Aryl-4,5-dihydro-1-pyrazole-1-carboxamide Derivatives Bearing a Sulfonamide Moiety Show Single-digit Nanomolar-to-Subnanomolar Inhibition Constants against the Tumor-associated Human Carbonic Anhydrases IX and XII.

A series of new 3-phenyl-5-aryl--(4-sulfamoylphenyl)-4,5-dihydro-1-pyrazole-1-carboxamide derivatives was designed here, synthesized, and studied for carbonic anhydrase (CAs, EC 4.2.1.1) inhibitory activity against the human (h) isozymes I, II, and VII (cytosolic, off-target isoforms), and IX and XII (anticancer drug targets). Generally, CA I was not effectively inhibited, whereas effective inhibitors were identified against both CAs II (Ks in the range of 5.2-233 nM) and VII (Ks in the range of 2.3-350 nM). Nonetheless, CAs IX and XII were the most susceptible isoforms to this class of inhibitors. In particular, compounds bearing an unsubstituted phenyl ring at the pyrazoline 3 position showed 1.3-1.5 nM Ks against CA IX. In contrast, a subset of derivatives having a 4-halo-phenyl at the same position of the aromatic scaffold even reached subnanomolar Ks against CA XII (0.62-0.99 nM). Docking studies with CA IX and XII were used to shed light on the derivative binding mode driving the preferential inhibition of the tumor-associated CAs. The identified potent and selective CA IX/XII inhibitors are of interest as leads for the development of new anticancer strategies.