Some N-(5-methyl-1,3,4-thiadiazol-2-yl)-4-[(3-substituted)ureido/ thioureido]benzenesulfonamides as carbonic anhydrase I and II Inhibitors

In the present study, N -(5-methyl-1,3,4-thiadiazol-2-yl)-4-[(3-substitue)ureido] benzenesulfonamide (1-9) and N -(5-methyl-1,3,4-thiadiazol-2-yl)-4-[(3-substitue) thioureido]benzenesulfonamide (10-14) derivatives were synthesized from 4-amino- N- (5-methyl-1,3,4-thiadiazol-2-yl)benzenesulfonamide (Sulfamethizole). All new compounds were characterized by elemental analysis and various spectroscopic methods (FTIR, 1 H-NMR and MS). These new sulfonamide derivatives were investigated as inhibitors of carbonic anhydrase especially human carbonic anhydrase I and II. The new compounds showed higher activity against the human cytosolic CA I (IC 50 values 0.095-15.65 nM) and CA II            (IC 50 values 0.057-17.95 nM) in comparison with the clinically used CAI inhibitor acetazolamide.