WO2012080286A2

WO2012080286A2 - Dyeing composition comprising a heterocyclic oxidation base and a cationic 3,5-diaminopyridine coupler

Info

Publication number: WO2012080286A2
Application number: PCT/EP2011/072669
Authority: WO
Inventors: Anne-Marie Couroux; Aziz Fadli; Valérie NICOU
Original assignee: LOreal SA
Current assignee: LOreal SA
Priority date: 2010-12-17
Filing date: 2011-12-14
Publication date: 2012-06-21
Anticipated expiration: 2013-06-17
Also published as: WO2012080286A3; WO2012080286A9

Abstract

The subject of the present invention is a composition for dyeing keratin fibres comprising, in a medium suitable for dyeing keratin fibres: - at least one oxidization base chosen from the heterocyclic bases 4,5-diaminopyrazole, pyrazolopyridine and diamino-N,N-dihydropyrazolone; and - at least one cationic 3,5-diaminopyridine coupler. The composition of the present invention makes it possible in particular to obtain a colouring in varied, strong, chromatic, powerful, attractive, sparingly selective shades which resist the various attacks that the hair may be subjected to.

Description

DYEING COMPOSITION COMPRISING A HETEROCYCLIC OXIDATION BASE AND A CATIONIC 3,5-DIAMINOPYRIDINE COUPLER

The subject of the invention is a dyeing composition comprising at least one particular heterocyclic oxidation base and at least one suitably selected cationic 3,5-diaminopyridine coupler, and also the dyeing process using this composition.

It is known practice to dye keratin fibres, and in particular human keratin fibres such as the hair, with dyeing compositions containing oxidation dye precursors, generally known as oxidation bases, such as ortho- or para- phenylenediamines, ortho- or para-aminophenols and heterocyclic compounds. These oxidation bases are colourless or weakly coloured compounds which, when combined with oxidizing products, can give rise to coloured compounds via a process of oxidative condensation.

It is also known that the shades obtained with these oxidation bases can be varied by combining them with couplers or coloration modifiers, the latter being chosen in particular from aromatic meta-diamines, meta-aminophenols, meta- diphenols and certain heterocyclic compounds such as indole compounds.

The variety of molecules used as oxidation bases and couplers allows a wide range of colours to be obtained.

The "permanent" coloration obtained by means of these oxidation dyes must, moreover, meet a certain number of requirements. Thus, it must have no toxicological drawbacks, it must allow shades to be obtained in the desired intensity and it must show good persistence with respect to external agents such as light, bad weather, washing, permanent-waving, perspiration and rubbing.

The dyes must also allow grey hair to be covered, and they must, finally, be as unselective as possible, i.e. they must produce the smallest possible coloration differences along the same keratin fibre, which is generally differently sensitized (i.e. damaged) between its end and its root.

It is known practice to use oxidation bases derived from 3-aminopyrazolo[1 ,5-a]pyridine in the field of the dyeing of keratin fibres. In particular, such bases have been disclosed in documents EP 1 792 903 and EP 1 792 606.

It is already known practice, in document EP 0 728 464, to use diaminopyrazole derivatives as oxidation bases in combination with heterocyclic couplers, in particular indole derivatives.

It is also known practice to use oxidation bases of the diamino-N,N- dihydro-pyrazolone type in the field of the dyeing of keratin fibres, for dyeing keratin fibres, especially the hair. In particular, such a base is described in document EP 1 550 656. However, the dyeing compositions of the prior art produce colorations which are not entirely satisfactory in terms of strength, chromaticity, selectivity and resistance to external agents.

The aim of the present invention is to obtain a composition for dyeing the hair which has improved dyeing properties in terms of strength and/or chromaticity and/or selectivity and/or resistance to external agents.

This aim is achieved with the present invention, the subject of which is a composition for dyeing keratin fibres comprising, in a suitable dyeing medium:

- at least one oxidation base chosen from:

· 4,5-diaminopyrazole oxidation bases of formula (I) and their addition salts, their solvates and the solvates of their salts;

in which:

- Ri, R₂, R3, R₄, R5 and R₆, which may be identical or different, represent a hydrogen atom; a C C₆ alkyl radical which is unsubstituted or substituted with at least one substituent chosen from OR, NHR, NRR', SR, SOR, S02R, COR, COOH, CONH2, CONHR, CONRR', PO(OH)₂, SH, S0₃X, a noncationic heterocycle, CI, Br or I, X denoting a hydrogen atom, Na, K or NH₄, and R and R', which may be identical or different, representing a C C₄ alkyl or alkenyl; a C₂-C₄ hydroxyalkyl radical; a C₂-C₄ aminoalkyl radical; a phenyl radical; a phenyl radical substituted with a halogen atom or a C C₄ alkyl, C C₄ alkoxy, nitro, trifluoromethyl, amino or Ci-C₄ alkylamino radical; a benzyl radical; a benzyl radical substituted with a halogen atom or with a C C alkyl, C C₄ alkoxy, methylenedioxy or amino radical; a radical of formula below:

- (CH₂)_m - X - (CH)_n - Z

Y

in which m and n are integers, which may be identical or different, between 0 and 3 inclusive, X represents an oxygen atom or else the N H group, Y represents a hydrogen atom or else a C C₄ alkyl radical, and Z represents a methyl radical when n is equal to 0, or Z represents a C C₄ alkyl radical, or an OR or NR"R"' group when n is greater than or equal to 1 , R" and R'", which may be identical or different, denoting a hydrogen atom or a C C₄ alkyl radical; or R₅ forms, with the nitrogen atom of the NR₃R₄ group in position 5, a heterocycle comprising at least 4 ring members;

at least one of the R₂, R3 and R₄ radicals represents a hydrogen atom; · aminopyrazolopyridine oxidation bases of formula (II) and also their addition salts, their solvates :

in which:

Ri , R2, R3, R₄ and R₅, which may be identical or different, represent a hydrogen or halogen atom; an -NHSO₃H radical; a hydroxyl radical; a (C C₄)alkyl radical; a (Ci-C₄)alkoxy radical; a (C C₄)alkylthio radical; mono(CrC₄)alkylamino; a di(Ci-C₄)alkylamino radical in which the two alkyl groups can, together with the nitrogen atom to which they are bonded, form a ring which can be interrupted with one or more nitrogen, oxygen or sulphur atoms; a heterocycle; a nitro radical; a phenyl radical; a carbonyl radical; a (C C₄)alkoxycarbonyl radical; a carboxamido radical; a cyano radical; an amino radical; a sulphonyl radical; a -C0₂H radical, an -SO₃H radical; a -P0₃H₂ radical; a -P0₄H₂ radical; or a group:

in which R'" represents an oxygen or nitrogen atom, Q represents an oxygen atom or an NH or NH(C C₄)alkyl group, and Y represents a hydroxyl, amino, C C₄ alkyl, (C C₄)alkoxy, (C C₄)alkylamino, or di(C C₄)alkylamino radical;

• oxidat

in which: Zi and Z₂ independently represent:

- a single covalent bond;

- a divalent radical chosen from:

- an -0(CH₂)_p- radical, p denoting an integer ranging from 0 to 6;

- an -NR'6(CH2)q(C₆H₄)t- radical, q denoting an integer ranging from 0 to 6 and t denoting 0 or 1 , R'₆ representing a hydrogen atom, or a C C₆ alkyl radical optionally substituted with one or more hydroxyl groups;

Zi can also represent a divalent radical -S-, -SO- or -S0₂- when R is a methyl radical;

R and R'₂ independently represent:

- a hydrogen;

- a C1-C1₀ alkyl radical, which is optionally substituted and optionally interrupted with a heteroatom or a group chosen from O, N, Si, S, SO and

S0₂;

- a halogen;

- an SO₃H radical;

- a substituted or unsubstituted, saturated, unsaturated or aromatic, 5- to 8-membered ring, optionally containing one or more heteroatoms or groups chosen from N, O, S, S0₂ and -CO-, it being possible for the ring to be cationic and/or substituted with a cationic radical;

- an -N⁺R₁₇R₁₈Ri₉ group, R₁₇, R₁₈ and R₁₉ being linear or branched C1-C5 alkyls optionally substituted with one or more hydroxyl groups;

when Zi , respectively Z₂, represents a covalent bond, then R , respectively R'₂, can also represent:

- an optionally substituted C C₆ alkylcarbonyl radical;

- an -O-CO-R, -CO-O-R, NR-CO-R' or -CO-NRR' radical in which R and R' independently represent a hydrogen atom or an optionally substituted C C₆ alkyl radical;

R'₃, R'₄ and R'₅, which may be identical or different, represent:

- a hydrogen atom;

- a hydroxyl radical;

- a Ci-C₆ alkoxy radical;

- a Ci-C₆ alkylthio radical;

- an amino radical;

- a monoalkylamino radical; - a Ci-C₆ dialkylamino radical in which the alkyl radicals can form, with the nitrogen atom to which they are attached, a saturated, unsaturated, aromatic or nonaromatic, 5- to 8-membered heterocycle which can contain one or more heteroatoms or groups chosen from N, O, S, S0₂ and CO, it being possible for the heterocycle to be cationic and/or substituted with a cationic radical;

- an optionally substituted C C₆ alkylcarbonyl radical;

- an -O-CO-R, -CO-O-R, NR-CO-R' or -CO-NRR' radical with R and R' as defined above;

- a halogen;

- an -NHSO₃H radical;

- an optionally substituted C C₄ alkyl radical;

- a saturated, unsaturated or aromatic, optionally substituted, carbon-based ring;

- R'₃, R'₄ and R'₅ can form, in pairs, an optionally partially saturated ring;

X represents an ion or group of ions for ensuring the electronegativity of the derivative of formula (III);

with the condition that at least one of the R and R'₂ groups represents a cationic radical;

• diamino-N,N-dihydropyrazolone oxidation bases of formula (IV), and also their addition salts, their solvates and the solvates of their salts:

in which:

RL R₂, R3 and R₄, which may be identical or different, represent:

- a linear or branched C C₆ alkyl radical optionally substituted with one or more radicals chosen from the group consisting of an OR₅ radical, an N R₆R₇ radical, a carboxy radical, a sulphonic radical, a carboxamido radical CON R₆R₇, a sulphonamido radical S0₂N R₆R₇, a heteroaryl, or an aryl optionally substituted with one or more (C C₄)alkyl, hydroxyl, C C₂ alkoxy, amino or di(C C₂)alkylamino groups;

- an aryl radical optionally substituted with one or more (C C₄)alkyl, hydroxyl, C C₂ alkoxy, amino or di(C C₂)alkylamino; - a 5- or 6-membered heteroaryl radical optionally substituted with one or more radicals chosen from (C C₄)alkyl and (CrC₂)alkoxy;

R₃ and R₄ can also represent a hydrogen atom;

R₅, R₆ and R₇, which may be identical or different, represent:

- a hydrogen atom;

- a linear or branched C C₄ alkyl radical optionally substituted with one or more radicals chosen from hydroxyl, C C₂ alkoxy, carboxamido CONR₈Rg, sulphonyl S0₂R₈, aryl optionally substituted with a (C C₄)alkyl, hydroxyl, C C₂ alkoxy, amino or di(Ci-C₂)alkylamino; an aryl radical optionally substituted with a (C C₄)alkyl, hydroxyl, C C₂ alkoxy, amino or di(C C₂)alkylamino;

R₆ and R₇, which may be identical or different, can also represent a carboxamido radical CONR₈R₉; or a sulphonyl radical S0₂R₈;

R₈ and R₉, which may be identical or different, represent a hydrogen atom; or a linear or branched C C₄ alkyl radical optionally substituted with one or more hydroxyl or C C₂ alkoxy; and R₂, on the one hand, and R₃ and R₄, on the other hand, can form, with the nitrogen atom(s) to which they are attached, a saturated or unsaturated heterocycle comprising 5 to 7 ring members, which is optionally substituted with one or more radicals chosen from the group consisting of halogen atoms, amino, di(Ci-C₄)-alkylamino, hydroxyl, carboxy, carboxamido and (C C₂)alkoxy radicals, and Ci-C₄ alkyl radicals optionally substituted with one or more hydroxyl, amino, (di)alkylamino, alkoxy, carboxy or sulphonyl radicals;

R₃ and R₄ can also form, together with the nitrogen atom to which they are attached, a 5- or 7-membered heterocycle of which the carbon atoms can be replaced with an oxygen or nitrogen atom, which is optionally substituted;

and

- at least one coupler chosen from the cationic aminopyridines of formula (V), their addition salts, their solvates and the solvates of their salts;

in which the Zi R'i group bears the cationic charge;

Zi is an oxygen atom or an NR'₂ group;

R'₂ is a hydrogen atom or a linear or branched C C₄ alkyl radical, a benzyl radical or an acetyl radical;

R is a linear or branched, saturated C₁-C₁₀ alkyl radical which is substituted or interrupted with a cationic radical, which is optionally interrupted with one or more oxygen atoms and/or with one or more NR'₂ groups, which is optionally substituted with one or more radicals chosen from C C₄ hydroxyalkyi and alkoxy and hydroxyl radicals, or R is a saturated, unsaturated or aromatic cationic heterocycle comprising from 5 to 8 ring members, which is optionally substituted with one or more radicals chosen from C C₄ alkyl, hydroxyl, C C₄ alkoxy, amino, (C C₄)alkyl- amino, di(C C₄)alkylamino, thio, (C C₄)alkylthio, carboxy, (C C₄)alkylcarbonyl, sulphonyl, amido and C C₄ hydroxyalkyi radicals;

when Zi represents NR'₂, then

^■ R' and R'₂ can form, together with the nitrogen atom to which they are attached, a saturated or unsaturated cationic heterocycle comprising from 5 to 8 ring members, which is optionally substituted with one or more radicals chosen from C C₁₀ alkyl radicals, and hydroxyl, C C₄ alkoxy, amino, (C C₄)alkylamino, di(C C₄)alkylamino, thio, (C C₄)alkylthio, carboxy, (C C₄)alkylcarbonyl, sulphonyl, amido and C C₄ hydroxyalkyi radicals, it being possible for this heterocycle to contain one or more heteroatoms chosen from N or O, preferably N, or

^■ R and R'₂ can form, together with the nitrogen atom to which they are attached, a saturated or unsaturated noncationic heterocycle comprising from 5 to 8 ring members, which is substituted with a cationic radical and optionally substituted with one or more radicals chosen from C₁-C₁₀ alkyl radicals, and hydroxyl, C C₄ alkoxy, amino, (C C₄)alkylamino, di(C C₄)alkylamino, thio, (C C₄)alkylthio, carboxy, (Ci-C₄)alkylcarbonyl, sulphonyl, amido and C C₄ hydroxyalkyi radicals;

R'₃ is chosen from a hydrogen atom, halogens chosen from fluorine, chlorine or bromine, and linear or branched C C₄ alkyl, carboxyl (-COOH) and (C C₄)- alkoxycarbonyl radicals;

An- represents an anion or a mixture of anions; with the exception of the following compounds:

and of the compositions resulting from mixing each of the compositions 1 to 3 with an equal weight of 20-volume aqueous hydrogen peroxide solution (6% by weight).

