Recent Developments in the Electrochemistry of Some Nitro Compounds of Biological Significance

Abstract

The redox chemistry of different nitro compounds of biological significance is focused to understand how the reduction of the nitro group can play an active role in several aspects as: electroanalytical determinations, free radical generation and stability and free radical reactivity. We have focused our studies to a lot of pharmaceuticals belonging mainly to the following families: calcium antagonists as nitrobenzene substituted 1,4-dihydropyridines, antibacterial and anti protozoan agents as nitroimidazoles and nitrofurans.The formation of the nitro radical anion as the product of the one electron reduction of nitro compounds generates a series of important consequences passing from chemical to biological aspects. We have used electrochemical techniques to study the formation, stability and reactivity of this nitro radical anion in different media. From cyclic voltammetric experiments it is possible qualitatively to visualize the formation of the nitro radical anion through the one-electron reversible couple due to the redox system nitro / nitro radical anion . Furthermore also is possible the quantitative determination of the kinetic rate constant of the nitro radical anion decay and the interaction constants with other molecules. Although substituents may affect the redox potential and consequently the stability or reactivity of the nitro radical anions, other factors are important in regulation of these properties. Among these factors, it is possible to mention the nature of the reaction media making possible the occurrence of intermolecular reactions of the father-son type between the nitro radical anion and an acidic hydrogen present in the molecules.

Cyclic Voltammetric Study of Some Anti‐Chagas‐Active 1,4‐Dioxidoquinoxalin‐2‐yl Ketone Derivatives

“…chloro, fluoro, difluoromethyl, and trifluoromethyl) or an electron-releasing group (i.e. methyl and methoxy) onto the conjugated quinoxaline ring have been reported in previous studies [7,12,13,14,16,17,18]. The present study correlates well with these earlier reports on the structural effects on potential.…”

“…In this publication, we have demonstrated that our quinoxaline derivatives affect the mitochondrial dehydrogenase activity [6]. Therefore, electrochemistry plays an important role when studying the formation of this radical species and its reactivity in one-pot systems [7]. The purpose of the present study was to investigate the electrochemical properties of a series of quinoxaline-di-N-oxide-2-ketone derivatives, and determine the possible relationship between their reduction potentials, their structure and their anti-chagasic activity.…”

Electrochemical Reduction Using Glassy Carbon Electrode in Aqueous Medium of a Potential Anti-Chagas Drug: NFOH

“…For this, a convenient experimental condition ͑aprotic medium, mixed solvents, alkaline-pH medium͒, in which the low disponibility of protons favors the R-NO 2 •− kinetic stability, is necessary. 11 Under such conditions, the electrochemical behavior of NF has been extensively studied by using working electrodes such as mercury, [12][13][14][15] gold, 14 glassy carbon, 14,16 and boron-doped diamond. 17,18 The molecular modification has been the most promising approach to introduce drugs in therapeutics and to obtain better drugs.…”

Rapid and Sensitive Voltammetric Determination of Aclonifen in Water Samples

“…[28][29][30][31] In the first pathway (Equation (4) and (5)), reversible formation of one-electron nitro radical anion is followed by irreversible three-electron reduction. As the stability of ArNO 2 · is increased by the absence of In the second possible pathway (Equation (6) and (7)), four-electron reduction of NO 2 to NHOH (Equation (6)) and two-electron reduction of NHOH to NH 2 (Equation (7)) takes place.…”