1,4-Diamino-2-(thiazol-2-yl)benzene derivatives, and dyes containing said compounds

1. 1,4-Diamino-2-(thiazol-2-yl)benzene derivatives of formula (I):

wherein

R1, R2, R3 and R4 independently of each other denote hydrogen, a C 1 -C 6 -alkyl, C 2 -C 4 -hydroxyalkyl, C 3 -C 4 -dihydroxyalkyl or C 2 -C 4 -alkoxy-(C 1 -C 2 )-alkyl group or R1 and R2 or R3 and R4 form a four-membered to eight-membered aliphatic ring, and at least two of the R1 to R4 groups denote hydrogen;

R5 denotes hydrogen, a halogen atom, a C 1 -C 4 -alkyl, C 1 -C 4 -hydroxyalkyl or C 1 -C 4 -alkoxy group;

R6 and R7 independently of each other denote hydrogen, a halogen atom, a nitro, C 1 -C 4 -alkoxy, C 1 -C 6 -alkyl, C 1 -C 4 -hydroxyalkyl or C 3 -C 4 dihydroxyalkyl group or a group of formula (II)

and R8 denotes hydrogen, an amino group, a halogen atom, a nitro group or a hydroxyl group.

2. 1,4-Diamino-2-(thiazol-2-yl)benzene derivative according to claim 1 , characterized in that in formula (I) one or more groups R5 to R7 denote hydrogen.

3. 1,4-Diamino-2-(thiazol-2-yl)benzene derivative according to claim 1 , characterized in that in formula (I) groups R1, R2, R3 and R4 denote hydrogen.

4. 1,4-Diamino-2-(thiazol-2-yl)benzene derivative according to claim 1 , characterized in that in formula (I) one or both of groups R6 and R7 denote a C 1 -C 4 -alkyl group or a C 1 -C 4 -hydroxyalkyl group.

5. 1,4-Diamino-2-(thiazol-2-yl)benzene derivative according to one of claims 1 to 4 , characterized in that it is selected from among 1,4-diamino-2-(thiazol-2-yl)benzene; 1,4-diamino-2-(4,5-dimethylthiazol-2-yl)benzene; 1,4-diamino-2-(4-phenylthiazol-2-yl)benzene and 1,4-diamino-2-(4-methylthiazol-2-yl)benzene.

6. Agent for oxidative dyeing of keratin fibers based on a developer-coupler combination, characterized in that it contains as developer at least one 1,4-diamino-2-(thiazol-2-yl)benzene derivative of formula (I) according to claim 1 .

7. Agent according to claim 6 , characterized in that it contains the 1,4-diamino-2-(thiazol-2-yl)benzene derivative of formula (I) in an amount from 0.005 to 20.0 wt %.

