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This study aimed to synthesize new potent quinoline derivatives based on hydrazone moieties and evaluate their antimicrobial activity. The newly synthesized hydrazono‐quinoline derivatives 2, 5a, 9, and 10b showed the highest antimicrobial activity with MIC values ≤1.0 μg/ml against bacteria and ≤8.0 μg/ml against the fungi. Further, these derivatives exhibited bactericidal and fungicidal effects with MBC/MIC and MFC/MIC ratio ≤4. Surprisingly, the most active compounds displayed good inhibition to biofilm formation with MBEC values ranging between (40.0 ± 10.0 – 230.0 ± 31.0) and (67.0 ± 24.0 – 347.0 ± 15.0) μg/ml against Staphylococcus aureus and Pseudomonas aeruginosa, respectively. The hemolytic assays confirmed that the hydrazono‐quinoline derivatives are non‐toxic with low % lysis values ranging from 4.62% to 14.4% at a 1.0 mg/ml concentration. Besides, compound 5a exhibited the lowest hemolytic activity value of ~4.62%. Furthermore, the study suggests that the hydrazono‐quinoline analogs exert their antibacterial activity as dual inhibitors for DNA gyrase and DNA topoisomerase IV enzymes with IC50 values ranging between (4.56 ± 0.3 – 21.67 ± 0.45) and (6.77 ± 0.4 – 20.41 ± 0.32) μM, respectively. Additionally, the recent work advocated that compound 5a showed the reference SAL at the ɣ‐radiation dose of 10.0 kGy in the sterilization process without affecting its chemical structure. Finally, the in silico drug‐likeness, toxicity properties, and molecular docking simulation were performed. Besides, the result exhibited good oral‐bioavailability, lower toxicity prediction, and lower binding energy with good binding mode rather than the positive control.

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Incorporating selenium metal bonded to the pyridine nucleus was achieved by the reaction of selenium metal with 2-chloropyridine carbonitrile 1 in the presence of sodium borohydride as reducing agent. The resulting non isolated selanyl sodium salt was subjected to react with various α-halogenated carbonyl compounds to afford the selenyl pyridine derivatives 3a-f  which compounds 3a-d underwent Thorpe-Ziegler cyclization to give 1-amino-2-substitutedselenolo[2,3-b]pyridine compounds 4a-d, while the other compounds 3e,f failed to be cyclized. Basic hydrolysis of amino selenolo[2,3-b]pyridine carboxylate 4a followed by decarboxylation furnished the corresponding amino selenolopyridine compound 6 which was used as a versatile precursor for synthesis of other heterocyclic compound 7-16. All the newly synthesized compounds were established by elemental and spectral analysis (IR, 1H NMR) in addition to mass spectra for some of them hoping these compounds afforded high biological activity.