Thermodynamic characteristics of NADH/NAD+ analogues in acetonitrile: 2-methyl, 4-methyl and 2,4-dimethyl 1-benzyl-dihydronicotinamides and the corresponding pyridinium species

1995 ◽  
Vol 73 (4) ◽  
pp. 531-538 ◽  
Author(s):  
Agnès Anne ◽  
Jacques Moiroux
Keyword(s):  
Cyclic Voltammetry ◽  
Hydride Transfer ◽  
Thermodynamic Characteristics ◽  
Redox Potentials ◽  
Methyl Substitution ◽  
Cation Radicals ◽  
Reduction Potentials ◽  
Electron Reduction ◽  
Transfer Thermodynamics ◽  
Electron Transfers

Procedures were elaborated for the syntheses of the title compounds. The thermodynamic changes brought about by each methyl substitution were then determined quantitatively. In acetonitrile, the respective one-electron oxidation and one-electron reduction potentials of the NADH and NAD+ analogues were obtained by means of direct and indirect (using ferrocene mediators) cyclic voltammetry. The redox potentials of formal hydride transfers were deduced from the studies of equilibrated reactions occurring between the analogues. The pKa's of the cation radicals ensued. Keywords: NADH/NAD+ methylated analogues, one-electron transfers, hydride transfer, thermodynamics.

scholarly journals One-Electron Reduction Potentials: Calibration of Theoretical Protocols for Morita–Baylis–Hillman Nitroaromatic Compounds in Aprotic Media

Molecules ◽  
2018 ◽  
Vol 23 (9) ◽  
pp. 2129 ◽  
Author(s):  
Amauri Francisco da Silva ◽  
Antonio João da Silva Filho ◽  
Mário Vasconcellos ◽  
Otávio Luís de Santana
Keyword(s):  
Cyclic Voltammetry ◽  
Biological Activity ◽  
Chemical Structure ◽  
Reduction Potential ◽  
Chemical Reactivity ◽  
Nitroaromatic Compounds ◽  
Reduction Potentials ◽  
Electron Reduction ◽  
The One ◽  
Antileishmanial Activities

Nitroaromatic compounds—adducts of Morita–Baylis–Hillman (MBHA) reaction—have been applied in the treatment of malaria, leishmaniasis, and Chagas disease. The biological activity of these compounds is directly related to chemical reactivity in the environment, chemical structure of the compound, and reduction of the nitro group. Because of the last aspect, electrochemical methods are used to simulate the pharmacological activity of nitroaromatic compounds. In particular, previous studies have shown a correlation between the one-electron reduction potentials in aprotic medium (estimated by cyclic voltammetry) and antileishmanial activities (measured by the IC50) for a series of twelve MBHA. In the present work, two different computational protocols were calibrated to simulate the reduction potentials for this series of molecules with the aim of supporting the molecular modeling of new pharmacological compounds from the prediction of their reduction potentials. The results showed that it was possible to predict the experimental reduction potential for the calibration set with mean absolute errors of less than 25 mV (about 0.6 kcal·mol−1).

scholarly journals Mutually Isomeric 2- and 4-(3-Nitro-1,2,4-triazol-1-yl)pyrimidines Inspired by an Antimycobacterial Screening Hit: Synthesis and Biological Activity against the ESKAPE Panel of Pathogens

Antibiotics ◽  
2020 ◽  
Vol 9 (10) ◽  
pp. 666
Author(s):  
Sergey Chuprun ◽  
Dmitry Dar’in ◽  
Elizaveta Rogacheva ◽  
Liudmila Kraeva ◽  
Oleg Levin ◽  
...  
Keyword(s):  
Cyclic Voltammetry ◽  
Antibacterial Activity ◽  
Reduction Potential ◽  
Gram Negative ◽  
Reduction Potentials ◽  
Apparent Correlation ◽  
Electron Reduction ◽  
Activity Loss ◽  
Eskape Pathogens ◽  
Bioactivity Profile

Starting from the structure of antimycobacterial screening hit OTB-021 which was devoid of activity against ESKAPE pathogens, we designed, synthesized and tested two mutually isomeric series of novel simplified analogs, 2- and 4-(3-nitro-1,2,4-triazol-1-yl)pyrimidines, bearing various amino side chains. These compounds demonstrated a reverse bioactivity profile being inactive against M. tuberculosis while inhibiting the growth of all ESKAPE pathogens (with variable potency patterns) except for Gram-negative P. aeruginosa. Reduction potentials (E1/2, V) measured for selected compounds by cyclic voltammetry were tightly grouped in the −1.3–−1.1 V range for a reversible single-electron reduction. No apparent correlation between the E1/2 values and the ESKAPE minimum inhibitory concentrations was established, suggesting possible significance of other factors, besides the compounds’ reduction potential, which determine the observed antibacterial activity. Generally, more negative E1/2 values were displayed by 2-(3-nitro-1,2,4-triazol-1-yl)pyrimidines, which is in line with the frequently observed activity loss on moving the 3-nitro-1,2,4-triazol-1-yl moiety from position 4 to position 2 of the pyrimidine nucleus.

