Compounds having formula (I) wherein R<3>, R<4>, R<7>, and R<8> are independently selected from the group consisting of hydrogen, lower alkyl, halogen, amine, mono(lower)alkylamine, di(lower)alkylamine, phenyl, or substituted phenyl possess antitumour activity and are new with the exception of the compound in which R<3>, R<4>, R<7>, R<8> are all hydrogen and the compound in which R<3> and R<7> are hydrogen, R<4> is chlorine, and R<8> is a 2-nitrophenyl group.
1. A compound having the formula (I): <img class="EMIRef" id="452401486-ib0012" /> and the dihydro derivative of formula (12): <img class="EMIRef" id="452401486-ib0013" /> wherein R<3> , R<4> , R<7> and R<8> are independently selected from the group consisting of hydrogen, C<1-6> alkyl, halogen, amine, mono(C<1-6> )alkylamine, di(C<1-6> )alkylamine, or phenyl (which may be substituted with 1 to 4 substituents selected from C<1-6> alkyl, halogen, amine, mono (C<1-6> )alkylamine, di(C<1-6> )alkylamine, nitro, hydroxy, C<1-6> alkoxy, or trifluoromethyl); with the exception of the compounds in which: R<3> , R<4> , R<7> and R<8> are all hydrogen; R<3> and R<7> are hydrogen, R<4> is chlorine, and R<8> is a 2-nitrophenyl group; R<3> and R<7> are hydrogen, R<4> is amino, and R<8> is a 2-nitrophenyl group; R<3> , R<7> and R<8> are hydrogen and R<4> is chlorine; and R<4> , R<7> and R<8> are hydrogen and R<3> is methyl. 2. A compound according to claim 1, which is selected from a compound of formula (4): <img class="EMIRef" id="452401486-ib0014" /> formula (8), <img class="EMIRef" id="452401486-ib0015" /> formula (11), <img class="EMIRef" id="452401486-ib0016" /> formula (13), and <img class="EMIRef" id="452401486-ib0017" /> formula (14), <img class="EMIRef" id="452401486-ib0018" /> wherein R<3> , R<4> , R<7> and R<8> are as defined in claim 1. 3. A compound according to claim 1 or 2, wherein the substituent groups R<3> , R<4> , R<7> and R<8> are chosen from hydrogen, methyl, ethyl, chlorine, dimethylamine, and nitrophenyl. 4. A compound according to claim 1 which is selected from: 3,7-diethyl-1,5-diazaanthraquinone; 3,7-dimethyl-1,5-diazaanthraquinone; 4,8-dimethyl-1,5-diazaanthraquinone; 4,8-dimethyl-3,7-dimethyl-1,5-diazaanthraquinone; 8-chloro-3-methyl-1,5-diazaanthraquinone; 8-chloro-1-dimethylamino-4-methyl-1,4-dihydro-1,5-diazaanthraquinone; 4-chloro-8-methyl-1,5-diazaanthraquinone; and 4-dimethylamino-8-methyl-1,5-diazaanthraquinone. 5. A pharmaceutical composition which includes as active ingredient a compound of any one of claims 1 to 4, together with a pharmaceutical carrier. 6. A compound according to any one of claims 1 to 4 for use as a medicament. 7. The use of a compound according to any of claims 1 to 4 or a pharmaceutical composition according to claim 5 in the manufacture of a medicament for the treatment of tumours.