Synthesis of novel benzenesulfonamide bearing 1,2,3-triazole linked hydroxy-trifluoromethylpyrazolines and hydrazones as selective carbonic anhydrase isoforms IX and XII inhibitors

A series of twenty four hydroxy-trifluoromethylpyrazoline-carbonyl-1,2,3-triazoles and four hydrazones bearing benzenesulfonamide moieties was obtained by condensation of carboxyhydrazides with substituted 1,3-diketones. All the newly synthesized compounds were investigated as inhibitors of physiologically and pharmacologically relevant human (h) carbonic anhydrsae (CA, EC 4.2.1.1) cytosolic isoforms hCA I and II, as well as transmembrane tumor-assosciated isoforms hCA IX and XII. These compounds exhibited excellent CA inhibitory potency against the four CA isoenzymes as compared to clinically used reference drug acetazolamide (AAZ). Some compounds bearing bulkier group at C-5′ position of 1,2,3-triazoles ring were weaker inhibitors of hCA I. Inhibition assay against hCA II indicates, that several derivatives exhibited upto 27-fold more effective inhibitory activity compared to AAZ. Five of the assayed compounds displayed low nanomolar potency (K_i ≤ 10 nM) against hCA IX, whereas five compounds were found to be endowed with excellent inhibitory potencies (K_i ≤ 5 nM) against hCA XII. The biological activity profile presented herein will be useful for designing new leads and provide candidates for preclinical investigations.