The subject of the present invention is also a composition for dyeing keratin fibres comprising, in a suitable dyeing medium:

- at least one oxidation base chosen from the oxidation bases of formulae (I), (II), (III) and (IV) as defined above,

- at least one coupler chosen from the cationic aminopyridines of formula (VI), their addition salts, their solvates and the solvates of their salts:

in which the Z'i R"i group bears the cationic charge;

Z'i is an oxygen atom or an NR"₂ group;

R"₂ is a hydrogen atom or a linear or branched C C₄ alkyl radical, a benzyl radical or an acetyl radical;

R"i is a linear or branched, saturated C1-C1₀ alkyl radical which is substituted or interrupted with a cationic radical, which is optionally interrupted with one or more oxygen atoms and/or with one or more NR"₂ groups, which is optionally substituted with one or more radicals chosen from C C₄ hydroxyalkyi and alkoxy and hydroxyl radicals, or R' is a saturated, unsaturated or aromatic cationic heterocycle comprising from 5 to 8 ring members, which is optionally substituted with one or more radicals chosen from C C₄ alkyl, hydroxyl, C C₄ alkoxy, amino, (C C₄)- alkylamino, di(C C₄)alkylamino, thio, (C C₄)alkylthio, carboxy, (C C₄)alkylcarbonyl, sulphonyl, amido and C C₄ hydroxyalkyi radicals;

when ΖΊ represents NR"₂, then

^■ R"i and R"₂ can form, together with the nitrogen atom to which they are attached, a saturated or unsaturated cationic heterocycle comprising from 5 to 8 ring members, which is optionally substituted with one or more radicals chosen from C1-C1₀ alkyl radicals, and hydroxyl, C C₄ alkoxy, amino, (C C₄)alkylamino, di(Ci-C₄)alkylamino, thio, (C C₄)alkylthio, carboxy, (C C₄)alkylcarbonyl, sulphonyl, amido and C C₄ hydroxylalkyl radicals, it being possible for this heterocycle to contain one or more heteroatoms chosen from N or O, preferably N, or

^■ R"i and R"₂ can form, together with the nitrogen atom to which they are attached, a saturated or unsaturated noncationic heterocycle comprising from 5 to 8 ring members, which is substituted with a cationic radical and optionally substituted with one or more radicals chosen from C1-C1₀ alkyl radicals, and hydroxyl, C C₄ alkoxy, amino, (C C₄)alkylamino, di(C C₄)alkylamino, thio, (C C₄)alkylthio, carboxy, (Ci-C₄)alkylcarbonyl, sulphonyl, amido and C C₄ hydroxylalkyl radicals;

R"₃ is chosen from a hydrogen atom, halogens chosen from fluorine, chlorine or bromine, and linear or branched C C₄ alkyl, carboxyl (-COOH) and (C C₄)alkoxy- carbonyl radicals;

An- represents an anion or a mixture of anions;

and

- at least one coupler chosen from benzene couplers. Preferably, the benzene coupler(s) is (are) chosen from meta-diphenols, meta-phenylenediamines and meta-aminophenols. Even more preferentially, the benzene coupler(s) is (are) chosen from the compounds of formula (VII) below and their addition salts, their solvat their salts:

in which:

R"'i represents a hydrogen atom or a C C₄ hydroxyalkyl radical;

R'"₂ represents an amino radical or a hydroxyl radical;

R'"₃ represents a hydrogen atom, a C C₄ alkyl radical, a C C₄ hydroxyalkyl radical or a Ci-C₄ hydroxyalkoxy radical;

R'"₄ represents a hydrogen atom or a halogen atom, for example a fluorine, chlorine, bromine or iodine atom.

Preferably, R'"₂ is a hydroxyl radical.

The subject of the invention is also a dyeing process using this composition. Another subject of the invention is the use of the composition of the present invention for dyeing keratin fibres, and in particular human keratin fibres such as the hair.

The invention also relates to multicompartment devices comprising compositions using at least one oxidation base chosen from the compounds of formulae (I), (II), (III) and (IV), their addition salts, their solvates and the solvates of their salts, and at least one coupler chosen from the compounds of formula (V) or (VI), and also their addition salts, their solvates and the solvates of their salts.

The composition of the present invention makes it possible in particular to obtain a composition for dyeing keratin fibres which is suitable for use in oxidation dyeing and makes it possible to obtain a colouring with varied, intense or chromatic, powerful, attractive and sparingly selective shades which are highly resistant to the various attacks that the hair may be subjected to, such as shampooing, sweat, permanent reshaping operations and light. In particular, the composition in accordance with the invention produces particularly chromatic shades.

In the context of the present invention, the expression "at least one" is equivalent to the expression "one or more". The present invention also covers the mesomeric forms and the stereoisomers of the various oxidation dyes of the invention.

It should be noted that, in the following text, and unless otherwise indicated, the limits of a range of values are included in this range.

Unless otherwise indicated, the limits of the ranges of values which are given in the context of the invention are included in these ranges.

In the context of the invention, and unless otherwise indicated, the expression "alkyl" used for alkyl radicals and also for groups comprising an alkyl component, means a linear or branched carbon-based chain containing from 1 to 4 carbon atoms, which is unsubstituted or substituted with one or more heterocycles, or with one or more phenyl groups or with one or more groups chosen from halogen atoms such as chlorine, bromine, iodine and fluorine; and hydroxyl, alkoxy, amino, carbonyl, carboxamido, sulphonyl, -C0₂H, -S0₃H, -P0₃H₂, -P0₄H₂, - NHSO₃H, sulphonamide, mono(CrC₄)alkylamino and tri(Ci-C₄)alkylammonium radicals, or alternatively with a di(C C₄)alkylamino radical in which the two alkyl groups can form, together with the nitrogen atom of said di(C C₄)alkylamino group to which they are bonded, a ring which can be interrupted with one or more nitrogen, oxygen or sulphur atoms.

Likewise, according to the invention, the expression "alkoxy" used for the alkoxy radicals and also for groups comprising an alkoxy component, means a linear or branched O-carbon-based chain containing from 1 to 4 carbon atoms, which is unsubstituted or substituted with one or more groups chosen from heterocycles; halogen atoms such as chlorine, bromine, iodine and fluorine; and hydroxyl, amino, carbonyl, carboxamido, sulphonyl, -C0₂H, -SO₃H, -P0₃H₂, -P0₄H₂, -NHSO₃H, sulphonamide, mono(CrC₄)alkylamino and tri(Ci-C₄)alkylammonium radicals, or alternatively with a di(C C₄)alkylamino radical in which the two alkyl groups can form, together with the nitrogen atom of said di(C C₄)alkylamino group to which they are bonded, a ring which can be interrupted with one or more nitrogen, sulphur and oxygen atoms.

According to the invention, the term "heterocycle" is intended to mean an aromatic or nonaromatic ring containing 5, 6, 7 or 8 ring members, and from 1 to 3 heteroatoms chosen from nitrogen, sulphur and oxygen atoms. These heterocycles can be condensed with other heterocycles or with a phenyl group. They can be substituted with a halogen atom; a (C C₄)alkyl radical; a (C C₄)alkoxy radical; a hydroxyl radical; an amino radical; a (C C₄)alkylamino radical; or di(C C₄)alkylamino in which the two alkyl groups can, together with the nitrogen atom to which they are bonded, form a ring which can be interrupted with one or more nitrogen, oxygen or sulphur atoms. These heterocycles can also be quaternized with a (CrC₄)alkyl radical.

Among these optionally condensed heterocycles, mention may in particular be made, by way of example, of the rings: thiadiazole, triazole, isoxazole, oxazole, azaphosphole, thiazole, isothiazole, imidazole, pyrazole, triazine, thiazine, pyrazine, pyridazine, pyrimidine, pyridine, diazepine, oxazepine, benzotriazole, benzoxazole, benzimidazole, benzothiazole, morpholine, piperidine, piperazine, azetidine, pyrrolidine, aziridine, 3-(2-hydroxyethyl)benzothiazol-3-ium and 1-(2- hydroxyethyl)pyridinium.

According to the invention, the term "phenyl" is intended to mean a phenyl radical which is unsubstituted or substituted with one or more cyano, carbonyl, carboxamido, sulphonyl, -C0₂H, -S0₃H, -P0₃H₂, -P0₄H₂, hydroxyl, amino or mono(CrC₄)alkylamino radicals, or di(C C₄)alkylamino radicals in which the two alkyl groups can form, together with the nitrogen atom of said di(C C₄)alkylamino group to which they are bonded, a ring which can be interrupted with one or more nitrogen, oxygen or sulphur atoms.

Among the groups

, mention may in particular be made of acetamide, dimethylurea, O-methylcarbamate, methylcarbonate and N-dimethyl- carbamate groups and the esters.

The coupler or base compounds described above can be in the form of addition salts, in particular chosen from the addition salts with an acid, such as the hydrochlorides, hydrobromides, sulphates, citrates, succinates, tartrates, lactates, tosylates, benzenesulphonates, phosphates and acetates. When they bear an acid substitute, they can be in the form of addition salts with a base, such as the sodium, potassium, ammonium or alkanolamine salts.

They can also be in the form of solvates, for example a hydrate, or a solvate of a linear or branched alcohol such as ethanol or isopropanol.

By way of examples of derivatives of formula (I) that can be used according to the invention, mention may be made of the compounds described in patents DE-A-38 43 892 and DE-A-41 33 957 and patent applications WO 94/08969, WO 94/08970, FR-A-2 733 749 and DE-A-195 43 988, for instance 4,5-diamino-1- methylpyrazole, 4,5-diamino-1-(2-hydroxyethyl)pyrazole, 4,5-diamino-1-(4'-chloro- benzyl)pyrazole, 4,5-diamino-1 ,3-dimethylpyrazole, 4,5-diamino-3-methyl-1-phenyl- pyrazole, 4,5-diamino-1-methyl-3-phenylpyrazole, 4-amino-1 ,3-dimethyl-5- hydrazinopyrazole, 1-benzyl-4,5-diamino-3-methylpyrazole, 4,5-diamino-3-tert- butyl-1-methylpyrazole, 4,5-diamino-1-tert-butyl-3-methylpyrazole, 4,5-diamino- 1- -hydroxyethyl)-3-methylpyrazole, 4,5-diamino-1-ethyl-3-methylpyrazole, 4,5-di- amino-1-ethyl-3-(4'-methoxyphenyl)pyrazole, 4,5-diamino-1-ethyl-3-hydroxymethyl- pyrazole, 4,5-diamino-3-hydroxymethyl-1-methylpyrazole, 4,5-diamino-3-hydroxy- methyl-1-isopropylpyrazole, 4,5-diamino-3-methyl-1-isopropylpyrazole and 4- amino-5-(2'-aminoethyl)amino-1 ,3-dimethylpyrazole and their addition salts, their solvates and the solvates of their salts.

According to one particular embodiment, the diaminopyrazole of formula (I) is such that R₆ is hydrogen. According to this variant, R₂, R₃ and R₄ represent a hydrogen atom or a C C₄ alkyl radical, and R₅ is an alkyl, hydroxyalkyl or alkoxyalkyl radical.

Preference is even more particularly given to 4,5-diamino-1-(2-hydroxyethyl)- 1 H-pyrazole and its salts, its solvates and the solvates of its salts, such as 4,5- diamino-1-(2-hydroxyethyl)- te of formula below:

BOH . H₂ S 0₄

Among the compounds of formula (II) above, preference is given to the 3-aminopyrazolo[1 ,5-a]pyridines corresponding to formula (ΙΓ) below, and also their addition salts, their solvat ir salts:

(II·)

in which:

RL R₂ and R₃, which may be identical or different, represent a hydrogen or halogen atom; a hydroxyl radical; a (C C₄)alkyl radical; a (C C₄)alkylthio radical; a (Ci-C₄)alkoxy radical; an -NHSO₃H radical; an amino radical; a (C C₄)alkylamino radical; a di(C C₄)alkylamino radical in which the two alkyl groups can, together with the nitrogen atom to which they are bonded, form a ring which can be interrupted with one or more nitrogen, oxygen or sulphur atoms; a heterocycle as defined above; a sulphonamide radical, a carbonyl radical, a (C C₄)alkoxycarbonyl radical, a carboxamido radical, or a group of formula:

R'" represents an oxygen or nitrogen atom, Q represents an oxygen atom or an NH or NH(C C₄)alkyl group, and Y represents a hydroxyl, amino, C C₄ alkyl, (C C₄)alkoxy, (C C₄)alkylamino or di(C C₄)alkylamino radical.

Among the 3-aminopyrazolo[1 ,5-a]pyridines of formula (II) that can be used as an oxidation base in the dyeing compositions in accordance with the invention, mention may in particular be made of:

- pyrazolo[1 ,5-a]pyridin-3-ylamine;

- 2-acetylaminopyrazolo[1 ,5-a]pyridin-3-ylamine;

- 2-morpholin-4-ylpyrazolo[1 ,5-a]pyridin-3-ylamine;

- 3-aminopyrazolo[1 ,5-a]pyridine-2-carboxylic acid;

- 2-methoxypyrazolo[1 ,5-a]pyridin-3-ylamino;

- (3-aminopyrazolo[1 ,5-a]pyridin-7-yl)methanol;

- 2-(3-aminopyrazolo[1 ,5-a]pyridin-5-yl)ethanol;

- 2-(3-aminopyrazolo[1 ,5-a]pyridin-7-yl)ethanol;

- (3-aminopyrazolo[1 ,5-a]pyridin-2-yl)methanol;

- 3,6-diaminopyrazolo[1 ,5-a]pyridine;

- 3,4-diaminopyrazolo[1 ,5-a]pyridine;

- pyrazolo[1 ,5-a]pyridine-3,7-diamine;

- 7-morpholin-4-ylpyrazolo[1 ,5-a]pyridin-3-ylamine;

- pyrazolo[1 ,5-a]pyridine-3,5-diamine;

- 5-morpholin-4-ylpyrazolo[1 ,5-a]pyridin-3-ylamine;

- 2-[(3-aminopyrazolo[1 ,5-a]pyridin-5-yl)(2-hydroxyethyl)amino]ethanol;

- 2-[(3-aminopyrazolo[1 ,5-a]pyridin-7-yl)(2-hydroxyethyl)amino]ethanol;

- 3-aminopyrazolo[1 ,5-a]pyridin-5-ol;

- 3-aminopyrazolo[1 ,5-a]pyridin-4-ol;

- 3-aminopyrazolo[1 ,5-a]pyridin-6-ol;

- 3-aminopyrazolo[1 ,5-a]pyridin-7-ol;

- 2-methoxy-6,7-dimethylpyrazolo[1 ,5-a]pyridin-3-amine;

- 2-[(3-aminopyrazolo[1 ,5-a]pyridin-2-yl)oxy]ethanol;

- 4-ethyl-2-methoxy-7-methylpyrazolo[1 ,5-a]pyridin-3-amine hydrochloride;

- 1-(3-aminopyrazolo[1 ,5-a]pyridin-2-yl)pyrrolidin-3-ol;

- 2,2'-[(3-aminopyrazolo[1 ,5-a]pyridin-2-yl)imino]diethanol; - 2-[(3-aminopyrazolo[1 ,5-a]pyridin-2-yl)amino]ethanol;

- N2-(2-pyridin-3-ylethyl)pyrazolo[1 ,5-a]pyridine-2,3-diamine;

and their addition salts, their solvates and the solvates of their salts.

Among the bases described above, 2-[(3-aminopyrazolo[1 ,5-a]pyridin-2- yl)oxy]ethanol and its addition salts with an acid are particularly preferred.

The vast majority of the 3-aminopyrazolo[1 ,5-a]pyridines of formula (I I) are compounds that are known in the pharmaceutical field, and are described in particular in patent US 5 457 200. These compounds can be prepared according to synthesis methods well known in the literature and as described, for example, in patent US 5 457 200.

The term "cationic heterocycle or ring" is intended to mean a ring containing one or more quaternary ammonium groups.

By way of example of radicals of the -N⁺R₁₇R₁₈Rig type, mention may be made of trimethylammonium, triethylammonium, dimethylethylammonium, diethylmethylammonium, diisopropylmethylammonium, diethylpropylammonium, beta-hydroxyethyldiethylammonium, di(beta-hydroxyethyl)methylammonium and tri(beta-hydroxyethyl)ammonium radicals.

By way of example of a cationic heterocycle, mention may be made of imidazolium, pyridinium, piperazinium, pyrrolidinium, morpholinium, pyrimidinium, thiazolium, benzimidazolium, benzothiazolium, oxazolium, benzotriazolium, pyrazolium, triazolium and benzoxazolium heterocycles.

By way of example of a cationic heterocycle, mention may be made of imidazoliums, pyridiniums, piperaziniums, pyrrolidiniums, morpholiniums, pyrimidiniums, thiazoliums, benzimidazoliums, benzothiazoliums, oxazoliums, benzotriazoliums, pyrazoliums, triazoliums and benzoxazoliums.

