The Oxidative Conversion of Hydroquinone Monophosphates to Quinone Ketals<sup>*</sup>

Duerckheimer, W.; La, Cohen

doi:10.1021/bi00900a028

Cited by 23 publications

(6 citation statements)

References 6 publications

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“…A variety of other 4,4-disubstituted 2,5-cyclohexadienone imines have been observed to split off the imino group upon acidification, yielding the respective cyclohexadienone derivative. However, formation of 4,4-dimethoxycyclohexa-2,5-dienone or its subsequent hydrolysis product 1,4-benzoquinone ( , ) could not be traced during acid hydrolysis of Me 2 -ketal, as proved with authentic standards. Another ketal derivative, Et 2 -ketal, resulting from reaction of NOPt with GSH in EtOH, liberated only NH 2 Pt and the quinonimine GS-QI upon acidification.…”

Section: Resultsmentioning

confidence: 97%

Formation of 4,4-Dialkoxycyclohexa-2,5-dienone N-(Thiol-S-yl)imine during Reaction of 4-Alkoxynitrosobenzenes with Thiols in Alcoholic Solvents

Gallemann

Greif

Eyer

et al. 1998

Chem. Res. Toxicol.

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During the interaction of nitrosoarenes with glutathione in aqueous media, intermediate generation of a highly resonance-stabilized sulfenamide cation has been repeatedly suggested. Most intermediates and end products could be explained by reactions of this sulfenamide cation with different nucleophiles such as excess thiol, solvent water, and metabolically produced arylamine. The present paper presents evidence for adduct formation of the sulfenamide cation with solvent alcohol at neutral pH. Sulfenamide cations generated from 4-nitrosophenetole and 4-nitrosoanisole, respectively, are strongly suggested to form the metastable ketals 4-ethoxy-4-methoxycyclohexa-2,5-dienone N-(glutathion-S-yl)imine and 4,4-dimethoxycyclohexa-2,5-dienone N-(glutathion-S-yl)imine, respectively, during reaction with solvent methanol. Reaction of the two sulfenamide cations in ethanol yielded 4,4-diethoxycyclohexa-2, 5-dienone N-(glutathion-S-yl)imine and 4-ethoxy-4-methoxycyclohexa-2, 5-dienone N-(glutathion-S-yl)imine, respectively. Although the metastability of the ketals did not allow isolation of pure solid material, chromatographic and chemical behavior as well as tandem MS fragmentation substantiate a ketal structure of these intermediates. To confirm the proposed structure, new compounds, 2, 6-dimethyl-4-nitrosophenetole, 2,6-dimethyl-4-nitrophenetole, 2, 6-dimethyl-4-phenetidine, and N-(glutathion-S-yl)-N-hydroxy-4-aminoacetophenone, were synthesized and included in supportive experiments. In summary, the detection of ketals corroborates once more the occurrence of a sulfenamide cation which obviously not only reacts with soft nucleophiles such as GSH but, to a limited extent, also reacts with hard nucleophiles. The toxicological significance of this result is discussed.

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Section: Resultsmentioning

confidence: 97%

Formation of 4,4-Dialkoxycyclohexa-2,5-dienone N-(Thiol-S-yl)imine during Reaction of 4-Alkoxynitrosobenzenes with Thiols in Alcoholic Solvents

Gallemann

Greif

Eyer

et al. 1998

Chem. Res. Toxicol.

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“…A solution to this problem was the use of cerium ammonium nitrate (CAN) in methanol, which afforded the dimethyl acetal of p-benzoquinone. 66 Nicolaou and coworkers applied the CAN oxidation to para-dialkoxybenzenes using ethylene glycol as a co-solvent in their studies toward the synthesis of esperamicinone (Scheme 42). 67 Formation of the ketone was a result of acetonide collapse induced by oxidation of the aromatic ring.…”

Section: Scheme 41mentioning

confidence: 99%

Oxidative Spiroacetalizations and Spirolactonizations of Arenes

Rodrı́guez¹,

Wipf²

2004

Synthesis

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Oxidative methods for arene spiroacetalization and spirolactonization provide highly functionalized intermediates for organic synthesis. In addition to metal salts, electrochemical oxidations, quinones and, especially, hypervalent iodine reagents allow selective transformations on the arene core structures while tolerating many other functional groups. This review discusses oxidative processes for spiroacetal and spirolactone synthesis, including selective and historically significant examples of monocyclic and fused ring product formations.