8. Agent according to claim 6 , characterized in that the coupler is selected from among 2,6-diaminopyridine, 2-amino-4-[(2-hydroxyethyl)amino]anisole, 2,4-diamino-1-fluoro-5-methylbenzene, 2,4-diamino-1-methoxy-5-methylbenzene, 2,4-diamino-1-ethoxy-5-methylbenzene, 2,4-diamino-1-(2-hydroxyethoxy)-5-methylbenzene, 2,4-di[(2-hydroxyethyl)amino]-1,5-dimethoxybenzene, 2,3-diamino-6-methoxypyridine, 3-amino-6-methoxy-2-(methylamino)pyridine, 2,6-diamino-3,5-dimethoxypyridine, 3,5-diamino-2,6-dimethoxypyridine, 1,3-diaminobenzene, 2,4-diamino-1-(2-hydroxyethoxy)benzene, 2,4-diamino-1,5-di(2-hydroxyethoxy)benzene, 1-(2-aminoethoxy)-2,4-diaminobenzene, 2-amino-1-(2-hydroxyethoxy)-4-methylaminobenzene, 2,4-diaminophenoxyacetic acid, 3-[di(2-hydroxyethyl)amino]aniline, 4-amino-2-di[(2-hydroxyethyl)amino]-1-ethoxybenzene, 5-methyl-2-(1-methylethyl)phenol, 3-[(2-hydroxyethyl)amino]aniline, 3-[(2-aminoethyl)amino]anilino, 1,3-di(2,4-diaminophenoxy)propane, di(2,4-diaminophenoxy)methane, 1,3-diamino-2,4-dimethoxybenzene, 2,6-bis(2-hydroxyethyl)aminotoluene, 4-hydroxyindole, 3-dimethylaminophenol, 3-diethylaminophenol, 5-amino-2-methylphenol, 5-amino-4-fluoro-2-methylphenol, 5-amino-4-methoxy-2-methylphenol, 5-amino-4-ethoxy-2-methylphenol, 3-amino-2,4-dichlorophenol, 5-amino-2,4-dichlorophenol, 3-amino-2-methylphenol, 3-amino-2-chloro-6-methylphenol, 3-aminophenol, 2-[(3-hydroxyphenyl)amino]acetamide, 5-[(2-hydroxyethyl)amino]-2-methylphenol, 3-[(2-hydroxyethyl)amino]phenol, 3-[(2-methoxyethyl)amino]phenol, 5-amino-2-ethylphenol, 2-(4-amino-2-hydroxyphenoxy)ethanol, 5-[(3-hydroxypropyl)amino]-2-methylphenol, 3-[(2,3-dihydroxypropyl)amino]-2-methylphenol, 3-[(2-hydroxyethyl)amino]-2-methylphenol, 2-amino-3-hydroxypyridine, 5-amino-4-chloro-2-methylphenol, 1-naphthol, 1,5-dihydroxynaphthalene, 1,7-dihydroxynaphthalene, 2,3-dihydroxynaphthalene, 2,7-dihydroxynaphthalene, 2-methyl-1-naphthol acetate, 1,3-dihydroxybenzene, 1-chloro-2,4-dihydroxybenzene, 2-chloro-1,3-dihydroxybenzene, 1,2-dichloro-3,5-dihydroxy-4-methylbenzene, 1,5-dichloro-2,4-dihydroxybenzene, 1,3-dihydroxy-2-methylbenzene, 3,4-methylenedioxyphenol, 3,4-methylenedioxyaniline, 5-[(2-hydroxyethyl)amino]-1,3-benzodioxole, 6-bromo-1-hydroxy-3,4-methylenedioxybenzene, 3,4-diaminobenzoic acid, 3,4-dihydro-6-hydroxy-1,4(2H)benzoxazine, 6-amino-3,4-dihydro-1,4[2H]-benzoxazine, 3-methyl-1-phenyl-5-pyrazolone, 5,6-dihydroxyindole, 5,6-dihydroxyindoline, 5-hydroxyindole, 6-hydroxyindole, 7-hydroxyindole and 2,3-indolinedione.

9. Agent according to claim 6 , characterized in that in addition to the 1,4-diamino-2-(thiazol-2-yl)benzene derivative of formula (I) it contains at least one other developer from the group consisting of 1,4-diaminobenzene, 2,5-diaminotoluene, 2-(2,5-diaminophenyl)ethyl alcohol, 4-aminophenol and derivatives thereof, 4,5-diaminopyrazole derivatives and tetraaminopyrimidines.

10. Agent according to claim 6 , characterized in that each of the developers and couplers is present in a total amount of 0.005 to 20 wt %, based on the total amount of oxidation dye.

11. Agent according to claim 6 , characterized in that it contains additionally at least one direct dye.

12. Agent according to claim 6 , characterized in that it has a pH from 6.5 to 11.5.

13. Agent according to claim 6 , characterized in that it is in the form of an aqueous or aqueous-alcoholic solution, a cream, a gel or an emulsion.

14. Agent according to claim 6 , characterized in that it is a hair colorant.