1,3-Dihydroxybenzene derivatives and colorants containing said compounds

1,3-Dihydroxybenzene derivative of formula (Ia) or a physiologically tolerated, water-soluble salt thereof

• 9
• wherein
• R′1 denotes a substituted pyridyl group, a pyrimidyl group, a group of formula
• 10
• or a group of formula
• 11
• wherein R′2, R′3, R′4, R′5 and R′6 independently of each other denote hydrogen, a halogen atom (F, Cl, Br, I), a cyano group, a hydroxyl group, a C1-C4-alkoxy group, a C1-C4-hydroxyalkoxy group, a C1-C6-alkyl group, a C1-C4-alkylthioether group, a mercapto group, a nitro group, an amino group, a C1-C4-alkylamino group, a hydroxy(C1-C4)alkylamino group, a di(C1-C4)alkylamino group, a di[hydroxy(C1-C4)-alkyl]amino group, a dihydroxy-(C3-C4)-alkylamino group, a [hydroxy-(C1-C4)-alkyl]-C1-C4-alkylamino group, a trifluoromethyl group, a —C(O)H group, a —C(O)CH3 group, a —C(O)CF3 group, an —Si(CH3)3 group, a C1-C4-hydroxyalkyl group or a C2-C4-dihydroxyalkyl group, or two adjacent R2 to R6 groups form an —O—CH2—O— bridge;
• X′1 denotes sulfur, nitrogen, oxygen, C—R′9 or N—R′8;
• X′2 denotes sulfur, nitrogen, oxygen, C—R′10 or N—R′8;
• X′3 denotes sulfur, nitrogen, oxygen, C—R′11 or N—R′8;
• R′7, R′9, R′10 and R′11 independently of each other denote hydrogen, a halogen atom (F, Cl, Br, I), a cyano group, a C1-C4-alkoxy group, a C1-C6-alkyl group, a C1-C4-alkylthioether group, a mercapto group, a nitro group, an amino group, a C1-C4-alkylamino group, a di(C1-C4)-alkylamino group, a di(C1-C4-hydroxyalkyl)amino group, a C1-C4-hydroxyalkylamino group, a trifluoromethyl group, a —C(O)CH3 group, a —C(O)CF3 group, an —Si(CH3)3 group, a C1-C4-hydroxyalkyl group or a C3-C4-dihydroxyalkyl group;
• and
• R′8 denotes hydrogen, a C1-C6-alkyl group, a C2-C4-hydroxyalkyl group, a phenyl group or an acetyl group,
• provided that at least one and at the most two of the X′1 to X′3 groups denote C—R′9,
• C—R′10 or C—R′11 and at the most one of the X′1 to X′3 groups denotes sulfur, oxygen or N—R′8, and R′1 does not stand for a phenyl group or hydroxyphenyl group.

Agent for dyeing keratin fibers based on a developer-coupler combination, characterized in that it contains at least one 1,3-dihydroxybenzene derivative of formula (Ia) or a physiologically tolerated, water-soluble salt thereof

• 12
• wherein
• R′1 denotes a substituted pyridyl group, a pyrimidyl group, a group of formula
• 13
• or a group of formula
• 14
• wherein R′2, R′3, R′4, R′5 and R′6 independently of each other denote hydrogen, a halogen atom (F, Cl, Br, I), a cyano group, a hydroxyl group, a C1-C4-alkoxy group, a C1-C4-hydroxyalkoxy group, a C1-C6-alkyl group, a C1-C4-alkylthioether group, a mercapto group, a nitro group, an amino group, a C1-C4-alkylamino group, a hydroxy(C1-C4)alkyl amino group, a di(C1-C4)alkylamino group, a di[hydroxy-(C1-C4)-alkyl]amino group, a dihydroxy-(C3-C4)-alkylamino group, a [hydroxy-(C1-C4)-alkyl]-C1-C4-alkylamino group, a trifluoromethyl group, a —C(O)H group, a —C(O)CH3 group, a —C(O)CF3 group, an —Si(CH3)3 group, a C1-C4-hydroxyalkyl group or a C2-C4-dihydroxyalkyl group, or two adjacent R2 to R6 groups form an —O—CH2—O— bridge;
• X′1 denotes sulfur, nitrogen, oxygen, C—R′9 or N—R′8;
• X′2 denotes sulfur, nitrogen, oxygen, C—R′10 or N—R′8;
• X′3 denotes sulfur, nitrogen, oxygen, C—R′11 or N—R′8;
• R′7, R′9, R′10 and R′11 independently of each other denote hydrogen, a halogen atom (F, Cl, Br, I), a cyano group, a C1-C4-alkoxy group, a C1-C6-alkyl group, a C1-C4-alkylthioether group, a mercapto group, a nitro group, an amino group, a C1-C4-alkylamino group, a di(C1-C4)-alkylamino group, a di(C1-C4-hydroxyalkyl)amino group, a C1-C4-hydroxyalkylamino group, a trifluoromethyl group, a —C(O)CH3 group, a —C(O)CF3 group, an —Si(CH3)3 group, a C1-C4-hydroxyalkyl group or a C3-C4-dihydroxyalkyl group;
• and
• R′8 denotes hydrogen, a C1-C6-alkyl group, a C2-C4-hydroxyalkyl group, a phenyl group or an acetyl group,
• provided that at least one and at the most two of the X′1 to X′3 groups denote C—R′9,
• C—R′10 or C—R′11 and at the most one of the X′1 to X′3 groups denotes sulfur, oxygen or N—R′8.