The carbonic anhydrase inhibitory capacities of compounds 15, 20, and 22 against carbonic anhydrases I, II, IX, and XII were inspected using the Carbonic Anhydrase Inhibitor Screening Kit (ab283387). The assay is based on quantitatively measuring the inhibition of the esterase activity of a carbonic anhydrase enzyme upon the introduction of a carbonic anhydrase inhibitor compound. Acetazolamide was employed as the reference inhibitor in the experiment.