- Synthesis of Substituted 4-Arylamino-1,2-naphthoquinones in One-Pot Reactions Using CotA-Laccase as Biocatalyst
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An efficient and environmentally benign biocatalytic strategy for the synthesis of substituted 4-arylamino-1,2-naphthoquinones was developed, through a cross-coupling reaction in which the 1,2-naphthoquinone nucleus, formed in the biocatalytic process mediated by CotA-laccase from Bacillus subtilis, is the key synthetic intermediate. Electrochemical data and kinetic parameters were determined revealing a significant higher specificity of CotA-laccase for 4-amino-3-hydroxynaphthalene-1-sulfonic acid (AHNSA). This ability of CotA-laccase to discriminate between oxidisable aromatic amines allows the set-up of one-pot reactions in the presence of the enzyme, between AHNSA and a set of appropriate aromatic amines under mild reaction conditions. (Figure presented.).
- Sousa, Ana Catarina,Santos, Iolanda,Piedade,Martins, Lígia O.,Robalo, M. Paula
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p. 3380 - 3387
(2020/05/18)
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- Method for dyeing keratinous fibres using an aminoindole in combination with a quinone derivative
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Method for dyeing keratinous fibres, characterized in that at least one composition (A) containing at least one aminoindole in a medium appropriate for dyeing is applied to these fibres, the application of the composition (A) being preceded or followed by the application of a composition (B) containing, in a medium appropriate for dyeing, at least one quinone derivative chosen from ortho- or para-benzoquinones, ortho- or para-benzoquinone monoimines or diimines, 1,2- or 1,4-naphthoquinones, ortho- or para-benzoquinone sulphonimides, α,ω-alkylene-bis-1,4-benzoquinones, or 1,2- or 1,4-naphthoquinone monoimines or diimines, the aminoindoles and the quinone derivatives being chosen such that the difference in redox potential ΔE between the redox potential Ei of the aminoindoles, determined at pH 7 in a phosphate medium on a vitreous carbon electrode by voltametry, and the redox potential Eq of the quinone derivative, determined at pH 7 in a phosphate medium by polarography on a mercury electrode relative to the saturated calomel electrode, in such that
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- Process for dyeing keratinous fibres with a hydroxyindole in combination with a quinone derivative; and novel 1,4-benzoquinones
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Process for dyeing keratinous fibres, comprising the step of applying to these fibres at least one composition A containing, in a medium appropriate for dyeing, at least one mono- or di-hydroxyindole the application of the composition A being preceded or followed by the application of a composition B containing, in a medium appropriate for dyeing, at least one quinone derivative chosen from ortho- or para-benzoquinones, monoimines or diimines of ortho- or para-benzoquinones, 1,2- or 1,4-naphthoquinones, sulphonimides of ortho- or para-benzoquinones, α, ω-alkylene-bis-1,4-benzoquinones, or 1,2- or 1,4-naphthoquinone-monoimines or -diimines; the mono- or di-hydroxyindoles and the quinone derivatives being chosen such that the oxidation-reduction potential difference ΔE between the oxidation-reduction potential Ei of the mono- or di-hydroxyindoles, determined at pH 7 in a phosphate medium on a vitreous carbon electrode by voltametry, and the oxidation-reduction potential Eq of the quinone derivative determined at pH 7 in a phosphate medium by polarography on a mercury electrode and relative to a saturated calomel electrode is such that
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