The mechanisms of the oxidation of NADH analogues 1. Photochemical oxidation of N-unsubstituted 1,4-dihydropyridines by various acceptors

Taraban, Marc B.; Kruppa, Alexander I.; Polyakov, N.E.; Leshina, Tatyana V.; Lusis, V. K.; Muceniece, D.; Дубурс, Г.

doi:10.1016/1010-6030(93)80044-a

Cited by 29 publications

(23 citation statements)

References 14 publications

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“…The decarboxylation reaction is a well known process when aromatic carboxylic acids are irradiated with UV light source (29–31). On the other hand, the hydrogen abstraction from the N‐1 position of dihydropyridines has been well established during the photooxidation by electron acceptors (32).…”

Section: Resultsmentioning

confidence: 99%

Photophysics and Photochemical Studies of 1,4-Dihydropyridine Derivatives

Pavez

Encinas²

2007

Photochemistry and Photobiology

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The absorption and fluorescence properties of nifedipine (NPDHP), felodipine (CPDHP) and a series of structurally related 1,4-dihydropyridines were studied in aqueous solution and organic solvents of different properties. The absorption and fluorescence spectra were found to depend on the chemical nature of the substituents at the position 4 of the 1,4-dihydropyridine ring (DHP) and on solvent properties. In aqueous solution, the fluorescence spectra of 4-phenyl substituted compounds are blue-shifted with respect to the alkyl substituted compounds. The more fluorescent compound is CPDHP. Nifedipine is not fluorescent. All compounds, with the exception of CPDHP, present monoexponential fluorescence decay with very short lifetime (0.2-0.4 ns). CPDHP showed a biexponential emission decay with a long-lived component of 1.7 ns; this behavior is explained in terms of different conformers because of the hindered rotation of the phenyl group by the ortho-substitution. Analysis of the solvent effect on the maximum of the absorption spectrum by using the linear solvent-energy relation solvato-chromic equation indicates the redshifts are influenced by the polarizability, hydrogen bonding ability and the hydrogen bond acceptance of the solvent. Whereas, the fluorescence characteristics (spectra, quantum yields and lifetimes) are sensitive to the polarizabilty and hydrogen bond ability of the solvents. Photo-decomposition of nifedipine is dependent on the solvent properties. Faster decomposition rates were obtained in nonprotic solvents. The 4-carboxylic derivative goes to decarboxylation. Under similar conditions, the other DHP compounds did not show appreciable photodecomposition.

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Section: Resultsmentioning

confidence: 99%

Photophysics and Photochemical Studies of 1,4-Dihydropyridine Derivatives

Pavez

Encinas²

2007

Photochemistry and Photobiology

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“…An additional molecular model system for studying the antioxidant activity of DFRA was the oxidation of DHP. The reactions involving DHP are often used as models of radical processes of electron and proton transfer in living systems with the participation of NADH [ 54 , 55 ]. Dihydropyridine was chosen for the studies because is capable of reacting with various radicals, including the OH radical.…”

Section: Resultsmentioning

confidence: 99%

“…In this case, the OH radical first reacts with the solvent CD 3 OD producing ● CD 2 OD C-centered radical [ 57 ]. As a result of hydrogen abstraction reaction by this radical, a neutral C-centered DHP radical is formed [ 54 ]. The main reaction product 1,1′-(2,6-dimethylpyridine-3,5-diyl)-di(propan-1-one) is formed via disproportionation reaction of two DHP radicals ( Figure 7 ).…”

Section: Resultsmentioning

confidence: 99%

Antioxidant Activity of Deferasirox and Its Metal Complexes in Model Systems of Oxidative Damage: Comparison with Deferiprone

et al. 2021

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Deferasirox is an orally active, lipophilic iron chelating drug used on thousands of patients worldwide for the treatment of transfusional iron overload. The essential transition metals iron and copper are the primary catalysts of reactive oxygen species and oxidative damage in biological systems. The redox effects of deferasirox and its metal complexes with iron, copper and other metals are of pharmacological, toxicological, biological and physiological importance. Several molecular model systems of oxidative damage caused by iron and copper catalysis including the oxidation of ascorbic acid, the peroxidation of linoleic acid micelles and the oxidation of dihydropyridine have been investigated in the presence of deferasirox using UV-visible and NMR spectroscopy. Deferasirox has shown antioxidant activity in all three model systems, causing substantial reduction in the rate of oxidation and oxidative damage. Deferasirox showed the greatest antioxidant activity in the oxidation of ascorbic acid with the participation of iron ions and reduced the reaction rate by about a 100 times. Overall, deferasirox appears to have lower affinity for copper in comparison to iron. Comparative studies of the antioxidant activity of deferasirox and the hydrophilic oral iron chelating drug deferiprone in the peroxidation of linoleic acid micelles showed lower efficiency of deferasirox in comparison to deferiprone.