By way of examples of derivatives of formula (I I I), mention may be made of the following compounds in which X^" is as defined above:

salt

-ium salt

salt salt salt

salt

-ium salt salt

salt

The nature of the counterion is not determining with regard to the dyeing power of the compounds of formula (III).

According to one embodiment, in formula (III), Zi and/or Z₂ represent(s) a covalent bond, an -NR'6(CH₂)q- radical or an -0(CH₂)_p- radical and R and/or R'₂ is (are) a cationic radical.

In formula (III), when R or R'₂ denotes a heterocycle, this heterocycle is preferably a cationic heterocycle or a heterocyle substituted with a cationic radical. By way of example, mention may be made of imidazoles substituted with a quaternary ammonium radical or imidazoliums, piperazines substituted with a quaternary ammonium radical or piperaziniums, pyrrolidines substituted with a quaternary ammonium radical or pyrrolidiniums, and diazepanes substituted with a quaternary ammonium radical or diazepaniums. According to a different embodiment, in formula (III), R or R'₂ represents an -N⁺R₁₇R₁₈Ri₉ group, R₁₈ and R₁₉ being linear or branched C C₅ alkyls optionally substituted with one or more hydroxyl groups, such as trialkylammonium, tri(hydroxyalkyl)ammonium, hydroxyalkyldialkylammonium or di(hydroxy- alkyl)alkylammonium.

In formula (III), the R'₃, R'₄ and R'₅ radicals independently may be a hydrogen atom, or a C C₄ alkyl radical which can be substituted. By way of example, mention may be made of methyl, ethyl, hydroxyethyl, aminoethyl, propyl and butyl radicals. According to one particular embodiment, R'₃, R'₄ and R'₅ independently represent a hydrogen or a C C₄ alkyl radical.

According to one particular embodiment, in formula (III), R'₄ and R'₅ together form a partially saturated or unsaturated 5- or 8-membered ring, in particular a

in which Zi , R'i , R'₃, R'₄ and R'₅ are as defined above for formula (III).

According to one particular embodiment of this formula, Zi represents a covalent bond, an -NR'6(CH₂)q- radical or an -0(CH₂)_p- radical and R is a cationic radical.

As cationic oxidation bases of formula (III), preference is quite particularly given to the following bases:

4-(3-Aminopyrazolo[1 ,5-a]pyridin-2-yl)-1 , 1 -dimethylpiperazin-1 -ium salt

3-[2-(3-Aminopyrazolo[1 ,5-a]pyridin-2-ylamino)ethyl]-1 -methyl-3H-imidazol-1 -ium salt and their addition salts, their solvates and the solvates of their salts. More particularly, in formula (IV), the and R₂ radicals, which may be identical or different, are chosen from:

- a Ci-C₆, preferably C C₄, alkyl radical, optionally substituted with a hydroxyl, a (CrC₂)alkoxy, an amino or a (di)(CrC₂)alkylamino;

- a phenyl, methoxyphenyl, ethoxyphenyl or benzyl radical.

Preferably, in formula (IV), the R^ and R₂ radicals, which may be identical or different, are chosen from a methyl, ethyl, 2-hydroxyethyl, 3-hydroxypropyl, 2- hydroxypropyl or phenyl radical.

According to another embodiment, the R^ and R₂ radicals form, together with the nitrogen atoms to which they are attached, a saturated or unsaturated, optionally substituted, 5- or 6-membered ring.

Preferably, in formula (IV), the R^ and R₂ radicals form, together with the nitrogen atoms to which they are attached, a pyrazolidine ring or a pyridazolidine ring, which is optionally substituted with one or more C C₄ alkyl, hydroxyl,

(Ci-C₂)alkoxy, carboxy, carboxamido, amino or (di)(C C₂)alkylamino radicals.

Even more advantageously, in formula (IV), the R^ and R₂ radicals form, together with the nitrogen atoms to which they are attached, a pyrazolidine ring or a pyridazolidine ring.

In formula (IV), the R₃ and R₄ radicals, which may be identical or different, are more particularly chosen from a hydrogen atom; a linear or branched C C₆, preferably C C₄, alkyl radical optionally substituted with one or more hydroxyl, (C

C₂)alkoxy or amino or a (di)(C C₂)alkylamino; a phenyl radical optionally substituted with one or more hydroxyl, amino or (C C₂)alkoxy radicals.

Preferably, in formula (IV), the R₃ and R₄ radicals, which may be identical or different, are chosen from a hydrogen atom, and a methyl, ethyl, isopropyl, 2-hydroxyethyl, 3-hydroxypropyl, 2-hydroxypropyl and 2-carboxyethyl radical.

According to one particular embodiment, the R₃ and R₄ radicals represent a hydrogen atom. According to another embodiment, in formula (IV), the R₃ and R₄ radicals form, together with the nitrogen atom to which they are attached, a 5- or 7- membered ring chosen from pyrrolidine, piperidine, homopiperidine, piperazine and homopiperazine heterocycles; it being possible for said rings to be substituted with one or more of the following radicals: hydroxyl, amino, (di)(CrC₂)alkylamino, carboxy, carboxamido, C C₄ alkyl which is optionally substituted with one or more hydroxyl, amino or (di)(CrC₂)alkylamino radicals.

More particularly, in formula (IV), the R₃ and R₄ radicals form, together with the nitrogen atom to which they are attached, a 5- or 7-membered ring chosen from pyrrolidine, 2,5-dimethylpyrrolidine, pyrrolidine-2-carboxylic acid, 3-hydroxy- pyrrolidine-2-carboxylic acid, 4-hydroxypyrrolidine-2-carboxylic acid, 2,4-dicarboxy- pyrrolidine, 3-hydroxy-2-hydroxymethylpyrrolidine, 2-carboxamidopyrrolidine, 3- hydroxy-2-carboxamidopyrrolidine, 2-(diethylcarboxamido)pyrrolidine, 2-hydroxy- methylpyrrolidine, 3,4-dihydroxy-2-hydroxymethylpyrrolidine, 3-hydroxypyrrolidine, 3,4-dihydroxypyrrolidine, 3-aminopyrrolidine, 3-methylaminopyrrolidine, 3-dimethyl- aminopyrrolidine, 4-amino-3-hydroxypyrrolidine, 3-hydroxy-4-(2-hydroxy- ethyl)aminopyrrolidine, piperidine, 2,6-dimethylpiperidine, 2-carboxypiperidine, 2- carboxamidopiperidine, 2-hydroxymethylpiperidine, 3-hydroxy-2-hydroxy- methylpiperidine, 3-hydroxypiperidine, 4-hydroxypiperidine, 3-hydroxy- methylpiperidine, homopiperidine, 2-carboxyhomopiperidine, 2-carboxamido- homopiperidine, homopiperazine, N-methylhomopiperazine and N-(2-hydroxy- ethyl)homopiperazine.

Preferably, in formula (IV), the R₃ and R₄ radicals form, together with the nitrogen atom to which they are attached, a 5- or 7-membered ring chosen from pyrrolidine, 3-hydroxypyrrolidine, 3-aminopyrrolidine, 3-dimethylaminopyrrolidine, pyrrolidine-2-carboxylic acid, 3-hydroxypyrrolidine-2-carboxylic acid, piperidine, hydroxypiperidine, homopiperidine, diazepane, N-methylhomopiperazine and Ν-β- hydroxyethylhomopiperazine.

In accordance with an even more preferred embodiment of the invention, the R₃ and R₄ radicals form, together with the nitrogen atom to which they attached, a 5-membered ring such as pyrrolidine, 3-hydroxypyrrolidine, 3-aminopyrrolidine or

3- dimethylaminopyrrolidine.

By way of examples of derivatives of formula (IV), mention may be made of the compounds presented below, their addition salts, their solvates and the solvates of their addition salts:

4,5-diamino-1 ,2-dimethyl-1 ,2-dihydropyrazol-3-one;

4- amino-5-methylamino-1 ,2-dimethyl-1 ,2-dihydropyrazol-3-one;

4-amino-5-dimethylamino-1 ,2-dimethyl-1 ,2-dihydropyrazol-3-one; 4-amino-5-(2-hydroxyethyl)amino-1 ,2-dimethyl-1 ,2-dihydropyrazol-3-one;

4-amino-5-(pyrrolidin-1-yl)-1 ,2-dimethyl-1 ,2-dihydropyrazol-3-one;

4-amino-5-(piperidin-1-yl)-1 ,2-dimethyl-1 ,2-dihydropyrazol-3-one;

4,5-diamino-1 ,2-di(2-hydroxyethyl)-1 ,2-dihydropyrazol-3-one;

4-amino-5-methylamino-1 ,2-di(2-hydroxyethyl)-1 ,2-dihydropyrazol-3-one;

4-amino-5-dimethylamino-1 ,2-di(2-hydroxyethyl)-1 ,2-dihydropyrazol-3-one;

4-amino-5-(2-hydroxyethyl)amino-1 ,2-di(2-hydroxyethyl)-1 ,2-dihydropyrazol-3-one;

4-amino-5-(pyrrolidin-1-yl)-1 ,2-di(2-hydroxyethyl)-1 ,2-dihydropyrazol-3-one;

4-amino-5-(piperidin-1-yl)-1 ,2-di(2-hydroxyethyl)-1 ,2-dihydropyrazol-3-one;

4,5-diamino-1 ,2-diethyl-1 ,2-dihydropyrazol-3-one;

4,5-diamino-1 ,2-phenyl-1 ,2-dihydropyrazol-3-one;

4,5-diamino-1-ethyl-2-methyl-1 ,2-dihydropyrazol-3-one;

4,5-diamino-2-ethyl-1-methyl-1 ,2-dihydropyrazol-3-one;

4,5-diamino-1-phenyl-2-methyl-1 ,2-dihydropyrazol-3-one;

4,5-diamino-2-phenyl-1-methyl-1 ,2-dihydropyrazol-3-one;

4,5-diamino-1-(2-hydroxyethyl)-2-methyl-1 ,2-dihydropyrazol-3-one;

4,5-diamino-2-(2-hydroxyethyl)-1-methyl-1 ,2-dihydropyrazol-3-one;

2,3-diamino-6,7-dihydro-1 H,5H-pyrazolo[1 ,2-a]pyrazol-1-one;

2-amino-3-methylamino-6,7-dihydro-1 H,5H-pyrazolo[1 ,2-a]pyrazol-1-one;

2-amino-3-dimethylamino-6,7-dihydro-1 H,5H-pyrazolo[1 ,2-a]pyrazol-1-one;

2-amino-3-ethylamino-6,7-dihydro-1 H,5H-pyrazolo[1 ,2-a]pyrazol-1-one;

2-amino-3-isopropylamino-6,7-dihydro-1 H,5H-pyrazolo[1 ,2-a]pyrazol-1-one;

2-amino-3-(2-hydroxyethyl)amino-6,7-dihydro-1 H,5H-pyrazolo[1 ,2-a]pyrazol-1-one;

2-amino-3-(2-hydroxypropyl)amino-6,7-dihydro-1 H,5H-pyrazolo[1 ,2-a]pyrazol-1- one;

2-amino-3-bis(2-hydroxyethyl)amino-6,7-dihydro-1 H,5H-pyrazolo[1 ,2-a]pyrazol-1- one;

2-amino-3-(pyrrolidin-1-yl)-6,7-dihydro-1 H,5H-pyrazolo[1 ,2-a]pyrazol-1-one;

2-amino-3-(3-hydroxypyrrolidin-1-yl)-6,7-dihydro-1 H,5H-pyrazolo[1 ,2-a]pyrazol-1- one;

2-amino-3-(piperidin-1-yl)-6,7-dihydro-1 H,5H-pyrazolo[1 ,2-a]pyrazol-1-one;

2,3-diamino-6-hydroxy-6,7-dihydro-1 H,5H-pyrazolo[1 ,2-a]pyrazol-1-one;

2,3-diamino-6-methyl-6,7-dihydro-1 H,5H-pyrazolo[1 ,2-a]pyrazol-1-one;

2,3-diamino-6-dimethyl-6,7-dihydro-1 H,5H-pyrazolo[1 ,2-a]pyrazol-1-one;

2,3-diamino-5,6,7,8-tetrahydro-1 H,6H-pyridazino[1 ,2-a]pyrazol-1-one;

2,3-diamino-5,8-dihydro-1 H,6H-pyridazino[1 ,2-a]pyrazol-1-one;

4-Amino-5-dimethylamino-1 ,2-diethyl-1 ,2-dihydropyrazol-3-one;

4-Amino-1 ,2-diethyl-5-ethylamino-1 ,2-dihydropyrazol-3-one; 4-Amino-1 ,2-diethyl-5-isopropylarnino-1 ,2-dihydropyrazol-3-one;

4-Amino-1 ,2-diethyl-5-(2-hydroxyethylamino)-1 ,2-dihydropyrazol-3-one;

4-Amino-5-(2-dimethylaminoethylamino)-1 ,2-diethyl-1 ,2-dihydropyrazol-3-one; 4-Amino-5-[bis(2-hydroxyethyl)amino]-1 ,2-diethyl-1 ,2-dihydropyrazol-3-one;

4-Amino-1 ,2-diethyl-5-(3-imidazol-1-ylpropylamino)-1 ,2-dihydropyrazol-3-one; 4-Amino-5-dimethylamino-1 ,2-diethyl-1 ,2-dihydropyrazol-3-one;

4-Amino-1 ,2-diethyl-5-ethylamino-1 ,2-dihydropyrazol-3-one;

4-Amino-1 ,2-diethyl-5-isopropylamino-1 ,2-dihydropyrazol-3-one;

4-Amino-1 ,2-diethyl-5-(2-hydroxyethylamino)-1 ,2-dihydropyrazol-3-one;

4-Amino-1 ,2-diethyl-5-(3-imidazol-1-ylpropylamino)-1 ,2-dihydropyrazol-3-one; 4-Amino-1 ,2-diethyl-5-(3-hydroxypyrrolidin-1-yl)-1 ,2-dihydropyrazol-3-one;

4-Amino-1 ,2-diethyl-5-pyrrolidin-1-yl-1 ,2-dihydropyrazol-3-one;

4-Amino-5-(3-dimethylaminopyrrolidin-1-yl)-1 ,2-diethyl-1 ,2-dihydropyrazol-3-one; 4-Amino-1 ,2-diethyl-5-(4-methylpiperazin-1-yl)pyrazolidin-3-one;

2,3-Diamino-6-hydroxy-6,7-dihydro-5H-pyrazolo[1 ,2-a]pyrazol-1-one;

some of which are represented below in order to illustrate the names with chemical structures:

Among these compounds, the diamino-N,N-dihydropyrazolone derivatives of formula (IV) or their addition salts, their solvates and the solvates of their salts, which are particularly preferred are:

2,3-Diamino-6,7-dihydro-1 H,5H-pyrazolo[1 ,2-a]pyrazol-1-one;

2-Amino-3-ethylamino-6,7-dihydro-1 H,5H-pyrazolo[1 ,2-a]pyrazol-1-one;

2-Amino-3-isopropylamino-6,7-dihydro-1 H,5H-pyrazolo[1 ,2-a]pyrazol-1-one;

2-Amino-3-(pyrrolidin-1-yl)-6,7-dihydro-1 H,5H-pyrazolo[1 ,2-a]pyrazol-1-one;

4,5-diamino-1 ,2-dimethyl-1 ,2-dihydropyrazol-3-one;

4,5-diamino-1 ,2-diethyl-1 ,2-dihydropyrazol-3-one;

4,5-diamino-1 ,2-di(2-hydroxyethyl)-1 ,2-dihydropyrazol-3-one;

2-amino-3-dimethylamino-6,7-dihydro-1 H,5H-pyrazolo[1 ,2-a]pyrazol-1-one;

2,3-diamino-5,6,7,8-tetrahydro-1 H,6H-pyridazino[1 ,2-a]pyrazol-1-one;

4-Amino-1 ,2-diethyl-5-(pyrrolidin-1-yl)-1 ,2-dihydropyrazol-3-one;

4-Amino-5-(3-dimethylaminopyrrolidin-1-yl)-1 ,2-diethyl-1 ,2-dihydropyrazol-3-one;

2,3-diamino-6-hydroxy-6,7-dihydro-1 H,5H-pyrazolo[1 ,2-a]pyrazol-1-one.

