Synthesis, moleculer modeling, and carbonic anhydrase inhibitor effects of novel 1-(1-benzyl-2-oxoindolin-3- ylidene)-4-(3-sulfamoylphenyl)thiosemicarbazides

In this study, we describe the synthesis of new 1-(1-benzyl-2-oxoindolin-3-ylidene)-4-(3-sulfamoylphenyl)thiosemicarbazides and evaluate their inhibitory activity against hCAs (6a–l). The inhibitory effects of compounds 6a–l were examined in vitro against hCA I, II, IX, and XII isoforms. Acetazolamide (AAZ) was employed as the standard reference compound in this study. The compounds 6a–l inhibited the tumor-associated hCA IX and XII isoenzymes at nanomolar levels, and showed weak inhibitory effects on the off-target hCA I and II isoenzymes. Selectivity index (SI) values of compounds 6a–l were determined to be significantly high for hCA IX and XII over hCA I and II compared to AAZ. Compound 6k (R1 = Cl, R2 = 3-Cl) showed the strongest inhibitory effect (Ki = 25.23 nM) and high selectivity (SI = 225, 185) against hCA IX over hCA I and II. Compound 6f (R1 = CH3, R2 = 4-Cl) was found to have the highest inhibitory effect (Ki = 36.65 nM) and high selectivity (SI = 377 and 192, respectively) against hCA XII over hCA I and II. Molecular docking and dynamic simulation analyses were conducted to explore how compounds 6f and 6k interact with active sites of hCA XII and IX enzymes.