Design, synthesis, and biological evaluation of 3-phenylimidazo[1,2-a]pyridine derivatives as diverse enzyme inhibitors

This study presents the single-step synthesis of a variety of 3-phenylimidazo[1,2-a]pyridine derivatives 1–24 by reacting different phenacyl bromides with 2-aminopyridine in the presence of DABCO (1,4-diazabicyclo[2.2.2]octane) as a base. Compounds were characterized by spectroscopic techniques to confirm their structures. All synthetic derivatives were evaluated against important metabolic drug targets, including human carbonic anhydrase I and II, α-glucosidase, and α-amylase enzymes. Pertinent to mention that all the synthetic analogs revealed potent inhibitory strength with K_i values in the range of 104.36—439.41 nM against hCA-I and 119.46—472.35 nM against hCA-II in comparison with the standard acetazolamide K_i = 466.53 ± 41.22 nM (for hCA-I) and K_i = 481.18 ± 33.05 nM (for hCA-II). All compounds showed potent inhibitory activity against α-glucosidase enzyme with IC₅₀ value 247.50—784.32 nM, compared to the standard acarbose = 22,800 nM. In addition, compounds were also identified as potent inhibitors of α-amylase with an IC₅₀ value of 342.67–1011.53 nM compared to the standard acarbose = 10,000 nM. In silico studies of the potential compounds 8, 13, 15, 19, 20, and 21 against hCA-I, hCA-II, α-glycosidase, and α-amylase were performed to assess the enzyme–ligand interactions with the residues of the active-site target enzymes.