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Title:
COMPOSITION FOR DYEING KERATIN FIBRES WITH A TETRAAZAPENTAMETHINE CATIONIC DIRECT DYE AND ANOTHER PARTICULAR DIRECT DYE
Document Type and Number:
WIPO Patent Application WO/2007/071689
Kind Code:
A1
Abstract:
The invention relates to a composition for dyeing keratin fibres, in particular human keratin fibres such as the hair, comprising, in a suitable dyeing medium, at least one tetraazapentamethine cationic direct dye of Formula (I), and which is characterized in that it also contains at least one azo, methine or azomethine direct dye containing a quaternary ammonium group included in a ring, other than the dyes of Formula (I). The invention also relates to the processes and dyeing devices using the said composition.

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Inventors:
DE BONI, Maxime (3 rue de Lagny, Paris, Paris, F-75020, FR)
RONDEAU, Christine (10 Bis rue de Verdun, Sartrouville, F-78500, FR)
Application Number:
EP2006/069935
Publication Date:
June 28, 2007
Filing Date:
December 19, 2006
Export Citation:
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Assignee:
L'ORÉAL (14 rue Royale, Paris, Paris, F-75008, FR)
DE BONI, Maxime (3 rue de Lagny, Paris, Paris, F-75020, FR)
RONDEAU, Christine (10 Bis rue de Verdun, Sartrouville, F-78500, FR)
International Classes:
A61Q5/06; A61K8/49
Attorney, Agent or Firm:
FEVRIER, Murielle (L'OREAL, 25-29 Quai Aulagnier - Dipi, Asnieres-sur-Seine Cedex, F-92665, FR)
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Claims:
CLAIMS

1. Composition for dyeing keratin fibres, in particular human keratin fibres and more particularly the hair, comprising, in a suitable dyeing medium, (i) at least one tetraazapentamethine compound of formula (I) and (ii) at least one azo, methine or azomethine direct dye containing a quaternary ammonium group included in a ring, other than the dyes of formula (I):

in which - W 1 represents a cationic heteroaromatic radical of formula (II) or (III):

(H) (III)

W 2 represents a heteroaromatic radical of formula (IV) or (V):

(TV) (V) in which: - Z 0 represents a radical CR 2 , a nitrogen atom or a radical NR 21 ,

Z 1 represents an oxygen or sulfur atom or a radical NR 9 , Z 2 represents a nitrogen atom or a radical CR 1 O, Z 3 represents a nitrogen atom or a radical CR 11 , Z 4 represents a nitrogen atom or a radical CR 12 , - Z 5 represents a nitrogen atom or a radical CR 13 ,

Z 6 represents a nitrogen atom or a radical CR 14 , Z 7 represents an oxygen or sulfur atom or a radical NR 15 , Z 8 represents a nitrogen atom or a radical CR-iβ,

Zg represents a nitrogen atom or a radical CR 1 7,

Z 10 represents a nitrogen atom or a radical CRi 8 ,

Z 11 represents a nitrogen atom or a radical CR- 1 9,

Z 12 represents a nitrogen atom or a radical CR 2 O, - Z 13 represents a radical CR 6 , a nitrogen atom or a radical NR 22 , it being understood that each of the rings of formulae (II), (III), (IV) and (V) comprise not more than three nitrogen atoms and that two of the three nitrogen atoms may be contiguous, the bond a of the 5-membered cationic heteroaromatic radical of formula (II) being linked to the nitrogen atom N 1 of formula (I), the bond b of the 6-membered cationic heteroaromatic radical of formula (III) being linked to the nitrogen atom N 1 of formula (I), the double bond a' of the 5-membered heteroaromatic radical of formula (IV) being linked to the nitrogen atom N 2 of formula (I), - the double bond b' of the 6-membered heteroaromatic radical of formula (V) being linked to the nitrogen atom N 2 of formula (I), the bond b, linking the cationic heteroaromatic radical of formula (III) to the nitrogen atom N 1 of formula (I), being in an ortho or para position relative to the nitrogen atom bearing the radical R 4 when Z 5 represents a radical CR 13 ; the bond b being in an ortho position relative to the nitrogen atom bearing the radical R 4 when Z 5 represents a nitrogen atom, the bond b', linking the heteroaromatic radical of formula (V) to the nitrogen atom N 2 of formula (I), being in an ortho or para position relative to the nitrogen atom bearing the radical R 7 when Z 11 represents a radical CR ig ; the bond b' being in an ortho position relative to the nitrogen atom bearing the radical R 7 when Z 11 represents a nitrogen atom,

R 2 , R 6 , R 1O and R 16 represent, independently of each other, a hydrogen atom; a linear or branched C 1 -C 4 alkyl radical, which is unsubstituted or substituted with one to three radicals chosen from hydroxyl, C 1 -C 2 alkoxy, C 2 -C 4 (poly)hydroxyalkoxy, amino, C 1 -C 2 (di)alkylamino, carboxyl and sulfonic radicals; a phenyl radical, which is unsubstituted or substituted with one to three radicals chosen from hydroxyl, C 1 -C 2 alkoxy, C 2 -C 4 (poly)hydroxyalkoxy, amino and C 1 -C 2 (di)alkylamino radicals; a carboxyl radical; a sulfonylamino radical,

R 1 , R 4 , R 5 , R 7 , R 9 , R 15 , R 21 and R 22 represent, independently of each other, a linear or branched C 1 -C 8 alkyl radical, which is unsubstituted or substituted with one to three radicals chosen from hydroxyl, C 1 -C 2 alkoxy, C 2 -C 4 (poly)hydroxyalkoxy, amino, C 1 -C 2

(di)alkylamino, carboxyl and sulfonic radicals;

R 0 , R3, Rs, R11, R12, Ri3, Ri4, Ri7, R18, Ri9 and R 2 o represent, independently of each other, a hydrogen atom, a linear or branched C 1 -C 1 6 hydrocarbon-based chain, this chain possibly being saturated or unsaturated with one to three unsaturations, this chain being unsubstituted or substituted with one to three radicals chosen from hydroxyl, C 1 -C 2 alkoxy, C 2 -C 4 (poly)hydroxyalkoxy, amino, C 1 -C 2 (di)alkylamino, carboxyl, sulfonic, sulfonylamino and C 2 -C 4 (poly)hydroxyalkylamino radicals or a halogen atom such as chlorine, fluorine or bromine; a phenyl radical, which is unsubstituted or substituted with one to three radicals chosen from hydroxyl, C 1 -C 2 alkoxy, C 2 -C 4 (poly)hydroxyalkoxy, amino, C 1 -C 2 (di)alkylamino, carboxyl, sulfonic, sulfonylamino and C 2 -C 4 (poly)hydroxyalkylamino radicals or a halogen atom such as chlorine, fluorine or bromine; a heteroaryl radical chosen from pyrazolyl, pyrrolyl, imidazolyl, thiazolyl, oxazolyl, triazolyl, pyridyl, pyrimidinyl, triazinyl, pyrazinyl and pyridazinyl radicals; in addition, this hydrocarbon-based chain may be interrupted with one or two oxygen, nitrogen or sulfur atoms or with an SO 2 radical, it being understood that R 0 , R3, Re, Rn, R12, R13, Ri 4 , R17, R18, R19 and R 20 do not comprise a peroxide bond or diazo or nitroso radicals,

R 2 with R 10 , R 11 with R 12 , R 6 with R 16 , and R 17 with R 18 can form, independently of each other, a 5- or 6-membered carbon-based aromatic ring, which is unsubstituted or substituted with one or two hydroxyl, amino, (di)(CrC 2 )alkylamino, C 1 -C 2 alkoxy or

C 2 -C 4 (poly)hydroxyalkylamino radicals, X is an organic or mineral anion.

2. Composition according to Claim 1 , characterized in that, in formula I, Z 1 represents an oxygen atom or a radical NR 9 and Z 7 represents an oxygen atom or a radical NR 15 .

3. Composition according to Claims 1 and 2, in which R 0 represents a hydrogen atom; a linear or branched C 1 -C 6 alkyl radical, which is unsubstituted or substituted with one to three radicals chosen from hydroxyl, C 1 -C 2 alkoxy, C 2 -C 4 (poly)hydroxyalkoxy, amino, C 1 -C 2 (di)alkylamino, C 2 -C 4 (poly)hydroxyalkylamino, carboxyl and sulfonic radicals; a phenyl radical, which is unsubstituted or substituted with one to three radicals chosen from hydroxyl, C 1 -C 2 alkoxy, C 2 -C 4 (poly)hydroxyalkoxy, amino, C 1 -C 2 (di)alkylamino, carboxyl and sulfonic radicals or a halogen atom such as chlorine, fluorine or bromine; an optionally cationic heteroaryl radical chosen from pyrazolyl, pyrrolyl, imidazolyl, thiazolyl, oxazolyl, triazolyl, pyridyl, pyrimidinyl, triazinyl, pyrazinyl and pyridazinyl radicals.

4. Composition according to any one of the preceding claims, in which R 0 represents a hydrogen atom; a methyl, ethyl or 2-methoxyethyl radical; a phenyl radical, which is unsubstituted or substituted with an amino, (di)methylamino or (di)(2-hydroxyethyl)amino radical, or an optionally cationic heteroaryl radical chosen from pyrazolyl, pyrrolyl, imidazolyl and pyridyl radicals.

5. Composition according to any one of the preceding claims, in which R 2 , Re, R-io and R 16 represent a hydrogen atom, a C 1 -C 4 alkyl radical, which is unsubstituted or substituted with one or two radicals chosen from hydroxyl, amino, C 1 -C 2 (di)alkylamino and carboxyl radicals, or a phenyl radical.

6. Composition according to any one of the preceding claims, in which R 2 , R 6 , R 1 O and R 16 preferably represent a hydrogen atom, a methyl, phenyl or 2-hydroxymethyl radical or a carboxyl.

7. Composition according to any one of the preceding claims, in which R 1 , R 4 , R 5 , R 7 , R 9 , R 15 , R 21 and R 22 preferably represent a C 1 -C 4 alkyl radical, which is unsubstituted or substituted with one or two radicals chosen from hydroxyl, C 1 -C 2 alkoxy, amino, C 1 -C 2 (di)alkylamino, carboxyl and sulfonic radicals.

8. Composition according to any one of the preceding claims, in which R 1 , R 4 , R 5 , R 7 , Rg, R 15 , R 21 and R 22 represent a methyl, ethyl, 2-hydroxyethyl, 1-carboxymethyl, 2- carboxyethyl or 2-sulfonylethyl radical.

9. Composition according to any one of the preceding claims, in which R 3 , R 8 , R 11 , R 12 , R- I 3, Ri 4 . R- 1 7. R- 1 8. R- 1 9 and R 20 represent, independently of each other, a hydrogen atom; a linear or branched C 1 -C 4 alkyl radical, which is unsubstituted or substituted with one or two radicals chosen from hydroxyl, C 1 -C 2 alkoxy, C 2 -C 4 (poly)hydroxyalkoxy, amino, C 1 -C 2 (di)alkylamino, carboxyl and sulfonic radicals; a phenyl radical, which is unsubstituted or substituted with one or two radicals chosen from hydroxyl, C 1 -C 2 alkoxy, C 2 -C 4 (poly)hydroxyalkoxy, amino, C 1 -C 2 (di)alkylamino, carboxyl and sulfonic radicals or a halogen atom such as chlorine, fluorine or bromine; a sulfonylamino radical; a C 2 -C 4 (poly)hydroxyalkylamino radical.

10. Composition according to any one of the preceding claims, in which R 3 , R 8 , R 11 , R 12 , Ri3, Ri 4 , Ri7, Ri8, Ri9 and R 20 represent, independently of each other, a hydrogen atom, a

methyl or 2-hydroxymethyl radical, a carboxyl, a methoxy, ethoxy or 2-hydroxyethyloxy radical, or an amino, methylamino, dimethylamino or 2-hydroxyethylamino radical.

1 1. Composition according to any one of the preceding claims, in which W 1 is a 2- pyridinium radical and W 2 is a 2-pyridine radical.

12. Composition according to Claim 11 , in which the compound of formula (I) is chosen from the following compounds:

- 2-[5-(N-methyl-2-pyridinylidene)-1 -formazano]-N-methylpyridinium chloride - 2-[5-(N-methyl-2-pyridinylidene)-3-methyl-1-formazano]-N-methylpyridinium chloride

- 2-[5-(N-methyl-2-pyridinylidene)-3-ethyl-1 -formazano]-N-methylpyridinium chloride

- 2-[5-(N-methyl-2-pyridinylidene)-3-isopropyl-1 -formazano]-N-methylpyridinium chloride

- 2-[5-(N-methyl-2-pyridinylidene)-3-phenyl-1 -formazano]-N-methylpyridinium chloride

- 2-[5-(N-methyl-2-pyridinylidene)-3-(4'-methoxyphenyl)-1-formazano]-N-methylpyridinium chloride

- 2-[5-(N-methyl-2-pyridinylidene)-3-(4'-hydroxyphenyl)-1-formazano]-N-methylpyridinium chloride

- 2-[5-(N-methyl-2-pyridinylidene)-3-(4'-N,N-dimethylaminophenyl)-1-formazano]-N- methylpyridinium chloride - 2-[5-(4-pyrrolidino-N-methyl-2-pyridinylidene)-1 -formazano]-4-pyrrolidino-N- methylpyridinium chloride

- 2-[5-(4-pyrrolidino-N-methyl-2-pyridinylidene)-3-methyl-1-formazano]-4-pyrrolidino-N- methylpyridinium chloride

- 2-[5-(4-pyrrolidino-N-methyl-2-pyridinylidene)-3-ethyl-1-formazano]-4-pyrrolidino-N- methylpyridinium chloride

- 2-[5-(4-pyrrolidino-N-methyl-2-pyridinylidene)-3-isopropyl-1-formazano]-4-pyrrolidino-N- methylpyridinium chloride

- 2-[5-(4-pyrrolidino-N-methyl-2-pyridinylidene)-3-phenyl-1-formazano]-4-pyrrolidino-N- methylpyridinium chloride - 2-[5-(4-pyrrolidino-N-methyl-2-pyridinylidene)-3-(4'-methoxyphenyl)-1 -formazano]-4- pyrrolidino-N-methylpyridinium chloride

- 2-[5-(4-pyrrolidino-N-methyl-2-pyridinylidene)-3-(4'-hydroxyphenyl)-1-formazano]-4- pyrrolidino-N-methylpyridinium chloride

- 2-[5-(4-pyrrolidino-N-methyl-2-pyridinylidene)-3-(4'-N,N-dimethylaminophenyl)-1- formazano]-4-pyrrolidino-N-methylpyridinium chloride

- 2-[5-(N-hydroxyethyl-2-pyridinylidene)-1-formazano]-N-hydroxyethylpyridinium chloride

- 2-[5-(N-hydroxyethyl-2-pyπdinylidene)-3-methyl-1-formazano]-N-hydroxyethylpyridinium chloride

- 2-[5-(N-hydroxyethyl-2-pyridinylidene)-3-ethyl-1-formazano]-N-hydroxyethylpyridinium chloride - 2-[5-(N-hydroxyethyl-2-pyridinylidene)-3-phenyl-1-formazano]-N-hydroxyethylpyridinium chloride

- 2-[5-(N-hydroxyethyl-2-pyridinylidene)-3-isopropyl-1-formazano]-N-hydroxyethylpyridinium chloride

- 2-[5-(N-hydroxyethyl-2-pyridinylidene)-3-(4'-methoxyphenyl)-1-formazano]-N- hydroxyethylpyridinium chloride

- 2-[5-(N-hydroxyethyl-2-pyridinylidene)-3-(4'-hydroxyphenyl)-1-formazano]-N- hydroxyethylpyridinium chloride

- 2-[5-(N-hydroxyethyl-2-pyridinylidene)-3-(4'-N,N-dimethylaminophenyl)-1-formazano]-N- hydroxyethylpyridinium chloride - 2-[5-(N-carboxyethyl-2-pyridinylidene)-1-formazano]-N-carboxyethylpyridinium chloride

- 2-[5-(N-carboxyethyl-2-pyridinylidene)-3-methyl-1-formazano]-N-carboxyethylpyridinium chloride

- 2-[5-(N-carboxyethyl-2-pyridinylidene)-3-ethyl-1-formazano]-N-carboxyethylpyridinium chloride - 2-[5-(N-carboxyethyl-2-pyridinylidene)-3-phenyl-1-formazano]-N-carboxyethylpyridinium chloride

- 2-[5-(N-carboxyethyl-2-pyridinylidene)-3-isopropyl-1-formazano]-N-carboxyethylpyridinium chloride

- 2-[5-(N-carboxyethyl-2-pyridinylidene)-3-(4'-methoxyphenyl)-1-formazano]-N- carboxyethylpyridinium chloride

- 2-[5-(N-carboxyethyl-2-pyridinylidene)-3-(4'-hydroxyphenyl)-1-formazano]-N- carboxyethylpyridinium chloride

- 2-[5-(N-carboxyethyl-2-pyridinylidene)-3-(4'-N,N-dimethylaminophenyl)-1-formazano]-N- carboxyethylpyridinium chloride.

13. Composition according to any one of Claims 1 to 10, in which W 1 is a 4-pyridinium radical and W 2 is a 4-pyridine radical.

14. Composition according to Claim 13, in which the compound of formula (I) is chosen from the following compounds:

- 4-[5-(N-methyl-4-pyridinylidene)-1 -formazano]-N-methylpyridinium chloride

- 4-[5-(N-methyl-4-pyridinylidene)-3-methyl-1 -formazano]-N-methylpyridinium chloride

- 4-[5-(N-methyl-4-pyιϊdinylidene)-3-ethyl-1 -formazano]-N-methylpyιϊdinium chloride

- 4-[5-(N-methyl-4-pyridinylidene)-3-isopropyl-1 -formazano]-N-methylpyridinium chloride

- 4-[5-(N-methyl-4-pyridinylidene)-3-phenyl-1 -formazano]-N-methylpyridinium chloride - 4-[5-(N-methyl-4-pyridinylidene)-3-(4'-methoxyphenyl)-1-formazano]-N-methylpyridinium chloride

- 4-[5-(N-methyl-4-pyridinylidene)-3-(4'-hydroxyphenyl)-1-formazano]-N-methylpyridinium chloride

- 4-[5-(N-methyl-4-pyridinylidene)-3-(4'-N,N-dimethylaminophenyl)-1-formazano]-N- methylpyridinium chloride

- 4-[5-(N-hydroxyethyl-4-pyridinylidene)-1-formazano]-N-hydroxyethylpyridinium chloride

- 4-[5-(N-hydroxyethyl-4-pyridinylidene)-3-methyl-1-formazano]-N-hydroxyethylpyridinium chloride

- 4-[5-(N-hydroxyethyl-4-pyridinylidene)-3-ethyl-1-formazano]-N-hydroxyethylpyridinium chloride

- 4-[5-(N-hydroxyethyl-4-pyridinylidene)-3-phenyl-1-formazano]-N-hydroxyethylpyridinium chloride

- 4-[5-(N-hydroxyethyl-4-pyridinylidene)-3-isopropyl-1-formazano]-N-hydroxyethylpyridinium chloride - 4-[5-(N-hydroxyethyl-4-pyridinylidene)-3-(4'-methoxyphenyl)-1 -formazano]-N- hydroxyethylpyridinium chloride

- 4-[5-(N-hydroxyethyl-4-pyridinylidene)-3-(4'-hydroxyphenyl)-1-formazano]-N- hydroxyethylpyridinium chloride

- 4-[5-(N-hydroxyethyl-4-pyridinylidene)-3-(4'-N,N-dimethylaminophenyl)-1-formazano]-N- hydroxyethylpyridinium chloride

- 4-[5-(N-carboxyethyl-4-pyridinylidene)-1-formazano]-N-carboxyethylpyridinium chloride

- 4-[5-(N-carboxyethyl-4-pyridinylidene)-3-methyl-1-formazano]-N-carboxyethylpyridinium chloride

- 4-[5-(N-carboxyethyl-4-pyridinylidene)-3-ethyl-1-formazano]-N-carboxyethylpyridinium chloride

- 4-[5-(N-carboxyethyl-4-pyridinylidene)-3-phenyl-1-formazano]-N-carboxyethylpyridinium chloride

- 4-[5-(N-carboxyethyl-4-pyridinylidene)-3-isopropyl-1-formazano]-N-carboxyethylpyridinium chloride - 4-[5-(N-carboxyethyl-4-pyridinylidene)-3-(4'-methoxyphenyl)-1 -formazano]-N- carboxyethylpyridinium chloride

- 4-[5-(N-carboxyethyl-4-pyridinylidene)-3-(4'-hydroxyphenyl)-1-formazano]-N- carboxyethylpyridinium chloride

- 4-[5-(N-carboxyethyl-4-pyπdinylidene)-3-(4'-N,N-dimethylaminophenyl)-1-formazano]-N- carboxyethylpyridinium chloride.