According to one particular embodiment, the composition of the invention contains an oxidation base chosen from:

4,5-Diamino-1 ,2-diethyl-1 ,2-dihydropyrazol-3-one;

4-Amino-1 ,2-diethyl-5-(pyrrolidin-1-yl)-1 ,2-dihydropyrazol-3-one; 4-Amino-5-(3-dimethylaminopyrrolidin-1-yl)-1 ,2-diethy^

2,3-diamino-6-hydroxy-6,7-dihydro-1 H,5H-pyrazolo[1 ,2-a]pyrazol-1-one;

2,3-diamino-6,7-dihydro-1 H,5H-pyrazolo[1 ,2-a]pyrazol-1-one;

2,3-diamino-5,6,7,8-tetrahydro-1 H,6H-pyridazino[1 ,2-a]pyrazol-1-one;

their addition salts, their solvates and the solvates of their salts.

Preferably, the cationic aminopyridines of formula (III) are chosen from the ollowing compounds:

An- having the same meaning as above;

their addition salts, their solvates and the solvates of their salts.

According to one particular embodiment, the composition comprises a benzene coupler, preferably of formula (VII). According to one particular embodiment, in formula (VII), R" represents a hydrogen atom.

According to another particular embodiment of the invention, in formula (VII), R'"₂ represents a hydroxyl radical. According to another particular embodiment of the invention, in formula (VII), R'"₃ represents a C C₄ alkyl radical. Preferably, R'"₃ represents a methyl radical.

According to another particular embodiment of the invention, in formula (VII), R'"₄ represents a halogen atom. Preferably, R'"₄ represents a chlorine atom.

According to one preferred embodiment, the composition in accordance with the invention comprises at least one benzene coupler chosen from 2-methyl-5- aminophenol, 5-N-^-hydroxyethyl)amino-2-methylphenol and 2-chloro-6-methyl-3- aminophenol.

The bases and the couplers used in the present invention are generally each present in an amount of between 0.001 and 10% by weight approximately of the total weight of the dyeing composition, preferably between 0.005 and 6%.

The dyeing composition of the invention can optionally comprise one or more additional oxidation bases conventionally used for dyeing keratin fibres, which are different from the oxidation bases described above.

By way of example, these additional oxidation bases are chosen from para- phenylenediamines, bis-phenylalkylenediamines, para-aminophenols, bis-para- aminophenols, ortho-aminophenols, heterocyclic bases, and their addition salts, their solvates and the solvates of their salts.

Among the para-phenylenediamines, mention may be made, by way of example, of para-phenylenediamine, para-toluenediamine, 2-chloro-para- phenylenediamine, 2,3-dimethyl-para-phenylenediamine, 2,6-dimethyl-para-phen- ylenediamine, 2,6-diethyl-para-phenylenediamine, 2,5-dimethyl-para-phenylene- diamine, Ν,Ν-dimethyl-para-phenylenediamine, N,N-diethyl-para-phenylene- diamine, Ν,Ν-dipropyl-para-phenylenediamine, 4-amino-N,N-diethyl-3-methyl- aniline, N,N-bis^-hydroxyethyl)-para-phenylenediamine, 4-N,N-bis -hydroxy- ethyl)amino-2-methylaniline, 4-N,N-bis^-hydroxyethyl)amino-2-chloroaniline, 2^-hydroxyethyl-para-phenylenediamine, 2-fluoro-para-phenylenediamine, 2-isopropyl-para-phenylenediamine, N-^-hydroxypropyl)-para-phenylenediamine, 2-hydroxymethyl-para-phenylenediamine, N,N-dimethyl-3-methyl-para- phenylenediamine, N,N-(ethyl^-hydroxyethyl)-para-phenylenediamine, Ν-(β,γ- dihydroxypropyl)-para-phenylenediamine, N-(4'-aminophenyl)-para- phenylenediamine, N-phenyl-para-phenylenediamine, 2^-hydroxyethyloxy-para- phenylenediamine, 2^-acetylaminoethyloxy-para-phenylenediamine, N-^-methoxyethyl)-para-phenylenediamine, 4-aminophenylpyrrolidine, 2-thienyl- para-phenylenediamine, 2^-hydroxyethylamino-5-aminotoluene, 3-hydroxy-1-(4'- aminophenyl)pyrrolidine, their addition salts with an acid, their solvates and the solvates of their salts. Among the para-phenylenediamines mentioned above, para-phenylene- diamine, para-toluenediamine, 2-isopropyl-para-phenylenediamine, 2^-hydroxy- ethyl-para-phenylenediamine, 2^-hydroxyethyloxy-para-phenylenediamine, 2,6- dimethyl-para-phenylenediamine, 2,6-diethyl-para-phenylenediamine, 2,3-dimethyl- para-phenylenediamine, N,N-bis^-hydroxyethyl)-para-phenylenediamine, 2-chloro- para-phenylenediamine, 2^-acetylaminoethyloxy-para-phenylenediamine, their addition salts with an acid, their solvates and the solvates of their salts are particularly preferred.

Among the bis-phenylalkylenediamines, mention may be made, by way of example, of N,N'-bis^-hydroxyethyl)-N,N'-bis(4'-aminophenyl)-

1 ,3-diaminopropanol, N,N'-bis^-hydroxyethyl)-N,N'-bis(4'- aminophenyl)ethylenediamine, N,N'-bis(4-aminophenyl)tetramethylenediamine, N,N'-bis(β-hydroxyethyl)-N,N'-bis(4-aminophenyl)tetramethylenediamine,

N,N'-bis(4-methylaminophenyl)tetramethylenediamine, N,N'-bis(ethyl)-N,N'-bis(4'- amino-3'-methylphenyl)ethylenediamine, 1 ,8-bis(2,5-diaminophenoxy)-3,6- dioxaoctane, their addition salts with an acid, their solvates and the solvates of their salts.

Among the para-aminophenols, mention may be made, by way of example, of para-aminophenol, 4-amino-3-methylphenol, 4-amino-3-fluorophenol, 4-amino-3- hydroxymethylphenol, 4-amino-2-methylphenol, 4-amino-2-hydroxymethylphenol, 4-amino-2-methoxymethylphenol, 4-amino-2-aminomethylphenol, 4-amino-2- - hydroxyethylaminomethyl)phenol, 4-amino-2-fluorophenol, 1-hydroxy-4- methylaminobenzene, 2,2'-methylenebis-4-aminophenol, their addition salts with an acid, their solvates and the solvates of their salts.

Among the ortho-aminophenols, mention may be made, by way of example, of 2-aminophenol, 2-amino-5-methylphenol, 2-amino-6-methylphenol, 5-acetamido- 2-aminophenol, their addition salts with an acid, their solvates and the solvates of their salts.

Among the heterocyclic bases, mention may be made, by way of example, of pyridine derivatives, pyrimidine derivatives and pyrazole derivatives.

Among the pyridine derivatives, mention may be made of the compounds described, for example, in patents GB 1 026 978 and GB 1 153 196, such as 2,5-diaminopyridine, 2-(4-methoxyphenyl)amino-3-aminopyridine, 2,3-diamino- 6-methoxypyridine, 2-^-methoxyethyl)amino-3-amino-6-methoxypyridine, 3,4- diaminopyridine, their addition salts with an acid, their solvates and the solvates of their salts.

Among the pyrimidine derivatives, mention may be made of the compounds described, for example, in patents DE 2359399; JP 88-169571 ; JP 05-63124; EP 0770375 or patent application WO 96/15765, such as 2,4,5,6- tetraaminopyrimidine, 4-hydroxy-2,5,6-triaminopyrimidine, 2-hydroxy-4,5,6-tri- aminopyrimidine, 2,4-dihydroxy-5,6-diaminopyrimidine, 2,5,6-triaminopyrimidine, and pyrazolopyrimidine derivatives such as those mentioned in patent application FR-A-2750048 and among which mention may be made of pyrazolo[1 ,5- a]pyrimidine-3,7-diamine; 2,5-dimethylpyrazolo[1 ,5-a]pyrimidine-3,7-diamine; pyrazolo[1 ,5-a]pyrimidine-3,5-diamine; 2,7-dimethylpyrazolo[1 ,5-a]pyrimidine-3,5- diamine; 3-aminopyrazolo[1 ,5-a]pyrimidin-7-ol; 3-aminopyrazolo[1 ,5-a]pyrimidin-5- ol; 2-(3-aminopyrazolo[1 ,5-a]pyrimidin-7-ylamino)ethanol, 2-(7-aminopyrazolo[1 ,5- a]pyrimidin-3-ylamino)ethanol, 2-[(3-aminopyrazolo[1 ,5-a]pyrimidin-7-yl)(2-hydroxy- ethyl)amino]ethanol, 2-[(7-aminopyrazolo[1 ,5-a]pyrimidin-3-yl)(2-hydroxyethyl)- amino]ethanol, 5,6-dimethylpyrazolo[1 ,5-a]pyrimidine-3,7-diamine, 2,6-dimethyl- pyrazolo[1 ,5-a]pyrimidine-3,7-diamine, 2,5,N7,N7-tetramethylpyrazolo[1 ,5- a]pyrimidine-3,7-diamine, 3-amino-5-methyl-7-imidazolylpropylaminopyrazolo[1 ,5- a]pyrimidine, their addition salts with an acid, their solvates and the solvates of their salts.

The additional oxidation base(s) is (are) generally each present in an amount of between 0.001 and 10% by weight approximately of the total weight of the dyeing composition, preferably between 0.005 and 6%.

By way of example of a coupler, mention may be made of sesamol, 1-β- hydroxyethylamino-3,4-methylenedioxybenzene, oc-naphthol, 2-methyl-1-naphthol, 1 ,5-dihydroxynaphthalene, 2,7-naphthalenediol, 1-acetoxy-2-methylnaphthalene, 6- hydroxyindole, 4-hydroxyindole, 4-hydroxy-N-methylindole, 3,5-diamino-2,6- dimethoxypyridine, 2,6-dihydroxy-3,4-dimethylpyridine, 3-amino-2-methylamino-6- methoxypyridine, 1-N-^-hydroxyethyl)amino-3,4-methylenedioxybenzene, 3- methyl-1-phenyl-5-pyrazolone, their addition salts with an acid, their solvates and the solvates of their salts.

The additional coupler(s) is (are) generally each present in an amount of between 0.001 and 10% by weight approximately of the total weight of the dyeing composition, preferably between 0.005 and 6%.

Generally, the addition salts of the additional oxidation bases and of the additional couplers that can be used in the context of the invention are in particular chosen from the addition salts with an acid, such as the hydrochlorides, hydrobromides, sulphates, citrates, succinates, tartrates, lactates, tosylates, benzenesulphonates, phosphates and acetates, and the addition salts with a base, such as sodium hydroxide, potassium hydroxide, aqueous ammonia, amines or alkanolamines. The dyeing composition in accordance with the invention can also contain one or more direct dyes which can in particular be chosen from nitrobenzene dyes, azo direct dyes, and methine direct dyes. These direct dyes may be nonionic, anionic or cationic in nature. They may be synthetic or of natural origin.

The medium suitable for dyeing, also called dyeing support, generally comprises water or a mixture of water and one or more organic solvents, for instance C C₄ lower alkanols, such as ethanol and isopropanol, polyols, for instance propylene glycol, dipropylene glycol or glycerol, and polyol ethers, for instance dipropylene glycol monomethyl ether.

The solvent(s) is (are) generally present in proportions which can be between

1 and 40% by weight approximately, relative to the total weight of the dyeing composition, and even more preferentially between 3 and 30% by weight approximately.

The dyeing composition in accordance with the invention can also contain various adjuvants conventionally used in compositions for dyeing the hair, such as anionic, cationic, nonionic, amphoteric or zwitterionic surfactants or mixtures thereof, anionic, cationic, nonionic, amphoteric or zwitterionic polymers or mixtures thereof, inorganic or organic thickeners, and in particular anionic, cationic, nonionic and amphoteric polymeric associative thickeners, antioxidants, penetrating agents, sequestrants, fragrances, buffers, dispersants, conditioning agents such as, for example, volatile or non-volatile, modified or unmodified silicones, film-forming agents, ceramides, preservatives and opacifiers.

The above adjuvants are generally present in an amount, for each of them, of between 0.01 and 20% by weight, relative to the total weight of the composition.

Of course, those skilled in the art will take care to select this or these optimal additional compound(s) in such a way that the advantageous properties intrinsically associated with the oxidation dyeing composition in accordance with the invention are not, or are not substantially, adversely affected by the envisaged addition(s).

The pH of the dyeing composition in accordance with the invention is generally between 3 and 12 approximately, and preferably between 5 and 1 1 approximately. It can be adjusted to the desired value by means of acidifying or basifying agents normally used in the dyeing of keratin fibres, or else by means of conventional buffer systems.

Among the acidifying agents, mention may be made, by way of example, of inorganic or organic acids, such as hydrochloric acid, (ortho)phosphoric acid, sulphuric acid, carboxylic acids such as acetic acid, tartaric acid, citric acid or lactic acid, and sulphonic acids. Among the basifying agents, mention may be made, by way of example, of aqueous ammonia, alkali metal carbonates, sodium metasilicate, sodium silicate, alkanolamines such as mono-, di- and triethanolamines, and also derivatives thereof, for example monoethanolamine, aminomethylpropanol, triethanolamine, sodium hydroxide or potassium hydroxide, for example sodium hydroxide solution, sodium pyrrolidine carboxylate, and the compounds of formula (A) below:

^Ra \ Λ

N W N

/ \

^Rc ^Rd (A)

in which W is a propylene residue optionally substituted with a hydroxyl group or a C1-C4 alkyl radical; and R_a, R_b, R_c and R_d, which may be identical or different, represent a hydrogen atom or a C C₄ alkyl or C C₄ hydroxyalkyl radical.

The composition according to the invention may comprise one or more oxidizing agents.

The oxidizing agents are those conventionally used for the oxidation dyeing of keratin fibres and are, for example, hydrogen peroxide, urea peroxide, alkali metal bromates, persalts such as perborates and persulphates, peracids and oxidase enzymes, among which mention may be made of peroxidases, 2-electron oxidoreductases such as uricases, and 4-electron oxygenases such as laccases. Hydrogen peroxide is particularly preferred.

The composition with or without oxidizing agent according to the invention can be in various forms, such as in the form of liquids, creams or gels, or in any form suitable for dyeing keratin fibres, and in particular human hair.

It can result from the mixing of several compositions at the time of use.

In one particular variant, it results from the mixing of two compositions, one comprising at least one oxidation base chosen from the compounds of formulae (I), (II), (III) and (IV) and their addition salts, their solvates and the solvates of their salts, and at least one coupler chosen from the compounds of the formula (V) or (VI), and also their addition salts, their solvates and the solvates of their salts, and another composition comprising at least one oxidizing agent as described above.

The composition of the invention is therefore applied to the hair for dyeing keratin fibres either as it is or in the presence of at least one oxidizing agent, for dyeing keratin fibres.

The process of the present invention is a process in which the composition without oxidant according to the present invention as defined above is applied to the fibres in the presence of an oxidizing agent for a period of time sufficient to develop the desired colouring. The colour can be revealed at acidic, neutral or alkaline pH and the oxidizing agent can be added to the composition of the invention just at the time of use or it can be used on the basis of an oxidizing composition containing it, applied simultaneously with or sequentially to the composition of the invention.

According to one particular embodiment, the composition without oxidizing agent according to the present invention is mixed, preferably at the time of use, with a composition containing, in a medium suitable for dyeing, at least one oxidizing agent. The mixture obtained is then applied to the keratin fibres. After a leave-in time of from 3 to 50 minutes approximately, preferably 5 to 30 minutes approximately, the keratin fibres are rinsed, optionally washed with shampoo, rinsed again, and then dried.

The oxidizing agents are those described above.

The oxidizing composition can also contain various adjuvants conventionally used in hair dyeing compositions and as defined above.

