The invention relates to the use of specific heterocyclic couplers which are cationic 7-amino-1,2,3,4-tetrahydroquinoline derivatives of formula (I) for dyeing keratin fibres such as the hair: in which formula (I): R
1
to R
6
, CAT
+
, An
−
, and R
a
to R
b
are as defined in the description.
该发明涉及使用特定的杂环
偶联剂,其为公离子性的
7-氨基-1,2,3,4-四氢喹啉衍
生物,
化学式为(I),用于染色角蛋白纤维,如头发:其中
化学式(I)中,R1到R6,CAT+,An−,以及Ra到Rb的定义见说明。