ChemInform Abstract The diamine(sulfoxide)-Pt(II) complexes (III) and analogues of (R,R)and (S,S)-trans-1,2-diaminocyclohexane are prepared as shown for (III) (no yields given). The complexes are the first well-defined antitumor Pt complexes containing sulfur as ligand. The antitumor activity( L 1210 leukemia) is dependent on both the nature of the amine and the nature of the sulfoxide. In the case of asym. sulfoxides such as methyl p-tolyl sulfoxide, preparation of the optically pure forms shows a distinct effect of chirality of the sulfoxide ligand on the biological activity. The possible mechanisms of antitumor action are discussed. The complexes may act by binding to DNA with subsequent loss of sulfoxide ligand.

The diamine(sulfoxide)‐Pt(II) complexes (III) and analogues of (R,R)and (S,S)‐trans‐1,2‐diaminocyclohexane are prepared as shown for (III) (no yields given).