New thieno[2,3-b]pyridine-based compounds: Synthesis, molecular modelling, antibacterial and antifungal activities

New thieno[2,3-b]pyridine clubbed various thiazole ring systems were synthesized by the reaction of 2-(1-(3-amino-4,6-dimethylthieno[2,3-b]pyridin-2-yl)ethylidene)hydrazine-1-carbothioamide with chloroacetone, phenacyl chloride, and chloroacetic acid. The molecular modeling of the synthesized compounds using DFT/B3LYP methodology revealed that all have a low HOMO and LUMO energies, −4.85 - −5.52 and −2.79 - −3.62, respectively, where the compound 10 has the highest values. The targeting thienopyridine analogues with various thiazole moieties 3–10 was assessed in order to create new antimicrobial agents and compared with ampicillin, gentamicin and miconazole as reference antibacterial and antifungal drugs. Compounds 8–10 exhibited potent antimicrobial activity against Gram positive S. aureus, Gram Gram negative E. coli bacteria, and C. albicans (antifungal), with IC₅₀ (18.9 ± 0.63––24.3 ± 0.74 µg/mL), (14.2 ± 0.41––19.5 ± 0.64 µg/mL), and (19.2 ± 0.58–––23.4 ± 0.65 µg/mL), respectively. Furthermore, Molecular docking stimulation on MOE program was applied to expect the effect and interactions of the newly thienopyridine analogues and E. coli DNA gyrase B as it expressed by PDB ID: 1AJ6.