Inhibitory effect of novel pyrazole carboxamide derivatives on human carbonic anhydrase enzyme

The synthesis, characterization and biological evaluation of novel pyrazole carboxamide derivatives (2-9) are presented. H-1 and C-13 NMR have been used for the structure description, possible tautomeric structures determination and hydrogen bonding observation. FT-IR results have confirmed the synthesis of the pyrazole derivatives while thermal gravimetric analysis has confirmed thermal stability up to 300 degrees C. The melting temperatures are strongly dependent on their crystal structure as confirmed by differential scanning calorimetry and X-ray diffraction measurements. Impacts of 2-9 as possible antiglaucoma agents were investigated on carbonic anhydrase I and II (CA-I and II) isozymes purified from human erythrocytes in vitro. Compounds 3 and 9 had the highest inhibitory effect while compounds 6 and 8 showed the lowest inhibition.