Transition metal complexes of pyrazole head 24-membered polyazamacrocyclic bimetal cores: synthesis, characterization, electrochemistry and spectral study

CHEMICAL & PHARMACEUTICAL BULLETIN

Kurdekar

et al. 2010

Self Cite

Epilepsy is an ever-present serious disease related to the neurological disorders. It is generally characterized by recurrent seizures that result from phasic changes in the firing properties of groups of neurons. The induction of a group of neurons into a pattern of burst-firing results in synchronized disruptive seizure discharge. The detailed studies reveals that, the excitatory and inhibitory neurotransmission as well as voltage-gated channels (that can be modulated selectively by natural or synthetic toxins) are the two major factors, that are found to be the crucial for seizure like activity.1,2) The antiepileptic drugs, which are in efficacious clinical practice, act by inducing prolonged inactivation of the Na ϩ channel, by blocking Ca 2ϩ channel currents or by enhancing inhibitory g-aminobutyrate (GABA)-ergic neurotransmission. Some of the other anticonvulsant agents act via a number of different mechanisms, which may include antagonism of glutamateergic neurotransmission.3) However it is seen that, the majorities of antiepileptic drugs do not provide satisfactory seizure control in all patients and typically cause notable adverse side effects. 4,5) It is hence becomes a crucial and challenging task in the field of medicinal chemistry to find more efficient and safer antiepileptic agents.In this regard, there are few attempts made, the organic moieties having anticonvulsant property were interacted with suitable metal ions and hence formed complexes are investigated for the anticonvulsant activity. Interestingly, a considerable enhancement of activity upon complexation has been observed, 6,7) which is certainly related to the increased lipophilicity upon complexation (which increases their permeability to the blood-brain barrier) and inertness of certain metal ligand linkages towards enzymatic degradation. 8,9) Quinoline derivatives have been known to possess a variety of biological activities such as antitumor, 10) antimalarial, 11) antidepressant, 12) antiulcer 13) and cardiac stimulant. 14)Along with these, there are reports suggesting that the quinolines have exhibited a very good anticonvulsant activity in the maximum electroshock method test. 15) In this regard, so many attempts are made by incorporating various hetero cyclic groups to the quinoline core, in order to obtain compounds with better anticonvulsant activity.16,17) Substitution of triazole or triazolone ring to the quinoline core has been found to increase receptor binding capacity and metabolic stability, which in turn enhances the anticonvulsant activity of the compound. 18,19) In the present research work, we have selected 2-hydroxy, 3-formyl quinoline as a precursor. The presence of oxygen functional groups in the quinoline core is expected to facilitate the elliptical activity 20) as well as complexation. Amino triazoles are incorporated to the precursor by means of Schiff base formation in the presence of Cu II and Zn II ions (these two are selected by considering the higher bioaccessiblity, as compared to the other transition met...

Section: Epr Studiessupporting

confidence: 64%

Anticonvulsant Activity and Toxicity Evaluation of CuII and ZnII Metal Complexes Derived from Triazole-Quinoline Ligands

Kulkarni

CHEMICAL & PHARMACEUTICAL BULLETIN

Kurdekar

et al. 2010

Self Cite

“…A sharp band at 1,676 cm -1 assigned to v(C=O) of the amide functionality in the free ligand is absent for all the complexes. This suggests conversion of the ligand into its imidol tautomer, which is confirmed by the presence of a new sharp band at around 1,646-1,630 cm -1 in the spectrum of the complexes, assigned to the azomethine group [14]. In all the complexes, the imidol hydroxyl group is present outside the coordination sphere, which is further supported by the presence of a sharp band at around 3,400 cm -1 in the spectra of the complexes suggesting the coordination of imidol nitrogen atoms.…”

Section: Resultsmentioning

confidence: 63%

Interaction of E. coli DNA with diazine-bridged late first row transition metal complexes derived from hexadentate compartmental ligands: an approach to DNA cleavage/binding studies

Revankar

2010

Transition Met Chem

Self Cite

Interaction of E. coli DNA with diazine-bridged late first row transition metal complexes derived from hexadentate compartmental ligands: an approach to DNA cleavage/binding studies Abstract A series of binuclear Co II , Ni II , Cu II and Zn II complexes having l-1,2 diazine bridging have been prepared and characterized by various physico-chemical methods. The hexadentate ligands were synthesized by condensing 3,5-dichloroformyl-1H-pyrazole with 2-hydrazinobenzothiazole (L 1 H) or 4-aminoantipyrine (L 2 H) in 1:2 ratio. Gel electrophoresis data indicate cleavage of E. coli DNA to a minute extent by both [Co 2 L 2 (l-Cl)Cl 2 (H 2 O) 2 ]ÁH 2 O and [Ni 2 L 2 (l-Cl)Cl 2 (H 2 O) 2 ]. Conversely, the data for the remaining complexes indicated binding but not cleavage. These results were confirmed by viscosity measurements and absorption spectral studies. An intercalative binding mode is predicted when the title complexes interact with DNA. ExperimentalAll the chemicals used were of reagent grade, and the solvents were dried and distilled before use according to standard procedures. Pyrazole-3,5-dicarboxylic acid, 4-aminoantipyrine and 2-mercaptobenzothiazole were purchased

“…In addition, spectra also evidenced at the two bands around 2960 and 3030 cm −1 , which were assigned to the pure modes of the C―H stretching vibrations. This variation in the range is due to the presence of aliphatic and aromatic C―H modules . However, in the complex spectra, the band due to benzimidazole ring vibrations showed a negative shift, further indicating the formation of C―N module and in turn the desired carbene complexes.…”

Section: Resultsmentioning

confidence: 96%

Nitrile‐functionalized Hg(II)‐ and Ag(I)‐N‐heterocyclic carbene complexes: synthesis, crystal structures, nuclease and DNA binding activities

Haque

Choo

et al. 2012

Applied Organom Chemis

Self Cite

Various nitrile‐functionalized benzimidazol‐2‐ylidene carbene complexes of Hg(II) and Ag(I) were synthesized by the interaction of 1‐benzyl/1‐butyl‐3‐(cyano‐benzyl)‐3 H‐benzimidazol‐1‐ium mono/dihexafluorophosphate with Hg(OAc)2/Ag2O in acetonitrile. Two of the benzimidazolium salts were structurally characterized by single crystal X‐ray diffraction technique. Structures of reported compounds were characterized by 1 H, 13C NMR, FT‐IR, UV–visible spectroscopic techniques, and molar conductivity and elemental analyses. For bis‐benzimidazolium salt, dinuclear Hg(II)– and Ag(I)–carbene complexes were obtained. Nuclease activity and binding interactions of the synthesized benzimidazolium salts and their Ag(I)–carbene complexes with DNA were studied using agarose gel electrophoresis and, absorption spectroscopy and viscosity measurements, respectively. Ag(I)–carbene complexes showed higher DNA binding activity compared to their respective benzimidazolium salts. However, a benzimidazolium salt and two of the Ag(I) complexes showed remarkably higher nuclease activity both, in the presence and absence of an oxidizing agent. Copyright © 2012 John Wiley & Sons, Ltd.