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“…The appearance of Pi in the medium is observed to be dependent on oxygen uptake, indicating that this is a genuine oxidative dephosphorylation and thus that conditions exist under which the quinol phosphate can, but not must, function as a phosphorylating agent (Clark et al 1958;Wieland & Pattermann, 1958). In chemical systems a large part of the Pi formed on quinol phosphate oxidation is produced directly by C-O bond fission (Durkheimer & Cohen, 1964;Lapidot & Samuel, 1964), and in such cases the quinol phosphate does not, of course, function as a phos-phorylating agent. However, Wodak (1968) has shown that the enzymic oxidation of duroquinol monophosphate by horseradish peroxidase + hydrogen peroxide proceeds almost exclusively with P-O bond fission, i.e.…”

Section: Quinolpho8phateoxidationandphosphoryltransfermentioning

confidence: 99%

The mitochondrial oxidation of quinol monophosphates

Young

1970

Biochemical Journal

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1. Mitochondria from ox heart and rat liver catalysed a slow cyanide-sensitive oxidation of 2,3-dimethylnaphthaquinol monophosphate, duroquinol monophosphate, menadiol 1-phosphate and menadiol 4-phosphate. 2. The release of P(i) was concomitant with oxygen uptake. 3. The oxidation was somewhat stimulated by Ca(2+) and P(i), and weakly inhibited by 2,4-dinitrophenol. 4. The quinol monophosphates effected a rapid reduction of free cytochrome c, and consequently addition of cytochrome c greatly increased the rate of the mitochondrial oxidation of 2,3-dimethylnaphthaquinol monophosphate. 5. This quinol phosphate interacts with the electron-transport chain at the level of cytochrome c. 6. Polylysine promoted an interaction between 2,3-dimethylnaphthaquinol monophosphate and cytochrome oxidase. Thus, although polylysine blocks mitochondrial oxidations via reduced cytochrome c, the oxidation of the quinol phosphate was strongly stimulated. 7. This stimulation was most effective in the most intact mitochondrial preparations and was inhibited by ADP and by P(i). 8. The implications of these results for factors limiting the rate of quinol phosphate oxidation, the mode of action of stimulators and the mechanism of P(i) formation are discussed.

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The Oxidative Conversion of Hydroquinone Monophosphates to Quinone Ketals^*

Cited by 23 publications

References 6 publications

Formation of 4,4-Dialkoxycyclohexa-2,5-dienone N-(Thiol-S-yl)imine during Reaction of 4-Alkoxynitrosobenzenes with Thiols in Alcoholic Solvents

Formation of 4,4-Dialkoxycyclohexa-2,5-dienone N-(Thiol-S-yl)imine during Reaction of 4-Alkoxynitrosobenzenes with Thiols in Alcoholic Solvents

Oxidative Spiroacetalizations and Spirolactonizations of Arenes

The mitochondrial oxidation of quinol monophosphates

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The Oxidative Conversion of Hydroquinone Monophosphates to Quinone Ketals*

Cited by 23 publications

References 6 publications

Formation of 4,4-Dialkoxycyclohexa-2,5-dienone N-(Thiol-S-yl)imine during Reaction of 4-Alkoxynitrosobenzenes with Thiols in Alcoholic Solvents

Formation of 4,4-Dialkoxycyclohexa-2,5-dienone N-(Thiol-S-yl)imine during Reaction of 4-Alkoxynitrosobenzenes with Thiols in Alcoholic Solvents

Oxidative Spiroacetalizations and Spirolactonizations of Arenes

The mitochondrial oxidation of quinol monophosphates

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The Oxidative Conversion of Hydroquinone Monophosphates to Quinone Ketals^*