′,3′,4′-substitued phenylazo)-1–2,5-dicholorphenylpyrazole (4a-i) derivatives, synthesized through nucleophilic substitution reactions between 2-[(substituted phenyl) hydrazono] malononitrile (3) and 2,5-dichlorophenyl hydrazine under reflux conditions in an ethanolic medium. These compounds exhibit potent antibacterial and anti-inflammatory properties, demonstrated through in vitro assays and molecular docking studies. The structural uniqueness of the synthesized pyrazoles contributes to their dual proficiency, marking a significant advancement in the field of organic chemistry. The structural characterization of the synthesized derivatives was accomplished using IR, 1H, 13C NMR, and mass spectrometry analyses. The antibacterial (in vitro) and anti-inflammatory (in vivo) potential of the newly synthesized substituted pyrazoles was systematically evaluated. Carrageenan-induced inflammation inhibition was notably prominent in compound 4 h, demonstrating remarkable anti-inflammatory activity. In vitro antibacterial assays were conducted against four bacterial strains, including Bacillus subtilis (MTCC 121), Staphylococcus aureus (MTCC 96), Escherichia coli (MTCC 1652), and Pseudomonas fluorescens (MTCC 741). The synthesized pyrazole derivatives exhibited moderate to excellent antibacterial activity against both Gram-positive and Gram-negative bacterial strains. Compound 4 g displayed the highest inhibitory zone with a Minimum Inhibitory Concentration (MIC) of 250 μg/mL against E.coli. Molecular docking analysis against COX-2 (PDB-ID: 4COX) was performed, employing celecoxib as a reference molecule. Compound 4e exhibited a remarkable docking score of -8.55, surpassing the reference compound celecoxib (Docking score = -10.38). Quantum chemical calculations utilizing the B3LYP methodology were also employed to determine the relative energies of compounds 4a–i. This comprehensive study unveils the successful synthesis of a novel series of pyrazole derivatives and their potent antibacterial and anti-inflammatory properties. The results offer valuable insights for the potential development of these derivatives as promising candidates for addressing bacterial infections and inflammatory disorders.