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“…It is our suggestion that the interaction between NF and Tyr could involve an elementary step of the single‐electron transfer. In addition to the above theoretical considerations, this assumption has a number of experimental grounds because NF molecule incorporates both the nitrophenyl and dihydropyridine functions, whereas the nitroaromatics ( 8,9 ) and dihydropyridine ring ( 10–12 ) have known to enter the single‐electron transfer reactions with electron donors and acceptors, respectively.…”

Section: Resultsmentioning

confidence: 99%

“…Therefore, the use of the photo‐CIDNP method to generate the paramagnetic species and to study the detailed mechanisms of their transformations appears to be well founded. The CIDNP technique has been chosen because it is an extremely effective tool to study the mechanisms of complex chemical reactions involving paramagnetic intermediates ( 13, 14 ), in particular, the reactions of analogous 1,4‐dihydropyridines with various electron acceptors ( 10–12 ) and nitroaromatics with alcohols in solution ( 8 ). In addition, the application of TR CIDNP technique will allow to detect the polarizations manifested only by those diamagnetic products stemming from radical stages, thus revealing the targeted processes even in the presence of potent competing reaction pathway‐the direct phototransformation of NF to NONF.…”

Section: Resultsmentioning

confidence: 99%

Photo‐CIDNP Study of the Interaction of Tyrosine with Nifedipine. An Attempt to Model the Binding Between Calcium Receptor and Calcium Antagonist Nifedipine^¶

Polyakov

Taraban

Leshina

2004

Photochem & Photobiology

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This article proposes a new approach to the modeling of the molecular‐level mechanism of ligand‐receptor interaction for Ca2+ receptor binding site. Chemically induced dynamic nuclear polarization (CIDNP) technique has been used to unravel fine details of the reaction in the model system composed of one of the known Ca2+ antagonist drugs, nifedipine (NF), and isolated amino acid residuals (e.g. tyrosine [Tyr]) of Ca2+ receptor binding site. It has been conclusively demonstrated that the reaction between NF and Tyr resulting in the oxidation product—nitroso form of NF—obeys the radical mechanism. CIDNP data in combination with the results of mathematical modeling of the structures of ligandreceptor complexes have allowed to propose the mechanism of the interaction of NF with Ca2+ receptor binding site.

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The mechanisms of the oxidation of NADH analogues 1. Photochemical oxidation of N-unsubstituted 1,4-dihydropyridines by various acceptors

Cited by 29 publications

References 14 publications

Photophysics and Photochemical Studies of 1,4-Dihydropyridine Derivatives

Photophysics and Photochemical Studies of 1,4-Dihydropyridine Derivatives

Antioxidant Activity of Deferasirox and Its Metal Complexes in Model Systems of Oxidative Damage: Comparison with Deferiprone

Photo‐CIDNP Study of the Interaction of Tyrosine with Nifedipine. An Attempt to Model the Binding Between Calcium Receptor and Calcium Antagonist Nifedipine^¶

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The mechanisms of the oxidation of NADH analogues 1. Photochemical oxidation of N-unsubstituted 1,4-dihydropyridines by various acceptors

Cited by 29 publications

References 14 publications

Photophysics and Photochemical Studies of 1,4-Dihydropyridine Derivatives

Photophysics and Photochemical Studies of 1,4-Dihydropyridine Derivatives

Antioxidant Activity of Deferasirox and Its Metal Complexes in Model Systems of Oxidative Damage: Comparison with Deferiprone

Photo‐CIDNP Study of the Interaction of Tyrosine with Nifedipine. An Attempt to Model the Binding Between Calcium Receptor and Calcium Antagonist Nifedipine¶

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Photo‐CIDNP Study of the Interaction of Tyrosine with Nifedipine. An Attempt to Model the Binding Between Calcium Receptor and Calcium Antagonist Nifedipine^¶