ABSTRACT
Electrochemical study of mefenamic acid (MFA) was carried out with details in water/ethanol mixture by the various voltammetric techniques. The results showed that the oxidation of MFA is highly dependent on pH and follows the Eir mechanism. The EpA1-pH diagram plotted based on the differential pulse voltammograms shows two linear segments, 66 and 26 mV/pH slope. Also, the diffusion coefficient and the surface excess, Ó¶* of MFA in aqueous buffered solution, determined by using the single potential-step chronoamperometry and chronocoulometry methods. Electrochemical nitration of MFA in an aqueous solution and the presence of nitrite ion (1) were both investigated by the cyclic voltammetry and controlled-potential coulometry techniques. Our results indicate that the oxidized form of MFA participates in a Michael-type addition reaction with nitrite ion (1) to form the corresponding Nitromefenamic acids (MFA-4-NO2 and MFA-5-NO2). Also, in another part, a computational study based on the density functional theory (DFT/B3LYP) was performed for the prediction of the best possible pathway in the nucleophilic addition of nitrite ion (1). The electrochemical reduction of produced nitromefenamic acids was investigated using cyclic voltammetry and controlled-potential coulometry techniques. Eventually, two new azo derivatives have been generated via electroreduction of produced nitromefenamic acids and conduction of diazotization reaction, respectively. Both nitro and azo products are approved as paints.
ABSTRACT
With the aim of obtaining information about drug-drug interaction (DDI) between acetaminophen and some of antidepressant drugs (fluoxetine, sertraline and nortriptyline), in the present work we studied the electrochemical oxidation of acetaminophen (paracetamol) in the presence of these drugs by means of cyclic voltammetry and Controlled-potential coulometry. The reaction between N-acetyl-p-benzoquinone-imine (NAPQI) produced from electrooxidation of acetaminophen and antidepressant drugs (see scheme 1) cause to reduce the concentration of NAPQI and decreases the effective concentration of antidepressants. The cyclic voltammetric data were analyzed by digital simulation to measure the homogeneous parameters for the suggesting electrode mechanism. The calculated observed homogeneous rate constants [Formula: see text] for the reaction of electrochemically generated N-acetyl-para benzoquinn-imine with antidepressant drugs was found to vary in the order [Formula: see text] > [Formula: see text] > [Formula: see text] at biological pH.
ABSTRACT
The reaction of K2[PdCl4] and PdCl2 with 5-methyl-5-(4-pyridyl)-2,4-imidazolidenedione (L) proceeded with the formation of two different Pd complexes, PdL2Cl2 (1) and PdL2Cl4 (2c), corresponded to a substitution reaction and a substitution reaction along with unanticipated oxidation, respectively. The nature of the oxidizing agent is unknown. These compounds have been studied by elemental analysis, IR, (1)H and (13)CNMR, molar conductivity, and cyclic voltammetry. In addition, structural optimization by DFT calculations and simulation of NMR spectra have been performed and compared with the experimental data. NBO analysis, HOMO and LUMO, have been used to elucidate the information regarding charge transfer within the molecules. Theoretical studies confirmed that in 1 and 2c the trans structures are about 41 and 33 kJ mol(-1) more stable than cis ones. Antibacterial activity and in vitro cytotoxicity of these compounds, as respectively assessed in six bacterial strains and two human tumor cell lines, have been investigated. Results showed the title complexes have the capacity of inhibiting the metabolic growth of bacteria and tumor cells to different extents.
