Inhibitors of cyclin dependent kinases as anti-cancer agent

Use of a compound of formula

• wherein:
• one of X1 and X2 is NR10 and the other of X1 and X2 is CR9;
• Z is NH, NHCO, NHSO2, NHCH2, CH2, CH2CH2, or CH═CH;
• R1, R2, R1 R9 and R10 are independently H, alkyl, aryl, aralkyl, heterocycle, halogeno, NO2, CN, OH, alkoxy, aryloxy, (R′″)nNH2, (R′″)nNH—R′, (R′″)nN—(R′)(R″), NH-aryl, N-(aryl)2, COOH, COO—R′, COO-aryl, CONH2, CONH—R′, CON—(R′)(R″), CONH-aryl, CON—(aryl)2, SO3H, SO2NH2, CF3, CO—R′, or CO-aryl, wherein alkyl, aryl, aralkyl and heterocycle groups may be further substituted with one or more groups selected from halogeno, NO2, CN, OH, O-methyl, NH2, COOH, CONH2 and CF3;
• R4, R5, R6, R7, and R8 are independently from each other H, substituted or unsubstituted lower alkyl, halogeno, NO2, CN, OH, substituted or unsubstituted alkoxy, NH2, NH—R′, N—(R′)(R″), COOH, COO—R′, CONH2, CONH—R′, CON—(R′)(R″), SO3H, SO2NH2, or CF3;
• wherein R1 R″ and R′″ are each independently alkyl groups that may be the same or different and n is 0 or 1;
• with the proviso that when R1 and R2 are H, X1 is NH, X2 is CH, and R3 is H, the phenyl group is not
• 3-(1,1,2,2-tetrafluoroethoxy)b or
• 3,4,5-trimethoxy,
• when the other groups R4—R8 are H;
• and pharmaceutically acceptable salts thereof;
• in the manufacture of a medicament for use in the treatment of a proliferative disease.