Palladium(II) complexes with R2edda derived ligands. Part IV. O,O′-dialkyl esters of (S,S)-ethylenediamine-N,N′-di-2-(4-methyl)-pentanoic acid dihydrochloride and their palladium(II) complexes: Synthesis, characterization and in vitro antitumoral activity against chronic lymphocytic leukemia (CLL) cells

Four novel bidentate N,N'-ligand precursors, including O,O'-dialkyl esters (alkyl = ethyl, n-propyl, n-butyl and n-pentyl), L1 center dot 2HCl-L4 center dot 2HCl, of (S,S)-ethylenediamine-N,N'-di-2-(4-methyl)-pentanoic acid dihydrochloride [(S,S)-H(4)eddl]Cl-2 and the corresponding palladium(II) complexes 1-4, were prepared and characterized by IR, H-1 NMR and C-13 NMR spectroscopy and elemental analysis. In vitro cytotoxicity of all compounds was determined against chronic lymphocytic leukemia cells (CLL). The compounds were found to exhibit higher antitumoral activity than cisplatin. The most active compound 2, [PdCl2{(S,S)-nPr(2)eddl}], was found to be 13.6 times more active than cisplatin on CLL cells. (C) 2010 Elsevier Masson SAS. All rights reserved.