952576-40-8Relevant academic research and scientific papers
Coupling compounds and hair dyeing compositions containing them
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Page/Page column 10, (2008/06/13)
The present invention refers to compounds of the formula (I) wherein R1 is (C1-C4)-alkyl, (C1-C4)-alkyl which is substituted by hydroxy, (C1-C4)-alkoxy, hydroxy-(C1-C4)-alkoxy, CN, -COOR5, -CON(R5)2 or -N(R5)2 or is phenyl; R2 is hydrogen, methyl or ethyl; R3 is (C1-C4)-alkylsulfonyl, (C1-C4)-alkylsulfonyl which is substituted by hydroxy, halogen, cyano, (C1-C4)-alkoxy or -N(R5)2 or is -SO2-CH=CH2, -SO2N(R5)2 or -PO(OR5)2; R4 is hydrogen, (C2-C4)-alkyl which is substituted by hydroxy, (C1-C4)-alkoxy or hydroxy-(C1-C4)-alkoxy; each of R5, independently is hydrogen, (C1-C4)-alkyl or hydroxy-(C2-C4)-alkyl; whereas R3 is not -NHSO2CH3 if R2 and R4 are both hydrogen and R1 is methyl, as well as hair dye compostions containing them.