The pH of the oxidizing composition containing the oxidizing agent is such that, after mixing with the dyeing composition, the pH of the resulting composition applied to the keratin fibres preferably ranges between 3 and 12 approximately, and even more preferentially between 5 and 1 1. It can be adjusted to the desired value by means of acidifying or basifying agents normally used in the dyeing of keratin fibres and as defined above.

The subject of the invention is also a dyeing kit or multicompartment device in which a first compartment contains the dyeing composition without oxidizing agent of the present invention defined above, comprising at least one oxidation base chosen from the compounds of formula (I), (II), (III) or (IV), their addition salts, their solvates and the solvates of their salts, and at least one coupler chosen from the compounds of formula (V) or (VI), and also their addition salts, their solvates and the solvates of their salts, and a second compartment contains at least one oxidizing agent.

A second device consists of a first compartment containing a composition comprising at least one oxidation base chosen from the compounds of formula (I), (II), (III) or (IV), their addition salts, their solvates and the solvates of their salts, and a second compartment containing a composition comprising at least one coupler chosen from the compounds of formula (V) or (VI), and also their addition salts, their solvates and the solvates of their salts.

A third device can optionally comprise the two compartments of the second device plus a third compartment containing a composition comprising at least one oxidizing agent. These devices can be fitted with a means for delivering the desired mixture onto the hair, such as the devices described in patent FR-2 586 913 in the name of the applicant.

The compounds of formulae (II) and (III) are synthesized according to a procedure such as those which are described in documents EP 1 792 903 and EP 1 792 606.

The compounds of formula (IV) are synthesized according to a procedure such as those which are described in document EP 0 550 656.

The cationic aminopyridines of formula (I I I) as defined above can be prepared according to various synthesis routes.

They can in particu ds of formula (b) below:

in which R"₃ is chosen from a hydrogen atom, halogens chosen from fluorine, chlorine or bromine, and linear or branched C C₄ alkyl, carboxyl (-COOH), and (Ci-C₄)alkoxycarbonyl radicals, and x represents 0, 1 or 2.

More particularly, the cationic aminopyridines of formula (III) can be prepared from a compound of

in which Y represents a halogen or an S0₂R"₄ group with R"₄ chosen from C C₄ alkyls, preferably methyl, a phenyl radical or a methylphenyl radical;

and R"₃ is chosen from a hydrogen atom, halogens chosen from fluorine, chlorine or bromine, and linear or branched C C₄ alkyl, carboxyl (-COOH) and (Ci-C₄)alkoxycarbonyl radicals;

according to a process comprising at least the following steps in this order:

• substitution of the Y group with a Z R' group as defined above;

• reduction of the nitro groups.

This process is summarized in the scheme below:

By way of example, when represents a C1-C10 alkyl radical substituted with a cationic radical, said alkyl radical being interrupted with one or more oxygen atoms and/or with one or more NR"₂ groups, then the synthesis process used may

in which A represents a linear or branched alkyl chain optionally interrupted with a heteroatom of O, N or S type.

The substitution reaction is carried out in a dipole solvent such as acetonitrile or THF or in DMF or NMP or in an alcohol such as ethanol, in the presence of a base such as triethylamine, ethyldiisopropylamine, sodium hydroxide or potassium hydroxide, for example, and one or more ΗΟΑΖΊ Η for 1 to 24 hours at a temperature of from 20°C to the reflux temperature of the solvent.

The hydroxyl function thus introduced is then substituted with a halide (mesyl or tosyl halide, for example) in a solvent such as acetonitrile or THF or in an alcohol such as ethanol, for example, in the presence of a base such as triethylamine, ethyldiisopropylamine, sodium hydroxide or potassium hydroxide, for example, for 1 to 24 hours at a temperature of from 20°C to the reflux temperature of the solvent. The substitution of the leaving group introduced in the preceding step is carried out either by reaction with an aromatic tertiary amine such as methylimidazole, so as to directly produce the cationic compounds, or by reaction with a particular primary or secondary amine, for instance Ν,Ν-dimethylethylenediamine or 2-piperidin-1- ylethanamine, so as to produce compounds which are alkylated with at least one equivalent of alkyl halide or methyl sulphate in a solvent such as THF or acetonitrile or dioxane or ethyl acetate for 15 minutes to 24 hours at a temperature ranging from 15°C to the reflux temperature of the solvent, so as to produce the cationic nitrous compounds.

The reduction of the nitro groups of these compounds is carried out under conventional conditions, for example by performing a hydrogenation reaction by heterogeneous catalysis in the presence of Pd/C, Pd(ll)/C, Ni/Ra, etc., or else by performing a reduction reaction with a metal, for example with zinc, iron, tin, etc. (see Advanced Organic Chemistry, 3^rd Edition, J. March, 1985, Wiley Interscience and Reduction in Organic Chemistry, M. Hudlicky, 1983, Ellis Horwood Series Chemical Science).

The examples which follow serve to illustrate the invention without, however, being limiting in nature.

EXAMPLES

Synthesis examples:

Example 1 : Synthesis of 2-[(3,5-diaminopyridin-2-yl)amino]-N,N,N-trimethyl ethanammonium chloride dihydrochloride

2HCI

Step 1 : Synthesis of N'-(3,5-dinitropyridin-2-yl)-N,N-dimethylethane-1 ,2-diamine

30 ml of ethanol and 10.15 g (0.05 mol) of 2-chloro-3,5-dinitropyridine are charged successively to a 50 ml three-necked flask fitted with a thermometer, a condenser, a bubble counter and a dropping funnel, with magnetic stirring. The medium is brought to 40°C and 8.8 g (0.1 mol) of N,N-dimethylethane-1 ,2-diamine are introduced dropwise, over the course of 5 minutes, by means of the dropping funnel, and the whole mixture is kept stirring for 1 hour.

After cooling of the reaction medium, the latter is poured onto a mixture of ice and water with stirring.

The yellow solid formed is isolated by filtration on a sinter funnel, washed with water and dried under vacuum at 30°C in the presence of desiccant until the weight is constant. 10.5 g (yield of 82.5%) of expected compound are obtained in the form of a yellow solid.

The mass spectrometry analysis confirms the expected compound: the quasi- molecular ions [M+H]⁺ and [M+Na]⁺ of the expected molecule are mainly detected, CgHnNsC . Step 2: Synthesis of 2-[(3,5-dinitropyridin-2-yl)amino]-N,N,N-trimethyl- eth

50 ml of ethyl acetate and 6.38 g (25 mmol) of N'-(3,5-dinitropyridin-2-yl)-N,N- dimethylethane-1 ,2-diamine are successively charged to a 100 ml three-necked flask fitted with a thermometer, a condenser, a bubble counter and a dropping funnel, with magnetic stirring. 3.15 g (25 mmol) of dimethyl sulphate are run into this solution, and the whole mixture is kept stirring for one hour.

The yellow solid formed is filtered, dried with suction, washed with ethyl acetate and then dried under vacuum at 50°C in the presence of desiccant until the weight is constant. 7 g (yield 73%) of expected compound are thus obtained in the form of a yellow solid.

The mass spectrometry analysis confirms the expected compound, the expected cation

is mainly detected at m/z, ESP+ = 270. Step 3: Synthesis of 2-[(3,5-diaminopyridin-2-yl)amino]-N,N,N-trimethylethan- ammonium chloride dihydrochloride

300 ml of ethanol, 20 ml of water, 24 g (62.95 mol) of 2-[(3,5-dinitropyridin-2- yl)amino]-N,N,N-trimethylethanammonium methyl sulphate and 52 ml (503 mmol) of cyclohexene are successively charged to a 1 litre three-necked flask fitted with a thermometer, a condenser and a bubble counter, with magnetic stirring. The medium is brought to 50°C and 12 g of palladium-on-carbon are introduced in fractions, and the whole mixture is brought to reflux for 2 hours.

After cooling under argon, the reaction medium is filtered under a stream of argon, on a sinter funnel packed with celite and over a vacuum flask containing 200 ml of 6.0 N hydrochloric 2-propanol at 0°C.

The expected compound crystallizes in the vacuum flask with stirring. The solid is filtered off, dried quickly by suction on a sinter funnel under argon, rinsed with a minimum amount of cold iPrOH and then with 3 x 100 ml of iPr₂0. The compound is dried under vacuum at 50°C in the presence of desiccant until the weight is constant. 17.5 g (yield 87.4%) of expected compound are obtained in the form of a beige solid.

The NMR (¹ H 400 MHz and ¹³C 100.61 MHz DMSO d₆ ) and mass spectrometry analyses are in accordance with the expected structure.

Example 2: Synthesis of 2-[(3,5-diaminopyridin-2-yl)(methyl)amino]-N,N,N-trimethyl- ethanammonium chloride dihydrochloride

S

50 ml of ethanol and 12.30 g (60.43 mmol) of 2-chloro-3,5-dinitropyridine are successively charged to a 250 ml three-necked flask fitted with a thermometer, a condenser, a bubble counter and a dropping funnel, with magnetic stirring. The medium is brought to 40°C and 9.26 ml (72.52 mmol) of Ν, Ν, Ν'-trimethylethane- 1 ,2-diamine are introduced dropwise over the course of 5 minutes, by means of the dropping funnel, and the whole mixture is brought to 65°C for 1 hour.

After cooling of the reaction medium, the latter is poured into a mixture of 200 g of ice and water with stirring.

The yellow solid formed is isolated by filtration on a sinter funnel, washed with water and dried under vacuum at 30°C in the presence of desiccant until the weight is constant. 10.7 g (yield of 62%) of yellow solid, corresponding to the expected compound, are thus isolated.

The mass spectrometry analysis confirms the expected compound: the quasi- molecular ions [M+H]⁺ and [M+Na]⁺ of the expected molecule are mainly detected,

Step 3: 2-[(3,5-dinitropyridin-2-yl)(methyl)amino]-N, N, N-trimethylethanammonium me

300 ml of ethyl acetate and 15.80 g (60 mmol) of N-(3,5-dinitropyridin-2-yl)-N, N', N'- trimethylethane-1 ,2-diamine are successively charged to a 500 ml three-necked flask fitted with a thermometer, a condenser, a bubble counter and a dropping funnel, with magnetic stirring.

12 g (120 mmol) of dimethyl sulphate are added dropwise to this solution and the whole mixture is stirred at reflux for one hour.

After cooling, the yellow solid formed is filtered off on a sinter funnel, dried by suction, washed with ethyl acetate and then dried under vacuum at 50°C in the presence of desiccant until the weight is constant. 22.3 g (yield 94%) of expected compound are thus isolated in the form of a yellow solid.

The mass spectrometry analysis confirms the expected compound. The expected cation [Ci i H₁₈N₅0₄]⁺ is mainly detected at m/z, ESP+=284.

Step 3: Synthesis of 2-[(3,5-diaminopyridin-2-yl)(methyl)amino]-N, N, N-trimethyl- ethanammonium chloride dihydrochloride

300 ml of ethanol, 5 ml of water, 20 g (50.60 mmol) of 2-[(3,5-dinitropyridin-2- yl)amino]-N,N,N-trimethylethanammonium methyl sulphate and 104 ml of cyclohexene are successively charged to a 1 litre three-necked flask fitted with a thermometer, a condenser and a bubble counter, with magnetic stirring.

The medium is brought to 50°C, 5 g of palladium-on-carbon are introduced in small fractions, and the whole mixture is brought to reflux for 2 hours.

After cooling under argon, the reaction medium is filtered, under a stream of argon, on a sinter funnel packed with celite and over a vacuum flask containing 250 ml of 6.0 N hydrochloric 2-propanol at 0°C.

The expected compound which crystallizes in the flask with stirring is filtered off, dried quickly by suction on a sinter funnel under argon, and rinsed with a minimum amount of cold iPrOH and then with 3 x 100 ml of iPr₂0. The compound is dried under vacuum at 50°C in the presence of desiccant until the weight is constant. 12.1 g (yield 81 %) of expected compound are thus isolated in the form of a beige solid.

The NMR (¹ H 400 MHz and ¹³C 100.61 MHz DMSO d₆) and mass spectrometry analyses are in accordance with the expected structure.

Example 3: Synthesis of 4-(3,5-diaminopyridin-2-yl)-1 , 1-dimethylpiperazin-1-

Step 1 : Synthesis of 1-(3,5-dinitropyridin-2-yl)-4-methylpiperazine

40 ml of ethanol and 5 g (24.57 mmol) of 2-chloro-3,5-dinitropyridine are successively charged to a 250 ml three-necked flask fitted with a thermometer, a condenser, a bubble counter and a dropping funnel, with magnetic stirring. The medium is brought to 40°C and 6.15 ml (49.13 mmol) of methylpiperazine are introduced dropwise over the course of 5 minutes by means of the dropping funnel, and then the whole mixture is brought to reflux for 1 hour and then left stirring at ambient temperature overnight.

A yellow solid crystallizes from the medium; it is isolated by filtration on a sinter funnel, washed with water and dried under vacuum at 30°C in the presence of desiccant until the weight is constant. 5.7 g (yield of 88%) of expected compound are thus isolated in the form of a yellow solid.

The mass spectrometry analysis confirms the structure of the expected compound. The quasi-molecular ions [M+H]⁺ and [M+Na]⁺ of the expected molecule are mainly detected, C10H13N5O4.

Step 2: Synthesis of 4-(3,5-dinitropyridin-2-yl)-1 , 1-dimethylpiperazin-1-ium methyl sulphate

100 ml of THF and 5.5 g (20 mmol) of 1-(3,5-dinitropyridin-2-yl)-4-methylpiperazine are successively charged to a 200 ml three-necked flask fitted with a thermometer, a condenser, a bubble counter and a dropping funnel, with magnetic stirring.

4.19 g (40 mmol) of dimethyl sulphate are added dropwise to this solution and the whole mixture is kept stirring at reflux for one hour.

The yellow solid formed is filtered off on a sinter funnel, dried by suction, washed with THF and then subsequently dried under vacuum at 50°C in the presence of desiccant until the weight is constant. 7.4 g (yield 94%) of expected compound are thus isolated in the form of a yellow solid.

The mass spectrometry analysis confirms the structure of the expected compound. The expected cation

is mainly detected.

Step 3: Synthesis of 4-(3,5-diaminopyridin-2-yl)-1 , 1-dimethylpiperazin-1-ium chlo

ci

50 ml of ethanol, 1 ml of water, 20 g (50.60 mmol) of 4-(3 , 5-d i n itro py rid i n-2-y I)- 1 , 1 - dimethylpiperazin-1-ium methyl sulphate and 36.56 ml of cyclohexene are successively charged to a 250 ml three-necked flask fitted with a thermometer, a condenser and a bubble counter, with magnetic stirring.

The medium is brought to 50°C and 3.5 g of palladium-on-carbon are introduced in small fractions and then the whole mixture is brought to reflux for 24 hours.

Under argon, the reaction medium is filtered on a sinter funnel packed with celite and over a vacuum flask containing 250 ml of 6.0 N hydrochloride 2-propanol at 0°C.

With stirring, the expected compound crystallizes in the flask; it is filtered off on a sinter funnel, dried quickly by suction under argon, and rinsed with a minimum amount of cold iPrOH and then with 3 x 100 ml of iPr₂0. The solid is then dried under vacuum at 50°C in the presence of desiccant until the weight is constant. 4.6 g (yield 88%) of expected compound are thus isolated in the form of a beige solid.

The expected cation [Cn H₂oN₅]⁺ is mainly detected.

Example 4: Synthesis of 1-{2-[(3,5-diaminopyridin-2-yl)amino]ethyl}-1-methyl- piperidinium chloride dihydrochloride, 2 HCI

with An^" is CI Step 1 : Synthesis of 3,5-dinitro-N-(2-piperidin-1-ylethyl)pyridin-2-amine

800 ml of ethanol and 10.17 g (50 mmol) of 2-chloro-3,5-dinitropyridine are successively charged to a 250 ml three-necked flask fitted with a thermometer, a condenser, a bubble counter and a dropping funnel, with magnetic stirring. This medium is brought to 40°C and 7 ml of 2-aminoethylpiperidine are introduced dropwise over the course of 5 minutes by means of the dropping funnel, and then the whole mixture is left to stir for one hour.

