4821-00-5Relevant articles and documents
A BIOSYNTHETIC APPROACH TO THE STRUCTURE OF EUMELANINS. THE ISOLATION OF OLIGOMERS FROM 5,6-DIHYDROXY-1-METHYLINDOLE.
Corradini, Maria Grazia,Napolitano, Alessandra,Prota, Giuseppe
, p. 2083 - 2088 (1986)
Enzymic oxidation, or autooxidation at pH 9, of 1 led to a mixture of fluorescent products the major of which could be isolated, as the acetyl derivative, and identified as 5,6,5',6'-tetraacetoxy-1,1'-dimethyl-2,4'-biindolyl (6).In the presence of metal cations, e.g.Ni(2+), autooxidation of 1, at pH 7.5, led to the isolation, besides the dimer 6 in lower amounts, of two more oligomers which were formulated as 5,6,5',6'-tetracetoxy-1,1'-dimethyl-2,2'-biindolyl (7) and 5,6-diacetoxy-1-methyl-2,4-di--indole (8).The unexpected reactivity of 1 to undergo oxidative coupling at 2- and 4- position rather than at 3- and 7- position, as previously believed, is discussed in relation to the current views on the structure and biosynthesis of eumelanins.
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Mattok,Heacock
, p. 484 (1964)
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Method for dyeing keratinous fibres using a monohydroxyindole or dihydroxyindole and a non-oxidizing aromatic carbonyl derivative and dyeing agent
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, (2008/06/13)
The present invention relates to a method for dyeing keratinous fibers, characterized in that the following are applied to the fibers: a) a composition (A) containing, in a medium appropriate for dyeing, at least one monohydroxyindole or dihydroxyindole, this application being preceded or followed by the application of b) a composition (B) containing, in a medium appropriate for dyeing, at least one aromatic carbonyl derivative chosen from hydroxyacetophenones, hydroxybenzophenones, 2-hydroxy-1,4-benzoquinones, hydroxy-1,4-naphthoquinones,amino-1,4-naphthoquinones,hydroxy-9,10-anthraquinones and amino-9,10-anthraquinones. It also relates to the dyeing agents for carrying it out.
An Improved Synthesis of 5,6-Diacetoxy-N-methylindole and of Epinine
Carpenter, Joel F.
, p. 1607 - 1609 (2007/10/02)
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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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, (2008/06/13)
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