15. Composition according to any one of Claims 1 to 10, in which W 1 is a 2-imidazolium radical and W 2 is a 2-imidazole radical.

16. Composition according to Claim 15, in which the compound of formula (I) is chosen from the following compounds:

- 2-[5-(1 ,3-dimethyl-2-imidazolidene)-1 -formazano]-1 ,3-dimethylimidazolium chloride

- 2-[5-(1 ,3-dimethyl-2-imidazolidene)-3-methyl-1-formazano]-1 ,3-dimethylimidazolium chloride

- 2-[5-(1 ,3-dimethyl-2-imidazolidene)-3-ethyl-1 -formazano]-1 ,3-dimethylimidazolium chloride - 2-[5-(1 ,3-dimethyl-2-imidazolidene)-3-isopropyl-1-formazano]-1 ,3-dimethylimidazolium chloride

- 2-[5-(1 ,3-dimethyl-2-imidazolidene)-3-phenyl-1-formazano]-1 ,3-dimethylimidazolium chloride

- 2-[5-(1 ,3-dimethyl-2-imidazolidene)-3-(4'-methoxyphenyl)-1 -formazano]-1 ,3- dimethylimidazolium chloride

- 2-[5-(1 ,3-dimethyl-2-imidazolidene)-3-(4'-hydroxyphenyl)-1-formazano]-1 ,3- dimethylimidazolium chloride

- 2-[5-(1 ,3-dimethyl-2-imidazolidene)-3-(4'-N,N-dimethylaminophenyl)-1-formazano]-1 ,3- dimethylimidazolium chloride - 2-[5-(1 ,3-dihydroxyethyl-2-imidazolidene)-1-formazano]-1 ,3-dihydroxyethylimidazolium chloride

- 2-[5-(1 ,3-dihydroxyethyl-2-imidazolidene)-3-methyl-1-formazano]-1 ,3- dihydroxyethylimidazolium chloride

- 2-[5-(1 ,3-dihydroxyethyl-2-imidazolidene)-3-ethyl-1 -formazano]-1 ,3- dihydroxyethylimidazolium chloride

- 2-[5-(1 ,3-dihydroxyethyl-2-imidazolidene)-3-phenyl-1-formazano]-1 ,3- dihydroxyethylimidazolium chloride

- 2-[5-(1 ,3-dihydroxyethyl-2-imidazolidene)-3-isopropyl-1-formazano]-1 ,3- dihydroxyethylimidazolium chloride - 2-[5-(1 ,3-dihydroxyethyl-2-imidazolidene)-3-(4'-methoxyphenyl)-1-formazano]-1 ,3- dihydroxyethylimidazolium chloride

- 2-[5-(1 ,3-dihydroxyethyl-2-imidazolidene)-3-(4'-hydroxyphenyl)-1-formazano]-1 ,3- dihydroxyethylimidazolium chloride

- 2-[5-(1 ,3-dihydroxyethyl-2-imidazolidene)-3-(4'-N,N-dimethylaminophenyl)-1-formazano]- 1 ,3-dihydroxyethylimidazolium chloride - 2-[5-(1 ,3-dicarboxyethyl-2-imidazolidene)-1-formazano]-1 ,3-dicarboxyethylimidazolium chloride

- 2-[5-(1 ,3-dicarboxyethyl-2-imidazolidene)-3-methyl-1-formazano]-1 ,3- dicarboxyethylimidazolium chloride

- 2-[5-(1 ,3-dicarboxyethyl-2-imidazolidene)-3-ethyl-1-formazano]-1 ,3- dicarboxyethylimidazolium chloride

- 2-[5-(1 ,3-dicarboxyethyl-2-imidazolidene)-3-phenyl-1-formazano]-1 ,3- dicarboxyethylimidazolium chloride

- 2-[5-(1 ,3-dicarboxyethyl-2-imidazolidene)-3-isopropyl-1-formazano]-1 ,3- dicarboxyethylimidazolium chloride - 2-[5-(1 ,3-dicarboxyethyl-2-imidazolidene)-3-(4'-methoxyphenyl)-1 -formazano]-1 ,3- dicarboxyethylimidazolium chloride

- 2-[5-(1 ,3-dicarboxyethyl-2-imidazolidene)-3-(4'-hydroxyphenyl)-1-formazano]-1 ,3- dicarboxyethylimidazolium chloride

- 2-[5-(1 ,3-dicarboxyethyl-2-imidazolidene)-3-(4'-N,N-dimethylaminophenyl)-1-formazano]- 1 ,3-dicarboxyethylimidazolium chloride.

17. Composition according to any one of Claims 1 to 10, in which W 1 is a 5-pyrazolium radical and W 2 is a 5-pyrazole radical.

18. Composition according to Claim 17, in which the compound of formula (I) is chosen from the following compounds:

- 5-[5-(1 ,2-dimethyl-5-pyrazolidene)-1 -formazano]-1 ,2-dimethylpyrazolinium chloride

- 5-[5-(1 ,2-dimethyl-5-pyrazolidene)-3-methyl-1 -formazano]-1 ,2-dimethylpyrazolinium chloride - 5-[5-(1 ,2-dimethyl-5-pyrazolidene)-3-ethyl-1-formazano]-1 ,2-dimethylpyrazolinium chloride

- 5-[5-(1 ,2-dimethyl-5-pyrazolidene)-3-isopropyl-1-formazano]-1 ,2-dimethylpyrazolinium chloride

- 5-[5-(1 ,2-dimethyl-5-pyrazolidene)-3-phenyl-1 -formazano]-1 ,2-dimethylpyrazolinium chloride - 5-[5-(1 ,2-dimethyl-5-pyrazolidene)-3-(4'-methoxyphenyl)-1-formazano]-1 ,2- dimethylpyrazolinium chloride

- 5-[5-(1 ,2-dimethyl-5-pyrazolidene)-3-(4'-hydroxyphenyl)-1-formazano]-1 ,2- dimethylpyrazolinium chloride

- 5-[5-(1 ,2-dimethyl-5-pyrazolidene)-3-(4'-N,N-dimethylaminophenyl)-1-formazano]-1 ,2- dimethylpyrazolinium chloride - 5-[5-(1 ,2-dihydroxyethyl-5-pyrazolidene)-1-formazano]-1 ,2-dihydroxyethylpyrazolinium chloride

- 5-[5-(1 ,2-dihydroxyethyl-5-pyrazolidene)-3-methyl-1 -formazano]-1 ,2- dihydroxyethylpyrazolinium chloride

- 5-[5-(1 ,2-dihydroxyethyl-5-pyrazolidene)-3-ethyl-1 -formazano]-1 ,2- dihydroxyethylpyrazolinium chloride

- 5-[5-(1 ,2-dihydroxyethyl-5-pyrazolidene)-3-phenyl-1-formazano]-1 ,2- dihydroxyethylpyrazolinium chloride

- 5-[5-(1 ,2-dihydroxyethyl-5-pyrazolidene)-3-isopropyl-1 -formazano]-1 ,2- dihydroxyethylpyrazolinium chloride - 5-[5-(1 ,2-dihydroxyethyl-5-pyrazolidene)-3-(4'-methoxyphenyl)-1-formazano]-1 ,2- dihydroxyethylpyrazolinium chloride

- 5-[5-(1 ,2-dihydroxyethyl-5-pyrazolidene)-3-(4'-hydroxyphenyl)-1-formazano]-1 ,2- dihydroxyethylpyrazolinium chloride

- 5-[5-(1 ,2-dihydroxyethyl-5-pyrazolidene)-3-(4'-N,N-dimethylaminophenyl)-1-formazano]- 1 ,2-dihydroxyethylpyrazolinium chloride

- 5-[5-(1 ,2-dicarboxyethyl-5-pyrazolidene)-1 -formazano]-1 ,2-dicarboxyethylpyrazolinium chloride

- 5-[5-(1 ,2-dicarboxyethyl-5-pyrazolidene)-3-methyl-1-formazano]-1 ,2- dicarboxyethylpyrazolinium chloride - 5-[5-(1 ,2-dicarboxyethyl-5-pyrazolidene)-3-ethyl-1 -formazano]-1 ,2- dicarboxyethylpyrazolinium chloride

- 5-[5-(1 ,2-dicarboxyethyl-5-pyrazolidene)-3-phenyl-1-formazano]-1 ,2- dicarboxyethylpyrazolinium chloride

- 5-[5-(1 ,2-dicarboxyethyl-5-pyrazolidene)-3-isopropyl-1-formazano]-1 ,2- dicarboxyethylpyrazolinium chloride

- 5-[5-(1 ,2-dicarboxyethyl-5-pyrazolidene)-3-(4'-methoxyphenyl)-1-formazano]-1 ,2- dicarboxyethylpyrazolinium chloride

- 5-[5-(1 ,2-dicarboxyethyl-5-pyrazolidene)-3-(4'-hydroxyphenyl)-1-formazano]-1 ,2- dicarboxyethylpyrazolinium chloride - 5-[5-(1 ,2-dicarboxyethyl-5-pyrazolidene)-3-(4'-N,N-dimethylaminophenyl)-1-formazano]- 1 ,2-dicarboxyethylpyrazolinium chloride.

19. Composition according to any one of Claims 1 to 10, in which W 1 is a 2- benzimidazolium radical and W 2 is a 2-pyridine radical.

20. Composition according to Claim 19, in which the compound of formula (I) is chosen from the following compounds:

- 2-[5-(N-methyl-2-pyridinylidene)-1-formazano]-1 ,3-dimethylbenzimidazolium chloride

- 2-[5-(N-methyl-2-pyridinylidene)-3-methyl-1 -formazano]-1 ,3-dimethylbenzimidazolium chloride - 2-[5-(N-methyl-2-pyridinylidene)-3-ethyl-1-formazano]-1 ,3-dimethylbenzimidazolium chloride

- 2-[5-(N-methyl-2-pyridinylidene)-3-isopropyl-1 -formazano]-1 ,3-dimethylbenzimidazolium chloride

- 2-[5-(N-methyl-2-pyridinylidene)-3-phenyl-1 -formazano]-1 ,3-dimethylbenzimidazolium chloride

- 2-[5-(N-methyl-2-pyridinylidene)-3-(4'-methoxyphenyl)-1-formazano]-1 ,3-dimethylbenzimidazolium chloride

- 2-[5-(N-methyl-2-pyridinylidene)-3-(4'-hydroxyphenyl)-1 -formazano]-1 ,3- dimethylbenzimidazolium chloride - 2-[5-(N-methyl-2-pyridinylidene)-3-(4'-N,N-dimethylaminophenyl)-1-formazano]-1 ,3- dimethylbenzimidazolium chloride

- 2-[5-(N-hydroxyethyl-2-pyridinylidene)-1 -formazano]-1 ,3-dihydroxyethylbenzimidazolium chloride

- 2-[5-(N-hydroxyethyl-2-pyridinylidene)-3-methyl-1 -formazano]-1 ,3- dihydroxyethylbenzimidazolium chloride

- 2-[5-(N-hydroxyethyl-2-pyridinylidene)-3-ethyl-1 -formazano]-1 ,3- dihydroxyethylbenzimidazolium chloride

- 2-[5-(N-hydroxyethyl-2-pyridinylidene)-3-phenyl-1-formazano]-1 ,3- dihydroxyethylbenzimidazolium chloride - 2-[5-(N-hydroxyethyl-2-pyridinylidene)-3-isopropyl-1-formazano]-1 ,3- dihydroxyethylbenzimidazolium chloride

- 2-[5-(N-hydroxyethyl-2-pyridinylidene)-3-(4'-methoxyphenyl)-1 -formazano]-1 ,3- dihydroxyethylbenzimidazolium chloride

- 2-[5-(N-hydroxyethyl-2-pyridinylidene)-3-(4'-hydroxyphenyl)-1-formazano]-1 ,3- dihydroxyethylbenzimidazolium chloride

- 2-[5-(N-hydroxyethyl-2-pyridinylidene)-3-(4'-N,N-dimethylaminophenyl)-1-formazano]-1 ,3-

dihydroxyethylbenzimidazolium chloride

- 2-[5-(N-carboxyethyl-2-pyridinylidene)-1 -formazano]-1 ,3-dicarboxyethylbenzimidazolium chloride

- 2-[5-(N-carboxyethyl-2-pyridinylidene)-3-methyl-1 -formazano]-1 ,3- dicarboxyethylbenzimidazolium chloride

- 2-[5-(N-carboxyethyl-2-pyridinylidene)-3-ethyl-1 -formazano]-1 ,3- dicarboxyethylbenzimidazolium chloride

- 2-[5-(N-carboxyethyl-2-pyridinylidene)-3-phenyl-1-formazano]-1 ,3- dicarboxyethylbenzimidazolium chloride - 2-[5-(N-carboxyethyl-2-pyridinylidene)-3-isopropyl-1-formazano]-1 ,3- dicarboxyethylbenzimidazolium chloride

- 2-[5-(N-carboxyethyl-2-pyridinylidene)-3-(4'-methoxyphenyl)-1 -formazano]-1 ,3- dicarboxyethylbenzimidazolium chloride

- 2-[5-(N-carboxyethyl-2-pyridinylidene)-3-(4'-hydroxyphenyl)-1-formazano]-1 ,3- dicarboxyethylbenzimidazolium chloride

- 2-[5-(N-carboxyethyl-2-pyridinylidene)-3-(4'-N,N-dimethylaminophenyl)-1-formazano]-1 ,3- dicarboxyethylbenzimidazolium chloride.

21. Composition according to any one of Claims 1 to 10, in which W 1 is a 2- benzimidazolium radical and W 2 is a 4-pyridine radical.

22. Composition according to Claim 21 , in which the compound of formula (I) is chosen from the following compounds:

- 2-[5-(N-methyl-4-pyridinylidene)-1-formazano]-1 ,3-dimethylbenzimidazolium chloride - 2-[5-(N-methyl-4-pyridinylidene)-3-methyl-1 -formazano]-1 ,3-dimethylbenzimidazolium chloride

- 2-[5-(N-methyl-4-pyridinylidene)-3-ethyl-1-formazano]-1 ,3-dimethylbenzimidazolium chloride

- 2-[5-(N-methyl-4-pyridinylidene)-3-isopropyl-1 -formazano]-1 ,3-dimethylbenzimidazolium chloride

- 2-[5-(N-methyl-4-pyridinylidene)-3-phenyl-1 -formazano]-1 ,3-dimethylbenzimidazolium chloride

- 2-[5-(N-methyl-4-pyridinylidene)-3-(4'-methoxyphenyl)-1-formazano]-1 ,3- dimethylbenzimidazolium chloride - 2-[5-(N-methyl-4-pyridinylidene)-3-(4'-hydroxyphenyl)-1-formazano]-1 ,3- dimethylbenzimidazolium chloride

- 2-[5-(N-methyl-4-pyridinylidene)-3-(4'-N,N-dimethylaminophenyl)-1-formazano]-1 ,3- dimethylbenzimidazolium chloride

- 2-[5-(N-hydroxyethyl-4-pyridinylidene)-1 -formazano]-1 ,3-dihydroxyethylbenzimidazolium chloride - 2-[5-(N-hydroxyethyl-4-pyridinylidene)-3-methyl-1-formazano]-1 ,3- dihydroxyethylbenzimidazolium chloride

- 2-[5-(N-hydroxyethyl-4-pyridinylidene)-3-ethyl-1 -formazano]-1 ,3- dihydroxyethylbenzimidazolium chloride

- 2-[5-(N-hydroxyethyl-4-pyridinylidene)-3-phenyl-1-formazano]-1 ,3- dihydroxyethylbenzimidazolium chloride

- 2-[5-(N-hydroxyethyl-4-pyridinylidene)-3-isopropyl-1 -formazano]-1 ,3- dihydroxyethylbenzimidazolium chloride

- 2-[5-(N-hydroxyethyl-4-pyridinylidene)-3-(4'-methoxyphenyl)-1 -formazano]-1 ,3- dihydroxyethylbenzimidazolium chloride - 2-[5-(N-hydroxyethyl-4-pyridinylidene)-3-(4'-hydroxyphenyl)-1-formazano]-1 ,3- dihydroxyethylbenzimidazolium chloride

- 2-[5-(N-hydroxyethyl-4-pyridinylidene)-3-(4'-N,N-dimethylaminophenyl)-1-formazano]-1 ,3- dihydroxyethylbenzimidazolium chloride

- 2-[5-(N-carboxyethyl-4-pyridinylidene)-1 -formazano]-1 ,3-dicarboxyethylbenzimidazolium chloride

- 2-[5-(N-carboxyethyl-4-pyridinylidene)-3-methyl-1 -formazano]-1 ,3- dicarboxyethylbenzimidazolium chloride

- 2-[5-(N-carboxyethyl-4-pyridinylidene)-3-ethyl-1 -formazano]-1 ,3- dicarboxyethylbenzimidazolium chloride - 2-[5-(N-carboxyethyl-4-pyridinylidene)-3-phenyl-1-formazano]-1 ,3- dicarboxyethylbenzimidazolium chloride

- 2-[5-(N-carboxyethyl-4-pyridinylidene)-3-isopropyl-1 -formazano]-1 ,3- dicarboxyethylbenzimidazolium chloride

- 2-[5-(N-carboxyethyl-4-pyridinylidene)-3-(4'-methoxyphenyl)-1 -formazano]-1 ,3- dicarboxyethylbenzimidazolium chloride

- 2-[5-(N-carboxyethyl-4-pyridinylidene)-3-(4'-hydroxyphenyl)-1-formazano]-1 ,3- dicarboxyethylbenzimidazolium chloride

- 2-[5-(N-carboxyethyl-4-pyridinylidene)-3-(4'-N,N-dimethylaminophenyl)-1-formazano]-1 ,3- dicarboxyethylbenzimidazolium chloride.

23. Composition according to any one of Claims 1 to 10, in which W 1 is a 2-imidazolium

radical and W 2 is a 2-pyridine radical.

24. Composition according to Claim 23, in which the compound of formula (I) is chosen from the following compounds: - 2-[5-(N-methyl-2-pyridinylidene)-1-formazano]-1 ,3-dimethylimidazolium chloride

- 2-[5-(N-methyl-2-pyridinylidene)-3-methyl-1 -formazano]-1 ,3-dimethylimidazolium chloride

- 2-[5-(N-methyl-2-pyridinylidene)-3-ethyl-1-formazano]-1 ,3-dimethylimidazolium chloride

- 2-[5-(N-methyl-2-pyridinylidene)-3-isopropyl-1-formazano]-1 ,3-dimethylimidazolium chloride - 2-[5-(N-methyl-2-pyridinylidene)-3-phenyl-1-formazano]-1 ,3-dimethylimidazolium chloride

- 2-[5-(N-methyl-2-pyridinylidene)-3-(4'-methoxyphenyl)-1-formazano]-1 ,3- dimethylimidazolium chloride

- 2-[5-(N-methyl-2-pyridinylidene)-3-(4'-hydroxyphenyl)-1 -formazano]-1 ,3- dimethylimidazolium chloride - 2-[5-(N-methyl-2-pyridinylidene)-3-(4'-N,N-dimethylaminophenyl)-1-formazano]-1 ,3- dimethylimidazolium chloride

- 2-[5-(N-hydroxyethyl-2-pyridinylidene)-1 -formazano]-1 ,3-dihydroxyethylimidazolium chloride

- 2-[5-(N-hydroxyethyl-2-pyridinylidene)-3-methyl-1 -formazano]-1 ,3- dihydroxyethylimidazolium chloride

- 2-[5-(N-hydroxyethyl-2-pyridinylidene)-3-ethyl-1 -formazano]-1 ,3- dihydroxyethylimidazolium chloride

- 2-[5-(N-hydroxyethyl-2-pyridinylidene)-3-phenyl-1-formazano]-1 ,3- dihydroxyethylimidazolium chloride - 2-[5-(N-hydroxyethyl-2-pyridinylidene)-3-isopropyl-1-formazano]-1 ,3- dihydroxyethylimidazolium chloride

- 2-[5-(N-hydroxyethyl-2-pyridinylidene)-3-(4'-methoxyphenyl)-1 -formazano]-1 ,3- dihydroxyethylimidazolium chloride

- 2-[5-(N-hydroxyethyl-2-pyridinylidene)-3-(4'-hydroxyphenyl)-1-formazano]-1 ,3- dihydroxyethylimidazolium chloride

- 2-[5-(N-hydroxyethyl-2-pyridinylidene)-3-(4'-N,N-dimethylaminophenyl)-1-formazano]-1 ,3- dihydroxyethylimidazolium chloride

- 2-[5-(N-carboxyethyl-2-pyridinylidene)-1 -formazano]-1 ,3-dicarboxyethylimidazolium chloride - 2-[5-(N-carboxyethyl-2-pyridinylidene)-3-methyl-1-formazano]-1 ,3- dicarboxyethylimidazolium chloride

- 2-[5-(N-carboxyethyl-2-pyridinylidene)-3-ethyl-1 -formazano]-1 ,3- dicarboxyethylimidazolium chloride

- 2-[5-(N-carboxyethyl-2-pyridinylidene)-3-phenyl-1-formazano]-1 ,3- dicarboxyethylimidazolium chloride - 2-[5-(N-carboxyethyl-2-pyridinylidene)-3-isopropyl-1-formazano]-1 ,3- dicarboxyethylimidazolium chloride

- 2-[5-(N-carboxyethyl-2-pyridinylidene)-3-(4'-methoxyphenyl)-1 -formazano]-1 ,3- dicarboxyethylimidazolium chloride

- 2-[5-(N-carboxyethyl-2-pyridinylidene)-3-(4'-hydroxyphenyl)-1-formazano]-1 ,3- dicarboxyethylimidazolium chloride

- 2-[5-(N-carboxyethyl-2-pyridinylidene)-3-(4'-N,N-dimethylaminophenyl)-1-formazano]-1 ,3- dicarboxyethylimidazolium chloride.

