Electrocatalytical Oxidation of Hydroquinone with Ferrocene Covalently Bound to L‐Cysteine Self‐Assembled Monolayers on a Gold Electrode

Kan, Xianwen; Deng, Xiang-hui; Zhang, Wenzhi; Wang, Guangfeng; Li, Maoguo; Tao, Haisheng; Fang, Bin

doi:10.1002/adic.200590068

Cited by 4 publications

(1 citation statement)

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“…Thiols are metabolized to sulfenic acids, which are unstable and readily undergo oxidation to their stable oxides, sulfinic and sulfonic acids, or combine with nucleophiles. Whereas there have been some studies on electrochemical oxidation of PTU, a lot of these studies were focusing on modifying electrodes to enhance electrocatalytic oxidation of PTU using cyclic voltammetry and differential pulse voltammetry. , Electrochemical oxidation of PTU is complicated by large overpotentials. Modified electrodes have been used due to their catalytic properties that lower the anodic overpotential and enhance the rate of electron transfer for the electrochemical oxidation of PTU.…”

Section: Introductionmentioning

confidence: 99%

Electrochemical versus Enzymatic in Vitro Oxidations of 6-propyl-2-thiouracil: Identification, Detection, and Characterization of Metabolites

Chipiso

Simoyi

2017

J. Phys. Chem. B

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6-Propylthiouracil, PTU, is a well-known antithyroid drug that has been the mainstay of treatment of Graves' disease. It is, however, also associated with liver toxicity and idiosyncratic toxicity. These toxicities are generally associated with metabolites derived from its bioactivation. In this manuscript, bioactivation of PTU was studied via two separate techniques: electrochemical oxidation and through the use of human liver microsomes. The aim of this work was to compare the bioactivation products of these two techniques. The electrochemical technique was studied online with a mass spectrometer, EC/ESI/MS. The microsomal oxidations were studied in tandem with liquid chromatography. The EC/ESI/MS technique was devoid of the normal reducing biological matrix prevalent in microsomal incubations. The predominant product at 400 mV was the dimeric PTU species with negligible formation of other metabolites. At higher potentials, complete desulfurization of PTU was observed with formation of sulfate. No sulfonic acid was observed, suggesting that the cleavage of the C-S bond was effected at the sulfinic acid stage, releasing a highly reducing sulfur species which is known to give rise to genotoxicity. The microsomal oxidations, surprisingly, showed formation of the unstable sulfenic acid, the S-oxide. Further incubation showed both the sulfinic and sulfonic acids. None of the systems showed any adducts with nucleophiles such as glutathione, showing that none of the reactive metabolites were stable enough to be adducted to nucleophiles in both the biological matrix and the electrochemical oxidizing environment.

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Section: Introductionmentioning

confidence: 99%