Preparation of 2,6-pyridinecarboxylic acids and salts of 2-aminobenzothiazole derivatives, synthesis of their transition metal complexes, chracterization of their structures and application areas of investigation

In this study, four novel proton transfer salts (ABTDPC, ClABTDPC, MeABTDPC and MeOABTDPC) have been prepared between 2-aminobenzothiazole derivatives (2-aminobenzothiazole (ABT), 2-amino-6-chlorobenzothiazole (ClABT), 2-amino-6-methylbenzothiazole (MeABT) and 2-amino-6-methoxybenzothiazole (MeOABT)) and 2,6-pyridinedicarboxylic acid (H2dipic), and their 18 transition metal complexes have also been synthesized. After recrystallization, 13 metal complexes have yielded proper crystal for single X-ray diffraction studies. The structures of amorphous proton transfer salts have been characterized by 1H-NMR, FT-IR, TGA, UV-Vis and elemental analysis methods while the structures of metal complexes (FeABTDPC, CuABTDPC, FeClABTDPC, CoClABTDPC, NiClABTDPC, CuClABTDPC1, CuClABTDPC2, FeMeABTDPC1, FeMeABTDPC2, CoMeABTDPC, NiMeABTDPC, CuMeABTDPC and NiMeOABTDPC) have been characterized by means of single crystal X-ray diffraction, ICP-OES, magnetic susceptibility and molar conductivity methods in addition to above mentioned techniques. The structures for amorphous metal complexes (CoABTDPC, NiABTDPC, FeMeABTDPC, CoMeABTDPC and CuMeOABTDPC) have been proposed by using elemental analysis, ICP-OES, TGA, FT-IR, 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 not affected hydratase activities, but have inhibited the esterease activities of isoenzymes. Esterase IC50 values have been determined in the range of 0,147-0,944 nM for hCA I and 0,128-0,912 mM for hCA II, respectively.Keywords: 2-Aminobenzothiazole, Carbonic Anhydrase Inhibition, Metal Complexes, 2,6-Pyridinedicarboxylic acid, Proton Transfer Salt.