25. Composition according to any one of Claims 1 to 10, in which W 1 is a 2-imidazolium radical and W 2 is a 4-pyridine radical.

26. Composition according to Claim 25, in which the compound of formula (I) is chosen from the following compounds:

- 2-[5-(N-methyl-4-pyridinylidene)-1-formazano]-1 ,3-dimethylimidazolium chloride - 2-[5-(N-methyl-4-pyridinylidene)-3-methyl-1-formazano]-1 ,3-dimethylimidazolium chloride

- 2-[5-(N-methyl-4-pyridinylidene)-3-ethyl-1-formazano]-1 ,3-dimethylimidazolium chloride

- 2-[5-(N-methyl-4-pyridinylidene)-3-isopropyl-1-formazano]-1 ,3-dimethylimidazolium chloride

- 2-[5-(N-methyl-4-pyridinylidene)-3-phenyl-1-formazano]-1 ,3-dimethylimidazolium chloride - 2-[5-(N-methyl-4-pyridinylidene)-3-(4'-methoxyphenyl)-1-formazano]-1 ,3- dimethylimidazolium chloride

- 2-[5-(N-methyl-4-pyridinylidene)-3-(4'-hydroxyphenyl)-1 -formazano]-1 ,3- dimethylimidazolium chloride

- 2-[5-(N-methyl-4-pyridinylidene)-3-(4'-N,N-dimethylaminophenyl)-1-formazano]-1 ,3- dimethylimidazolium chloride

- 2-[5-(N-hydroxyethyl-4-pyridinylidene)-1 -formazano]-1 ,3-dihydroxyethylimidazolium chloride

- 2-[5-(N-hydroxyethyl-4-pyridinylidene)-3-methyl-1 -formazano]-1 ,3- dihydroxyethylimidazolium chloride - 2-[5-(N-hydroxyethyl-4-pyridinylidene)-3-ethyl-1-formazano]-1 ,3- dihydroxyethylimidazolium chloride

- 2-[5-(N-hydroxyethyl-4-pyridinylidene)-3-phenyl-1-formazano]-1 ,3- dihydroxyethylimidazolium chloride

- 2-[5-(N-hydroxyethyl-4-pyridinylidene)-3-isopropyl-1 -formazano]-1 ,3- dihydroxyethylimidazolium chloride - 2-[5-(N-hydroxyethyl-4-pyridinylidene)-3-(4'-methoxyphenyl)-1-formazano]-1 ,3- dihydroxyethylimidazolium chloride

- 2-[5-(N-hydroxyethyl-4-pyridinylidene)-3-(4'-hydroxyphenyl)-1-formazano]-1 ,3- dihydroxyethylimidazolium chloride

- 2-[5-(N-hydroxyethyl-4-pyridinylidene)-3-(4'-N,N-dimethylaminophenyl)-1-formazano]-1 ,3- dihydroxyethylimidazolium chloride

- 2-[5-(N-carboxyethyl-4-pyridinylidene)-1 -formazano]-1 ,3-dicarboxyethylimidazolium chloride

- 2-[5-(N-carboxyethyl-4-pyridinylidene)-3-methyl-1 -formazano]-1 ,3- dicarboxyethylimidazolium chloride - 2-[5-(N-carboxyethyl-4-pyridinylidene)-3-ethyl-1-formazano]-1 ,3- dicarboxyethylimidazolium chloride

- 2-[5-(N-carboxyethyl-4-pyridinylidene)-3-phenyl-1-formazano]-1 ,3- dicarboxyethylimidazolium chloride

- 2-[5-(N-carboxyethyl-4-pyridinylidene)-3-isopropyl-1 -formazano]-1 ,3- dicarboxyethylimidazolium chloride

- 2-[5-(N-carboxyethyl-4-pyridinylidene)-3-(4'-methoxyphenyl)-1 -formazano]-1 ,3- dicarboxyethylimidazolium chloride

- 2-[5-(N-carboxyethyl-4-pyridinylidene)-3-(4'-hydroxyphenyl)-1-formazano]-1 ,3- dicarboxyethylimidazolium chloride - 2-[5-(N-carboxyethyl-4-pyridinylidene)-3-(4'-N,N-dimethylaminophenyl)-1-formazano]-1 ,3- dicarboxyethylimidazolium chloride.

27. Composition according to any one of Claims 1 to 10, in which W 1 is a 2- benzimidazolium radical and W 2 is a 2-benzimidazole radical.

28. Composition according to Claim 27, in which the compound of formula (I) is chosen from the following compounds:

- 2-[5-(1 ,3-dimethyl-2-benzimidazolidene)-1-formazano]-1 ,3-dimethylbenzimidazolium chloride - 2-[5-(1 ,3-dimethyl-2-benzimidazolidene)-3-methyl-1-formazano]-1 ,3- dimethylbenzimidazolium chloride

- 2-[5-(1 ,3-dimethyl-2-benzimidazolidene)-3-ethyl-1-formazano]-1 ,3- dimethylbenzimidazolium chloride

- 2-[5-(1 ,3-dimethyl-2-benzimidazolidene)-3-isopropyl-1-formazano]-1 ,3- dimethylbenzimidazolium chloride - 2-[5-(1 ,3-dimethyl-2-benzimidazolidene)-3-phenyl-1-formazano]-1 ,3- dimethylbenzimidazolium chloride

- 2-[5-(1 ,3-dimethyl-2-benzimidazolidene)-3-(4'-methoxyphenyl)-1 -formazano]-1 ,3- dimethylbenzimidazolium chloride

- 2-[5-(1 ,3-dimethyl-2-benzimidazolidene)-3-(4'-hydroxyphenyl)-1 -formazano]-1 ,3- dimethylbenzimidazolium chloride

- 2-[5-(1 ,3-dimethyl-2-benzimidazolidene)-3-(4'-N,N-dimethylaminophenyl)-1-formazano]- 1 ,3-dimethylbenzimidazolium chloride

- 2-[5-(1 ,3-dihydroxyethyl-2-benzimidazolidene)-1-formazano]-1 ,3- dihydroxyethylbenzimidazolium chloride - 2-[5-(1 ,3-dihydroxyethyl-2-benzimidazolidene)-3-methyl-1-formazano]-1 ,3- dihydroxyethylbenzimidazolium chloride

- 2-[5-(1 ,3-dihydroxyethyl-2-benzimidazolidene)-3-ethyl-1-formazano]-1 ,3- dihydroxyethylbenzimidazolium chloride

- 2-[5-(1 ,3-dihydroxyethyl-2-benzimidazolidene)-3-phenyl-1-formazano]-1 ,3- dihydroxyethylbenzimidazolium chloride

- 2-[5-(1 ,3-dihydroxyethyl-2-benzimidazolidene)-3-isopropyl-1-formazano]-1 ,3- dihydroxyethylbenzimidazolium chloride

- 2-[5-(1 ,3-dihydroxyethyl-2-benzimidazolidene)-3-(4'-methoxyphenyl)-1-formazano]-1 ,3- dihydroxyethylbenzimidazolium chloride - 2-[5-(1 ,3-dihydroxyethyl-2-benzimidazolidene)-3-(4'-hydroxyphenyl)-1 -formazano]-1 ,3- dihydroxyethylbenzimidazolium chloride

- 2-[5-(1 ,3-dihydroxyethyl-2-benzimidazolidene)-3-(4'-N,N-dimethylaminophenyl)-1- formazano]-1 ,3-dihydroxyethylbenzimidazolium chloride

- 2-[5-(1 ,3-dicarboxyethyl-2-benzimidazolidene)-1-formazano]-1 ,3- dicarboxyethylbenzimidazolium chloride

- 2-[5-(1 ,3-dicarboxyethyl-2-benzimidazolidene)-3-methyl-1-formazano]-1 ,3- dicarboxyethylbenzimidazolium chloride

- 2-[5-(1 ,3-dicarboxyethyl-2-benzimidazolidene)-3-ethyl-1-formazano]-1 ,3- dicarboxyethylbenzimidazolium chloride - 2-[5-(1 ,3-dicarboxyethyl-2-benzimidazolidene)-3-phenyl-1-formazano]-1 ,3- dicarboxyethylbenzimidazolium chloride

- 2-[5-(1 ,3-dicarboxyethyl-2-benzimidazolidene)-3-isopropyl-1-formazano]-1 ,3- dicarboxyethylbenzimidazolium chloride

- 2-[5-(1 ,3-dicarboxyethyl-2-benzimidazolidene)-3-(4'-methoxyphenyl)-1-formazano]-1 ,3- dicarboxyethylbenzimidazolium chloride - 2-[5-(1 ,3-dicarboxyethyl-2-benzimidazolidene)-3-(4'-hydroxyphenyl)-1-formazano]-1 ,3- dicarboxyethylbenzimidazolium chloride

- 2-[5-(1 ,3-dicarboxyethyl-2-benzimidazolidene)-3-(4'-N,N-dimethylaminophenyl)-1- formazano]-1 ,3-dicarboxyethylbenzimidazolium chloride.

29. Composition according to any one of the preceding claims, characterized in that the compound(s) of formula I is (are) present in a concentration ranging from 0.001 % to 5% and preferably from 0.05% to 2% by weight relative to the total weight of the composition.

30. Composition according to any one of the preceding claims, characterized in that the azo, methine or azomethine cationic direct dye containing a quaternary ammonium group included in a ring, other than the compounds of formula (I), comprises in its structure at least one saturated or unsaturated heterocycle comprising in its chain of ring members at least one nitrogen atom bearing a positive permanent charge, the said heterocycle being 4- to 8- membered and being optionally fused with one or more other heterocycles or aromatic nuclei and optionally comprising one or more other heteroatoms chosen from nitrogen, sulfur and oxygen, each of these rings possibly being optionally substituted.

31. Composition according to the preceding claim, characterized in that the nitrogen atom bearing a permanent positive charge is preferably substituted with an optionally substituted C 1 -C30 alkyl radical or with an optionally substituted phenyl radical.

32. Composition according to the preceding claim, characterized in that the substituents on the alkyl groups are chosen from halogen atoms and hydroxyl, amino, mono- or di(C r C 4 )alkylamino, mono- or dihydroxy(Ci-C 4 )alkylamino, C6-C30 aryl and cyano groups.

33. Composition according to Claim 31 , characterized in that the substituents on the aryl groups are chosen from halogen atoms and Ci-C 30 alkyl, hydroxyl, amino, mono- or di(d- C 4 )alkylamino, mono- or dihydroxy(Ci-C 4 )alkylamino, cyano, nitro and C 2 -Ci 0 acyl groups.

34. Composition according to Claim 31 or 32, characterized in that the substituent on the nitrogen atom bearing a permanent charge is a C 1 -C 4 alkyl group.

35. Composition according to the preceding claim, characterized in that this substituent is a methyl group.

36. Composition according to any one of the preceding claims, characterized in that the azo, methine or azomethine direct dye containing a quaternary ammonium group included in a ring is chosen from the compounds of formula (Vl):

G-N=N-J (Vl) in which: the symbol G represents a group chosen from the structures Gi to G3 below:

G 1 G 0

G 3 in which: R 24 denotes a C 1 -C 4 alkyl radical, a phenyl radical which may be substituted with a C 1 -C 4 alkyl radical, or a halogen atom chosen from chlorine, bromine, iodine and fluorine;

R 25 denotes a C 1 -C 4 alkyl radical or a phenyl radical;

R 26 and R 27 , which may be identical or different, represent a C 1 -C 4 alkyl radical, a phenyl radical, or form together in G 1 a benzene ring substituted with one or more C 1 -C 4 alkyl, C 1 -C 4 alkoxy or NO 2 radicals, or form together in G 2 a benzene ring optionally substituted with one or more C 1 -C 4 alkyl, C 1 -C 4 alkoxy or NO 2 radicals;

R 26 may also denote a hydrogen atom;

Z represents an oxygen or sulfur atom or a group -NR 25 ;

M represents a group -CH, -CR (R denoting C 1 -C 4 alkyl) or -NR 28 (X " ),-; K represents a group -CH, -CR (R denoting C 1 -C 4 alkyl) or -NR 28 (X " ),-;

P represents a group -CH, -CR (R denoting C 1 -C 4 alkyl) or -NR 28 (X " ) r ;

r denotes 0 or 1 ;

R 2 8 represents an O " atom, a d-C 4 alkoxy radical or a d-C 4 alkyl radical; R 2 9 and R30, which may be identical or different, represent a hydrogen atom or a halogen atom chosen from chlorine, bromine, iodine and fluorine, a d-C 4 alkyl or CrC 4 alkoxy radical, or an -NO 2 radical;

X " represents an anion preferably chosen from chloride, iodide, methyl sulfate, ethyl sulfate, acetate and perchlorate;

the symbol J represents: -(a) a group of structure Ji below:

in which:

R 31 represents a hydrogen atom, a halogen atom chosen from chlorine, bromine, iodine and fluorine, a C r C 4 alkyl or d-C 4 alkoxy radical, an -OH, -NO 2 , -NHR 34 , -NR 35 R 36 or C r C 4 -NHCOalkyl radical, or forms with R 32 a 5- or 6-membered ring optionally containing one or more heteroatoms chosen from nitrogen, oxygen and sulfur;

R 32 represents a hydrogen atom, a halogen atom chosen from chlorine, bromine, iodine and fluorine, a CrC 4 alkyl or CrC 4 alkoxy radical, or forms with R 33 or R 34 a 5- or 6-membered ring optionally containing one or more heteroatoms chosen from nitrogen, oxygen and sulfur; R 33 represents a hydrogen atom, an -OH radical, a radical -NHR 34 or a radical -NR 35 R 36 ;

R 34 represents a hydrogen atom, a CrC 4 alkyl radical, a CrC 4 monohydroxyalkyl, C 2 -C 4 polyhydroxyalkyl radical or a phenyl radical;

R 35 and R 36 , which may be identical or different, represent a CrC 4 alkyl radical, a CrC 4 monohydroxyalkyl or C 2 -C 4 polyhydroxyalkyl radical;

-(b) a 5- or 6-membered nitrogenous heterocyclic group, which may contain other heteroatoms and/or carbonyl groups and may be substituted with one or more CrC 4 alkyl, amino or phenyl radicals, and especially a group of structure J 2 below:

in which:

R 37 and R38, which may be identical or different, represent a hydrogen atom, a C 1 3-C 1 0 alkyl radical or a phenyl radical; Y denotes a -CO- radical or a -C(CH 3 )= radical; n represents 0 or 1 , with, when n denotes 1 , U denotes a -CO- radical.

37. Composition according to any one of Claims 1 to 35, characterized in that the azo, methine or azomethine direct dye containing a quaternary ammonium group included in a ring is chosen from the compounds of formula (VII) below:

in which:

R 12 represents a hydrogen atom or a CrC 4 alkyl radical,

R 13 represents a hydrogen atom, an alkyl radical which may be substituted with a -CN radical or with an amino group, a 4'-aminophenyl radical, or forms with R 12 a heterocycle optionally containing oxygen and/or nitrogen, which may be substituted with a C 1 -C 4 alkyl radical,

R 14 and R 15 , which may be identical or different, represent a hydrogen atom, a halogen atom such as bromine, chlorine, iodine or fluorine, a C 1 -C 4 alkyl or C 1 -C 4 alkoxy radical, or a -CN radical,

X " represents an anion preferably chosen from chloride, methyl sulfate and acetate,

B represents a group chosen from structures B1 to B6 below:

B4 B5 B6

in which R 16 represents a CrC 4 alkyl radical,

Ri7 and Ri 8 , which may be identical or different, represent a hydrogen atom or a d-C 4 alkyl radical.

38. Composition according to any one of Claims 1 to 35, characterized in that the azo, methine or azomethine direct dye containing a quaternary ammonium group included in a ring is chosen from the compounds of formulae (VIII) and (IX) below:

in which:

Rig represents a hydrogen atom, a d-C 4 alkoxy radical, a halogen atom such as bromine, chlorine, iodine or fluorine, or an amino radical,

R 2 0 represents a hydrogen atom, a d-C 4 alkyl radical or forms, with a carbon atom of the benzene ring, a heterocycle optionally containing oxygen and/or substituted with one or more

Ci-C 4 alkyl groups,

R 21 represents a hydrogen atom or a halogen atom such as bromine, chlorine, iodine or fluorine,

R 22 and R 2 3, which may be identical or different, represent a hydrogen atom or a C 1 -C 4 alkyl radical,

Di and D 2 , which may be identical or different, represent a hydrogen atom or a -CH group, m represents 0 or 1 , it being understood that when Ri 9 represents an unsubstituted amino group, then Di and D 2 simultaneously represent a -CH group and m = 0,

X " represents an anion preferably chosen from chloride, methyl sulfate and acetate,

E represents a group chosen from structures E1 to E8 below:

E1 E2

- S l -

E5

E6

E7 E8 in which R' represents a C 1 -C 4 alkyl radical; when m represents 0 and D 1 represents a nitrogen atom, then E may also denote a group of structure E9 below:

in which R' represents a C 1 -C 4 alkyl radical.

39. Composition according to any one of Claims 1 to 35, characterized in that the azo, methine or azomethine direct dye containing a quaternary ammonium group included in a ring is chosen from the compounds of formula (X) below:

X-

(X) in which:

Z and D, which may be identical or different, represent a nitrogen atom or a -CH group, R 7 and R 8 , which may be identical or different, represent a hydrogen atom; a C 1 -C 4 alkyl

radical which may be substituted with a -CN, -OH or -NH 2 radical, or form, with a carbon atom of the benzene ring, a heterocycle optionally containing oxygen or nitrogen, which may be substituted with one or more C 1 -C 4 alkyl radicals; a 4'-aminophenyl radical,

Rg and R'g, which may be identical or different, represent a hydrogen atom or a halogen atom chosen from chlorine, bromine, iodine and fluorine, or a cyano, C 1 -C 4 alkyl, C 1 -C 4 alkoxy or acetyloxy radical,

X " represents an anion preferably chosen from chloride, methyl sulfate and acetate, A represents a group chosen from structures A 1 to A ig below:

in which R 10 represents a C 1 -C 4 alkyl radical which may be substituted with a hydroxyl radical and R 11 represents a C 1 -C 4 alkoxy radical.

40. Composition according to any one of Claims 1 to 35, characterized in that the azo, methine or azomethine direct dye containing a quaternary ammonium group included in a ring is chosen from the compounds of formulae (Xl), (XII) and (XIII) below:

A-N-Z 2 -N-A 1 R 1 R 2

(XIII)

in which:

A and A 1 , independently of each other, are residues of formula:

Z represents an aliphatic or aromatic diamine,

R 1 and R 2 , independently of each other, represent a hydrogen atom, a C 1 -C 4 alkyl group or may form, together with two nitrogen atoms to which they are attached or with Z and Z 2 , a 5-,

6- or 7-membered ring,

X represents the residue of a chain unit forming a bridge, n represents an integer 2, 3 or 4,

Z 1 represents a residue of aromatic diamines, Z 2 represents a residue of aliphatic diamines, KK represents a residue of a coupling compound,

R 3 and R 4 , independently of each other, represent a hydrogen atom or a CrC 4 alkyl group, R 5 and Re, independently of each other, represent a hydrogen atom, a CrC 4 alkyl group or a C 1 -C 4 alkoxy group, An " represents a colourless anion.

