One-pot strategy for thiazole tethered 7-ethoxy quinoline hybrids: Synthesis and potential antimicrobial agents as dihydrofolate reductase (DHFR) inhibitors with molecular docking study

•A series of thiazole-tethered 7-ethoxy quinoline hybrids-based scaffolds were synthesized.•In vitro antimicrobial screening activity, MIC, MBC, MFC, and SAR were studies.•The most active derivatives were tested against DHFR inhibitory assay.•The docking study revealed high binding affinities toward DHFR (PDB: 1DLS) as well as achieved the MEPs study. Over the world and especially the developing countries, one of the major threats to human health is antibiotic resistance due to antibiotics abuse. This challenge can be solved by discovering new targets and inhibitors. The current study involved synthesis quinoline based thiazole analogues for quinoline antibiotic class using classic organic synthesis. The designed derivatives were tested against eight standard microbial pathogens. Among them, seven derivatives showed good antimicrobial activity with MIC and MBC values ranged between (0.97–62.5) µg/mL, and (1.94–118.7) µg/mL, respectively. Additionally, the active derivatives displayed good activity against three MDR bacterial stains. Compounds 11b, and 5a exhibited to be the most active derivatives against S. aureus and E. coli with MIC (1.95–7.81) µg/mL and MBC (3.31–15.62) µg/mL followed by other derivatives compared with Ciprofloxacin and Vancomycin. Besides, compounds 6, 11c, and 15 appeared the most active derivatives against MDR P. aeruginosa with MIC and MBC values lower than 10 µg/mL. These derivatives considered effective for treating bacterial infection by inhibiting DHFR enzyme that showed IC50 values (10.02–25.11) µM in comparison to Trimethoprim (18.95 µM). Molecular docking study against DHFR enzyme (1DLS) was carried out, and the active derivatives bind to some the nearly the same amino acid residues as MTX that support our hypothesis. Furthermore, the MEP surfaces were generated using DFT calculation to determine the regions might be responsible for forming different types of interaction and confirm the binding mode in docking study. [Display omitted]