The medium, which has become heterogeneous, is then poured onto 500 g of ice. A yellow solid precipitates more abundantly; it is isolated by filtration on a sinter funnel, washed with water and dried under vacuum at 30°C in the presence of desiccant until the weight is constant. 1 1.5 g (yield 78%) of expected compound are thus isolated in the form of a yellow solid.

The mass spectrometry analysis confirms the structure of the expected compound: the quasi-molecular ions [M+H]⁺ and [M+Na]⁺ of the expected molecule Ci₂H₁₇N₅0₄ are mainly detected.

Step 2: Synthesis of 1-{2-[(3,5-dinitropyridin-2-yl)amino]ethyl}-1-methylpiperidinium m

50 ml of ethyl acetate and 6.16 g (20 mmol) of 13,5-dinitro-N-(2-piperidin-1- ylethyl)pyridin-2-amine are successively charged to a 200 ml three-necked flask fitted with a thermometer, a condenser, a bubble counter and a dropping funnel, with magnetic stirring.

2.52 g (20 mmol) of dimethyl sulphate are added dropwise to this solution and the whole mixture is kept stirring for one hour.

The yellow solid formed is filtered off on a sinter funnel, dried by suction, washed with ethyl acetate and then subsequently dried under vacuum at 50°C in the presence of desiccant until the weight is constant. 7.6 g (yield 90%) of expected compound are thus isolated in the form of a yellow solid.

The mass spectrometry analysis confirms the structure of the expected compound. The expected cation [Ci₃H₂oN₅0₄]⁺ is mainly detected.

Step 3: Synthesis of 1-{2-[(3,5-diaminopyridin-2-yl)amino]ethyl}-1-methyl- piperidinium chloride dihydrochloride

150 ml of ethanol, 5 ml of water, 6 g (14.2 mmol) of 1-{2-[(3,5-dinitropyridin-2- yl)amino]ethyl}-1-methylpiperidinium methyl sulphate and 1.2 g of palladium-on- carbon are successively charged to a 300 ml hydrogenation autoclave.

After purging the medium with nitrogen and then with hydrogen, the reaction is carried out under a hydrogen pressure of 8 bar with an exothermicity of 75°C. After cooling and hydrogen purging, the catalyst is removed under nitrogen and the liquors are poured, under nitrogen, into 100 ml of 6 N hydrochloric isopropanol. The beige solid which crystallizes slowly under cold conditions is dried rapidly with suction on a sinter funnel under argon, and rinsed with a minimum amount of cold iPrOH and then with 3 x 100 ml of iPr₂0. The solid obtained is dried under vacuum at 50°C in the presence of desiccant until the weight is constant. 4.8 g (yield 94%) of expected compound are thus isolated in the form of a beige solid.

The expected cation [Ci₃H₂4N₅]⁺ is mainly detected.

Example 5: Synthesis of 1-(3,5-diaminopyridin-2-yl)-N,N,N-trimethylpyrrolidin-3- ammonium chloride hydrochloride

The procedure is identical to that described in Example 4, the amine being N- dimethylpyrrolidin-3-amine.

The beige-coloured 1-(3,5-diaminopyridin-2-yl)-N,N,N-trimethylpyrrolidin-3-ammon- ium chloride hydrochloride is obtained with a yield of 65%.

The expected cation [Ci₂H₂₂N₅]⁺ is mainly detected. Example 6: Synthesis of 1-{3-[(3,5-diaminopyridin-2-yl)amino]propyl}-3-(2- hydroxyethyl)-1 H-imidazol-3-ium chloride dihydrochloride

The process is performed in an identical manner to that of Example 4, with substitution using 3-aminopropylimidazole and cationization using chloroethanol, followed by a catalytic reduction in an autoclave.

The expected cation [Ci₃H₂i N₅0]⁺ is mainly detected.

EXAMPLES OF DYEING 1

The following compositions 1 C1 , 1 C2 and C3 were prepared

1 C1 1 C2 1 C3

4-(3-aminopyrazolo[1 ,5-a]pyridin-2-yl)-1 , 1

dimethylpiperazin-1-ium chloride 0.005 mol

hydrochloride

1-{2-[(3-aminopyrazolo[1 ,5-a]pyridin-2- 0.008 mol

yl)amino]ethyl}-3-methyl-1 H-imidazol-3-ium

chloride hydrochloride

2-[(3-aminopyrazolo[1 ,5-a]pyridin-2- 0.0085 mol yl)oxy]ethanol hydrochloride

4-(3,5-diaminopyridin-2-yl)-1 , 1- dimethylpiperazin-1-ium chloride 0.005 mol 0.008 mol 0.0085 mol hydrochloride

Polyglycerolated oleoyl alcohol comprising

2 mol of glycerol 4 g A.M. 4 g A.M. 4 g A.M.

Polyglycerolated oleoyl alcohol comprising

4 mol of glycerol (78% A.M.) 6 g A.M. 6 g A.M. 6 g A.M.

Oleic acid 3 g 3 g 3 g

Oleoyl amine comprising 2 EO, sold under

the name ETHOMEEN 012 by the company

AKZO 7 g A.M. 7 g A.M. 7 g A.M. Diethylaminopropyl laurylamino

succinamate, sodium salt containing 55%

A.M. 3 g A.M. 3 g A.M. 3 g A.M.

Oleoyl alcohol 5 g 5 g 5 g

Alkyl (70/30 C13/C15, 50% linear) ether

carboxylic acid monoethanolamide (2EO) 10 g A.M. 10 g A.M. 10 g A.M.

Propylene glycol 9.5 g 9.5 g 9.5 g

Ethyl alcohol 5 g 5 g 5 g

Hexylene glycol 9.3 g 9.3 g 9.3 g

Sodium metabisulphite as an aqueous 0.455 g

solution containing 35% A.M. A.M. 0.455 g A.M. 0.455 g A.M.

Ammonium acetate 0.8 g 0.8 g 0.8 g

Antioxidant, sequestering agent q.s q.s q.s

Fragrance, preservative q.s q.s q.s

Aqueous ammonia containing 20% of NH₃ 10.2 g 10.2 g 10.2 g

Demineralized water q.s.100 g q.s.100 g q.s.100 g

A.M.: Active Material

Method of application

The composition was diluted extemporaneously with 1 times its weight of 20- volumes aqueous hydrogen peroxide solution.

The mixture was applied to grey hair containing 90% white hairs, in a proportion of 10 g of mixture for 1 g of hair. After a leave-on time of 30 minutes at ambient temperature, the hair was then rinsed, washed with a standard shampoo and dried. Results

The hair colouring was evaluated visually.

The colourings obtained are particularly strong and chromatic.

The following compositions 1 C1 , 1 C2 and 1 C3 were prepared.

1 C1 1 C2 1 C3

4-(3-aminopyrazolo[1 ,5-a]pyridin-2-yl)-1 , 1- 0.006 mol

A.M.: Active Material Method of application

The composition was diluted extemporaneously with 1 times its weight of 20-volumes aqueous hydrogen peroxide solution.

The mixture was applied to grey hair containing 90% of white hairs, in a proportion of 10 g of mixture for 1 g of hair. After a leave-on time of 30 minutes at ambient temperature, the hair was then rinsed, washed with a standard shampoo and dried.

Results

The hair colouring was evaluated visually.

The colourings obtained are particularly strong and chromatic.

The following compositions 1 C4, 1 C5 and 1 C6 were prepared

1 C4 1 C5 1 C6

4-(3-aminopyrazolo[1 ,5-a]pyridin-2-yl)-1 , 1

dimethylpiperazin-1-ium chloride 0.005 mol

hydrochloride

1-{2-[(3-aminopyrazolo[1 ,5-a]pyridin-2- 0.008 mol

yl)amino]ethyl}-3-methyl-1 H-imidazol-3-ium

chloride hydrochloride

2-[(3-aminopyrazolo[1 ,5-a]pyridin-2- 0.0085 mol yl)oxy]ethanol hydrochloride

4-(3,5-diaminopyridin-2-yl)-1-(2- hydroxyethyl)-1-methylpiperazin-1- 0.005 mol 0.008 mol 0.0085 mol chloride hydrochloride

Polyglycerolated oleoyl alcohol comprising

2 mol of glycerol 4 g A.M. 4 g A.M. 4 g A.M.

Polyglycerolated oleoyl alcohol comprising

4 mol of glycerol (78% A.M.) 6 g A.M. 6 g A.M. 6 g A.M.

Oleic acid 3 g 3 g 3 g

Oleoyl amine comprising 2 EO, sold under

the name ETHOMEEN 012 by the

company AKZO 7 g A.M. 7 g A.M. 7 g A.M. Diethylaminopropyl laurylamino

succinamate, sodium salt containing 55%

A.M. 3 g A.M. 3 g A.M. 3 g A.M.

Oleoyl alcohol 5 g 5 g 5 g

Alkyl (70/30 C13/C15, 50% linear) ethyl

carboxylic acid monoethanolamide (2 EO) 10 g A.M. 10 g A.M. 10 g A.M.

Propylene glycol 9.5 g 9.5 g 9.5 g

Ethyl alcohol 5 g 5 g 5 g

Hexylene glycol 9.3 g 9.3 g 9.3 g

Sodium metabisulphite as an aqueous

solution containing 35% A.M. 0.455 g A.M. 0.455 g A.M. 0.455 g A.M.

Ammonium acetate 0.8 g 0.8 g 0.8 g

Antioxidant, sequestering agent q.s q.s q.s

Fragrance, preservative q.s q.s q.s

Aqueous ammonia containing 20% of NH₃ 10.2 g 10.2 g 10.2 g

Demineralized water q.s.100 g q.s.100 g q.s.100 g

A.M.: Active Material

Method of application

The mixture was applied to grey hair containing 90% of white hairs, in a proportion of 10 g of mixture for 1 g of hair. After a leave-on time of 30 minutes at ambient temperature, the hair was then rinsed, washed with a standard shampoo and dried. Results

The hair colouring was evaluated visually.

The colourings obtained are particularly strong and chromatic.

The following compositions 1 C7, 1 C8 and 1 C9 were pre pared.

1 C7 1 C8 1 C9

4-(3-aminopyrazolo[1 ,5-a]pyridin-2-yl)-1 , 1- 0.005 mol

dimethylpiperazin-1-ium chloride hydrochloride

1-{2-[(3-aminopyrazolo[1 ,5-a]pyridin-2- 0.008 mol

yl)amino]ethyl}-3-methyl-1 H-imidazol-3-ium

chloride hydrochloride

2-[(3-aminopyrazolo[1 ,5-a]pyridin-2- 0.0085 mol yl)oxy]ethanol hydrochloride

4-{2-[(3,5-diaminopyridin-2-yl)oxy]ethyl}-1 , 1- dimethylpiperazin-1-ium chloride 0.005 mol 0.008 mol 0.0085 mol hydrochloride

Polyglycerolated oleoyl alcohol comprising

2 mol of glycerol 4 g A.M. 4 g A.M. 4 g A.M.

Polyglycerolated oleoyl alcohol comprising

4 mol of glycerol (78% A.M.) 6 g A.M. 6 g A.M. 6 g A.M.

Oleic acid 3 g 3 g 3 g

Oleoyl amine comprising 2 EO, sold under

the name ETHOMEEN 012 by the company

AKZO 7 g A.M. 7 g A.M. 7 g A.M.

Diethylaminopropyl laurylamino

succinamate, sodium salt containing 55%

A.M. 3 g A.M. 3 g A.M. 3 g A.M.

Oleoyl alcohol 5 g 5 g 5 g

Alkyl (70/30 C13/C15, 50% linear) ether

carboxylic acid monoethanolamide (2 EO) 10 g A.M. 10 g A.M. 10 g A.M.

Propylene glycol 9.5 g 9.5 g 9.5 g

Ethyl alcohol 5 g 5 g 5 g

Hexylene glycol 9.3 g 9.3 g 9.3 g

Sodium metabisulphite as an aqueous 0.455 g

solution containing 35% A.M. A.M. 0.455 g A.M. 0.455 g A.M.

Ammonium acetate 0.8 g 0.8 g 0.8 g

Antioxidant, sequestering agent q.s q.s q.s

Fragrance, preservative q.s q.s q.s

Aqueous ammonia containing 20% of NH₃ 10.2 g 10.2 g 10.2 g

Demineralized water q.s.100 g q.s.100 g q.s.100 g

A.M.: Active Material

Method of application

The composition was diluted extemporaneously with 1 times its weight of 20-volumes aqueous hydrogen peroxide solution. The mixture was applied to grey hair containing 90% of white hairs, in a proportion of 10 g of mixture for 1 g of hair. After a leave-time of 30 minutes at ambient temperature, the hair was then rinsed, washed with a standard shampoo and dried. Results

The hair colouring was evaluated visually.

The colourings obtained are particularly strong and chromatic. EXAMPLES OF DYEING 2

The following compositions 2C1 and 2C1 were prepared.

2C1 2C1

2,3-diamino-6,7-dihydro-1 H,5H-pyrazolo[1 ,2-a]pyrazol- 0.008 mol 0.008 mol 1-one dimethanesulphonate

4-(3,5-diaminopyridin-2-yl)-1 , 1-dimethylpiperazin-1-ium 0.008 mol 0.006 mol chloride hydrochloride

0.002 mol

1-methyl-2-hydroxy-4-aminobenzene

Polyglycerolated oleoyl alcohol comprising 2 mol of

glycerol 4 g A.M. 4 g A.M.

Polyglycerolated oleoyl alcohol comprising 4 mol of

glycerol (78% A.M.) 6 g A.M. 6 g A.M.

Oleic acid 3 g 3 g

Oleoyl amine comprising 2 EO, sold under the name

ETHOMEEN 012 by the company AKZO 7 g A.M. 7 g A.M.

Diethylaminopropyl laurylamino succinamate, sodium

salt containing 55% A.M. 3 g A.M. 3 g A.M.

Oleoyl alcohol 5 g 5 g

Alkyl (70/30 C13/C15, 50% linear) ether carboxylic

acid monoethanolamide (2 EO) 10 g A.M. 10 g A.M.

Propylene glycol 9.5 g 9.5 g

Ethyl alcohol 5 g 5 g

Hexylene glycol 9.3 g 9.3 g Sodium metabisulphite as an aqueous solution

containing 35% A.M. 0.455 g A.M. 0.455 g A.M.

Ammonium acetate 0.8 g 0.8 g

Antioxidant, sequestering agent q.s q.s

Fragrance, preservative q.s q.s

Aqueous ammonia containing 20% of NH₃ 10.2 g 10.2 g

Demineralized water q.s.100 g q.s.100 g

A.M.: Active Material

Method of application

Results

The hair colouring was evaluated visually.

The colourings obtained are particularly chromatic.

The following composition 2C2 was prepared.

A.M.: Active Material

Method of application

The hair colouring was evaluated visually.

The colouring obtained is particularly chromatic.

The following composition 2C3 was prepared.

2C3

2,3-diamino-6,7-dihydro-1 H,5H-pyrazolo[1 ,2-a]pyrazol-1-one 0.008 mol dimethanesulphonate

4-{2-[(3,5-diaminopyridin-2-yl)oxy]ethyl}-1 , 1-dimethylpiperazin-1- 0.008 mol ium chloride hydrochloride

Polyglycerolated oleoyl alcohol comprising 2 mol of glycerol 4 g A.M.

Polyglycerolated oleoyl alcohol comprising 4 mol of glycerol (78% 6 g A.M.

A.M.: Active Material Method of application

Results

The hair colouring was evaluated visually.

The colouring obtained is particularly chromatic. EXAMPLES OF DYEING 3

The following composition 3C1 was prepared.

A.M.: Active Material

Method of application

The hair colouring was evaluated visually.

A.M.: Active Material Method of application

Results

The hair colouring was evaluated visually.

The colouring obtained is particularly strong and chromatic.

The following composition 3C3 was prepared.

Ammonium acetate 0.8 g

Antioxidant, sequestering agent q.s

Fragrance, preservative q.s

Aqueous ammonia containing 20% of NH₃ 10.2 g

Demineralized water q.s.100 g

A.M.: Active Material

Method of application

Results

The hair colouring was evaluated visually.

