Platinum(II) and palladium(II) complexes with methyl 3,4-diamino-2,3,4,6-tetradeoxy-(alpha)-L-lyxo-hexopyranoside

To develop new complexes of Pt(II) and Pd(II) that have ligands in a shape complementary to DNA, we designed and synthesized a methyl 3,4-diamino-2,3,4,6-tetradeoxy-(alpha)-L-lyxo-hexopyranoside (V). This synthetic ligand imitates the shape of daunosamine, a DNA minor groove binding sugar moiety present in the antineoplastic anthracycline antibiotics doxorubicin and daunorubicin. Ligand V, was used to form the Pt(II) and Pd(II) chloride complexes [MCl2(V)]1, 2, 3, and 4, which have potential antitumor properties. We characterized these complexes by X-ray diffraction and in solution by 1H-, 13C-, 15N- and 195Pt-NMR. Both Pt(II) and Pd(II) complexes seem to be isostructural, as shown by X-ray diffraction and molecular modeling. The complexes formed dimers in the crystal lattice with short M-M and Cl...N(H) hydrogen bonds. Detailed dynamic NMR studies in CD2Cl2 and CD3CN solutions confirm the monomeric structure in both solvents as well as solvation around the metal and intermolecular hydrogen bonding of NH in CD3CN.