41. Composition according to any one of the preceding claims, characterized in that the azo, methine or azomethine direct dye containing a quaternary ammonium group included in a ring is chosen from the compounds of the formulae below:

Basic Red 51 :

Basic Yellow 87:

Basic Orange 31 :

42. Composition according to any one of the preceding claims, characterized in that the azo, methine or azomethine direct dyes containing a quaternary ammonium group included in a ring, other than the dyes of formula (I), preferably represent from 0.001 % to 10% by weight approximately relative to the total weight of the dye composition, and even more preferentially from 0.005% to 5% by weight approximately relative to this weight.

43. Composition according to any one of the preceding claims, characterized in that it

comprises at least one additional direct dye other than the direct dyes of the invention.

44. Composition according to Claim 43, characterized in that the additional direct dye(s) is (are) present in a concentration ranging from 0.001 % to 20% by weight relative to the total weight of the composition.

45. Composition according to any one of the preceding claims, characterized in that it also comprises an oxidizing agent.

46. Composition according to any one of the preceding claims, characterized in that it comprises at least one oxidation base chosen from the group formed by para- phenylenediamines, bis(phenyl)alkylenediamines, para-aminophenols, ortho-aminophenols and heterocyclic bases, and the addition salts thereof.

47. Composition according to Claim 46, characterized in that the oxidation base(s) is (are) present in a concentration ranging from 0.001 % to 10% by weight relative to the total weight of the composition.

48. Composition according to either of Claims 46 and 47, characterized in that it comprises at least one coupler chosen from the group formed by meta-phenylenediamines, meta-aminophenols, meta-diphenols, naphthalene-based couplers and heterocyclic couplers, and the addition salts thereof.

49. Composition according to Claim 48, characterized in that the coupler(s) is (are) present in a concentration ranging from 0.001 % to 10% by weight relative to the total weight of the composition.

50. Process for dyeing keratin fibres, and in particular human keratin fibres such as the hair, characterized in that at least one dye composition as defined in any one of Claims 1 to 44 is applied to the fibres for a time that is sufficient to obtain the desired coloration, after which the fibres are rinsed, optionally washed with shampoo, rinsed again and dried.

51. Process for dyeing keratin fibres, and in particular human keratin fibres such as the hair, characterized in that at least one dye composition as defined in any one of Claims 1 to 44 is applied to the fibres for a time that is sufficient to obtain the desired coloration, without final rinsing.

52. Process for dyeing keratin fibres, and in particular human keratin fibres such as the hair, characterized in that it includes a preliminary step that consists in separately storing, on the one hand, a composition (A1 ) comprising, in a suitable dyeing medium, at least one cationic direct dye (i) as defined in Claims 1 to 28, and, on the other hand, a composition (B1 ) containing, in a suitable dyeing medium, at least one oxidizing agent, and then in mixing them together at the time of use, followed by applying this mixture to the keratin fibres, composition (A1 ) or composition (B1 ) containing at least one azo, methine or azomethine direct dye containing a quaternary ammonium group included in a ring, other than the dyes of formula (I) and as defined in Claims 1 and 30 to 41.

53. Process for dyeing keratin fibres, and in particular human keratin fibres such as the hair, characterized in that it includes a preliminary step that consists in separately storing, on the one hand, a composition (A2) comprising, in a suitable dyeing medium, at least one cationic direct dye (i) as defined in Claims 1 to 28 and at least one oxidation base, and, on the other hand, a composition (B2) containing, in a suitable dyeing medium, at least one oxidizing agent, and then in mixing them together at the time of use, followed by applying this mixture to the keratin fibres, composition (A2) or composition (B2) containing at least one azo, methine or azomethine direct dye containing a quaternary ammonium group included in a ring, other than the dyes of formula (I) and as defined in Claims 1 and 30 to 41.

54. Multi-compartment device or multi-compartment dyeing "kit", characterized in that a first compartment contains composition (A1 ) or (A2) as defined in Claim 49 or 50 and a second compartment contains composition (B1 ) or (B2) as defined in Claim 52 or 53.

Description:

COMPOSITION FOR DYEING KERATIN FIBRES WITH A TETRAAZAPENTAMETHINE CATIONIC DIRECT DYE AND ANOTHER PARTICULAR DIRECT DYE

The invention relates to a composition for dyeing keratin fibres, in particular human keratin fibres such as the hair, comprising, in a suitable dyeing medium, at least one tetraazapentamethine cationic direct dye, and which is characterized in that it also contains at least one oxidation base and at least one other particular direct dye.

The invention also relates to the processes and dyeing devices using the said composition.

Two types of dyeing may be distinguished in the field of hair dyeing.

The first is semi-permanent or temporary dyeing, or direct dyeing, which involves dyes capable of giving the hair's natural coloration a more or less pronounced colour change, which may be resistant to shampoo washing several times. These dyes are known as direct dyes; they may be used with or without an oxidizing agent. In the presence of an oxidizing agent, the aim is to obtain lightening dyeing. Lightening dyeing is performed by applying to the hair an extemporaneous mixture of a direct dye and an oxidizing agent, and makes it possible especially to obtain, via lightening of the melanin of the hair, an advantageous effect such as a unified colour in the case of grey hair, or to bring out the colour in the case of naturally pigmented hair.

The second is permanent dyeing or oxidation dyeing. This is performed with "oxidation" dyes comprising oxidation dye precursors and couplers. Oxidation dye precursors, commonly known as "oxidation bases", are compounds that are initially colourless or weakly coloured, which develop their dyeing power on the hair in the presence of oxidizing agents added at the time of use, leading to the formation of coloured compounds and dyes. The formation of these coloured compounds and dyes results either from an oxidative condensation of the "oxidation bases" with themselves, or from an oxidative condensation of the "oxidation bases" with coloration modifiers commonly known as "couplers", which are generally present in the dye compositions used in oxidation dyeing.

To vary the shades obtained with the said oxidation dyes, or to enrich them with tints, direct dyes may be added thereto.

Among the already known cationic direct dyes available in the field of dyeing keratin fibres,

especially human keratin fibres, are tetraazapentamethine compounds, the structure of which is discussed in the text hereinbelow; however, these dyes lead to colorations which have characteristics that are still insufficient as regards the strength and the homogeneity of the colour distributed along the fibre: the coloration is then said to be too selective, and as regards the staying power in terms of resistance to the various attacking factors to which the hair may be subjected (light, bad weather, shampooing).

Now, after considerable research conducted in this matter, the Applicant has discovered that it is possible to obtain novel compositions for dyeing keratin fibres, which are capable of leading to strong and sparingly selective colorations, but which nevertheless withstand the various attacking factors to which the hair may be subjected, by combining at least one tetraazapentamethine cationic direct dye known in the prior art and at least one other particular direct dye that are respectively defined below.

This discovery is the basis of the present invention.

A first subject of the present invention is thus a composition for dyeing keratin fibres and in particular human keratin fibres such as the hair, containing, in a suitable dyeing medium, (i) at least one cationic direct dye whose structure corresponds to formula (I) defined below, characterized in that it also contains (ii) at least one azo, methine or azomethine direct dye containing at least one quaternary ammonium group included in a ring, other than the dyes of formula (I):

in which - W 1 represents a cationic heteroaromatic radical of formula (II) or (III):

(H) (10)

W 2 represents a heteroaromatic radical of formula (IV) or (V):

(FV) CO in which:

Z 0 represents a radical CR 2 , a nitrogen atom or a radical NR 2 i,

Z 1 represents an oxygen or sulfur atom or a radical NR 9 , - Z 2 represents a nitrogen atom or a radical CR 1 0,

Z 3 represents a nitrogen atom or a radical CRn,

Z 4 represents a nitrogen atom or a radical CR 12 ,

Z 5 represents a nitrogen atom or a radical CR 1 3,

Z 6 represents a nitrogen atom or a radical CR 14 , - Z 7 represents an oxygen or sulfur atom or a radical NR 15 ,

Z 8 represents a nitrogen atom or a radical CR 16 ,

Z 9 represents a nitrogen atom or a radical CR 17 ,

Z 10 represents a nitrogen atom or a radical CR 18 ,

Z 11 represents a nitrogen atom or a radical CR 19 , - Z 12 represents a nitrogen atom or a radical CR 20 ,

Z 13 represents a radical CR 6 , a nitrogen atom or a radical NR 22 , it being understood that each of the rings of formulae (II), (III), (IV) and (V) comprise not more than three nitrogen atoms and that two of the three nitrogen atoms may be contiguous, - the bond a of the 5-membered cationic heteroaromatic radical of formula (II) being linked to the nitrogen atom N 1 of formula (I), the bond b of the 6-membered cationic heteroaromatic radical of formula (III) being linked to the nitrogen atom N 1 of formula (I), the double bond a' of the 5-membered heteroaromatic radical of formula (IV) being linked to the nitrogen atom N 2 of formula (I), the double bond b' of the 6-membered heteroaromatic radical of formula (V) being linked to the nitrogen atom N 2 of formula (I), the bond b, linking the cationic heteroaromatic radical of formula (III) to the nitrogen atom N 1 of formula (I), being in an ortho or para position relative to the nitrogen atom bearing the radical R 4 when Z 5 represents a radical CR 13 ; the bond b being in an ortho position relative to the nitrogen atom bearing the radical R 4 when Z 5 represents

a nitrogen atom, the bond b', linking the heteroaromatic radical of formula (V) to the nitrogen atom N 2 of formula (I), being in an ortho or para position relative to the nitrogen atom bearing the radical R 7 when Z 11 represents a radical CR 19 ; the bond b' being in an ortho position relative to the nitrogen atom bearing the radical R 7 when Z 11 represents a nitrogen atom,

R 2 , Re, R-io and R 16 represent, independently of each other, a hydrogen atom; a linear or branched C 1 -C 4 alkyl radical, which is unsubstituted or substituted with one to three radicals chosen from hydroxyl, C 1 -C 2 alkoxy, C 2 -C 4 (poly)hydroxyalkoxy, amino, C 1 -C 2 (di)alkylamino, carboxyl and sulfonic radicals; a phenyl radical, which is unsubstituted or substituted with one or two radicals chosen from hydroxyl, C 1 -C 2 alkoxy, C 2 -C 4 (poly)hydroxyalkoxy, amino and C 1 -C 2 (di)alkylamino radicals; a carboxyl radical; a sulfonylamino radical, R 1 , R 4 , R 5 , R 7 , Rg, R- 15 , R 21 and R 22 represent, independently of each other, a linear or branched C 1 -C 8 alkyl radical, which is unsubstituted or substituted with one to three radicals chosen from hydroxyl, C 1 -C 2 alkoxy, C 2 -C 4 (poly)hydroxyalkoxy, amino, C 1 -C 2 (di)alkylamino, carboxyl and sulfonic radicals;

R 0 , R3, Re, R11, R12, Ri3, Ri 4 , Ri7, R18, Ri9 and R 20 represent, independently of each other, a hydrogen atom, a linear or branched C 1 -C 16 hydrocarbon-based chain, this chain possibly being saturated or unsaturated with one to three unsaturations, this chain being unsubstituted or substituted with one to three radicals chosen from hydroxyl, C 1 -C 2 alkoxy, C 2 -C 4 (poly)hydroxyalkoxy, amino, C 1 -C 2 (di)alkylamino, carboxyl, sulfonic, sulfonylamino and C 2 -C 4 (poly)hydroxyalkylamino radicals or a halogen atom such as chlorine, fluorine or bromine; a phenyl radical, which is unsubstituted or substituted with one to three radicals chosen from hydroxyl, C 1 -C 2 alkoxy, C 2 -C 4 (poly)hydroxyalkoxy, amino, C 1 -C 2 (di)alkylamino, carboxyl, sulfonic, sulfonylamino and C 2 -C 4 (poly)hydroxyalkylamino radicals or a halogen atom such as chlorine, fluorine or bromine; a heteroaryl radical chosen from pyrazolyl, pyrrolyl, imidazolyl, thiazolyl, oxazolyl, triazolyl, pyridyl, pyrimidinyl, triazinyl, pyrazinyl and pyridazinyl radicals; in addition, this hydrocarbon-based chain may be interrupted with one or two oxygen, nitrogen or sulfur atoms or with an SO 2 radical, it being understood that R 0 , R3, Rs, R 11 , R 12 , R 1 S, R 14 , R 17 , R 1 S, R19 and R 20 do not comprise a peroxide bond or diazo or nitroso radicals,

R 2 with R 10 , R 11 with R 12 , R 6 with R 16 , and R 17 with R 18 can form, independently of each other, a 5- or 6-membered carbon-based aromatic ring, which is unsubstituted or substituted with one or two hydroxyl, amino, (di)(CrC 2 )alkylamino, C 1 -C 2 alkoxy or

C 2 -C 4 (poly)hydroxyalkylamino radicals, X is an organic or mineral anion.

For the purposes of the present patent application, the expression "branched hydrocarbon- based chain" means a branched hydrocarbon-based chain that may also form one to five 3- to 7-membered carbon-based rings, this chain possibly comprising one to three unsaturations, i.e. one to three double bonds and/or triple bonds.

The term "C 2 -C 4 (poly)hydroxyalkoxy" means a C 2 -C 4 alkoxy group substituted with 1 or 2 hydroxyl groups.

For the purposes of the present invention, the expression "C 2 -C 4 (poly)hydroxyalkylamino" means an alkylamino group substituted with 1 or 2 hydroxyl groups.

The expression according to which the hydrocarbon-based chain may be interrupted with one or more oxygen, nitrogen or sulfur atoms or with an SO 2 radical, or according to which this chain is unsaturated, means that the carbon-based chain may be modified in the following manner:

For the purposes of the present patent application, an organic or mineral anion is chosen, for example, from a halide such as chloride, bromide, fluoride or iodide; a hydroxide; a sulfate; a hydrogen sulfate; a (d-CβJalkyl sulfate, for instance a methyl sulfate or an ethyl sulfate; an acetate; a tartrate; an oxalate; a (C"rC 6 )alkylsulfonate such as methyl sulfonate; an arylsulfonate, which is unsubstituted or substituted with a C 1 -C 4 alkyl radical, for instance a 4- tolylsulfonate.

Preferably, Ro represents a hydrogen atom; a linear or branched C 1 -C 6 alkyl radical, which is unsubstituted or substituted with one to three radicals chosen from hydroxyl, CrC 2 alkoxy, C 2 -C 4 (poly)hydroxyalkoxy, amino, C 1 -C 2 (di)alkylamino, C 2 -C 4 (poly)hydroxyalkylamino, carboxyl and sulfonic radicals; a phenyl radical, which is unsubstituted or substituted with one to three radicals chosen from hydroxyl, C 1 -C 2 alkoxy, C 2 -C 4 (poly)hydroxyalkoxy, amino, CrC 2 (di)alkylamino, carboxyl and sulfonic radicals or a halogen atom such as chlorine, fluorine or bromine, an optionally cationic heteroaryl radical chosen from pyrazolyl, pyrrolyl, imidazolyl, thiazolyl, oxazolyl, triazolyl, pyridyl, pyrimidinyl, triazinyl, pyrazinyl and pyridazinyl radicals.

Even more preferably, R 0 preferably represents a hydrogen atom; a linear or branched C 1 -C 3 alkyl radical, which is unsubstituted or substituted with one or two radicals chosen from hydroxyl, C 1 -C 2 alkoxy, amino, C 1 -C 2 (di)alkylamino, carboxyl and sulfonic radicals; a phenyl radical, which is unsubstituted or substituted with one or two radicals chosen from hydroxyl, amino, C 1 -C 2 (di)alkylamino and C 2 -C 4 (poly)hydroxyalkylamino radicals, or an optionally cationic heteroaryl radical chosen from pyrazolyl, pyrrolyl, imidazolyl and pyridyl radicals.

According to one particularly preferred embodiment, R 0 represents a hydrogen atom; a methyl, ethyl, propyl, butyl, 2-hydroxyethyl, 2-aminoethyl, 1-carboxymethyl, 2-carboxyethyl, 2-sulfonylethyl or 2-methoxyethyl; a phenyl radical, which is unsubstituted or substituted with one or two radicals chosen from amino, C 1 -C 2 (di)alkylamino and C 2 -C 4 (poly)hydroxyalkylamino radicals, or an optionally cationic heteroaryl radical chosen from pyrazolyl, pyrrolyl, imidazolyl and pyridyl radicals.

R 0 even more preferably represents a hydrogen atom; a methyl, ethyl or 2-methoxyethyl radical; a phenyl radical, which is unsubstituted or substituted with an amino, (di)methylamino or (di)(2-hydroxyethyl)amino radical, or an optionally cationic heteroaryl radical chosen from imidazolyl and pyridyl radicals.

R 2 , R 6 , R 1O and R 16 preferably represent a hydrogen atom, a phenyl radical or a C 1 -C 4 alkyl radical, which is unsubstituted or substituted with one or two radicals chosen from hydroxyl, amino, C 1 -C 2 (di)alkylamino and carboxyl radicals.

According to one particularly preferred embodiment, R 2 , R 6 , R 10 and R 16 preferably represent a hydrogen atom, a methyl, phenyl or 2-hydroxymethyl radical, a carboxyl or a phenyl radical.

Ri, R 4 , R5, R 7 , Rg, Ri5, R 21 and R 22 preferably represent a CrC 4 alkyl radical, which is unsubstituted or substituted with one or two radicals chosen from hydroxyl, C 1 -C 2 alkoxy, amino, CrC 2 (di)alkylamino, carboxyl and sulfonic radicals.

According to one particularly preferred embodiment, R 1 , R 4 , R 5 , R 7 , R 9 , R 15 , R 21 and R 22 preferably represent a methyl, ethyl, 2-hydroxyethyl, 1-carboxymethyl, 2-carboxyethyl or 2- sulfonylethyl radical.

R 3 , R 8 , R 11 , R 12 , R 13 , R 14 , R 17 , R 18 , R 1 9 and R 20 preferably represent, independently of each other, a hydrogen atom; a linear or branched C 1 -C 4 alkyl radical, which is unsubstituted or substituted with one or two radicals chosen from hydroxyl, C 1 -C 2 alkoxy, C 2 -C 4 (poly)hydroxyalkoxy, amino, C 1 -C 2 (di)alkylamino, carboxyl and sulfonic radicals; a phenyl radical, which is unsubstituted or substituted with one or two radicals chosen from hydroxyl, C 1 -C 2 alkoxy, C 2 -C 4 (poly)hydroxyalkoxy, amino, C 1 -C 2 (di)alkylamino, carboxyl and sulfonic radicals or a halogen atom such as chlorine, fluorine or bromine; a sulfonylamino radical; a C 2 -C 4 (poly)hydroxyalkylamino radical.

More preferably, R 3 , R 8 , R 11 , R 12 , R 13 , R 14 , R 17 , R 18 , R 19 and R 20 represent a hydrogen atom, a C 1 -C 4 alkyl radical, which is unsubstituted or substituted with one or two radicals chosen from hydroxyl radicals or a C 1 -C 2 alkoxy radical; an amino radical; a C 1 -C 2 (di)alkylamino radical; a carboxyl radical; a C 2 -C 4 (poly)hydroxyalkylamino radical.

According to one particularly preferred embodiment, R 3 , R 8 , R 11 , R 12 , R 13 , R 14 , R 17 , R 18 , R 19 and R 20 represent, independently of each other, a hydrogen atom, a methyl or 2- hydroxymethyl radical, a carboxyl, a methoxy, ethoxy or 2-hydroxyethyloxy radical, or an amino, methylamino, dimethylamino or 2-hydroxyethylamino radical.