The colouring obtained is particularly strong and chromatic.

Claims

1. Composition for dyeing keratin fibres comprising, in a suitable dyeing medium:

- at least one oxidation base chosen from

• the 4,5-diaminopyrazole derivatives of formula (I), their addition salts, their solvates and the solvates of their salts:

in which:

- Ri , R₂, R3, R₄, R5 and R₆, which may be identical or different, represent a hydrogen atom; a C C₆ alkyl radical which is unsubstituted or substituted with at least one substituent chosen from OR, NHR, NRR', SR, SOR, S02R, COR, COOH, CONH2, CONHR, CONRR', PO(OH)₂, SH, S0₃X, a noncationic heterocycle, CI, Br or I, X denoting a hydrogen atom, Na, K or NH₄, and R and R', which may be identical or different, representing a C C₄ alkyl or alkenyl; a C₂-C₄ hydroxyalkyl radical; a C₂-C₄ aminoalkyl radical; a phenyl radical; a phenyl radical substituted with a halogen atom or a C C₄ alkyl, C C₄ alkoxy, nitro, trifluoromethyl, amino or Ci-C₄ alkylamino radical; a benzyl radical; a benzyl radical substituted with a halogen atom or with a C C alkyl, C C₄ alkoxy, methylenedioxy or amino radical; a radical of formula below:

- (CH₂)_m - X - (CH)_n - Z

Y

in which m and n are integers, which may be identical or different, between 0 and 3 inclusive, X represents an oxygen atom or else the NH group, Y represents a hydrogen atom or else a C C₄ alkyl radical, and Z represents a methyl radical when n is equal to 0, or Z represents a C C₄ alkyl radical, or an OR or NR"R"' group when n is greater than or equal to 1 , R" and R'", which may be identical or different, denoting a hydrogen atom or a C C₄ alkyl radical; or R₅ forms, with the nitrogen atom of the NR₃R₄ group in position 5, a heterocycle comprising at least 4 ring members;

at least one of the R^ R₂, R3 and R₄ radicals represents a hydrogen atom; • The aminopyrazolopyridine oxidation bases of formula (II) and also their addition salts, their eir salts:

in which:

RL R₂, R3, R₄ and R₅, which may be identical or different, represent a hydrogen or halogen atom; an -NHSO₃H radical; a hydroxyl radical; a (C C₄)alkyl radical; a (Ci-C₄)alkoxy radical; a (C C₄)alkylthio radical; mono(CrC₄)alkylamino; a di(Ci-C₄)alkylamino radical in which the two alkyl groups can, together with the nitrogen atom to which they are bonded, form a ring which can be interrupted with one or more nitrogen, oxygen or sulphur atoms; a heterocycle; a nitro radical; a phenyl radical; a carbonyl radical; a (C C₄)alkoxycarbonyl radical; a carboxamido radical; a cyano radical; an amino radical; a sulphonyl radical; a -C0₂H radical, an -SO₃H radical; a -P0₃H₂ radical; a -P0₄H₂ radical; or a group:

• the a

in which:

Zi and Z₂ independently represent:

- a single covalent bond;

- a divalent radical chosen from:

- an -0(CH₂)_p- radical, p denoting an integer ranging from 0 to 6; - an -NR'6(CH2)q(C₆H₄)t- radical, q denoting an integer ranging from 0 to 6 and t denoting 0 or 1 , R'₆ representing a hydrogen atom, or a C C₆ alkyl radical optionally substituted with one or more hydroxyl groups;

R and R'₂ independently represent:

- a hydrogen;

- a C1-C1₀ alkyl radical, which is optionally substituted and optionally interrupted with a heteroatom or a group chosen from O, N, Si, S, SO and S0₂;

- a halogen;

- an SO₃H radical;

- an optionally substituted C C₆ alkylcarbonyl radical;

R'₃, R'₄ and R'₅, which may be identical or different, represent:

- a hydrogen atom;

- a hydroxyl radical;

- a Ci-C₆ alkoxy radical;

- a Ci-C₆ alkylthio radical;

- an amino radical;

- a monoalkylamino radical;

- a Ci-C₆ dialkylamino radical in which the alkyl radicals can form, with the nitrogen atom to which they are attached, a saturated, unsaturated, aromatic or nonaromatic, 5- to 8-membered heterocycle which can contain one or more heteroatoms or groups chosen from N, O, S, S0₂ and CO, it being possible for the heterocycle to be cationic and/or substituted with a cationic radical;

- an optionally substituted C C₆ alkylcarbonyl radical;

- an -O-CO-R, -CO-O-R, N R-CO-R' or -CO-N RR' radical with R and R' as defined above;

- a halogen;

- an -NHSO₃H radical;

- an optionally substituted C C₄ alkyl radical;

• the oxidation bases chosen from the diamino-N,N-dihydropyrazolone derivatives of formula (IV), and also their salts, their solvates and the solvates of their salts:

in which:

RL R₂, R3 and R₄, which may be identical or different, represent:

- an aryl radical optionally substituted with one or more (C C₄)alkyl, hydroxyl, C C₂ alkoxy, amino or di(C C₂)alkylamino;

- a 5- or 6-membered heteroaryl radical optionally substituted with one or more radicals chosen from (C C₄)alkyl and (C C₂)alkoxy;

R₃ and R₄ can also represent a hydrogen atom; R₅, R₆ and R₇, which may be identical or different, represent:

- a hydrogen atom;

- a linear or branched C C₄ alkyl radical optionally substituted with one or more radicals chosen from hydroxyl, C C₂ alkoxy, carboxamido CONR₈Rg, sulphonyl

S0₂R₈, aryl optionally substituted with a (C C₄)alkyl, hydroxyl, C C₂ alkoxy, amino or di(CrC₂)alkylamino; an aryl radical optionally substituted with a (C C₄)alkyl, hydroxyl, C C₂ alkoxy, amino or di(C C₂)alkylamino; R₆ and R₇, which may be identical or different, can also represent a carboxamido radical CONR₈R₉; or a sulphonyl radical S0₂R₈;

R₈ and R₉, which may be identical or different, represent a hydrogen atom; or a linear or branched C C₄ alkyl radical optionally substituted with one or more hydroxyl or C C₂ alkoxy; and R₂, on the one hand, and R₃ and R₄, on the other hand, can form, with the nitrogen atom(s) to which they are attached, a saturated or unsaturated heterocycle comprising 5 to 7 ring members, which is optionally substituted with one or more radicals chosen from the group consisting of halogen atoms, amino, di(Ci-C₄)- alkylamino, hydroxyl, carboxy, carboxamido and (C C₂)alkoxy radicals, and Ci-C₄ alkyl radicals optionally substituted with one or more hydroxyl, amino, (di)alkylamino, alkoxy, carboxy or sulphonyl radicals; R₃ and R₄ can also form, together with the nitrogen atom to which they are attached, a 5- or 7-membered heterocycle of which the carbon atoms can be replaced with an oxygen or nitrogen atom, which is optionally substituted;

and

- at least one coupler chosen from the cationic aminopyridines of formula (V), their addition salts, their solva

in which the ZiR'i group bears the cationic charge;

Zi is an oxygen atom or an NR'₂ group; R'₂ is a hydrogen atom or a linear or branched C C₄ alkyl radical, a benzyl radical or an acetyl radical;

when Zi represents NR'₂, then

^■ R and R'₂ can form, together with the nitrogen atom to which they are attached, a saturated or unsaturated cationic heterocycle comprising from 5 to 8 ring members, which is optionally substituted with one or more radicals chosen from C C₁₀ alkyl radicals, and hydroxyl, C C₄ alkoxy, amino, (C C₄)alkylamino, di(C C₄)alkylamino, thio, (C C₄)alkylthio, carboxy, (C C₄)alkylcarbonyl, sulphonyl, amido and C C₄ hydroxyalkyi radicals, it being possible for this heterocycle to contain one or more heteroatoms chosen from N or O, preferably N, or

■ R and R'₂ can form, together with the nitrogen atom to which they are attached, a saturated or unsaturated noncationic heterocycle comprising from 5 to 8 ring members, which is substituted with a cationic radical and optionally substituted with one or more radicals chosen from C₁-C₁₀ alkyl radicals, and hydroxyl, C C₄ alkoxy, amino, (C C₄)alkylamino, di(C C₄)alkylamino, thio, (C C₄)alkylthio, carboxy, (Ci-C₄)alkylcarbonyl, sulphonyl, amido and C C₄ hydroxyalkyi radicals;

An- represents an anion or a mixture of anions;

with the exception of the following compounds:

1 2 3

2,3-diamino-6,7-dihydro-1 H,5H- pyrazolo[1 ,2-a]pyrazol-1-one 10^"3 mol 10^"3 mol 10^"3 mol dimethanesulphonate

2-[(3,5-diaminopyridin-2-yl)amino]-N,N,N- 10^"3 mol

trimethylethanammonium chloride

and of the compositions resulting from mixing each of the compositions 1 to 3 with an equal weight of 20-volumes aqueous hydrogen peroxide solution (6% by weight).

2 - Composition for dyeing keratin fibres comprising, in a suitable dyeing medium:

- at least one heterocyclic oxidation base as defined in Claim 1 ,

- at least one coupler chosen from the cationic aminopyridines of formula (VI) their addition salts, their solva

in which the Z ' group bears the cationic charge;

Z'i is an oxygen atom or an NR"₂ group; R"₂ is a hydrogen atom or a linear or branched C C₄ alkyl radical, a benzyl radical or an acetyl radical;

R"i is a linear or branched, saturated C1-C10 alkyl radical which is substituted or interrupted with a cationic radical, which is optionally interrupted with one or more oxygen atoms and/or with one or more NR"₂ groups, which is optionally substituted with one or more radicals chosen from C C₄ hydroxyalkyi and alkoxy and hydroxyl radicals, or R"i is a saturated, unsaturated or aromatic cationic heterocycle comprising from 5 to 8 ring members, which is optionally substituted with one or more radicals chosen from C C₄ alkyl, hydroxyl, C C₄ alkoxy, amino, (C C₄)- alkylamino, di(C C₄)alkylamino, thio, (C C₄)alkylthio, carboxy, (C C₄)alkylcarbonyl, sulphonyl, amido and C C₄ hydroxyalkyi radicals;

when Z'i represents NR"₂, then

^■ R"i and R"₂ can form, together with the nitrogen atom to which they are attached, a saturated or unsaturated cationic heterocycle comprising from 5 to 8 ring members, which is optionally substituted with one or more radicals chosen from C1-C10 alkyl radicals, and hydroxyl, C C₄ alkoxy, amino, (C C₄)alkylamino, di(Ci-C₄)alkylamino, thio, (C C₄)alkylthio, carboxy, (C C₄)alkylcarbonyl, sulphonyl, amido and C C₄ hydroxyalkyi radicals, it being possible for this heterocycle to contain one or more heteroatoms chosen from N or O, preferably N, or

■ R"i and R"₂ can form, together with the nitrogen atom to which they are attached, a saturated or unsaturated noncationic heterocycle comprising from 5 to 8 ring members, which is substituted with a cationic radical and optionally substituted with one or more radicals chosen from C1-C10 alkyl radicals, and hydroxyl, C C₄ alkoxy, amino, (C C₄)alkylamino, di(C C₄)alkylamino, thio, (C C₄)alkylthio, carboxy, (Ci-C₄)alkylcarbonyl, sulphonyl, amido and C C₄ hydroxylalkyl radicals;

An- represents an anion or a mixture of anions;

and

- at least one coupler chosen from benzene couplers.

3. Composition according to Claim 1 , in which, in formula (I), R₆ is hydrogen, R^ R₂, R₃ and R₄ represent a hydrogen atom or a C C₄ alkyl radical, and R₅ is a C C₄ alkyl, hydroxyalkyi or alkoxyalkyl radical.

4. Composition according to any one of Claims 1 to 3, in which the compound of formula (I) is chosen from 4,5-diamino-1 -(2-hydroxyethyl)-1 H- pyrazole and its addition salts, its solvates and the solvates of its salts, such as 4,5-diamino-1 -(2-hydroxyethyl)-1 H-pyrazole solvate.

5. Composition according to Claim 1 , in which the compounds of formula (II) are chosen from the compou low:

R

in which:

Ri , R₂ and R₃, which may be identical or different, represent a hydrogen or halogen atom; a hydroxyl radical; a (C C₄)alkyl radical; a (C C₄)alkylthio radical; a (Ci-C₄)alkoxy radical; an -NHSO₃H radical; an amino radical; a (C C₄)alkylamino radical; a di(C C₄)alkylamino radical in which the two alkyl groups can, together with the nitrogen atom to which they are bonded, form a ring which can be interrupted with one or more nitrogen, oxygen or sulphur atoms; a heterocycle; a sulphonamide radical, a carbonyl radical, a (C C₄)alkoxycarbonyl radical, a carboxamido radical, or a group of formula below:

in which R'" represents an oxygen or nitrogen atom, X represents an oxygen atom or an NH or NH(C C₄)alkyl group, and Y represents a hydroxyl, amino, C C₄ alkyl, (C C₄)alkoxy, (C C₄)alkylamino, or di(C C₄)alkylamino radical.

6. Composition according to any one of the preceding claims, in which the 3- aminopyrazolo[1 ,5-a]pyridines of formula (II) are chosen from:

- pyrazolo[1 ,5-a]pyridin-3-ylamine;

- 2-acetylaminopyrazolo[1 ,5-a]pyridin-3-ylamine;

- 2-morpholin-4-ylpyrazolo[1 ,5-a]pyridin-3-ylamine;

- 3-aminopyrazolo[1 ,5-a]pyridine-2-carboxylic acid;

- 2-methoxypyrazolo[1 ,5-a]pyridin-3-ylamino;

- (3-aminopyrazolo[1 ,5-a]pyridin-7-yl)methanol;

- 2-(3-aminopyrazolo[1 ,5-a]pyridin-5-yl)ethanol;

- 2-(3-aminopyrazolo[1 ,5-a]pyridin-7-yl)ethanol;

- (3-aminopyrazolo[1 ,5-a]pyridin-2-yl)methanol;

- 3,6-diaminopyrazolo[1 ,5-a]pyridine;

- 3,4-diaminopyrazolo[1 ,5-a]pyridine;

- pyrazolo[1 ,5-a]pyridine-3,7-diamine; - 7-morpholin-4-ylpyrazolo[1 ,5-a]pyridin-3-ylamine;

- pyrazolo[1 ,5-a]pyridine-3,5-diamine;

- 5-morpholin-4-ylpyrazolo[1 ,5-a]pyridin-3-ylamine;

- 2-[(3-aminopyrazolo[1 ,5-a]pyridin-5-yl)(2-hydroxyethyl)arnino]ethanol;

- 2-[(3-aminopyrazolo[1 ,5-a]pyridin-7-yl)(2-hydroxyethyl)amino]ethanol;

- 3-aminopyrazolo[1 ,5-a]pyridin-5-ol;

- 3-aminopyrazolo[1 ,5-a]pyridin-4-ol;

- 3-aminopyrazolo[1 ,5-a]pyridin-6-ol;

- 3-aminopyrazolo[1 ,5-a]pyridin-7-ol;

- 2-methoxy-6,7-dimethylpyrazolo[1 ,5-a]pyridin-3-amine;

- 2-[(3-aminopyrazolo[1 ,5-a]pyridin-2-yl)oxy]ethanol;

- 4-ethyl-2-methoxy-7-methylpyrazolo[1 ,5-a]pyridin-3-amine hydrochloride;

- 1-(3-aminopyrazolo[1 ,5-a]pyridin-2-yl)pyrrolidin-3-ol;

- 2,2'-[(3-aminopyrazolo[1 ,5-a]pyridin-2-yl)imino]diethanol;

- 2-[(3-aminopyrazolo[1 ,5-a]pyridin-2-yl)amino]ethanol;

- N2-(2-pyridin-3-ylethyl)pyrazolo[1 ,5-a]pyridine-2,3-diamine;

and their addition salts, their solvates and the solvates of their salts.

