In vitro antitumour activity of two isomeric cyclopalladiated compounds derived from benzoylbenzylidenimines

The DNA thermal stabilizing effect and antitumour properties of two diastereoisomeric cyclopalladiated compounds, Pd2 [4‐CH3O–C6H4NC(COC6H5)C6H4]2(μ‐OAc)2 (I and II), derived from benzoylbenzylideneimines have been studied. The atropisomers containing two acetate‐bridged PdL2 units have a folded structure in boat form. The results show that both complexes interact with the DNA double helix but that compound II stabilizes the DNA more than compound I. It was also observed that the in vitro antiproliferative activity of compound II against colon (CX‐1) and lung (LX‐1) human tumour cells is higher than that of compound I. It is probable that the higher reactivity of compound II relative to compound I is due to the specific orientation of the benzoyl group with respect to the COCN chiral bond.