Comparative antitumor studies on platinum(II) and platinum(IV) complexes containing 1,2-diaminocyclohexane

The synthesis and characterization of a group of platinum(IV) compounds containing the various isomeric forms of 1,2-diaminocyclohexane (DACH) are described. Antitumor tests with the new complexes, as well as with other platinum(II) compounds containing the DACH ligand, revealed that trans,cis-PtIV(SS-DACH)(OH)2Cl2, 7, is more active than its mirror image, trans,cis-PtIV(RR-DACH)(OH)2Cl2, 6, against L1210 leukemia implanted in mice. However, activity is dependent on the tumor model, and against B16 melanoma implanted in mice, the activities of the two enantiomers are reversed, with 6 being more active than 7. The results of the tests are discussed in light of the mechanism by which Pt(IV) compounds are believed to express their antitumor effects.