Studies on metal complexes of 1-((8-hydroxyquinolin-5-yl)methyl)-3-(thiazol-2-ylimino)indolin-2-one

Abstract

Novel ligand 1-((8-hydroxyquinolin-5-yl)methyl)-3-(thiazol-2-ylimino)indolin-2-one was synthesized by condensation of 5-(chloromethyl)-1,8a-dihydroquinolin-8-ol with 3-(thiazol-2-ylimino)indolin-2-one. Metal complexes of this ligand were prepared using various transition metal ion salts, viz., Mn(II), Fe(II), Co(II), Ni(II), Cu(II), and Zn(II). All synthesized compounds were characterized by various spectroscopic techniques. Thermogravimetric analysis of metal complexes was also carried out. Geometry of the metal complexes was carried out by electronic spectral analysis and magnetic measurement studies. The ligand and metal complexes were screened for their antibacterial activities against Escherichia coli, Staphylococcus aureus, Klebsiella pneumoniae, Proteus vulgaris, and Pseudomonas aeruginosa. The metal complexes are found more potent bactericides than the ligand. The interaction of ligand and its complexes with plasmid (pUC 19) DNA and calf thymus DNA was investigated by gel electrophoresis measurements. The superoxide dismutase mimetic activity of the ligand and its metal complexes has also been assessed for their ability to inhibit the reduction of nitrobluetetrazolium chloride.

Novel Antimicrobial 8-Hydroxyquinoline-Based Agents: Current Development, Structure–Activity Relationships, and Perspectives

“…Other studies report the antibacterial activity of 8HQ derivatives containing phenyl esters or heterocycles, linked to position 5 by a methylene spacer (Figure ). − Substituted phenyl esters present high activity against S. aureus and Gram-negative bacteria, and an electron-withdrawing group at para ( 6a – c ) is favorable for the activity, with some derivatives being more active than penicillin G. However, the introduction of an electron-donor group ( 6d – e ) reduces the antibacterial effect .…”

“…69 Derivatives containing an unsubstituted heterocycle (6f−g) show better antibacterial activity than phenyl-substituted esters (6a−e), with MIC values in the nanomolar range (MIC evaluated in agar medium). 70 However, as shown in Figure 6, the introduction of a substituted bulky heterocycle (6h) seems to reduce the antibacterial effect significantly, 68 although this derivative was evaluated by a different methodology (serial dilution method).…”