A. In a first preferred variant, the compounds of formula I are chosen from the family defined by the compounds for which W 1 is a 2-pyridinium radical and W 2 is a 2-pyridine radical. Even more preferably, they are the following compounds:

- 2-[5-(N-methyl-2-pyridinylidene)-1 -formazano]-N-methylpyridinium chloride

- 2-[5-(N-methyl-2-pyridinylidene)-3-methyl-1 -formazano]-N-methylpyridinium chloride

- 2-[5-(N-methyl-2-pyridinylidene)-3-ethyl-1 -formazano]-N-methylpyridinium chloride - 2-[5-(N-methyl-2-pyridinylidene)-3-isopropyl-1-formazano]-N- methylpyridinium chloride

- 2-[5-(N-methyl-2-pyridinylidene)-3-phenyl-1 -formazano]-N-methylpyridinium chloride

- 2-[5-(N-methyl-2-pyridinylidene)-3-(4'-methoxyphenyl)-1-form azano]-N-methylpyridinium chloride

- 2-[5-(N-methyl-2-pyridinylidene)-3-(4'-hydroxyphenyl)-1-form azano]-N-methylpyridinium chloride - 2-[5-(N-methyl-2-pyridinylidene)-3-(4'-N,N-dimethylaminophen yl)-1-formazano]-N- methylpyridinium chloride

- 2-[5-(4-pyrrolidino-N-methyl-2-pyridinylidene)-1-formazano]- 4-pyrrolidino-N- methylpyridinium chloride

- 2-[5-(4-pyrrolidino-N-methyl-2-pyridinylidene)-3-methyl-1-fo rmazano]-4-pyrrolidino-N- methylpyridinium chloride

- 2-[5-(4-pyrrolidino-N-methyl-2-pyridinylidene)-3-ethyl-1-for mazano]-4-pyrrolidino-N- methylpyridinium chloride

- 2-[5-(4-pyrrolidino-N-methyl-2-pyridinylidene)-3-isopropyl-1 -formazano]-4-pyrrolidino-N- methylpyridinium chloride - 2-[5-(4-pyrrolidino-N-methyl-2-pyridinylidene)-3-phenyl-1 -formazano]-4-pyrrolidino-N- methylpyridinium chloride

- 2-[5-(4-pyrrolidino-N-methyl-2-pyridinylidene)-3-(4'-methoxy phenyl)-1-formazano]-4- pyrrolidino-N-methylpyridinium chloride

- 2-[5-(4-pyrrolidino-N-methyl-2-pyridinylidene)-3-(4'-hydroxy phenyl)-1-formazano]-4- pyrrolidino-N-methylpyridinium chloride

- 2-[5-(4-pyrrolidino-N-methyl-2-pyridinylidene)-3-(4'-N,N-dim ethylaminophenyl)-1- formazano]-4-pyrrolidino-N-methylpyridinium chloride

- 2-[5-(N-hydroxyethyl-2-pyridinylidene)-1-formazano]-N-hydrox yethylpyridinium chloride

- 2-[5-(N-hydroxyethyl-2-pyridinylidene)-3-methyl-1-formazano] -N-hydroxyethylpyridinium chloride

- 2-[5-(N-hydroxyethyl-2-pyridinylidene)-3-ethyl-1-formazano]- N-hydroxyethylpyridinium chloride

- 2-[5-(N-hydroxyethyl-2-pyridinylidene)-3-phenyl-1-formazano] -N-hydroxyethylpyridinium chloride - 2-[5-(N-hydroxyethyl-2-pyridinylidene)-3-isopropyl-1 -formazano]-N-hydroxyethylpyridinium chloride

- 2-[5-(N-hydroxyethyl-2-pyridinylidene)-3-(4'-methoxyphenyl)- 1-formazano]-N- hydroxyethylpyridinium chloride

- 2-[5-(N-hydroxyethyl-2-pyridinylidene)-3-(4'-hydroxyphenyl)- 1-formazano]-N- hydroxyethylpyridinium chloride

- 2-[5-(N-hydroxyethyl-2-pyridinylidene)-3-(4'-N,N-dimethylami nophenyl)-1-formazano]-N-

hydroxyethylpyridinium chloride

- 2-[5-(N-carboxyethyl-2-pyridinylidene)-1-formazano]-N-carbox yethylpyridinium chloride

- 2-[5-(N-carboxyethyl-2-pyridinylidene)-3-methyl-1-formazano] -N-carboxyethylpyridinium chloride - 2-[5-(N-carboxyethyl-2-pyridinylidene)-3-ethyl-1-formazano]- N-carboxyethylpyridinium chloride

- 2-[5-(N-carboxyethyl-2-pyridinylidene)-3-phenyl-1-formazano] -N-carboxyethylpyridinium chloride

- 2-[5-(N-carboxyethyl-2-pyridinylidene)-3-isopropyl-1-formaza no]-N-carboxyethylpyridinium chloride

- 2-[5-(N-carboxyethyl-2-pyridinylidene)-3-(4'-methoxyphenyl)- 1-formazano]-N- carboxyethylpyridinium chloride

- 2-[5-(N-carboxyethyl-2-pyridinylidene)-3-(4'-hydroxyphenyl)- 1-formazano]-N- carboxyethylpyridinium chloride - 2-[5-(N-carboxyethyl-2-pyridinylidene)-3-(4'-N,N-dimethylami nophenyl)-1-formazano]-N- carboxyethylpyridinium chloride

B. In a second preferred variant, the compounds of formula I are chosen from the family defined by the compounds for which W 1 is a 4-pyridinium radical and W 2 is a 4-pyridine radical. Even more preferably, they are the following compounds:

- 4-[5-(N-methyl-4-pyridinylidene)-1 -formazano]-N-methylpyridinium chloride

- 4-[5-(N-methyl-4-pyridinylidene)-3-methyl-1 -formazano]-N-methylpyridinium chloride

- 4-[5-(N-methyl-4-pyridinylidene)-3-ethyl-1 -formazano]-N-methylpyridinium chloride

- 4-[5-(N-methyl-4-pyridinylidene)-3-isopropyl-1 -forrnazano]-N-methylpyridinium chloride - 4-[5-(N-methyl-4-pyridinylidene)-3-phenyl-1-formazano]-N-met hylpyridinium chloride

- 4-[5-(N-methyl-4-pyridinylidene)-3-(4'-methoxyphenyl)-1-form azano]-N-methylpyridinium chloride

- 4-[5-(N-methyl-4-pyridinylidene)-3-(4'-hydroxyphenyl)-1-form azano]-N-methylpyridinium chloride - 4-[5-(N-methyl-4-pyridinylidene)-3-(4'-N,N-dimethylaminophen yl)-1-formazano]-N- methylpyridinium chloride

- 4-[5-(N-hydroxyethyl-4-pyridinylidene)-1-formazano]-N-hydrox yethylpyridinium chloride

- 4-[5-(N-hydroxyethyl-4-pyridinylidene)-3-methyl-1-formazano] -N-hydroxyethylpyridinium chloride - 4-[5-(N-hydroxyethyl-4-pyridinylidene)-3-ethyl-1-formazano]- N-hydroxyethylpyridinium chloride

- 4-[5-(N-hydroxyethyl-4-pyridinylidene)-3-phenyl-1-formazano] -N-hydroxyethylpyridinium chloride

- 4-[5-(N-hydroxyethyl-4-pyridinylidene)-3-isopropyl-1-formaza no]-N-hydroxyethylpyridinium chloride - 4-[5-(N-hydroxyethyl-4-pyridinylidene)-3-(4'-methoxyphenyl)- 1 -formazano]-N- hydroxyethylpyridinium chloride

- 4-[5-(N-hydroxyethyl-4-pyridinylidene)-3-(4'-hydroxyphenyl)- 1-formazano]-N- hydroxyethylpyridinium chloride

- 4-[5-(N-hydroxyethyl-4-pyridinylidene)-3-(4'-N,N-dimethylami nophenyl)-1-formazano]-N- hydroxyethylpyridinium chloride

- 4-[5-(N-carboxyethyl-4-pyridinylidene)-1-formazano]-N-carbox yethylpyridinium chloride

- 4-[5-(N-carboxyethyl-4-pyridinylidene)-3-methyl-1-formazano] -N-carboxyethylpyridinium chloride

- 4-[5-(N-carboxyethyl-4-pyridinylidene)-3-ethyl-1-formazano]- N-carboxyethylpyridinium chloride

- 4-[5-(N-carboxyethyl-4-pyridinylidene)-3-phenyl-1-formazano] -N-carboxyethylpyridinium chloride

- 4-[5-(N-carboxyethyl-4-pyridinylidene)-3-isopropyl-1-formaza no]-N-carboxyethylpyridinium chloride - 4-[5-(N-carboxyethyl-4-pyridinylidene)-3-(4'-methoxyphenyl)- 1 -formazano]-N- carboxyethylpyridinium chloride

- 4-[5-(N-carboxyethyl-4-pyridinylidene)-3-(4'-hydroxyphenyl)- 1-formazano]-N- carboxyethylpyridinium chloride

- 4-[5-(N-carboxyethyl-4-pyridinylidene)-3-(4'-N,N-dimethylami nophenyl)-1-formazano]-N- carboxyethylpyridinium chloride

C. In a third preferred variant, the compounds of formula I are chosen from the family defined by the compounds for which W 1 is a 2-imidazolium radical and W 2 is a 2-imidazole radical. Even more preferably, they are the following compounds: - 2-[5-(1 ,3-dimethyl-2-imidazolidene)-1-formazano]-1 ,3-dimethylimidazolium chloride

- 2-[5-(1 ,3-dimethyl-2-imidazolidene)-3-methyl-1-formazano]-1 ,3-dimethylimidazolium chloride

- 2-[5-(1 ,3-dimethyl-2-imidazolidene)-3-ethyl-1 -formazano]-1 ,3-dimethylimidazolium chloride

- 2-[5-(1 ,3-dimethyl-2-imidazolidene)-3-isopropyl-1 -formazano]-1 ,3-dimethylimidazolium chloride

- 2-[5-(1 ,3-dimethyl-2-imidazolidene)-3-phenyl-1-formazano]-1 ,3-dimethylimidazolium

chloride

- 2-[5-(1 ,3-dimethyl-2-imidazolidene)-3-(4'-methoxyphenyl)-1 -formazano]-1 ,3- dimethylimidazolium chloride

- 2-[5-(1 ,3-dimethyl-2-imidazolidene)-3-(4'-hydroxyphenyl)-1-formazan o]-1 ,3- dimethylimidazolium chloride

- 2-[5-(1 ,3-dimethyl-2-imidazolidene)-3-(4'-N,N-dimethylaminophenyl)- 1-formazano]-1 ,3- dimethylimidazolium chloride

- 2-[5-(1 ,3-dihydroxyethyl-2-imidazolidene)-1 -formazano]-1 ,3-dihydroxyethylimidazolium chloride - 2-[5-(1 ,3-dihydroxyethyl-2-imidazolidene)-3-methyl-1-formazano]-1 ,3- dihydroxyethylimidazolium chloride

- 2-[5-(1 ,3-dihydroxyethyl-2-imidazolidene)-3-ethyl-1 -formazano]-1 ,3- dihydroxyethylimidazolium chloride

- 2-[5-(1 ,3-dihydroxyethyl-2-imidazolidene)-3-phenyl-1-formazano]-1 ,3- dihydroxyethylimidazolium chloride

- 2-[5-(1 ,3-dihydroxyethyl-2-imidazolidene)-3-isopropyl-1-formazano]- 1 ,3- dihydroxyethylimidazolium chloride

- 2-[5-(1 ,3-dihydroxyethyl-2-imidazolidene)-3-(4'-methoxyphenyl)-1 -formazano]-1 ,3- dihydroxyethylimidazolium chloride - 2-[5-(1 ,3-dihydroxyethyl-2-imidazolidene)-3-(4'-hydroxyphenyl)-1-fo rmazano]-1 ,3- dihydroxyethylimidazolium chloride

- 2-[5-(1 ,3-dihydroxyethyl-2-imidazolidene)-3-(4'-N,N-dimethylaminoph enyl)-1-formazano]- 1 ,3-dihydroxyethylimidazolium chloride

- 2-[5-(1 ,3-dicarboxyethyl-2-imidazolidene)-1-formazano]-1 ,3-dicarboxyethylimidazolium chloride

- 2-[5-(1 ,3-dicarboxyethyl-2-imidazolidene)-3-methyl-1-formazano]-1 ,3- dicarboxyethylimidazolium chloride

- 2-[5-(1 ,3-dicarboxyethyl-2-imidazolidene)-3-ethyl-1-formazano]-1 ,3- dicarboxyethylimidazolium chloride - 2-[5-(1 ,3-dicarboxyethyl-2-imidazolidene)-3-phenyl-1-formazano]-1 ,3- dicarboxyethylimidazolium chloride

- 2-[5-(1 ,3-dicarboxyethyl-2-imidazolidene)-3-isopropyl-1-formazano]- 1 ,3- dicarboxyethylimidazolium chloride

- 2-[5-(1 ,3-dicarboxyethyl-2-imidazolidene)-3-(4'-methoxyphenyl)-1 -formazano]-1 ,3- dicarboxyethylimidazolium chloride

- 2-[5-(1 ,3-dicarboxyethyl-2-imidazolidene)-3-(4'-hydroxyphenyl)-1-fo rmazano]-1 ,3-

dicarboxyethylimidazolium chloride

- 2-[5-(1 ,3-dicarboxyethyl-2-imidazolidene)-3-(4'-N,N-dimethylaminoph enyl)-1-formazano]- 1 ,3-dicarboxyethylimidazolium chloride

D. In a fourth preferred variant, the compounds of formula I are chosen from the family defined by the compounds for which W 1 is a 5-pyrazolium radical and W 2 is a 5-pyrazole radical. Even more preferably, they are the following compounds:

- 5-[5-(1 ,2-dimethyl-5-pyrazolidene)-1 -formazano]-1 ,2-dimethylpyrazolinium chloride

- 5-[5-(1 ,2-dimethyl-5-pyrazolidene)-3-methyl-1 -formazano]-1 ,2-dimethylpyrazolinium chloride

- 5-[5-(1 ,2-dimethyl-5-pyrazolidene)-3-ethyl-1-formazano]-1 ,2-dimethylpyrazolinium chloride

- 5-[5-(1 ,2-dimethyl-5-pyrazolidene)-3-isopropyl-1-formazano]-1 ,2-dimethylpyrazolinium chloride

- 5-[5-(1 ,2-dimethyl-5-pyrazolidene)-3-phenyl-1 -formazano]-1 ,2-dimethylpyrazolinium chloride

- 5-[5-(1 ,2-dimethyl-5-pyrazolidene)-3-(4'-methoxyphenyl)-1-formazano ]-1 ,2- dimethylpyrazolinium chloride

- 5-[5-(1 ,2-dimethyl-5-pyrazolidene)-3-(4'-hydroxyphenyl)-1-formazano ]-1 ,2- dimethylpyrazolinium chloride - 5-[5-(1 ,2-dimethyl-5-pyrazolidene)-3-(4'-N,N-dimethylaminophenyl)-1 -formazano]-1 ,2- dimethylpyrazolinium chloride

- 5-[5-(1 ,2-dihydroxyethyl-5-pyrazolidene)-1 -formazano]-1 ,2-dihydroxyethylpyrazolinium chloride

- 5-[5-(1 ,2-dihydroxyethyl-5-pyrazolidene)-3-methyl-1 -formazano]-1 ,2- dihydroxyethylpyrazolinium chloride

- 5-[5-(1 ,2-dihydroxyethyl-5-pyrazolidene)-3-ethyl-1 -formazano]-1 ,2- dihydroxyethylpyrazolinium chloride

- 5-[5-(1 ,2-dihydroxyethyl-5-pyrazolidene)-3-phenyl-1-formazano]-1 ,2- dihydroxyethylpyrazolinium chloride - 5-[5-(1 ,2-dihydroxyethyl-5-pyrazolidene)-3-isopropyl-1 -formazano]-1 ,2- dihydroxyethylpyrazolinium chloride

- 5-[5-(1 ,2-dihydroxyethyl-5-pyrazolidene)-3-(4'-methoxyphenyl)-1-for mazano]-1 ,2- dihydroxyethylpyrazolinium chloride

- 5-[5-(1 ,2-dihydroxyethyl-5-pyrazolidene)-3-(4'-hydroxyphenyl)-1-for mazano]-1 ,2- dihydroxyethylpyrazolinium chloride

- 5-[5-(1 ,2-dihydroxyethyl-5-pyrazolidene)-3-(4'-N,N-dimethylaminophe nyl)-1-formazano]-

1 ,2-dihydroxyethylpyrazolinium chloride

- 5-[5-(1 ,2-dicarboxyethyl-5-pyrazolidene)-1 -formazano]-1 ,2-dicarboxyethylpyrazolinium chloride

- 5-[5-(1 ,2-dicarboxyethyl-5-pyrazolidene)-3-methyl-1-formazano]-1 ,2- dicarboxyethylpyrazolinium chloride

- 5-[5-(1 ,2-dicarboxyethyl-5-pyrazolidene)-3-ethyl-1 -formazano]-1 ,2- dicarboxyethylpyrazolinium chloride

- 5-[5-(1 ,2-dicarboxyethyl-5-pyrazolidene)-3-phenyl-1-formazano]-1 ,2- dicarboxyethylpyrazolinium chloride - 5-[5-(1 ,2-dicarboxyethyl-5-pyrazolidene)-3-isopropyl-1-formazano]-1 ,2- dicarboxyethylpyrazolinium chloride

- 5-[5-(1 ,2-dicarboxyethyl-5-pyrazolidene)-3-(4'-methoxyphenyl)-1-for mazano]-1 ,2- dicarboxyethylpyrazolinium chloride

- 5-[5-(1 ,2-dicarboxyethyl-5-pyrazolidene)-3-(4'-hydroxyphenyl)-1-for mazano]-1 ,2- dicarboxyethylpyrazolinium chloride

- 5-[5-(1 ,2-dicarboxyethyl-5-pyrazolidene)-3-(4'-N,N-dimethylaminophe nyl)-1-formazano]- 1 ,2-dicarboxyethylpyrazolinium chloride

E. In a fifth preferred variant, the compounds of formula I are chosen from the family defined by the compounds for which W 1 is a 2-benzimidazolium radical and W 2 is a 2- pyridine radical. Even more preferably, they are the following compounds:

- 2-[5-(N-methyl-2-pyridinylidene)-1-formazano]-1 ,3-dimethylbenzimidazolium chloride

- 2-[5-(N-methyl-2-pyridinylidene)-3-methyl-1 -formazano]-1 ,3-dimethylbenzimidazolium chloride - 2-[5-(N-methyl-2-pyridinylidene)-3-ethyl-1 -formazano]-1 ,3-dimethylbenzimidazolium chloride

- 2-[5-(N-methyl-2-pyridinylidene)-3-isopropyl-1 -formazano]-1 ,3-dimethylbenzimidazolium chloride

- 2-[5-(N-methyl-2-pyridinylidene)-3-phenyl-1 -formazano]-1 ,3-dimethylbenzimidazolium chloride

- 2-[5-(N-methyl-2-pyridinylidene)-3-(4'-methoxyphenyl)-1-form azano]-1 ,3- dimethylbenzimidazolium chloride

- 2-[5-(N-methyl-2-pyridinylidene)-3-(4'-hydroxyphenyl)-1 -formazano]-1 ,3- dimethylbenzimidazolium chloride - 2-[5-(N-methyl-2-pyridinylidene)-3-(4'-N,N-dimethylaminophen yl)-1-formazano]-1 ,3- dimethylbenzimidazolium chloride

- 2-[5-(N-hydroxyethyl-2-pyridinylidene)-1 -formazano]-1 ,3-dihydroxyethylbenzimidazolium chloride

- 2-[5-(N-hydroxyethyl-2-pyridinylidene)-3-methyl-1 -formazano]-1 ,3- dihydroxyethylbenzimidazolium chloride - 2-[5-(N-hydroxyethyl-2-pyridinylidene)-3-ethyl-1-formazano]- 1 ,3- dihydroxyethylbenzimidazolium chloride

- 2-[5-(N-hydroxyethyl-2-pyridinylidene)-3-phenyl-1-formazano] -1 ,3- dihydroxyethylbenzimidazolium chloride

- 2-[5-(N-hydroxyethyl-2-pyridinylidene)-3-isopropyl-1 -formazano]-1 ,3- dihydroxyethylbenzimidazolium chloride

- 2-[5-(N-hydroxyethyl-2-pyridinylidene)-3-(4'-methoxyphenyl)- 1 -formazano]-1 ,3- dihydroxyethylbenzimidazolium chloride

- 2-[5-(N-hydroxyethyl-2-pyridinylidene)-3-(4'-hydroxyphenyl)- 1-formazano]-1 ,3- dihydroxyethylbenzimidazolium chloride - 2-[5-(N-hydroxyethyl-2-pyridinylidene)-3-(4'-N,N-dimethylami nophenyl)-1-formazano]-1 ,3- dihydroxyethylbenzimidazolium chloride

- 2-[5-(N-carboxyethyl-2-pyridinylidene)-1 -formazano]-1 ,3-dicarboxyethylbenzimidazolium chloride

- 2-[5-(N-carboxyethyl-2-pyridinylidene)-3-methyl-1 -formazano]-1 ,3- dicarboxyethylbenzimidazolium chloride

- 2-[5-(N-carboxyethyl-2-pyridinylidene)-3-ethyl-1 -formazano]-1 ,3- dicarboxyethylbenzimidazolium chloride

- 2-[5-(N-carboxyethyl-2-pyridinylidene)-3-phenyl-1-formazano] -1 ,3- dicarboxyethylbenzimidazolium chloride - 2-[5-(N-carboxyethyl-2-pyridinylidene)-3-isopropyl-1-formaza no]-1 ,3- dicarboxyethylbenzimidazolium chloride

