Synthesis and structural studies of proton transfer salt between 2-aminopyridine and 4 oxo 4 ((4 sulfamoylphenyl)amino)but-2-enoic acid and their transition metal complexes, and studies on their applications

In this study, first, 4-oxo-4-((4-sulfamoylphenyl)amino)but-2-enoic acid (HSAMAL) have been synthesized from the reaction between sulfonylamide (SA) and maleic anhydride (MAL) and second, proton transfer salt ((HAP+)(SAMAL-)) has been prepared from 2 aminopyridine (AP) and HSAMAL. Five transition metal complexes (Fe(II), Co(II), Ni(II), Cu(II), Zn(II)) of the salt have also been synthesized. The structure of proton transfer compound has been proposed by using 1H NMR, 13C-NMR, UV-Vis techniques. The structure of amorphous metal complexes have been proposed by using FT-IR, ICP OES, UV-Vis, magnetic susceptibility and molar conductivity techniques. In addition, in vitro studies have been performed to determine the inhibition effects of synthesized compounds on human erythrocyte hCA I and hCA II isoenzymes. It has been observed that synthesized compounds have affected esterase activities of hCA I and hCA II and the inhibition values of these compounds are comparable with the inhibition values of control compound acetazolamide (AAZ).