trans-Thionate Derivatives of Pt(II) and Pd(II) with Water-Soluble Phosphane PTA and DAPTA Ligands: Antiproliferative Activity against Human Ovarian Cancer Cell Lines

Abstract

A series of PTA and DAPTA platinum(II) and palladium(II) thionate complexes of the type trans-[M(SN)2P2] were prepared from the reaction of cis-[MCl2P2] [M = Pt, Pd; P = PTA (1,3,5-triaza-7-phosphaadamantane), DAPTA (3,7-diacetyl-1,3,7-triaza-5- phosphabicyclo[3.3.1]nonane)] with the in situ generated sodium salts of the heterocyclic thiones S-m-methylpyrimidine-2-thione, S-4,6-dimethylpyrimidine-2- thione, S-4,6-dihydroxypyrimidine-2-thione, benzothiazole-2-thione, benzoxazole-2-thione, S-1,3,4,-thiadiazole-2-thione, S-4,5-H-thiazolan-2-thione, and S-pyrimidine-4(1H)-one-2-thione. The X-ray structures of six of the compounds confirm the trans disposition and, only in the case of [Pd 2Cl2(S-pyrimidine-4(1H)-one-2-thionate) 2(PTA)2], a dinuclear structure with a Pd-Pd distance of 3.0265(14)Å was observed. In vitro cytotoxicities against human ovarian cancer cell lines A2780 and A2780cisR were evaluated for ten complexes showing a high inhibition of cellular growth with a comparable inhibitory potency (IC50) against A2780 cells to that of cisplatin. Notably, the compounds also show significant (up to 7-fold higher) activity in cisplatin-resistant A2780cisR cell lines. © 2013 American Chemical Society.We thank the Spanish Ministry for Education, Junta de Castilla y León, as well as the University of Burgos for generous financial support (Grants CTQ2008-06716-CO3-01, BU033A06, and 112-541A-487.01).Peer Reviewe