N-heteroarylmethyl-p-phenylenediamine derivatives as well as oxidation dyeing agents containing these compounds

A N-heteroarylmethyl-p-phenylenediamine derivative of the general formula (I), or a physiologically tolerated, water-soluble salt thereof,

• wherein
• X1 is sulfur, nitrogen, C—R6 or N—R5,
• X2 is sulfur, nitrogen, C—R6 or N—R5,
• X3 is sulfur, nitrogen, oxygen, C—R6 or N—R5,
• R1 is hydrogen, a C1—C4 alkyl group or a C1—C4 hydroxyalkyl group,
• R2, R3 may be the same or different and, independently of one another, are hydrogen or a C1-C6 alkyl group,
• R4, R6 may be the same or different and, independently of one another, are hydrogen, a halogen atom, a cyano group, a C1-C4 alkoxy group, a C1-C6 alkyl group, a C1-C4 alkyl thioether 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 trifluoromethane 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
• R5 is hydrogen, a C1-C6 alkyl group, a C1-C4 hydroxyalkyl group, a phenyl group or an acetyl group,
• at least one and not more than two of the X1 to X3 groups being C—R6 and not more than one of the X1 to X3 groups being sulfur, or N—R5.