This disclosure describes symmetrical 1,4-bis(substituted-amino)-5,8-dihydroxyanthraquinones useful as chelating agents and for inducing regression and/or palliation of cancer diseases in mammals.
CROSS REFERENCE TO RELATED APPLICATION
This application is a continuation of application Ser. No. 485,143, filed Apr. 15, 1983, which is a division of application Ser. No. 244,452, filed Nov. 2, 1981, now U.S. Pat. No. 4430501 which is a division of application Ser. No. 63,285, filed Aug. 2, 1979, now U.S. Pat. No. 4,278,689 which is a division of application Ser. No. 923,602, filed July 11, 1978, now U.S. Pat. No. 4,197,249 which is a continuation-in-part of abandoned application Ser. No. 873,040, L filed Jan. 30, 1978 which is a continuation-in-part of abandoned application Ser. No. 824,872, filed Aug. 15, 1977.
Compounds of formula (I) ##STR1## in which R.sub.1, R.sub.2, R.sub.3 and R.sub.4 are each separately selected from hydrogen, X, NH--A--NHR and NH--A--N(O)R'R" wherein X is hydroxy, halogeno, amino, C.sub.1-4 alkoxy or C.sub.2-8 alkanoyloxy, A is a C.sub.2-4 alkylene group with a chain length between NH and NHR or N(O)R'R" of at least 2 carbon atoms and R, R' and R" are each separately selected from C.sub.1-4 alkyl groups and C.sub.2-4 hydroxyalkyl and C.sub.2-4 dihydroxyalkyl groups in which the carbon atom attached to the nitrogen atom does not carry a hydroxy group and no carbon atom is substituted by two hydroxy groups, or R' and R" together are a C.sub.2-6 alkylene group which with the nitrogen atom to which R" and R" are attached forms a heterocyclic group having 3 to 7 atoms in the ring, but with the proviso that at least one of R.sub.1 to R.sub.4 is a group NH--A--N(O)R'R", and physiologically acceptable salts thereof are of value in the treatment of cancer.
