The present invention relates to a compound of formula (I-0) or a salt thereof. The invention further relates to the use of such compound as a colouring agent. The invention also relates to a colouring composition comprising such compound.

A method for producing 1,4-diphenylamino-5,8-dihydroxyanthraquinone provides a dye with high colour strength and excellent brilliance for colouring plastics.

A method for producing 1,4-diphenylamino-5,8-dihydroxyanthraquinone provides a dye with high colour strength and excellent brilliance for colouring plastics.

An anthraquinone compound represented by formula (1) (In the formula, R.sub.1 and R.sub.4 represent a hydrogen atom, a C1-12 alkyl group, a C1-12 alkoxy group, a halogen atom, CO.sub.2R.sub.9, OCOR.sub.9, COR.sub.9, a cyano group, or a trifluoromethyl group. R.sub.2, R.sub.3, R.sub.5, and R.sub.6 represent a hydrogen atom, a C1-4 alkyl group, a C1-4 alkoxy group, a halogen atom, CO.sub.2R.sub.9, OCOR.sub.9, COR.sub.9, a cyano group, or a trifluoromethyl group, R.sub.7 and R.sub.8 represent a hydrogen atom or a C1-8 alkyl group. R.sub.9 represents a C1-12 alkyl group, a substituent represented by formula (a) (in the formula, R.sub.10 represents a hydrogen atom, a C1-8 alkyl group, or a C1-8 alkoxy group), or a substituent represented by formula (b) (in the formula, R.sub.11 represents a hydrogen atom or a C1-8 alkyl group)).

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