Synthesis of Imidazo[1,2‐b]pyridazine Scaffold Based Amide Derivatives as Potential Inhibitors for Bacterial Activity

Abstract

AbstractA series of fifteen novel amide derivatives based on imidazo[1,2‐b]pyridazine scaffold were synthesized by taking imidazo[1,2‐b]pyridazine‐3‐carboxylic acid intermediates with respective substituted amines to yield good to excellent. The molecular structures of the newly synthesized compounds were elucidated using spectroscopic techniques (1H NMR, 13C NMR, and LCMS) and supported by single‐crystal X‐ray diffraction (SXRD) for the two compounds, 9 and 18. These compounds were evaluated in vitro for antimicrobial activity against two Gram‐positive bacteria (S. aureus and B. subtilis) and two Gram‐negative bacteria (E. coli and P. aeruginosa). Interestingly, compounds 10 and 16, displayed comparable antibacterial activity to the positive control (Tetracycline: 6.25 μg/mL) against Gram‐negative bacteria, particularly Pseudomonas aeruginosa, with a minimum inhibitory concentration (MIC) of 6.25 μg/mL. Compound 17 exhibited moderate antibacterial activity with an MIC of 10 μg/mL against the Gram‐positive bacterium Bacillus subtilis, whereas the positive control demonstrated an MIC of 6.25 μg/mL. These antibacterial activities were found to have a good correlation with Insilco computational molecular docking experiments using the receptor UDP‐N‐acetylglucosamine‐enolpyruvate reductase, Mtb MurB.