Etude theorique de mecanismes E.C. par chronopotentiometrie en couche mince. Application a la reduction du nitrosobenzene

Vallat, A.; Sureau-Doucet, A.; Person, M.; Laviron, E.

doi:10.1016/0013-4686(84)80035-3

Cited by 5 publications

(4 citation statements)

References 9 publications

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“…Two facts support formation of the cyclic nitrone: (a) absence of the reduction wave of the carbonyl group present in the product of reactions (1 1) and (12) and (b) strictly 4 : 2 : 2 ratio for il : is : i6.…”

Section: N--qmentioning

confidence: 85%

“…For similar reasons, it is impossible to exclude the possibility of further intramolecular condensation of the nitrone formed in reaction (15): (15) If this eight-membered cyclic compound is formed, wave is again corresponds to a reduction of the N -0 , wave i6 to that of the C = N bonds. Two facts support formation of the cyclic nitrone: (a) absence of the reduction wave of the carbonyl group present in the product of reactions (1 1) and (12) and (b) strictly 4 : 2 : 2 ratio for il : is : i6.…”

Section: N--qmentioning

confidence: 92%

“…With increasing pH, the decreasing wave il+L is gradually replaced by a four--electron wave i3 at more negative potentials (Fig,ure 4. curves [7][8][9][10][11][12], the half-wave potential of which remain:; pH-independent ( Figure 5A). …”

Section: Direct Current Polarograpby Of Anthranil (Iii)mentioning

confidence: 99%

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Polarographic and electrochemical studies of some aromatic and heterocyclic nitro compounds: Part VI. Polarographic, voltammetric, and controlled potential reduction of ortho‐nitrobenzaldehyde anthranil

Fijałek

Zuman

1993

Electroanalysis

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In acidic media, at pH < 7, the nitro group, in ortho-nitrobenzaldehyde (I) is reduced in a fourelectron step to ortho-formylphenylhydroxylamine (11). The protonated form of I1 is reduced by two electrons to ortho-aminobenzaldehyde (IV), which is further reduced in a two-electron process to ortho-aminobenzylalcohol. At pH > 7, the arylhydroxylamine (11) condenses to form a nitrone, which is further reduced in two two-electron waves, corresponding to the cleavage of the N -0 bond and reduction of the azomethine bond. At pH 7, formation of anthranil (111) from I1 is a relatively slow process: in cyclic voltammetry (CV) and d.c. polarography, I1 is further reduced to IV; in controlled potential electrolysis at a mercury pool electrode, the same products are obtained at 0" C, but at 25" C, III is the predominant product.

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Section: N--qmentioning

confidence: 85%

Section: N--qmentioning

confidence: 92%

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Polarographic and electrochemical studies of some aromatic and heterocyclic nitro compounds: Part VI. Polarographic, voltammetric, and controlled potential reduction of ortho‐nitrobenzaldehyde anthranil

Fijałek

Zuman

1993

Electroanalysis

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“…[15] Even though most of the studies have been performed from the electrosynthetic point of view, [16][17] the chemical reduction of nitrobenzene to phenylhydroxylamine has been also performed using reductants or catalysts. [18][19][20] In this regard, the electrochemical reduction of nitrosobenzene (PhNO) has been also studied due to its importance as intermediate precursor of most of the final products obtained by reduction of nitrobenzene, either in aqueous media [21][22][23] or in solvents like dimethylformamide, [24,25] acetonitrile, [26][27][28][29] DMSO, [30][31] mixtures of solvents [32,33] and liquid ammonia. [34] In presence of proton donors, the electrochemical reduction of nitrosobenzene is simpler with respect to that of nitrobenzene in the sense that its reduction involves the half of the electron and proton transfer steps (Eq.…”

Section: Introductionmentioning

confidence: 99%

Revisiting the Electrochemical Reduction Mechanism of Nitrosobenzene in Acetonitrile. Concomitant Reactions and Voltammetric Simulation

Palacios‐Ramírez,

González

2024

ChemElectroChem

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The electrochemical reduction mechanism of nitrosobenzene in acetonitrile was reconsidered in this work. The commonly accepted mechanism assumes that the nitrosobenzene radical anion dimerize to yield a dianion, which decompose into azoxybenzene as the reduction product. Even though this proposal is consistent with preparative experiments, it does not reproduce fully the experimental voltammetric behaviour when it is simulated. Also, It does not explain why the apparent electron number is different in the time scale of cyclic voltammetry and preparative electrolysis. To understand these discrepancies, it was proposed the intervention of reactions consuming part of the starting nitrosobenzene, which allowed to reconsider the role of alternative chemical reactions like that occurring between the anion of phenylhydroxylamine with nitrosobenzene and the hydroxyl ion with nitrosobenzene. In this framework, these concomitant reactions were additionally included in the mechanism to simulate the voltammetric behaviour at different scan rates. Thermodynamic and kinetic parameters of the extended mechanism are reported. Since in the hydroxyl ion is either product or reactive in some reaction steps, the global mechanism was deemed to occurs as a kind of loop.

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Polarographic and electrochemical studies of some aromatic and heterocyclic nitro compounds, part I: General mechanistic aspects

et al. 1992

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ABSTRrlCTComparing reduction potentials of aromatic nitro compounds with those of corresponding nitroso compounds, by studying shifts o f half-wave and peak potentials with pH and by following the decrease of limiting current in buffered 35% DMF-water mixtures, the sequence of protons and electrons in the fourelectron reduction step was proved to be: H ', e, H ', c, Ze, 2H+. Arylhydroxylamines formed in the fourelectron reduction of nitro compounds can be protonated and further reduced, they can undergo dehydration (provided that the dehydration product is stable), they can undergo chemical reactions with intermediates of the reduction of the nitro group, like ArNO, they can be electrooxidized to nitrosobenzenes (which can undergo chemical reactions) or they can react with carbony1 groups when present. Stabilization of the dehydrated form can occur in quinonemethide (nifedipine) o r in some quinone-like heterocyclic derivatives. Side reactions of ArNHOH and ArNO are demonstrated by smaller peaks in CV and by controlled potential electrolysis. Reactions of ArNHOH with carbony1 groups were observed by formation of new waves of nitrones in the reduction of nitrobenzenaldehydes.

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Etude theorique de mecanismes E.C. par chronopotentiometrie en couche mince. Application a la reduction du nitrosobenzene

Cited by 5 publications

References 9 publications

Polarographic and electrochemical studies of some aromatic and heterocyclic nitro compounds: Part VI. Polarographic, voltammetric, and controlled potential reduction of ortho‐nitrobenzaldehyde anthranil

Polarographic and electrochemical studies of some aromatic and heterocyclic nitro compounds: Part VI. Polarographic, voltammetric, and controlled potential reduction of ortho‐nitrobenzaldehyde anthranil

Revisiting the Electrochemical Reduction Mechanism of Nitrosobenzene in Acetonitrile. Concomitant Reactions and Voltammetric Simulation

Polarographic and electrochemical studies of some aromatic and heterocyclic nitro compounds, part I: General mechanistic aspects

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