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Potentiation of the Antimicrobial Activity of 4-Benzylimino-2, 3-Dimethyl-1-Phenylpyrazal-5-One by Metal Chelation

Author Affiliations

  • 1Department of Chemistry, University of Benin, NIGERIA
  • 2Department of Chemistry, Michael Okpara University of Agriculture, NIGERIA

Res.J.chem.sci., Volume 1, Issue (8), Pages 6-11, November,18 (2011)


A Schiff base ligand, 4-benzylimino-2-3-dimethyl-l-phenylpyrazal-5-one have been synthesized by the condensation of Benzaldehyde and 4-aminoantipyrine. Its divalent metal complexes of Fe, Co, Ni, Cu and Zn were also synthesized. The ligand and the complexes were characterized by FTIR, UV/visible, H-NMR, 13C-NMR, and GCMS. The ligand behaved as a bidentate donor by using its carbonyl and azomethine N as binding sites for the metals. Tetrahedral structures were proposed for the all complexes excepting the Cu(II) complex. The ligand showed low activity against some microbes but the complexes were remarkably active against the bacteria and fungi species.


  1. Bahl B.S. and Bahl A., Elementary Organic Chemistry, Schand and Company Ltd, New Delhi, 60 (1993)
  2. Kovala-Demertzi D., Platinum(II) and palladium(II) Schiff base complexes of pyridine-2-carbaldehyde thiosemicarbazone as alternative antiherpes simplex virus agents., Bio. Chem. App., (1), 1-6 (2007)
  3. Silverstein R.M., Bassler G.C. and Morril T.C., Spectrometric identification of Organic Compounds, John Wiley and Sons, New York ,50-56 (1974)
  4. Finar I.L. Organic Chemistry, Vol 2, 5th Ed., Dorling Kindersley Publishers Ltd, India, 627(2007)
  5. Agarwal R.K., Singh L. and Sharma D.K. ,Synthesis, spectral, and biological properties of copper(II) complexes of thiosemicarbazones of Schiff bases derived from 4-aminoantipyrine and aromatic aldehydes, Bio.Chem. Appl.,.2006, 1-10 (2006)
  6. Scovill J.P., Klayman D.L. and Franchino C.F., 2-acetylpyridine thiosemicarbazones complexes with transition metals as antimalarial and antileukemic agents, J. of Med.Chem., 25(10),1261–1264 (2009)
  7. Costa R.F.F., Rebolledo A.P. and Matencio T., Metal complexes of 2-benzoylpyridine-derived thiosemicarbazones: structural, electrochemical and biological studies, J. of Coord Chem., 58(15), 1307–1319 (2005)
  8. Hugo, W.B. and Russel, A.D. Pharmaceutical Microbiology, Black Well Science, Ltd, U.S.A. 182 (2002)
  9. Sulekh C. and Amit K. S., Antitingal and Spectra Studies of Cr(III) and Mn(II) compexes derived from 3, 3- Thiodropropionic Acid derivative, Res. Lett. Inorg. Chem., 89 (2009)
  10. Quiroga A.G., P´erez J.M. and L´opez-Solera I., Novel tetranuclear orthometalated complexes of Pd(II) and Pt(II) derived from p-isopropylbenzaldehyde thiosemicarbazone with cytotoxic activity in cis-DDP resistant tumor cell lines Interaction of these complexes with DNA, J. of Med. Chem., 41(9), 1399–1408 (1988)
  11. Kovala-Demertzi D., Boccarelli A. and Coluccia M., In vitro antitumor activity of 2-acetyl pyridine 4N-ethyl thiosemicarbazone and its platinum(II) and palladium(II) complexes, Chemotherapy. 53(2), 148–152 (2007)
  12. Pandey O.P., Synthesis, spectral and antibacterial studies of binuclear titanium (IV) / zirconium(IV) complexes of piperazine dithiosemicarbazones, Bio. Chem Appl., 1(1), 35–44. (2003)
  13. Shipman J. Thiosemicarbazones of 2-acetylpyridine, 2-acetylquinoline, 1-acetylisoquinoline, and related compounds as inhibitors of herpes simplex virus in vitro and in a cutaneous herpes guinea pig model, Avr. Res.6(4), 197–222 (1986)
  14. Beraldo H. Semicarbazones and thiosemicarbazones: their wide pharmacological profile and clinical applications. Quim. Nova, 27(3),461–471(2004)
  15. Quiroga A.G., P´erez J.M. and L´opez-Solera I. Binuclear chloro-bridged palladated and platinated complexes derived from p-isopropylbenzaldehyde thiosemicarbazone with cytotoxicity against cisplatin resistant tumor cell lines, J. of Inorg. Biochem., 69(4), 275–281(1988)