Exploration of Novel 4‐substituted Coumarin Derivatives as Selective Human Carbonic Anhydrase IX and XII Inhibitors: Synthesis, Biological Evaluation, and In Silico Studies

Carbonic anhydrases (CAs) are metalloenzymes present in both prokaryotes and eukaryotes, catalyzing the reversible conversion of carbon dioxide and water into bicarbonate ions and protons. Among the various isoforms of CA, human CA (hCA) IX and hCA XII play a critical role in regulating the intracellular and extracellular pH of hypoxic tumor cells. In the present work, we designed and synthesized a series of 4-substituted coumarin derivatives as potent hCA inhibitors. In this study, we synthesized two series of 4-substituted coumarin derivatives (7a-j and 8a-j) designed as selective inhibitors of these tumor-associated isoforms. All compounds demonstrated selective inhibition of hCA IX and hCA XII, with K_i values ranging from 0.32 to 8.77 µM. Among them, 7c and 7d from the first series exhibited the good activity, with K_i values of 0.63 and 0.32 µM against hCA IX, and 1.78 and 1.20 µM against hCA XII, respectively; similarly, in the second series, 8b and 8j displayed good activity, with K_i values of 0.48 and 0.61 µM against hCA IX, and 0.66 and 0.96 µM against hCA XII. Molecular docking studies were performed for all synthesized molecules to investigate their binding modes, and molecular dynamics simulations of 200 ns for selected compounds 7c and 8b further confirmed the stability of their complexes within the active sites of hCA IX and hCA XII.