Oxidation of quinolones with peracids (an in situ EPR study)

Authors

  • Andrej Staško,

    1. Faculty of Chemical and Food Technology, Institute of Physical Chemistry and Chemical Physics, Slovak University of Technology in Bratislava, Bratislava, Slovak Republic
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  • Viktor Milata,

    1. Faculty of Chemical and Food Technology, Institute of Organic Chemistry, Catalysis and Petrochemistry, Slovak University of Technology in Bratislava, Bratislava, Slovak Republic
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  • Zuzana Barbieriková,

    1. Faculty of Chemical and Food Technology, Institute of Physical Chemistry and Chemical Physics, Slovak University of Technology in Bratislava, Bratislava, Slovak Republic
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  • Vlasta Brezová

    Corresponding author
    1. Faculty of Chemical and Food Technology, Institute of Physical Chemistry and Chemical Physics, Slovak University of Technology in Bratislava, Bratislava, Slovak Republic
    • Correspondence to: Vlasta Brezová, Faculty of Chemical and Food Technology, Institute of Physical Chemistry and Chemical Physics, Slovak University of Technology in Bratislava, Radlinského 9, SK-812 37 Bratislava, Slovak Republic. E-mail: vlasta.brezova@stuba.sk

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Abstract

4-Oxoquinoline derivatives (quinolones) represent heterocyclic compounds with a variety of biological activities, along with interesting chemical reactivity. The quinolone derivatives possessing secondary amino hydrogen at the nitrogen of the enaminone system are oxidized with 3-chloroperbenzoic acid to nitroxide radicals in the primary step while maintaining their 4-pyridone ring. Otherwise, N-methyl substituted quinolones also form nitroxide radicals coupled with the opening of the 4-pyridone ring in a gradual oxidation of the methyl group via the nitrone–nitroxide spin-adduct cycle. This was confirmed in an analogous oxidation using N,N-dimethylaniline as a model compound. N-Ethyl quinolones in contrast to its N-methyl analog form only one nitroxide radical without a further degradation. Copyright © 2013 John Wiley & Sons, Ltd.

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