Diamino pyrazols, their synthesis, keratin fibre dyeing composit

Details Diamino pyrazols, their synthesis, keratin fibre dyeing composit Diamino pyrazols, their synthesis, keratin fibre dyeing composit

1999-05-07

2000-09-12

Ramsuer, Robert W.

Organic compounds -- part of the class 532-570 series

Organic compounds

Heterocyclic carbon compounds containing a hetero ring...

8423, 5483721, C07D23138, A61K 713

Patent

active

061180084

DESCRIPTION:

BRIEF SUMMARY
The subject-matter of the invention is novel 5-substituted 3,4-diaminopyrazole compounds, their processes of preparation, the compositions for the oxidation dyeing of keratinous fibres comprising them as oxidation base, and dyeing methods employing this composition.
It is known to dye keratinous fibres, and in particular human hair, with dyeing compositions comprising oxidation dye precursors, in particular ortho- or para-phenylenediamines, ortho- or para-aminophenols, or heterocyclic compounds, such as diaminopyrazole derivatives, generally known as oxidation bases. Oxidation dye precursors, or oxidation bases, are colourless or weakly coloured compounds which, in combination with oxidants, can give rise, by an oxidative coupling process, to coloured and colouring compounds.
It is also known that it is possible to vary the shades obtained with these oxidation bases by combining them with couplers or colouring modifiers, the latter being chosen in particular from aromatic meta-diamines, meta-aminophenols, meta-diphenols and certain heterocyclic compounds.
The variety of molecules employed as oxidation bases and couplers makes it possible to obtain a rich palette of colours.
The so-called "permanent" colouring obtained by virtue of these oxidation dyes must, furthermore, satisfy a certain number of requirements. Thus, it must be without disadvantage toxicologically, it must make it possible to obtain shades in the desired intensity and it must behave well in the face of external agents (light, weathering, washing, permanent waving, perspiration or rubbing).
The dyes must also make it possible to cover white hair and, finally, must be as non-selective as possible, that is to say must make it possible to obtain differences in colouring which are as slight as possible all along the same keratinous fibre, because the fibre can exhibit different sensitivity (i.e. damage) between its tip and its root.
para-Aminophenol is generally used, alone or as a mixture with other bases and in combination with appropriate couplers, to obtain red shades and para-phenylenediamines are generally used to obtain blue shades.
Provision has already been made, in particular in Patent Application EP-A-375,977, to use certain diaminopyrazole derivatives, namely, more specifically, 3,4-diaminopyrazole compounds, for the oxidation dyeing of keratinous fibres in red shades. However, the use of the diaminopyrazoles disclosed in this patent application does not make it possible to obtain a rich palette of colours and, furthermore, the method for preparing these compounds is lengthy and expensive.
The Applicant Company has now just discovered, entirely unexpectedly and surprisingly, that novel 5-substituted 3,4-diaminopyrazole compounds of formula (I) defined below are not only suitable for use as oxidation dye precursors but, in addition, they make it possible to obtain dyeing compositions resulting in shades with highlights ranging from red to blue and also, surprisingly, in natural shades. These compounds turn out to be easy to synthesize.
The Applicant Company has also discovered, unexpectedly, that, with these novel 5-substituted 3,4-diaminopyrazole compounds of formula (I) defined below, the colorations obtained at acidic pH were more intense than those obtained at basic pH.
Finally, it has been discovered that the 5-substituted 3,4-diaminopyrazoles of the invention resulted in a better absorption of dye on locks and in colorations which are more resistant to light than those obtained with the 3,4-diaminopyrazole compounds unsubstituted at the 5 position known in the prior art, in particular those disclosed in Application EP-A-375,977.
These discoveries are at the basis of the present invention.
A first subject-matter of the invention is thus novel 5-substituted 3,4-diaminopyrazole compounds of the following formula (I) and their addition salts with an acid: ##STR1## in which: R.sub.1, R.sub.2, R.sub.3, R.sub.4 and R.sub.5, which are identical or different, represent a hydrogen atom; a linear or branched C.sub.1 -C.sub.6 alkyl radical

REFERENCES:
patent: 5500439 (1996-03-01), Ulrich et al.
English Language Derwent Abstract of DE 4 234 885. (1994).
English Language Derwent Abstract of FR 2 586 913. (1987).
English Language Derwent Abstract of FR 2 630 438. (1989).

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