scholarly journals Inhibition of plant fatty acid synthesis by nitroimidazoles

1981 ◽  
Vol 198 (1) ◽  
pp. 193-198 ◽  
Author(s):  
A V Jones ◽  
J L Harwood ◽  
M R Stratford ◽  
P K Stumpf
Keyword(s):  
Fatty Acid ◽  
Fatty Acid Synthesis ◽  
Soluble Fraction ◽  
Acid Synthesis ◽  
Long Chain Fatty Acids ◽  
Reduction Potentials ◽  
Marked Inhibition ◽  
Mechanism Of Inhibition ◽  
Pea Seeds ◽  
Electron Reduction

1. The effect of the addition of a number of nitroimidazoles was tested on fatty acid synthesis by germinating pea seeds, isolated lettuce chloroplasts and a soluble fraction from pea seeds. 2. All the compounds tested had a marked inhibition on stearate desaturation by lettuce chloroplasts and on the synthesis of very-long-chain fatty acids by pea seeds. 3. In contrast, the effect of the drugs on total fatty acid synthesis from [14C]acetate in chloroplasts was related to the compound's electron reduction potentials. 4. Of the compounds used, only metronidazole had a marked inhibition on palmitate elongation in the systems tested. 5. The mechanism of inhibition of plant fatty acid synthesis by nitroimidazoles is discussed and the possible relevance of these findings to their neurotoxicity is suggested.

Effect of NO2 substitution and solvent on UV-visible spectra, redox potentials and electron transfer mechanisms of copper β-nitrotriarylcorroles. Proposed electrogeneration of a Cu(I) oxidation state

2016 ◽  
Vol 20 (07) ◽  
pp. 753-765 ◽  
Author(s):  
Lina Ye ◽  
Zhongping Ou ◽  
Yuanyuan Fang ◽  
Yang Song ◽  
Bihong Li ◽  
...  
Keyword(s):  
Absorption Spectra ◽  
Soret Band ◽  
Redox Potentials ◽  
Nonaqueous Media ◽  
Initial Assignment ◽  
Visible Spectra ◽  
Phenyl Rings ◽  
Uv Visible ◽  
Electron Reduction ◽  
Transfer Mechanisms

Three copper triarylcorroles containing a [Formula: see text]-pyrrole nitro substituent were synthesized and characterized as to their spectral and electrochemical properties in nonaqueous media. The examined compounds are represented as [Formula: see text]-NO2(YPh)3CorCu, where Cor is the trianion of a triphenylcorrole and Y is a Cl, H or CH3 substituent at the para-position of the three meso-phenyl rings of the compound. The data from absorption spectra, electrochemistry and thin-layer spectroelectrochemistry are consistent with an initial assignment of Cu[Formula: see text]-Cor[Formula: see text] in CH2Cl2, DMF and pyridine and electrogeneration of a formal Cu(II) corrole with an unreduced macrocycle, represented as Cu[Formula: see text]-Cor[Formula: see text], after the first one-electron reduction in these solvents. The doubly reduced [Formula: see text]-nitrocorrole has a sharp Soret band at 439 nm and a well-defined Q-band at 611 nm in CH2Cl2. Similar absorption spectra are seen for the three examined doubly reduced nitrocorroles in DMF and pyridine, suggesting formation of a Cu(I) species with an unreduced macrocycle which is represented as Cu[Formula: see text]-Cor[Formula: see text]. Changes in redox potentials and absorption spectra of the nitrocorroles are examined as a function of solvent and substituents on the meso-phenyl rings of the compounds and comparisons are made between spectral and electrochemical data of the newly synthesized corroles and that of structurally related tetraarylcorroles lacking a [Formula: see text]-nitro group.

The influence of the host–guest interaction on the oxidation of natural flavonoid dyes

2011 ◽  
Vol 76 (12) ◽  
pp. 1651-1667 ◽  
Author(s):  
Šárka Ramešová ◽  
Romana Sokolová ◽  
Ilaria Degano ◽  
Magdaléna Hromadová ◽  
Miroslav Gál ◽  
...  
Keyword(s):  
Cyclic Voltammetry ◽  
Inclusion Complex ◽  
Fluorescence Intensity ◽  
Oxidation Product ◽  
Aqueous Media ◽  
Electrochemical Methods ◽  
Redox Potentials ◽  
Decomposition Products ◽  
Degradation Processes ◽  
Bioorganic Compounds

The influence of the molecular cavity protection on degradation processes of bioorganic compounds quercetin and luteolin used as the original dyes in old tapestries was studied. The degradation processes were studied by electrochemical methods in aqueous media. The products of the exhaustive electrolysis were separated and identified by GC-MS analysis. Cyclic voltammetry characteristics indicate that the inclusion complex is formed. The inclusion affects the redox potentials of both oxidation waves related to the different dissociation forms of the flavonoid molecule. It was shown that decomposition products formed by the oxidation of quercetin are stabilized in the cavity of β-cyclodextrin, including the main oxidation product 2(3′,4′-dihydroxybenzoyl)-2,4,6-trihydroxybenzofuran-3(2H)-one. The formation of the 1:1 inclusion complex of luteolin with β-cyclodextrin is supported by the enhancement of fluorescence intensity. In the case of quercetin, a decrease of fluorescence intensity occurs when 1:1 inclusion complex with β-cyclodextrin is formed.

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