Design, synthesis, antimicrobial activity and in silico molecular docking studies of some sulfur containing pyrazole-pyridine hybrids

We developed and synthesized novel 4-thiazolidinone hybrids with pyridine and pyrazole heterocycles (5a-5o). The structures of the synthesized products were elucidated by IR, ¹H NMR and ¹³C NMR spectroscopy and mass spectrometry. The synthesized hybrids were investigated for their antimicrobial activity against several bacterial and fungal strains using the Mueller–Hinton broth method. Compound 5-(3-methoxybenzylidene)-2-(1-phenyl-3-(p-tolyl)-1H-pyrazol-4-yl)-3-(pyridin-3-yl)thiazolidin-4-one (MIC = 50 μg/mL) exhibited prominent activity against gram-negative E. coli while compounds 5-(2-methylbenzylidene)-2-(1-phenyl-3-(p-tolyl)-1H-pyrazol-4-yl)-3-(pyridin-3-yl)thiazolidin-4-one and 5-(4-methylbenzylidene)-2-(1-phenyl-3-(p-tolyl)-1H-pyrazol-4-yl)-3-(pyridin-3-yl)thiazolidin-4-one exhibited MIC value of 250 μg/mL against C. albicans. Molecular docking study against microbial DNA gyrase could provide valuable insights into the binding modes of these molecules. They were found to exhibit excellent binding affinity (average Glide docking score: −7.989 and binding energy: −49.807 kcal/mol) through significant bonded and non-bonded interactions.