Anthraquinone compound

An anthraquinone compound of the following formula in the free acid form, ##STR649## wherein R and R.sub.1 independently of one another are each hydrogen or alkyl, A is divalent group of the following formula (a), (b), (c), (d), (e), or (f), the formula (a) being ##STR650## in which R.sub.3, R.sub.4 and R.sub.5 independently of one another are each hydrogen, methyl, ethyl, methoxy or ethoxy, m is 0 or 1, n is 0, 1 or 2, and the asterisked linkage bonds to ##STR651## the formula (b) being ##STR652## in which p is 0, 1, 2 or 3, the formula (c) having --CH.sub.2).sub.q, in which q is an interger of from 2 through 6, the formula (d) being ##STR653## in which r.sub.1 and r.sub.2 are each 0, 1 or 2, and r.sub.1 +r.sub.2 =1 or 2, the formula (e) being ##STR654## in which s is an integer of from 2 through 6, t is 0, 1 or 2, and * is as defined above, and the formula (f) being ##STR655## in which u and v independently of one another are each 0, 1 or 2, B.sub.1 is phenylene unsubstituted or substituted once or twice by methyl, ethyl, methoxy, ethoxy, chloro, bromo or nitro, or naphthylene unsubstituted or substituted by sulfo, Z.sub.1 is vinyl or --CH.sub.2 CH.sub.2 L in which L is a group capable of being split by the action of an alkali, l is 0, 1 or 2, and X is a group of the following formula (g), (h) or (i), the formula (g) being ##STR656## in which R.sub.2 is hydrogen or alkyl, B.sub.2 is phenylene unsubstituted or substituted once or twice by methyl, ethyl, methoxy, ethoxy, chloro, bromo, nitro, carboxy or sulfo, or naphthylene unsubstituted or substituted by sulfo, and Z.sub.2 is vinyl or --CH.sub.2 CH.sub.2 L in which L is as defined above, the formula ##STR657## in which R.sub.6 and R.sub.7 independently of one another are each hydrogen, alkyl, phenyl, naphthyl or benzyl, and the formula (i) being ##STR658## in which R, A and l are as defined above.