7. Composition according to any one of the preceding claims, in which, in formula (III), Zi and/or Z₂ represent(s) a covalent bond, an -NR'6(CH₂)q- radical or an -0(CH₂)_p- and R and/or R'₂ is (are) a cationic radical.

8. Composition according to any one of the preceding claims, in which, in formula (III), R or R'₂ denotes imidazoles substituted with a quaternary ammonium radical or imidazoliums, piperazines substituted with a quaternary ammonium radical or piperaziniums, pyrrolidines substituted with a quaternary ammonium radical or pyrrolidiniums, or diazepanes substituted with a quaternary ammonium radical or diazepaniums.

9. Composition according to any one of the preceding claims, in which, in formula (III), R and R'₂ independently represent a hydrogen atom, or a trialkylammonium, tri(hydroxyalkyl)ammonium, hydroxyalkyldialkylammonium or di(hydroxyalkyl)alkylammonium group.

10. Composition according to any one of the preceding claims, in which the R'₃, R'₄ and R'₅ radicals of formula (III) independently represent a hydrogen atom or a Ci-C₄ alkyl radical which can be substituted.

1 1. Composition according to any one of the preceding claims, in which the compound of formula (III) corresponds to:

in which Zi , R'i , R'₃, R'₄ and R'₅ are as defined in any one of the preceding claims.

12. Composition according to Claim 1 1 , in which Zi represents a covalent bond, an -NR'6(CH₂)q- radical or an -0(CH₂)_p- radical and R is a cationic radical.

13. Composition according to any one of the preceding claims, in which the compound of formula (III) is chosen from:

salt

salt

-ium salt salt

salt salt salt salt salt salt

salt

salt -ium salt salt salt

i.e. last row

(3-Amino-2-methoxypyrazolo[1 ,5-a]pyridin-4-yl)trimethylammoniurri salt and their addition salts, their solvates and the solvates of their salts.

14. Composition according to any one of the preceding claims, in which the compounds of formulae (I) and (II) are chosen from:

4-(3-Aminopyrazolo[1 ,5-a]pyridin-2-yl)-1 , 1-dimethylpiperazin-1-ium salt

3-[2-(3-Aminopyrazolo[1 ,5-a]pyridin-2-ylamino)ethyl]-1-methyl-3H-imidazol-1-ium salt,

and 2-[(3-aminopyrazolo[1 ,5-a]pyridin-2-yl)oxy]ethanol, their addition salts, their solvates and the solvates of their salts.

15. Composition according to Claim 1 , in which, in formula (IV), and R₂ are chosen from a C C₆ alkyl radical optionally substituted with a hydroxyl, (CrC₂)alkoxy, amino or (di)(CrC₂)alkylamino; a phenyl radical, and a methoxyphenyl, ethoxyphenyl or benzyl radical, preferably a methyl, ethyl, 2-hydroxyethyl, 3-hydroxypropyl, 2-hydroxypropyl or phenyl radical.

16. Composition according to Claim 1 , in which and R₂ form, together with the nitrogen atoms to which they are attached, a saturated or unsaturated, optionally substituted, 5- or 6-membered ring, preferably a pyrazolidine ring or a pyridazolidine ring, which is optionally substituted with one or more C C₄ alkyl radicals, a hydroxyl, a (C C₂)alkoxy, a carboxy, a carboxamido, an amino or a (di)(C C₂)alkylamino.

17. Composition according any one of the preceding claims, in which, in formula (IV), R₃ and R₄ are chosen from a hydrogen atom; a linear or branched Ci-C₆ alkyl radical optionally substituted with one or more hydroxyl, (C C₂)alkoxy, or amino or a (di)(C C₂)alkylamino; a phenyl radical optionally substituted with one or more hydroxyl, amino or (C C₂)alkoxy radicals, preferably a hydrogen atom, and a methyl, ethyl, isopropyl, 2-hydroxyethyl, 3-hydroxypropyl, 2-hydroxypropyl and 2-carboxyethyl radical.

18. Composition according to any one of the preceding claims, in which, in formula (IV), R₃ and R₄ form, together with the nitrogen atom to which they are attached, a 5- or 7-membered ring chosen from pyrrolidine, piperidine, homopiperidine, piperazine and homopiperazine heterocycles; it being possible for said rings to be substituted with one or more of the following radicals: hydroxyl, amino, (di)(C C₂)alkylamino, carboxy, carboxamido, C C₄ alkyl which is optionally substituted with one or more hydroxyl, amino or (di)(C C₂) alkylamino, preferably a 5- or 7-membered ring chosen from pyrrolidine, 2,5-dimethylpyrrolidine, pyrrolidine- 2-carboxylic acid, 3-hydroxypyrrolidine-2-carboxylic acid, 4-hydroxypyrrolidine-2- carboxylic acid, 2,4-dicarboxypyrrolidine, 3-hydroxy-2-hydroxymethylpyrrolidine, 2- carboxamidopyrrolidine, 3-hydroxy-2-carboxamidopyrrolidine, 2-(diethyl- carboxamido)pyrrolidine, 2-hydroxymethylpyrrolidine, 3,4-dihydroxy-2-hydroxy- methylpyrrolidine, 3-hydroxypyrrolidine, 3,4-dihydroxypyrrolidine, 3- aminopyrrolidine, 3-methylaminopyrrolidine, 3-dimethylaminopyrrolidine, 4-amino-3- hydroxypyrrolidine, 3-hydroxy-4-(2-hydroxyethyl)aminopyrrolidine, piperidine, 2,6- dimethylpiperidine, 2-carboxypiperidine, 2-carboxamidopiperidine, 2-hydroxy- methylpiperidine, 3-hydroxy-2-hydroxymethylpiperidine, 3-hydroxypiperidine, 4- hydroxypiperidine, 3-hydroxymethylpiperidine, homopiperidine, 2- carboxyhomopiperidine, 2-carboxamidohomopiperidine, homopiperazine, N- methylhomopiperazine and N-(2-hydroxyethyl)homopiperazine.

19. Composition according to Claims 1 to 18, in which the compound of formula (IV) or one of its addition salts is chosen from:

2,3-Diamino-6,7-dihydro-1 H,5H-pyrazolo[1 ,2-a]pyrazol-1-one;

2-Amino-3-ethylamino-6,7-dihydro-1 H,5H-pyrazolo[1 ,2-a]pyrazol-1-one;

2-Amino-3-isopropylamino-6,7-dihydro-1 H,5H-pyrazolo[1 ,2-a]pyrazol-1-one;

2-Amino-3-(pyrrolidin-1-yl)-6,7-dihydro-1 H,5H-pyrazolo[1 ,2-a]pyrazol-1-one;

4,5-diamino-1 ,2-dimethyl-1 ,2-dihydropyrazol-3-one;

4,5-diamino-1 ,2-diethyl-1 ,2-dihydropyrazol-3-one;

4,5-diamino-1 ,2-di(2-hydroxyethyl)-1 ,2-dihydropyrazol-3-one;

2-amino-3-(2-hydroxyethyl)amino-6,7-dihydro-1 H,5H-pyrazolo[1 ,2-a]pyrazol-1-one; 2-amino-3-dimethylamino-6,7-dihydro-1 H,5H-pyrazolo[1 ,2-a]pyrazol-1-one;

2,3-diamino-5,6,7,8-tetrahydro-1 H,6H-pyridazino[1 ,2-a]pyrazol-1-one;

4-Amino-1 ,2-diethyl-5-(pyrrolidin-1-yl)-1 ,2-dihydropyrazol-3-one;

4-Amino-5-(3-dimethylaminopyrrolidin-1-yl)-1 ,2-diethyl-1 ,2-dihydropyrazol-3-one; 2,3-diamino-6-hydroxy-6,7-dihydro-1 H,5H-pyrazolo[1 ,2-a]pyrazol-1-one.

20. Composition according to any one of the preceding claims, in which, in formula (V), the cationic radical is a linear, branched or cyclic, saturated or unsaturated radical comprising a quaternary ammonium, this quaternary ammonium being of the -N⁺RaRbRc type, Ra, Rb and Rc, which may be identical or different, representing a C C₆ alkyl radical which can be substituted with a hydroxyl, it being possible for Ra and Rb together to form a heterocycle comprising from 5 to 8 ring members, the Rc radical then being a C C₆ alkyl radical which can be substituted with a hydroxyl.

21. Composition according to Claim 20, in which, in formula (V), the cationic radical is chosen from trimethylammonium, triethylammonium, dimethylethylammonium, diethylmethylammonium, diisopropylmethylammonium, diethylpropylammonium, hydroxyethyldiethylammonium, di-beta-hydroxyethyl- methylammonium, tri-beta-hydroxyethylammonium, piperidinium, N-methyl- piperidinium, pyrrolidinium, N-methylpyrrolidinium, morpholinium, N-methyl- morpholinium, imidazolium, hydroxyethylimidazolium, methylimidazolium, piperazinium and N-methylpiperazinium radicals.

22. Composition according to any one of the preceding claims, in which, in formula (VI), R"i is a C C₈ alkyl radical substituted or interrupted with a cationic radical, optionally interrupted with one or more oxygen atoms and/or with one or more NR"₂ groups, which is optionally substituted with a hydroxyl radical.

23. Composition according to any one of Claims 1 to 22, in which, in formula (VI), ΖΊ is an oxygen atom or NR"₂ with R"₂ chosen from hydrogen or a linear or branched C C₄ alkyl radical, and R"i represents a saturated linear C₂-C₈ alkyl radical, optionally interrupted with an oxygen atom or with an NH group, optionally substituted with a hydroxyl radical, and substituted or interrupted with a cationic radical chosen from trimethylammonium, imidazolium, piperazinium, piperidinium, pyrrolidinium and morpholinium radicals.

24. Composition according to any one of the preceding claims, in which, in formula (VI), ΖΊ is an NR"₂ group and R"i and R"₂ form, together with the nitrogen atom to which they are attached, a saturated or unsaturated cationic heterocycle comprising from 5 to 8 ring members, which is optionally substituted with one or more radicals chosen from C Ci₀ alkyl or C Ci₀ hydroxyalkyl radicals.

25. Composition according to any one of the preceding claims, in which, in formula (VI), ΖΊ is an NR"₂ group and R"i and R"₂ form, together with the nitrogen atom to which they are attached, a saturated or unsaturated, noncationic heterocycle comprising from 5 to 8 ring members, which is substituted with a cationic radical.

26. Composition according to any one of the preceding claims, in which the compounds of formula (V) are chosen from the following compounds: 2-[(3,5- diaminopyridin-2-yl)amino]-N,N,N-trimethylethanammonium, 2-[(3,5-diaminopyridin- 2-yl)(methyl)amino]-N,N,N-trimethylethanammonium, 4-{2-[(3,5-diaminopyridin-2- yl)oxy]ethyl}-1 , 1-dimethylpiperazin-1-ium, 1-{2-[(3,5-diaminopyridin-2-yl)amino]- ethyl}-1-methylpiperidinium, 1-(3,5-diaminopyridin-2-yl)-N,N,N-trimethylpyrrolidin-3- ammonium, 1-{3-[(3,5-diaminopyridin-2-yl)amino]propyl}-3-(2-hydroxyethyl)-1 H- imidazol-3-ium, 1-{3-[(3,5-diaminopyridin-2-yl)amino]propyl}-1-methylpiperidiniurn,

1- {2-[(3,5-diaminopyridin-2-yl)amino]ethyl}-1-methylpyrrolidinium, 1-{3-[(3,5- diaminopyridin-2-yl)amino]propyl}-1-methylpyrrolidiniurn, 1-{2-[(3,5-diaminopyridin-

2- yl)amino]ethyl}-3-methyl-1 H-imidazol-3-ium, 4-{3-[(3,5-diaminopyridin-2-yl)amino]- propyl}-4-methylmorpholin-4-ium, 4-{2-[(3,5-diaminopyridin-2-yl)amino]ethyl}-4- methylmorpholin-4-ium, 1-[2-({2-[(3,5-diaminopyndin-2-yl)arnino]ethyl}arnino)ethyl]-

1- methylpiperidinium, 1-[2-({2-[(3,5-diaminopyridin-2-yl)amino]ethyl}arnino)ethyl]-1- methylpyrrolidinium, 1-[2-({2-[(3,5-diaminopyridin-2-yl)amino]ethyl}arnino)ethyl]-3- methyl-1 H-imidazol-3-ium, 4-[2-({2-[(3,5-diaminopyridin-2- yl)amino]ethyl}amino)ethyl]-4-methylmorpholin-4-ium, 2-({2-[(3,5-diaminopyridin-2- yl)amino]ethyl}amino)-N,N,N-trimethylethanammonium, 3-({2-[(3,5-diaminopyridin-

2- yl)amino]ethyl}amino)-N,N,N-trimethylpropan-1 -ammonium, 2-{2-[(3,5- diaminopyridin-2-yl)amino]ethoxy}-N,N,N-trimethylethanammonium, 3-{2-[(3,5- diaminopyridin-2-yl)amino]ethoxy}-N , N , N-trimethylpropan-1 -ammonium, 1 -(2-{2- [(3,5-diaminopyridin-2-yl)amino]ethoxy}ethyl)-1-methylpiperidinium, 1-(2-{2-[(3,5- diaminopyridin-2-yl)amino]ethoxy}ethyl)-1-methylpyrrolidinium, 1-{3-[(3,5- diaminopyridin-2-yl)amino]propyl}-3-methyl-1 H-imidazol-3-ium, 1-[3-({2-[(3,5- diaminopyridin-2-yl)amino]ethyl}amino)propyl]-3-methyl-1 H-imidazol-3-ium, 4-[3-({2- [(3,5-diaminopyridin-2-yl)amino]ethyl}amino)propyl]-1 , 1-dimethylpiperazin-1-ium, 1- (3-{2-[(3,5-diaminopyridin-2-yl)amino]ethoxy}propyl)-1-methylpiperidinium, 4-[3-({2- [(3,5-diaminopyridin-2-yl)amino]ethyl}amino)propyl]-4-methylmorpholin-4-ium, 3-({2- [(3,5-diaminopyridin-2-yl)amino]ethyl}amino)-N-ethyl-N-methyl-N-propylpropan-1- ammonium, 3-[(3,5-diaminopyridin-2-yl)amino]-N,N, N-trimethylpropan-1 - ammonium, 3-[(3,5-diaminopyridin-2-yl)(methyl)amino]-N,N, N-trimethylpropan-1 - ammonium, 3-[(3,5-diaminopyridin-2-yl)oxy]-N,N, N-trimethylpropan-1 -ammonium,

1- {2-[(3,5-diaminopyridin-2-yl)amino]ethyl}-3-(2-hydroxyethyl)-1 H-imidazol-3-ium, 4- (3,5-diaminopyridin-2-yl)-1-(2-hydroxyethyl)-1-methylpiperazin-1-ium, 4-(3,5- diaminopyridin-2-yl)-1 , 1-bis(2-hydroxyethyl)piperazin-1-ium, 4-(3,5-diaminopyridin-

2- yl)(2-trimethylethane)morpholinammonium, 4-(3,5-diaminopyridin-2-yl)(2- methyldiethylethane)morpholinammonium, N-[4-(3,5-diaminopyridin-2-yl)morpholin-

2-ylmethyl]-N-methylpyrrolidinium, (3,5-diaminopyridin-2-yl)-3-trimethyl- piperidinammonium, (3,5-diaminopyridin-2-yl)-4-trimethylpiperidinammonium and 4- (3,5-diaminopyridin-2-yl)-1 , 1-dimethylpiperazin-1-ium.

27. Composition according to any one of Claims 2 to 19, in which the compound(s) of formula (VII) is (are) chosen from 2-methyl-5-aminophenol, 5-Ν-(β- hydroxyethyl)amino-2-methylphenol and 2-chloro-6-methyl-5-aminophenol.

28. Composition according to any one of the preceding claims, comprising at least one oxidizing agent.

30. Process for dyeing keratin fibres, in which the composition as defined in any one of the preceding claims is applied to the keratin fibres in the presence of at least one oxidizing agent for a period of time sufficient to develop the desired colouring.