- 2-[5-(N-carboxyethyl-2-pyridinylidene)-3-(4'-methoxyphenyl)- 1-formazano]-1 ,3- dicarboxyethylbenzimidazolium chloride

- 2-[5-(N-carboxyethyl-2-pyridinylidene)-3-(4'-hydroxyphenyl)- 1-formazano]-1 ,3- dicarboxyethylbenzimidazolium chloride

- 2-[5-(N-carboxyethyl-2-pyridinylidene)-3-(4'-N,N-dimethylami nophenyl)-1-formazano]-1 ,3- dicarboxyethylbenzimidazolium chloride

F. In a sixth preferred variant, the compounds of formula I are chosen from the family defined by the compounds for which W 1 is a 2-benzimidazolium radical and W 2 is a 4- pyridine radical. Even more preferably, they are the following compounds:

- 2-[5-(N-methyl-4-pyridinylidene)-1-formazano]-1 ,3-dimethylbenzimidazolium chloride

- 2-[5-(N-methyl-4-pyridinylidene)-3-methyl-1 -formazano]-1 ,3-dimethylbenzimidazolium chloride

- 2-[5-(N-methyl-4-pyridinylidene)-3-ethyl-1 -formazano]-1 ,3-dimethylbenzimidazolium chloride

- 2-[5-(N-methyl-4-pyridinylidene)-3-isopropyl-1 -formazano]-1 ,3-dimethylbenzimidazolium chloride

- 2-[5-(N-methyl-4-pyridinylidene)-3-phenyl-1 -formazano]-1 ,3-dimethylbenzimidazolium chloride - 2-[5-(N-methyl-4-pyridinylidene)-3-(4'-methoxyphenyl)-1-form azano]-1 ,3- dimethylbenzimidazolium chloride

- 2-[5-(N-methyl-4-pyridinylidene)-3-(4'-hydroxyphenyl)-1 -formazano]-1 ,3- dimethylbenzimidazolium chloride

- 2-[5-(N-methyl-4-pyridinylidene)-3-(4'-N,N-dimethylaminophen yl)-1-formazano]-1 ,3- dimethylbenzimidazolium chloride

- 2-[5-(N-hydroxyethyl-4-pyridinylidene)-1 -formazano]-1 ,3-dihydroxyethylbenzimidazolium chloride

- 2-[5-(N-hydroxyethyl-4-pyridinylidene)-3-methyl-1 -formazano]-1 ,3- dihydroxyethylbenzimidazolium chloride - 2-[5-(N-hydroxyethyl-4-pyridinylidene)-3-ethyl-1-formazano]- 1 ,3- dihydroxyethylbenzimidazolium chloride

- 2-[5-(N-hydroxyethyl-4-pyridinylidene)-3-phenyl-1-formazano] -1 ,3- dihydroxyethylbenzimidazolium chloride

- 2-[5-(N-hydroxyethyl-4-pyridinylidene)-3-isopropyl-1 -formazano]-1 ,3- dihydroxyethylbenzimidazolium chloride

- 2-[5-(N-hydroxyethyl-4-pyridinylidene)-3-(4'-methoxyphenyl)- 1 -formazano]-1 ,3- dihydroxyethylbenzimidazolium chloride

- 2-[5-(N-hydroxyethyl-4-pyridinylidene)-3-(4'-hydroxyphenyl)- 1-formazano]-1 ,3- dihydroxyethylbenzimidazolium chloride - 2-[5-(N-hydroxyethyl-4-pyridinylidene)-3-(4'-N,N-dimethylami nophenyl)-1-formazano]-1 ,3- dihydroxyethylbenzimidazolium chloride

- 2-[5-(N-carboxyethyl-4-pyridinylidene)-1 -formazano]-1 ,3-dicarboxyethylbenzimidazolium chloride

- 2-[5-(N-carboxyethyl-4-pyridinylidene)-3-methyl-1 -formazano]-1 ,3- dicarboxyethylbenzimidazolium chloride

- 2-[5-(N-carboxyethyl-4-pyridinylidene)-3-ethyl-1 -formazano]-1 ,3-

dicarboxyethylbenzimidazolium chloride

- 2-[5-(N-carboxyethyl-4-pyridinylidene)-3-phenyl-1-formazano] -1 ,3- dicarboxyethylbenzimidazolium chloride

- 2-[5-(N-carboxyethyl-4-pyridinylidene)-3-isopropyl-1 -formazano]-1 ,3- dicarboxyethylbenzimidazolium chloride

- 2-[5-(N-carboxyethyl-4-pyridinylidene)-3-(4'-methoxyphenyl)- 1 -formazano]-1 ,3- dicarboxyethylbenzimidazolium chloride

- 2-[5-(N-carboxyethyl-4-pyridinylidene)-3-(4'-hydroxyphenyl)- 1-formazano]-1 ,3- dicarboxyethylbenzimidazolium chloride - 2-[5-(N-carboxyethyl-4-pyridinylidene)-3-(4'-N,N-dimethylami nophenyl)-1-formazano]-1 ,3- dicarboxyethylbenzimidazolium chloride

G. In a seventh preferred variant, the compounds of formula I are chosen from the family defined by the compounds for which W 1 is a 2-imidazolium radical and W 2 is a 2-pyridine radical. Even more preferably, they are the following compounds:

- 2-[5-(N-methyl-2-pyridinylidene)-1-formazano]-1 ,3-dimethylimidazolium chloride

- 2-[5-(N-methyl-2-pyridinylidene)-3-methyl-1 -formazano]-1 ,3-dimethylimidazolium chloride

- 2-[5-(N-methyl-2-pyridinylidene)-3-ethyl-1-formazano]-1 ,3-dimethylimidazolium chloride

- 2-[5-(N-methyl-2-pyridinylidene)-3-isopropyl-1-formazano]-1 ,3-dimethylimidazolium chloride

- 2-[5-(N-methyl-2-pyridinylidene)-3-phenyl-1-formazano]-1 ,3-dimethylimidazolium chloride

- 2-[5-(N-methyl-2-pyridinylidene)-3-(4'-methoxyphenyl)-1-form azano]-1 ,3- dimethylimidazolium chloride

- 2-[5-(N-methyl-2-pyridinylidene)-3-(4'-hydroxyphenyl)-1 -formazano]-1 ,3- dimethylimidazolium chloride

- 2-[5-(N-methyl-2-pyridinylidene)-3-(4'-N,N-dimethylaminophen yl)-1-formazano]-1 ,3- dimethylimidazolium chloride

- 2-[5-(N-hydroxyethyl-2-pyridinylidene)-1 -formazano]-1 ,3-dihydroxyethylimidazolium chloride - 2-[5-(N-hydroxyethyl-2-pyridinylidene)-3-methyl-1-formazano] -1 ,3- dihydroxyethylimidazolium chloride

- 2-[5-(N-hydroxyethyl-2-pyridinylidene)-3-ethyl-1 -formazano]-1 ,3- dihydroxyethylimidazolium chloride

- 2-[5-(N-hydroxyethyl-2-pyridinylidene)-3-phenyl-1-formazano] -1 ,3- dihydroxyethylimidazolium chloride

- 2-[5-(N-hydroxyethyl-2-pyridinylidene)-3-isopropyl-1 -formazano]-1 ,3-

dihydroxyethylimidazolium chloride

- 2-[5-(N-hydroxyethyl-2-pyridinylidene)-3-(4'-methoxyphenyl)- 1 -formazano]-1 ,3- dihydroxyethylimidazolium chloride

- 2-[5-(N-hydroxyethyl-2-pyridinylidene)-3-(4'-hydroxyphenyl)- 1-formazano]-1 ,3- dihydroxyethylimidazolium chloride

- 2-[5-(N-hydroxyethyl-2-pyridinylidene)-3-(4'-N,N-dimethylami nophenyl)-1-formazano]-1 ,3- dihydroxyethylimidazolium chloride

- 2-[5-(N-carboxyethyl-2-pyridinylidene)-1 -formazano]-1 ,3-dicarboxyethylimidazolium chloride - 2-[5-(N-carboxyethyl-2-pyridinylidene)-3-methyl-1-formazano] -1 ,3- dicarboxyethylimidazolium chloride

- 2-[5-(N-carboxyethyl-2-pyridinylidene)-3-ethyl-1 -formazano]-1 ,3- dicarboxyethylimidazolium chloride

- 2-[5-(N-carboxyethyl-2-pyridinylidene)-3-phenyl-1-formazano] -1 ,3- dicarboxyethylimidazolium chloride

- 2-[5-(N-carboxyethyl-2-pyridinylidene)-3-isopropyl-1 -formazano]-1 ,3- dicarboxyethylimidazolium chloride

- 2-[5-(N-carboxyethyl-2-pyridinylidene)-3-(4'-methoxyphenyl)- 1 -formazano]-1 ,3- dicarboxyethylimidazolium chloride - 2-[5-(N-carboxyethyl-2-pyridinylidene)-3-(4'-hydroxyphenyl)- 1-formazano]-1 ,3- dicarboxyethylimidazolium chloride

- 2-[5-(N-carboxyethyl-2-pyridinylidene)-3-(4'-N,N-dimethylami nophenyl)-1-formazano]-1 ,3- dicarboxyethylimidazolium chloride

H. In an eighth preferred variant, the compounds of formula I are chosen from the family defined by the compounds for which W 1 is a 2-imidazolium radical and W 2 is a 4-pyridine radical. Even more preferably, they are the following compounds:

- 2-[5-(N-methyl-4-pyridinylidene)-1-formazano]-1 ,3-dimethylimidazolium chloride

- 2-[5-(N-methyl-4-pyridinylidene)-3-methyl-1 -formazano]-1 ,3-dimethylimidazolium chloride - 2-[5-(N-methyl-4-pyridinylidene)-3-ethyl-1-formazano]-1 ,3-dimethylimidazolium chloride

- 2-[5-(N-methyl-4-pyridinylidene)-3-isopropyl-1-formazano]-1 ,3-dimethylimidazolium chloride

- 2-[5-(N-methyl-4-pyridinylidene) — 3-phenyl-1-formazano]-1 ,3-dimethylimidazolium chloride - 2-[5-(N-methyl-4-pyridinylidene)-3-(4'-methoxyphenyl)-1-form azano]-1 ,3- dimethylimidazolium chloride

- 2-[5-(N-methyl-4-pyridinylidene)-3-(4'-hydroxyphenyl)-1 -formazano]-1 ,3- dimethylimidazolium chloride

- 2-[5-(N-methyl-4-pyridinylidene)-3-(4'-N,N-dimethylaminophen yl)-1-formazano]-1 ,3- dimethylimidazolium chloride - 2-[5-(N-hydroxyethyl-4-pyridinylidene)-1 -formazano]-1 ,3-dihydroxyethylimidazolium chloride

- 2-[5-(N-hydroxyethyl-4-pyridinylidene)-3-methyl-1 -formazano]-1 ,3- dihydroxyethylimidazolium chloride

- 2-[5-(N-hydroxyethyl-4-pyridinylidene)-3-ethyl-1 -formazano]-1 ,3- dihydroxyethylimidazolium chloride

- 2-[5-(N-hydroxyethyl-4-pyridinylidene)-3-phenyl-1-formazano] -1 ,3- dihydroxyethylimidazolium chloride

- 2-[5-(N-hydroxyethyl-4-pyridinylidene)-3-isopropyl-1 -formazano]-1 ,3- dihydroxyethylimidazolium chloride - 2-[5-(N-hydroxyethyl-4-pyridinylidene)-3-(4'-methoxyphenyl)- 1-formazano]-1 ,3- dihydroxyethylimidazolium chloride

- 2-[5-(N-hydroxyethyl-4-pyridinylidene)-3-(4'-hydroxyphenyl)- 1-formazano]-1 ,3- dihydroxyethylimidazolium chloride

- 2-[5-(N-hydroxyethyl-4-pyridinylidene)-3-(4'-N,N-dimethylami nophenyl)-1-formazano]-1 ,3- dihydroxyethylimidazolium chloride

- 2-[5-(N-carboxyethyl-4-pyridinylidene)-1 -formazano]-1 ,3-dicarboxyethylimidazolium chloride

- 2-[5-(N-carboxyethyl-4-pyridinylidene)-3-methyl-1 -formazano]-1 ,3- dicarboxyethylimidazolium chloride - 2-[5-(N-carboxyethyl-4-pyridinylidene)-3-ethyl-1-formazano]- 1 ,3- dicarboxyethylimidazolium chloride

- 2-[5-(N-carboxyethyl-4-pyridinylidene)-3-phenyl-1-formazano] -1 ,3- dicarboxyethylimidazolium chloride

- 2-[5-(N-carboxyethyl-4-pyridinylidene)-3-isopropyl-1 -formazano]-1 ,3- dicarboxyethylimidazolium chloride

- 2-[5-(N-carboxyethyl-4-pyridinylidene)-3-(4'-methoxyphenyl)- 1 -formazano]-1 ,3- dicarboxyethylimidazolium chloride

- 2-[5-(N-carboxyethyl-4-pyridinylidene)-3-(4'-hydroxyphenyl)- 1-formazano]-1 ,3- dicarboxyethylimidazolium chloride - 2-[5-(N-carboxyethyl-4-pyridinylidene)-3-(4'-N,N-dimethylami nophenyl)-1-formazano]-1 ,3- dicarboxyethylimidazolium chloride

I. In a ninth preferred variant, the compounds of formula I are chosen from the family defined by the compounds for which W 1 is a 2-benzimidazolium radical and W 2 is a 2-benzimidazole radical. Even more preferably, they are the following compounds: - 2-[5-(1 ,3-dimethyl-2-benzimidazolidene)-1-formazano]-1 ,3-dimethylbenzimidazolium chloride

- 2-[5-(1 ,3-dimethyl-2-benzimidazolidene)-3-methyl-1-formazano]-1 ,3- dimethylbenzimidazolium chloride

- 2-[5-(1 ,3-dimethyl-2-benzimidazolidene)-3-ethyl-1-formazano]-1 ,3- dimethylbenzimidazolium chloride

- 2-[5-(1 ,3-dimethyl-2-benzimidazolidene)-3-isopropyl-1-formazano]-1 ,3- dimethylbenzimidazolium chloride

- 2-[5-(1 ,3-dimethyl-2-benzimidazolidene)-3-phenyl-1-formazano]-1 ,3- dimethylbenzimidazolium chloride - 2-[5-(1 ,3-dimethyl-2-benzimidazolidene)-3-(4'-methoxyphenyl)-1 -formazano]-1 ,3- dimethylbenzimidazolium chloride

- 2-[5-(1 ,3-dimethyl-2-benzimidazolidene)-3-(4'-hydroxyphenyl)-1 -formazano]-1 ,3- dimethylbenzimidazolium chloride

- 2-[5-(1 ,3-dimethyl-2-benzimidazolidene)-3-(4'-N,N-dimethylaminophen yl)-1-formazano]- 1 ,3-dimethylbenzimidazolium chloride

- 2-[5-(1 ,3-dihydroxyethyl-2-benzimidazolidene)-1-formazano]-1 ,3- dihydroxyethylbenzimidazolium chloride

- 2-[5-(1 ,3-dihydroxyethyl-2-benzimidazolidene)-3-methyl-1-formazano] -1 ,3- dihydroxyethylbenzimidazolium chloride - 2-[5-(1 ,3-dihydroxyethyl-2-benzimidazolidene)-3-ethyl-1-formazano]- 1 ,3- dihydroxyethylbenzimidazolium chloride

- 2-[5-(1 ,3-dihydroxyethyl-2-benzimidazolidene)-3-phenyl-1-formazano] -1 ,3- dihydroxyethylbenzimidazolium chloride

- 2-[5-(1 ,3-dihydroxyethyl-2-benzimidazolidene)-3-isopropyl-1-formaza no]-1 ,3- dihydroxyethylbenzimidazolium chloride

- 2-[5-(1 ,3-dihydroxyethyl-2-benzimidazolidene)-3-(4'-methoxyphenyl)- 1-formazano]-1 ,3- dihydroxyethylbenzimidazolium chloride

- 2-[5-(1 ,3-dihydroxyethyl-2-benzimidazolidene)-3-(4'-hydroxyphenyl)- 1 -formazano]-1 ,3- dihydroxyethylbenzimidazolium chloride - 2-[5-(1 ,3-dihydroxyethyl-2-benzimidazolidene)-3-(4'-N,N-dimethylami nophenyl)-1- formazano]-1 ,3-dihydroxyethylbenzimidazolium chloride

- 2-[5-(1 ,3-dicarboxyethyl-2-benzimidazolidene)-1-formazano]-1 ,3- dicarboxyethylbenzimidazolium chloride

- 2-[5-(1 ,3-dicarboxyethyl-2-benzimidazolidene)-3-methyl-1-formazano] -1 ,3- dicarboxyethylbenzimidazolium chloride - 2-[5-(1 ,3-dicarboxyethyl-2-benzimidazolidene)-3-ethyl-1-formazano]- 1 ,3- dicarboxyethylbenzimidazolium chloride

- 2-[5-(1 ,3-dicarboxyethyl-2-benzimidazolidene)-3-phenyl-1-formazano] -1 ,3- dicarboxyethylbenzimidazolium chloride

- 2-[5-(1 ,3-dicarboxyethyl-2-benzimidazolidene)-3-isopropyl-1-formaza no]-1 ,3- dicarboxyethylbenzimidazolium chloride

- 2-[5-(1 ,3-dicarboxyethyl-2-benzimidazolidene)-3-(4'-methoxyphenyl)- 1-formazano]-1 ,3- dicarboxyethylbenzimidazolium chloride

- 2-[5-(1 ,3-dicarboxyethyl-2-benzimidazolidene)-3-(4'-hydroxyphenyl)- 1-formazano]-1 ,3- dicarboxyethylbenzimidazolium chloride - 2-[5-(1 ,3-dicarboxyethyl-2-benzimidazolidene)-3-(4'-N,N-dimethylami nophenyl)-1- formazano]-1 ,3-dicarboxyethylbenzimidazolium chloride.

Among all the compounds described above, the compounds of family A (first variant) will be preferred most particularly.

In the compositions of the invention, the compound(s) of formula (I) is (are) preferably present in a concentration ranging from 0.001 % to 10%, preferably from 0.005% to 5% and even more preferentially from 0.01 % to 2% by weight relative to the total weight of the composition.

The compounds of formula (I) may especially be obtained via a process in which at least two equivalents of at least one hydrazone chosen from the hydrazones of formula A and the hydrazones of formula B:

KY 1

Formula A Formula B in which Z 14 , ._ 1b , £_ 1ti u . ιu . « have m ^ ocm . ^ mocniings as Z 7 , Z 8 , Z 13 , and R 5 , respectively, of formula IV,

Y being an organic or mineral anion,

x being an integer ranging from 1 to 3,

Z 17 , Z 18 , Z 19 , Z 2 O, R 26 and R 27 have the same meanings as Z 9 , Z 10 , Z 11 , Z 12 , Rs and R 7 , respectively, of formula V,

Y' being an organic or mineral anion, x' being an integer ranging from 1 to 3, are reacted with one equivalent of an aldehyde of formula R 23 CHO, R 23 having the same meaning as Ro of formula I. Two equivalents of the same hydrazone or of two different hydrazones may thus be reacted.

According to one preferred variant, the aldehyde of formula R 23 CHO is generated in the reaction medium from an aldehyde precursor of formula R' 23 CH 2 OH in the presence of an oxidizing system; R' 23 then has the same meaning as R 0 of formula I.

This oxidizing system may be a chemical oxidizing agent or a biocatalytic oxidizing agent such as an enzyme.

In particular, the process for preparing the compound of formula (I) according to the present invention may be performed in the presence of an aldehyde precursor of formula R' 23 CH 2 OH and of at least one enzyme capable of generating an aldehyde from the aldehyde precursor of formula R' 23 CH 2 OH.

The process for enzymatically synthesizing the compounds of formula (I) defined above is performed by reacting at least two equivalents of at least one hydrazone chosen from the hydrazones of formula A and the hydrazones of formula B in which Z 14 , Z 15 , Z 16 and R 25 have the same meanings as Z 7 , Z 8 , Z 13 and R 5 , respectively, of formula IV,

Y being an organic or mineral anion, x being an integer ranging from 1 to 3,

Z 17 , Z 18 , Z 19 , Z 20 , R 26 and R 27 having the same meanings as Z 9 , Z 10 , Z 11 , Z 12 , R 8 and R 7 , respectively, of formula V, Y' being an organic or mineral anion, x' being an integer ranging from 1 to 3, with one equivalent of an aldehyde of formula R 23 CHO, R 23 having the same meaning as Ro of formula I.

