Synthesis, Characterization and Antibacterial Activity Evaluation of 4-amino Antipyrine Derivatives and Their Transition Metal Complexes

Due to their importance as catalysts in many reactions and their biological activities, an interest in the synthesis and characterization of transition metal complexes containing Schiff bases is increasing. Schiff base ligands have achieved considerable attention by the scientist over the decades as potential drug agent, Azomethine linkage (-CH=N-) of Schiff base play a significant role in medical chemistry. Derivatives of Schiff bases of 4-aminoantipyrine viz, 4-(2-hydroxy-3-methoxy benzylid ene amino)-1,2-dihydro-2,3-dimethyl-1-phenylpyrazol-5-one (4) and 4-((5-methylfuran-2-yl) methylene amino)-1,2-dihydro-2,3-dimethyl-1-phenylpyrazol-5-one (5) and their Co (II), Ni (II), Cu (II) complexes were successfully synthesized, the Schiff bases ligand (4) and (5) were synthesized by condensation reaction. The structures of all the synthesized ligands were confirmed by using IR, UV-Visible, 1H NMR, and 13C NMR. The Cu (II), Ni (II) and Co (II) complexes were confirmed by using IR and VU-Visible. The complexes are electrolytic in nature as indicated by molar conductance measurements. The data have shown that all complexes possess octahedral geometry. In-vitro antibacterial activity of all the synthesized ligands and their metal complexes were carried out by using disc diffusion method against Staphylococcus aureus, Escherichia coli and Pseudomonas aeruginosa bacterial strain. Compound Co (4) has exhibited better antibacterial activity than the standard drug against S. aureus (25 mm zone of inhibition compared to the standard antibiotic Oxacillin (23 mm zone of inhibition).