Depending on the reagents used, the reaction is performed with or without an oxidizing system, with or without a cofactor for the enzyme, and with or without a system for

regenerating the cofactor.

For the purpose of the present patent application, the term "without an oxidizing system" means that no oxidizing system other than atmospheric oxygen is used.

Preferably, the reaction is performed in aerobic medium at a pH of between 3 and 11 and at a temperature of between 6°C and 80°C.

More generally, the aldehyde precursor that may be used to prepare the compound of formula (I) may be chosen from primary alcohols, sarcosine, 4-hydroxymandelate, N6- methyllysine, dimethylglycine, methylglutamate, 2-oxo acids, for example 2-oxo acid pyruvate, benzoylformate, phenylpyruvate or threonine. It will preferably be chosen from primary alcohols.

The enzymes capable of generating an aldehyde from this aldehyde precursor may be chosen especially from the alcohol dehydrogenases EC 1.1.1.1 , the alcohol dehydrogenases EC 1.1.1.2, the alcohol dehydrogenases EC 1.1.1.71 , the aromatic alcohol dehydrogenases EC 1.1.1.90, also known as aryl alcohol dehydrogenases, the aromatic alcohol dehydrogenases EC 1.1.1.97, the 3-hydroxybenzyl alcohol dehydrogenases EC 1.1.1.97, the coniferyl alcohol dehydrogenases EC 1.1.1.194, the cinnamyl alcohol dehydrogenases EC 1.1.1.195, the methanol dehydrogenases EC 1.1.1.244, the aromatic alcohol oxidases EC 1.1.3.7, also known as aryl alcohol oxidases, the alcohol oxidases EC 1.1.3.13, the 4- hydroxymandelate oxidases EC 1.1.3.19, the long-chain hydrocarbon alcohol oxidases EC 1.1.3.20, the methanol oxidases EC 1.1.3.31 , the alcohol dehydrogenases EC 1.1.99.20, the sarcosine oxidases EC 1.5.3.1 , the N6-methyllysine oxidases EC 1.5.3.4, the dimethylglycine oxidases EC 1.5.3.10, the sarcosine dehydrogenases EC 1.5.99.1 , the dimethylglycine dehydrogenases EC 1.5.99.2, the methylglutamate dehydrogenases EC 1.5.99.5, the 2-oxo acid decarboxylases EC 4.1.1.1 , the benzoylformate decarboxylases EC 4.1.1.7, the phenylpyruvate decarboxylases EC 4.1.1.43 and the threonine aldolases EC 4.1.2.5.

Mention may also be made of the following enzymes capable of generating an aldehyde, the preferred substrate of which is given in parentheses: N-methyl L-amino acid oxidase EC 1.5.3.2 (N-methyl-L-amino acid), trimethylamine dehydrogenase EC 1.5.99.7 (trimethylamine), dimethylamine dehydrogenase EC 1.5.99.10 (dimethylamine), nitroethane oxidase EC 1.7.3.1 (nitroethane), indole 2,3-dioxigenase EC 1.13.1 1.17 (indole), taurine

dioxygenase EC 1.14.1 1.17 (taurine), acetoin ribose 5 phosphate transaldolase EC 2.2.1.4 (3-hydroxybutan-2-one), diamine aminotransferase EC 2.6.1.29 (alpha omega diamine + 2- oxogluterate), alkenylglycerophosphocholine hydrolase EC 3.3.2.2

(alkenylglycerophosphocholine), alkenylglycerophosphoethanolamine hydrolase EC 3.3.2.5 (alkenylglycerophosphocholine), alkylalidase EC 3.8.1.1 (halomethane), phosphonoacetaldehyde hydrolase EC 3.11.1.1 (phosphonoacetaldehyde), indolepyruvate decarboxylase EC 4.1.1.74 (3-indol-3-yl pyruvate) mandelonitrile lyase EC 4.1.2.10 (mandelonitrile), hydroxymandelonitrile lyase EC 4.1.2.1 1 (hydroxymandelonitrile), ketopantoaldolase EC 4.1.2.12 (2-hydroxy-2-isopropylbutanedioate), dimethylaniline-N-oxide aldolase EC 4.1.2.24 (dimethylaniline-N-oxide), phenylserine aldolase EC 4.1.2.26 (phenylserine), sphinganine-1 -phosphate aldolase EC 4.1.2.27 (sphinganine-1-phosphate), 17-alpha hydroxyprogesterone aldolase EC 4.1.2.30 (17-alpha hydroxyprogesterone), trimethylamine oxide aldolase EC 4.1.2.23 (trimethylamine oxide), fucosterol epoxide lyase EC 4.1.2.23 (fucosterol epoxide), (3E)-4-(2-carboxyphenyl)-2-oxobut-3-enoate aldolase EC 4.1.2.34 ((3E)-4-(2-carboxyphenyl)-2-oxobut-3-enoate), lactate aldolase EC 4.1.2.36 (lactate), benzoin aldolase EC 4.1.2.38 (benzoin), octoamine dehydratase EC 4.2.1.87 (1-(4- hydroxyphenyl)-2-aminoethanol), synephrine dehydratase EC 4.2.1.88 (1-(4-hydroxyphenyl)- 2-(methylamino)ethanol), ethanolamine phosphate phospholyase EC 4.2.3.2 (ethanolamine phosphate), ethanolamine ammonia lyase EC 4.3.1.7 (ethanolamine), dichloromethane dehalogenase EC 4.5.1.3 (dichloromethane), styrene oxide isomerase EC 5.3.99.7 (styrene oxide).

The enzyme capable of generating an aldehyde from the aldehyde precursor used in the dye composition according to the invention may be derived from an extract of plants, of animals, of microorganisms (bacterium, fungus, yeast or microalga) or from viruses, or from cells that are differentiated or undifferentiated, obtained in vivo or in vitro, which are genetically modified or unmodified, or synthetic (obtained via chemical or biotechnological synthesis).

Examples of useful enzymes that may be mentioned in particular are the genera Plectranthus, Pinus, Gastropode, Manduca, Pichia, Candida, Pleurotus, and Pseudomonas, and even more particularly the following species: Plectranthus colloides, Pinus strobus, which is a species of plant origin, Gastropode mollusc and Manduca sexta, which are of animal origin, Pichia pastoris and Candida boidinii, which are yeasts, Pleurotus pulmonarius, which is a fungus, and Pseudomonas pseudoalcaligenes, which is a bacterium.

The choice of the enzyme depends on the nature of the aldehyde precursor. For example,

when the aldehyde precursor is an alcohol, then the enzyme is chosen from enzymes capable of generating an aldehyde from this alcohol. When the aldehyde precursor is methylglutamate, then the enzyme is a methylglutamate dehydrogenase.

According to one preferred variant, the aldehyde precursor is a primary alcohol and the enzyme is an enzyme capable of generating the aldehyde from an alcohol. For example, when the primary alcohol is a Ci-Cβ aliphatic alcohol, then the enzyme capable of generating the aldehyde is chosen from alcohol oxidases, alcohol dehydrogenases, methanol dehydrogenases and methanol oxidases. When the primary alcohol is benzyl alcohol, 4-tert- butylbenzyl alcohol, 3-hydroxy-4-methoxybenzyl alcohol, veratryl alcohol, 4-methoxybenzyl alcohol, cinnamyl alcohol or 2,4-hexadien-1-ol, aryl alcohol oxidases or aromatic alcohol dehydrogenases may be used as aldehyde precursor.

For the enzyme dehydrogenases, it is essential to include the cofactor(s) required for their activity, more specifically NAD + or NADP + or other molecules capable of acting as electron acceptor. The addition of a system for regenerating the cofactors may be used for reaction purposes or economic purposes. This regeneration system may be enzymatic, chemical or electrochemical.

A very wide variety of oxidizing agents may be used to perform this process: aqueous hydrogen peroxide solution, organic peracids such as peracetic acid, persalts such as permanganate, perborate and persulfates, chromates or dichromates, hypochlorites, hypobromites, ferricyanides, and peroxides such as manganese dioxide or lead dioxide. Aqueous hydrogen peroxide solution will preferably be used.

The concentration of enzyme substrate (aldehyde precursor) may be between 0.001 M and 6 M and preferably between 0.1 M and 4 M.

The reaction may be performed between pH 3 and pH 1 1 and preferably between pH 5 and pH 9.5.

The reaction temperature may be between 10°C and 80°C and preferably between 20°C and 65°C.

The hydrazone concentration of the reaction medium is between 0.01 M and 3 M and preferably between 0.1 M and 1 M.

The content of cofactor for said enzymes may be between 0.01 mM and 1 M and preferably between 0.1 mM and 10 mM.

During the implementation of the synthesis of the compounds of formula (I), the reagents: the hydrazone(s), the enzyme(s), the substrate for said enzyme, and/or the cofactor for said enzyme, and the oxidizing agent and/or the system for regenerating the cofactor are mixed together, and the pH and the temperature are adjusted.

The compounds of formula I may also be prepared via a process in which a compound of formula (F1 ) or (F2)

Formula Fl Formula F2 with Z 14 , Z 15 , z. 16 , K 0 , K 24 ana R 25 for formula F i ana ^ 7 , z. 18 , £19, Z 20 , Ro, R 24 and R 26 for formula F2 having the meanings described above, is reacted in the presence of one equivalent of a hydrazone of formula (A) or (B).

According to one preferred variant, the compounds of formula (F1 ) or (F2) may be obtained by reacting a compound of formula R" 2 3C(OR 24 )3 and a hydrazone of formula (A) or (B) in the presence or absence of a protic solvent whose boiling point ranges between 66°C and 180°C. R" 2 3 has the same meaning as Ro of formula (I) and R 24 represents a radical chosen from methyl and ethyl groups.

Preferably, the reaction is performed in the presence of triethyl orthoformate and trimethyl orthoacetate at a temperature of between 0°C and 150°C for a period of between 30 minutes and 12 hours.

Preferably, the protic solvent is chosen from H 2 O, ethanol and methanol.

(ii) azo, methine or azomethine direct dye containing a quaternary ammonium group included in a ring, other than the dye of formula (I).

For the purposes of the present invention, the term "azo, methine or azomethine cationic direct dye" means a dye that is capable of colouring keratin fibres in the absence of any oxidizing agent, comprising in its structure at least one group -T1 =T2-, T1 and T2 denoting, independently of each other, a nitrogen atom or a CH group.

For the purposes of the present invention, the term "cationic direct dye containing a quaternary ammonium group included in a ring" means a dye that is capable of colouring keratin fibres in the absence of any oxidizing agent, comprising in its structure at least one saturated or unsaturated heterocycle comprising in its chain of ring members at least one nitrogen atom bearing a positive permanent charge, the said heterocycle being 4- to 8- membered and being optionally fused with one or more other heterocycles or aromatic nuclei and optionally comprising one or more other heteroatoms chosen from nitrogen, sulfur and oxygen. Each of these rings may be optionally substituted.

The nitrogen atom borne by a positive permanent charge is preferably substituted with an optionally substituted C 1 -C30 alkyl radical or with an optionally substituted phenyl radical.

The possible substituents on the alkyl groups are preferably chosen from halogen atoms and hydroxyl, amino, mono- or di(Ci-C 4 )alkylamino, mono- or dihydroxy(Ci-C 4 )alkylamino, C 6 -C 30 aryl and cyano groups.

The possible substituents on the aryl groups are preferably chosen from halogen atoms and Ci-C 30 alkyl, hydroxyl, amino, mono- or di(Ci-C 4 )alkylamino, mono- or dihydroxy(d- C 4 )alkylamino, cyano, nitro and C 2 -Ci 0 acyl groups.

Preferably, this substituent on the nitrogen atom bearing a permanent charge is a CrC 4 alkyl group.

Even more preferentially, this substituent is a methyl group.

As azo, methine or azomethine direct dyes bearing a quaternary ammonium group included in a ring, other than the dyes of formula (I) that may be used in the context of the present invention, mention may be made more particularly of: the following dyes described in patent application EP 1 025 834: • of formula (Vl)

G-N=N-J (Vl)

in which: the symbol G represents a group chosen from the structures Gi to G 3 below:

in which:

R 24 denotes a CrC 4 alkyl radical, a phenyl radical which may be substituted with a d-C 4 alkyl radical, or a halogen atom chosen from chlorine, bromine, iodine and fluorine;

R 2 5 denotes a CrC 4 alkyl radical or a phenyl radical;

R 2 6 and R 2 7, which may be identical or different, represent a CrC 4 alkyl radical, a phenyl radical, or form together in Gi a benzene ring substituted with one or more CrC 4 alkyl, CrC 4 alkoxy or NO 2 radicals, or form together in G 2 a benzene ring optionally substituted with one or more CrC 4 alkyl, CrC 4 alkoxy or NO 2 radicals;

R 26 may also denote a hydrogen atom;

Z represents an oxygen or sulfur atom or a group -NR 25 ;

M represents a group -CH, -CR (R denoting C 1 -C 4 alkyl) or -NR 28 (X " ) r ;

K represents a group -CH, -CR (R denoting C 1 -C 4 alkyl) or -NR 28 (X " ) r ;

P represents a group -CH, -CR (R denoting C 1 -C 4 alkyl) or -NR 28 (X " ),-; r denotes 0 or 1 ;

R 28 represents an O " atom, a C 1 -C 4 alkoxy radical or a C 1 -C 4 alkyl radical;

R 29 and R 30 , which may be identical or different, represent a hydrogen atom or a halogen atom chosen from chlorine, bromine, iodine and fluorine, a C 1 -C 4 alkyl or C 1 -C 4 alkoxy radical, or an -NO 2 radical;

X " represents an anion preferably chosen from chloride, iodide, methyl sulfate, ethyl sulfate, acetate and perchlorate;

the symbol J represents: -(a) a group of structure Ji below:

in which: R3 1 represents a hydrogen atom, a halogen atom chosen from chlorine, bromine, iodine and fluorine, a CrC 4 alkyl or d-C 4 alkoxy radical, an -OH, -NO 2 , -NHR 34 , -NR 35 R 36 or CrC 4

-NHCOalkyl radical, or forms with R 32 a 5- or 6-membered ring optionally containing one or more heteroatoms chosen from nitrogen, oxygen and sulfur;

R 32 represents a hydrogen atom, a halogen atom chosen from chlorine, bromine, iodine and fluorine, a C 1 -C 4 alkyl or d-C 4 alkoxy radical, or forms with R 33 or R 34 a 5- or 6-membered ring optionally containing one or more heteroatoms chosen from nitrogen, oxygen and sulfur;

R 33 represents a hydrogen atom, an -OH radical, a radical -NHR 34 or a radical -NR 35 R 36 ;

R 34 represents a hydrogen atom, a Ci-C 4 alkyl radical, a CrC 4 monohydroxyalkyl, C 2 -C 4 polyhydroxyalkyl radical or a phenyl radical; R 35 and R 36 , which may be identical or different, represent a C 1 -C 4 alkyl radical, a C 1 -C 4 monohydroxyalkyl or C 2 -C 4 polyhydroxyalkyl radical;

-(b) a 5- or 6-membered nitrogenous heterocyclic group, which may contain other heteroatoms and/or carbonyl groups and may be substituted with one or more C 1 -C 4 alkyl, amino or phenyl radicals, and especially a group of structure J 2 below:

in which:R 37 and R 38 , which may be identical or different, represent a hydrogen atom, a C 13 - C 1 O alkyl radical or a phenyl radical; Y denotes a -CO- radical or a -C(CH 3 )= radical; n represents O or 1 , with, when n denotes 1 , U denotes a -CO- radical; • of formula (VII) below:

in which:R 12 represents a hydrogen atom or a CrC 4 alkyl radical,

R 13 represents a hydrogen atom, an alkyl radical which may be substituted with a -CN radical or with an amino group, a 4'-aminophenyl radical, or forms with R 12 a heterocycle optionally containing oxygen and/or nitrogen, which may be substituted with a C 1 -C 4 alkyl radical,

R 14 and R 15 , which may be identical or different, represent a hydrogen atom, a halogen atom such as bromine, chlorine, iodine or fluorine, a C 1 -C 4 alkyl or C 1 -C 4 alkoxy radical, or a -CN radical,

X " represents an anion preferably chosen from chloride, methyl sulfate and acetate,

B represents a group chosen from structures B1 to B6 below:

B1 B2 B3

B4 B5 B6 in which R 16 represents a C 1 -C 4 alkyl radical,

R 17 and R 18 , which may be identical or different, represent a hydrogen atom or a C 1 -C 4 alkyl radical,

• the compounds of formulae (VIII) and (IX) below:

in which:

R 19 represents a hydrogen atom, a C 1 -C 4 alkoxy radical, a halogen atom such as bromine, chlorine, iodine or fluorine, or an amino radical,

R 20 represents a hydrogen atom, a C 1 -C 4 alkyl radical or forms, with a carbon atom of the benzene ring, a heterocycle optionally containing oxygen and/or substituted with one or more

C 1 -C 4 alkyl groups,

R 21 represents a hydrogen atom or a halogen atom such as bromine, chlorine, iodine or fluorine,

R 22 and R 23 , which may be identical or different, represent a hydrogen atom or a C 1 -C 4 alkyl radical,

D 1 and D 2 , which may be identical or different, represent a hydrogen atom or a -CH group, m represents 0 or 1 , it being understood that when R 19 represents an unsubstituted amino group, then D 1 and D 2 simultaneously represent a -CH group and m = 0,

X " represents an anion preferably chosen from chloride, methyl sulfate and acetate,

E represents a group chosen from structures E1 to E8 below:

E5

E6

E7 E8 in which R' represents a d-C 4 alkyl radical; when m represents 0 and D 1 represents a nitrogen atom, then E may also denote a group of structure E9 below:

in which R' represents a CrC 4 alkyl radical.

• the compounds of formula (X) below:

X-

(X)

in which: Z and D, which may be identical or different, represent a nitrogen atom or a -CH group,

R 7 and R 8 , which may be identical or different, represent a hydrogen atom; a d-C 4 alkyl radical which may be substituted with a -CN, -OH or -NH 2 radical, or form, with a carbon atom of the benzene ring, a heterocycle optionally containing oxygen or nitrogen, which may be substituted with one or more CrC 4 alkyl radicals; a 4'-aminophenyl radical,

Rg and R'g, which may be identical or different, represent a hydrogen atom or a halogen atom chosen from chlorine, bromine, iodine and fluorine, or a cyano, d-C 4 alkyl, CrC 4 alkoxy or acetyloxy radical, X " represents an anion preferably chosen from chloride, methyl sulfate and acetate, A represents a group chosen from structures Ai to Aig below:

^14 A 15

A 17

^18

in which R 10 represents a CrC 4 alkyl radical which may be substituted with a hydroxyl radical and Rn represents a CrC 4 alkoxy radical,

the dyes described in patent application EP 714 954, of formulae:

( A-N -Z-N ~\ — X A-N-Z 1 -N-N-KK

(XI) R 1 R, R, (χII)

A-N-Z 2 -N-A 1

(XIII) in which:

A and A 1 , independently of each other, are residues of formula:

Z represents an aliphatic or aromatic diamine,

R 1 and R 2 , independently of each other, represent a hydrogen atom, a C 1 -C 4 alkyl group or may form, together with two nitrogen atoms to which they are attached or with Z and Z 2 , a 5-,

6- or 7-membered ring, X represents the residue of a chain unit forming a bridge, n represents an integer 2, 3 or 4,

Z 1 represents a residue of aromatic diamines,

Z 2 represents a residue of aliphatic diamines,

KK represents a residue of a coupling compound, R 3 and R 4 , independently of each other, represent a hydrogen atom or a C 1 -C 4 alkyl group,

R 5 and R 6 , independently of each other, represent a hydrogen atom, a C 1 -C 4 alkyl group or a

C 1 -C 4 alkoxy group,

An " represents a colourless anion, and also the cationic dyes described in patent applications WO 95/01772, WO 95/15144, EP 714 954, EP 1 170 000, EP 1 166 753, EP 1 166 754 and EP 1 170 001 , which are different from the above dyes. The passage in these patent applications that is devoted to cationic dyes is incorporated in the present patent application.

The dyes that will preferably be used are Basic Red 51 of formula (XIV):

Basic Yellow 87 of formula (XV):

and Basic Orange 31 of formula (XVI):

The azo, methine or azomethine direct dye(s) containing a quaternary ammonium group included in a ring, which is (are) used according to the invention, preferably represent(s) from 0.001 % to 10% by weight approximately relative to the total weight of the dye composition and even more preferentially from 0.005% to 5% by weight approximately relative to this weight.

The suitable dyeing medium (or support) generally consists of water or of a mixture of water and of at least one organic solvent to dissolve the compounds that are not sufficiently water- soluble. Examples of organic solvents that may be mentioned include CrC 4 lower alkanols, such as ethanol and isopropanol; aromatic alcohols, for instance benzyl alcohol, and also similar products and mixtures thereof.

The solvents may be present in proportions preferably between 1 % and 40% by weight approximately and even more preferentially between 5% and 30% by weight approximately relative to the total weight of the dye composition.

The pH of the dye composition in accordance with the invention is generally between 2 and 1 1 approximately and preferably between 5 and 10 approximately. It may be adjusted to the desired value by means of acidifying or basifying agents usually used in the dyeing of keratin fibres.

Among the acidifying agents, examples that may be mentioned include mineral or organic acids, for instance hydrochloric acid, orthophosphoric acid, sulfuric acid, carboxylic acids, for instance acetic acid, tartaric acid, citric acid and lactic acid, and sulfonic acids.

Among the basifying agents, examples that may be mentioned include aqueous ammonia, alkali metal carbonates, alkanolamines such as monoethanolamine, diethanolamine and triethanolamine, and also derivatives thereof, sodium hydroxide, potassium hydroxide and the compounds of formula (XVII) below:

in which w is a propylene residue optionally substituted with a hydroxyl group or a CrCβ alkyl radical; R 3 , R 4 , R 5 and R 6 , which may be identical or different, represent a hydrogen atom or a C-i-Cδ alkyl or CrCβ hydroxyalkyl radical. In addition to the direct dye(s) of the invention defined above, the dye compositions in accordance with the invention may contain one or more other additional direct dyes that may be chosen, for example, from nitrobenzene dyes, anthraquinone dyes, naphthoquinone dyes, triarylmethane dyes, xanthene dyes and non- cationic azo dyes.

When intended for oxidation dyeing, the dye composition in accordance with the invention contains, in addition to the cationic direct dye(s) (i) and (ii), one or more oxidation bases chosen from the oxidation bases conventionally used for oxidation dyeing, and among which mention may be made especially of para-phenylenediamines, bis(phenyl)alkylenediamines, para-aminophenols, ortho-aminophenols and heterocyclic bases.

Among these oxidation bases, mention may be made most particularly of: - (I) the para-phenylenediamines of formula (XVIII) below, and the addition salts thereof with an acid:

XVIII) in which:

Ri represents a hydrogen atom, a C 1 -C 4 alkyl radical, a C 1 -C 4 monohydroxyalkyl radical, a C 2 -C 4 polyhydroxyalkyl radical, a (Ci-C 4 )alkoxy(Ci-C 4 )alkyl radical, a CrC 4 alkyl radical substituted with a nitrogenous group, a phenyl group or a 4'-aminophenyl group;

R 2 represents a hydrogen atom, a CrC 4 alkyl radical, a d-C 4 monohydroxyalkyl radical, a C 2 -C 4 polyhydroxyalkyl radical, a (Ci-C 4 )alkoxy(Ci-C 4 )alkyl radical or a C 1 -C 4 alkyl radical substituted with a nitrogenous group;

R 1 and R 2 may also form with the nitrogen atom that bears them a 5- or 6-membered nitrogenous heterocycle optionally substituted with one or more alkyl, hydroxy or ureido groups; R 3 represents a hydrogen atom, a halogen atom such as a chlorine atom, a C 1 -C 4 alkyl radical, a sulfo radical, a carboxy radical, a C 1 -C 4 monohydroxyalkyl radical, a C 1 -C 4 hydroxyalkoxy radical, an acetylamino(C 1 -C 4 )alkoxy radical, a C 1 -C 4 mesylaminoalkoxy radical or a carbamoylamino(C-ι-C 4 )alkoxy radical,

R 4 represents a hydrogen or halogen atom or a C 1 -C 4 alkyl radical.

Among the nitrogenous groups of formula (XVIII) above, mention may be made in particular of amino, mono(CrC 4 )alkylamino, di(CrC 4 )alkylamino, tri(Ci-C 4 )alkylamino, monohydroxy(CrC 4 )alkylamino, imidazolinium and ammonium radicals.

Examples of para-phenylenediamines of formula (XVIII) above that may especially be mentioned include para-phenylenediamine, para-tolylenediamine, 2-chloro-para- phenylenediamine, 2,3-dimethyl-para-phenylenediamine, 2,6-dimethyl-para- phenylenediamine, 2,6-diethyl-para-phenylene diamine, 2,5-dimethyl-para- phenylenediamine, N,N-dimethyl-para-phenylenediamine, N,N-diethyl-para- phenylenediamine, N,N-dipropyl-para-phenylenediamine, 4-amino-N,N-diethyl-3- methylaniline, N,N-bis(β-hydroxyethyl)-para-phenylenediamine, 4-amino-N,N-bis(β-hydroxy- ethyl)-2-methylaniline, 4-amino-2-chloro-N,N-bis(β-hydroxyethyl) aniline, 2-β-hydroxyethyl- para-phenylenediamine, 2-fluoro-para-phenylenediamine, 2-isopropyl-para- phenylenediamine, N-(β-hydroxypropyl)-para-phenylene diamine, 2-hydroxymethyl-para- phenylenediamine, N,N-dimethyl-3-methyl-para-phenylenediamine, N,N-(ethyl-β- hydroxyethyl)-para-phenylenediamine, N-(β,γ-dihydroxypropyl)-para-phenylenediamine, N- (4'-aminophenyl)-para-phenylenediamine, N-phenyl-para-phenylenediamine, 2-β-hydroxy- ethyloxy-para-phenylenediamine, 2-β-acetylaminoethyloxy-para-phenylenediamine, N-(β- methoxyethyl)-para-phenylenediamine, 2-methyl-1-N-β-hydroxyethyl-para- phenylenediamine, and the addition salts thereof with an acid.

Among the para-phenylenediamines of formula (XVIII) above, para-phenylenediamine, para- tolylenediamine, 2-isopropyl-para-phenylenediamine, 2-β-hydroxyethyl-para-phenylene- diamine, 2-β-hydroxyethyloxy-para-phenylenediamine, 2,6-dimethyl-para-phenylenediamine, 2,6-diethyl-para-phenylenediamine, 2,3-dimethyl-para-phenylenediamine, N,N-bis(β-hydroxy- ethyl)-para-phenylenediamine and 2-chloro-para-phenylenediamine, and the addition salts thereof with an acid are most particularly preferred.

- (II) According to the invention, the term double bases is understood to refer to the compounds containing at least two aromatic nucleii bearing amino and/or hydroxyl groups.

Among the double bases that may be used as oxidation bases in the dye compositions in accordance with the invention, mention may be made in particular of the compounds corresponding to formula (XIX) below, and the addition salts thereof with an acid:

in which

- Z 1 and Z 2 , which may be identical or different, represent a hydroxyl or -NH 2 group that may be substituted with a CrC 4 alkyl radical or with a linker arm Y;

- the linker arm Y represents a linear or branched alkylene chain containing from 1 to 14 carbon atoms, which may be interrupted by or terminated with one or more nitrogenous groups and/or one or more heteroatoms such as oxygen, sulfur or nitrogen atoms, and optionally substituted with one or more hydroxyl or CrCβ alkoxy radicals;

- R 5 and R 6 represent a hydrogen or halogen atom, a CrC 4 alkyl radical, a CrC 4 monohydroxyalkyl radical, a C 2 -C 4 polyhydroxyalkyl radical, a CrC 4 aminoalkyl radical or a linker arm Y;

- Rj, R S , Rg, R-io, Rn and Ri 2 , which may be identical or different, represent a hydrogen atom, a linker arm Y or a C 1 -C 4 alkyl radical; it being understood that the compounds of formula (XIX) contain only one linker arm Y per molecule.

Among the nitrogenous groups of formula (XIX) above, mention may be made in particular of amino, mono(CrC 4 )alkylamino, di(CrC 4 )alkylamino, tri(CrC 4 )alkylamino, monohydroxy(d- C 4 )alkylamino, imidazolinium and ammonium radicals.

Among the double bases of formula (XIX) above, mention may be made more particularly of N,N'-bis(β-hydroxyethyl)-N,N'-bis(4'-aminophenyl)-1 ,3-diaminopropanol, N,N'-bis(β- 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 and 1 ,8-bis(2,5-diaminophenoxy)- 3,5-dioxaoctane, and the addition salts thereof with an acid.

Among these double bases of formula (XIX), N,N'-bis(β-hydroxyethyl)-N,N'-bis(4'-amino- phenyl)-1 ,3-diaminopropanol and 1 ,8-bis(2,5-diaminophenoxy)-3,5-dioxaoctane, or one of the addition salts thereof with an acid, are particularly preferred.

- (Ill) para-Aminophenols that may especially be mentioned include those corresponding to formula (XX) below, and the addition salts thereof with an acid:

in which:

R 13 represents a hydrogen atom, a halogen atom such as fluorine, a d-C 4 alkyl, Ci-C 4 monohydroxyalkyl, (Ci-C 4 )alkoxy(Ci-C 4 )alkyl, C 1 -C 4 aminoalkyl or hydroxy(Ci-C 4 )alkylamino(Ci-C 4 )alkyl radical,

R- I4 represents a hydrogen atom or a halogen atom such as fluorine, a CrC 4 -alkyl, Ci-C 4 monohydroxyalkyl, C 2 -C 4 polyhydroxyalkyl, CrC 4 aminoalkyl, CrC 4 cyanoalkyl or (Ci-C 4 )alkoxy(Ci-C 4 )alkyl radical.

Among the para-aminophenols of formula (XX) above, mention may be made more particularly of para-aminophenol, 4-amino-3-methylphenol, 4-amino-3-fluorophenol, 4-amino- 3-hydroxymethyl phenol, 4-amino-2-methylphenol, 4-amino-2-hydroxymethylphenol, 4-amino-2-methoxymethylphenol, 4-amino-2-aminomethylphenol and 4-amino-2- (β-hydroxyethylaminomethyl)phenol, and the addition salts thereof with an acid.

- (IV) The ortho-aminophenols that may be used as oxidation bases in the context of the present invention are chosen especially from 2-aminophenol, 2-amino-1-hydroxy-5-

methylbenzene, 2-amino-1-hydroxy-6-methylbenzene and 5-acetamido-2-aminophenol, and the addition salts thereof with an acid.

- (V) Among the heterocyclic bases that may be used as oxidation bases in the dye compositions in accordance with the invention, mention may be made more particularly of pyridine derivatives, pyrimidine derivatives, pyrazole derivatives, and the addition salts thereof with an acid.

Among the pyridine derivatives, mention may be made more particularly 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-(β-methoxyethyl)amino-3-amino-6-methoxypyridine and 3,4- diaminopyridine, and the addition salts thereof with an acid.

Among the pyrimidine derivatives, mention may be made more particularly of the compounds described, for example, in German patent DE 2359 399 or Japanese patents JP 88-169571 and JP 91-10659 or patent application WO 96/15765, such as 2,4,5,6-tetraaminopyrimidine, 4-hydroxy-2,5,6-triaminopyrimidine, 2-hydroxy-4,5,6-triaminopyrimidine, 2,4-dihydroxy-5,6- diaminopyrimidine and 2,5,6-triaminopyrimidine, and pyrazolopyrimidine derivatives such as those mentioned in patent application FR-A-2 750 048 and among which mention may be made especially of pyrazolo[1 ,5-a]pyrimidine-3,7-diamine; 2,5-dimethyl-pyrazolo[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— yl)(2- hydroxyethyl)amino]ethanol; 2-[(7-amino pyrazolo[1 ,5-a]pyrimidin-3-yl)(2-hydroxyethyl) amino] ethanol; 5,6-dimethylpyrazolo[1 ,5-a]pyrimidine-3,7-diamine; 2,6-dimethylpyrazolo[1 ,5- a]pyrimidine-3,7-diamine; 2,5,N7,N7-tetramethylpyrazolo[1 ,5-a]pyrimidine-3,7-diamine and 3- amino-5-methyl-7-imidazolylpropylaminopyrazolo[1 ,5-a]pyrimidine and the addition salts thereof and the tautomeric forms thereof, when a tautomeric equilibrium exists, and the addition salts thereof with an acid.

Among the pyrazole derivatives, mention may be made more particularly of the compounds described in patents DE 3 843 892, DE 4 133 957 and patent applications WO 94/08969, WO 94/08970, FR-A-2 733 749 and DE 195 43 988, such as 4,5-diamino-1-methylpyrazole,

3,4-diaminopyrazole, 4,5-diamino-1 -(4'-chlorobenzyl)pyrazole, 4,5-diamino-1 ,3-dimethyl-

pyrazole, 4,5-diamino-3-methyl-1-phenylpyrazole, 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-(β-hydroxyethyl)-3-methylpyrazole, 4,5-diamino-1-(β-hydroxyethyl)pyrazole, 4,5- diamino-1-ethyl-3-methylpyrazole, 4,5-diamino-1-ethyl-3-(4'-methoxyphenyl)pyrazole, 4,5- diamino-1-ethyl-3-hydroxymethylpyrazole, 4,5-diamino-3-hydroxymethyl-1-methylpyrazole, 4,5-diamino-3-hydroxymethyl-1-isopropylpyrazole, 4,5-diamino-3-methyl-1-isopropylpyrazole, 4-amino-5-(2'-aminoethyl)amino-1 ,3-dimethylpyrazole, 3,4,5-triaminopyrazole, 1 -methyl- 3,4,5-triaminopyrazole, 3,5-diamino-ethyl-4-methylaminopyrazole and 3,5-diamino-4-(β- hydroxyethyl)amino-1-methylpyrazole, and the addition salts thereof with an acid.

When used, the oxidation base(s) preferably represent(s) from 0.0005% to 12% by weight approximately relative to the total weight of the dye composition, and even more preferably from 0.005% to 6% by weight approximately relative to this weight.

When it is intended for oxidation dyeing, the dye composition in accordance with the invention may also contain, in addition to the cationic direct dyes (i) and (ii) and also oxidation bases, one or more couplers so as to modify or to enrich with tints the shades obtained using the cationic direct dyes (i) and (ii) and the oxidation base(s).

The couplers that may be used in the dye composition according to the invention are those conventionally used in oxidation dye compositions, i.e. meta-aminophenols, meta- phenylenediamines, meta-diphenols, naphthols and heterocyclic couplers, for instance indole derivatives, indoline derivatives, sesamol and derivatives thereof, pyridine derivatives, pyrazolotriazole derivatives, pyrazolones, indazoles, benzimidazoles, benzothiazoles, benzoxazoles, 1 ,3-benzodioxoles and quinolines, and the addition salts thereof with an acid.

These couplers are more particularly chosen from 2,4-diamino-1-(β- hydroxyethyloxy)benzene, 2-methyl-5-aminophenol, 5-N-(β-hydroxyethyl)amino-2-methyl- phenol, 3-aminophenol, 1 ,3-dihydroxybenzene, 1 ,3-dihydroxy-2-methylbenzene, 4-chloro-

1 ,3-dihydroxybenzene, 2-amino-4-(β-hydroxyethylamino)-1-methoxybenzene, 1 ,3- diaminobenzene, 1 ,3-bis(2,4-diaminophenoxy)propane, sesamol, 1-amino-2-methoxy-4,5- methylenedioxybenzene and α-naphthol, 6-hydroxyindole, 4-hydroxyindole, 4-hydroxy-N- methylindole, 6-hydroxyindoline, 2,6-dihydroxy-4-methylpyridine, 1 H-3-methylpyrazol-3-one, 1-phenyl-3-methylpyrazol-5-one, 2-amino-3-hydroxypyridine, 3,6-dimethylpyrazolo[3,2-c]- 1 ,2,4-triazole and 2,6-dimethylpyrazolo[1 ,5-b]-1 ,2,4-triazole, and the addition salts thereof

with an acid.

In general, the addition salts with an acid of the oxidation bases and couplers are especially chosen from the hydrochlorides, hydrobromides, sulfates, tartrates, lactates and acetates.

When they are present, the coupler(s) preferably represent(s) from 0.0001 % to 10% by weight approximately relative to the total weight of the dye composition, and even more preferentially from 0.005% to 5% by weight approximately relative to this weight.

The dye composition in accordance with the invention may also contain various adjuvants conventionally used in hair dye compositions, such as antioxidants, penetrants, sequestrants, fragrances, buffers, nonionic, anionic or amphoteric polymers, non-silicone cationic polymers, nonionic, cationic or amphoteric surfactants, ceramides, preserving agents, screening agents and opacifiers.

Needless to say, a person skilled in the art will take care to select the optional additional compound(s) such that the advantageous properties intrinsically associated with the dye composition in accordance with the invention are not, or are not substantially, adversely affected by the envisaged addition(s).

The dye composition according to the invention may be in various forms, such as in the form of liquids, shampoos, creams or gels, or in any other form that is suitable for dyeing keratin fibres, and especially human hair. It may be obtained by extemporaneously mixing a composition, optionally a pulverulent composition, containing the cationic direct dye(s) of formula (I) with a composition containing at least one azo, methine or azomethine direct dye containing at least one quaternary ammonium group included in a ring, as defined above.

When the combination of the cationic direct dye (i) and of the azo, methine or azomethine direct dye containing at least one quaternary ammonium group included in a ring (ii) according to the invention is used in a composition intended for oxidation dyeing (one or more oxidation bases are then used, optionally in the presence of one or more couplers) or when it is used in a composition intended for lightening direct dyeing, then the dye composition in accordance with the invention then also contains at least one oxidizing agent chosen, for example, from hydrogen peroxide, urea peroxide, alkali metal bromates, persalts such as perborates and persulfates, and enzymes such as peroxidases, laccases and two- electron oxidoreductases. The use of hydrogen peroxide or of enzymes is particularly

preferred.

Another subject of the invention is a process for dyeing keratin fibres, and in particular human keratin fibres such as the hair, using the dye composition as defined above.

According to a first variant of this dyeing process in accordance with the invention, at least one dye composition as defined above is applied to the fibres for a time that is sufficient to develop the desired coloration, after which the fibres are rinsed, optionally washed with shampoo, rinsed again and dried.

The time required to develop the coloration on the keratin fibres is generally between 3 and 60 minutes and even more precisely between 5 and 40 minutes.

According to a second variant of this dyeing process in accordance with the invention, at least one dye composition as defined above is applied to the fibres for a time that is sufficient to develop the desired coloration, without final rinsing.

According to another particular embodiment of this dyeing process, and when the dye composition in accordance with the invention contains at least one oxidizing agent, the dyeing process comprises a preliminary step that consists in separately storing, on the one hand, a composition (A1 ) comprising, in a suitable dyeing medium, at least one cationic direct dye (i) as defined above and, on the other hand, a composition (B1 ) containing, in a suitable dyeing medium, at least one oxidizing agent, and then in mixing them together at the time of use, followed by applying this mixture to keratin fibres, composition (A1 ) or composition (B1 ) containing at least one azo, methine or azomethine direct dye containing at least one quaternary ammonium group included in a ring, other than the dyes of formula (I) as defined above.

According to another particular embodiment of this dyeing process, and when the dye composition in accordance with the invention contains at least one oxidation base and at least one oxidizing agent, the dyeing process includes a preliminary step that consists in separately storing, on the one hand, a composition (A2) comprising, in a suitable dyeing medium, at least one cationic direct dye (i) as defined above and at least one oxidation base, and, on the other hand, a composition (B2) containing, in a suitable dyeing medium, at least one oxidizing agent, and then in mixing them together at the time of use, followed by applying this mixture to the keratin fibres, composition (A2) or composition (B2) containing at

least one azo, methine or azomethine direct dye containing at least one quaternary ammonium group included in a ring (ii), other than the dyes of formula (I) and as defined above.

Another subject of the invention is a multi-compartment device or dyeing "kit" or any other multi-compartment packaging system, of which a first compartment contains composition (A1 ) or (A2) as defined above and a second compartment contains composition (B1 ) or (B2) as defined above. These devices may be equipped with a means for applying the desired mixture to the hair, such as the devices described in patent FR 2 586 913 in the name of the Applicant.

The examples that follow are intended to illustrate the invention without, however, limiting its scope.

EXAMPLES

Application Examples

Example 1

The dye composition below was prepared (amounts expressed as grams of active material):

The composition is applied firstly to locks of natural grey hair containing 90% white hairs, and secondly to locks of permanent-waved grey hair containing 90% white hairs, for 30 minutes at room temperature (20°C).

After the action time, the locks are rinsed, shampooed and then rinsed and dried. They are dyed in a sparingly selective chromatic deep purple shade.

Example 2

In Example 1 , by replacing dye 1 weight for weight with dye 2 and Basic Red 51 with Basic Yellow 87, a strong and sparingly selective violet-brown shade is obtained.