Three Arene‐Ru(II) compounds of 2‐halogen‐5‐aminopyridine: Synthesis, characterization, and cytotoxicity

Abstract

Three novel compounds, (η6‐p‐cymene)RuCl2(2‐fluoro‐5‐aminopyridine) (compound 1), (η6‐p‐cymene)RuCl2(5‐amino‐2‐chlorpyridine) (compound 2) and (η6‐p‐cymene)RuCl2(2‐bromo‐ 5‐aminopyridine) (compound 3), were synthesized and characterized. The compound 1 and 3 were determined by X‐ray diffraction, showing a distorted piano‐stool type of geometry with similar bond lengths and angles around the ruthenium. Compound 2 exhibited moderate in vitro activity against A549 and MCF‐7 human cancer cells, the other two lower activities. The UV–vis and fluorescent absorption titrations showed that three compounds binded with CT‐DNA in a minor groove. The intrinsic binding constants (Kb) were calculated to be 2.13(±0.03) × 105 M−1, 2.89(±0.03) × 105 M−1 and 2.45(±0.03) × 105 M−1 for compound 1, 2 and 3, respectively, by using UV–vis absorption titrations data. Among the three compound, the highest value of intrinsic binding constant of compound 2 was consistent with its highest cytoxicity against A549 and MCF‐7 human cancer cells in vitro.

Synthesis and Characterization of New Ruthenium (II) Complexes of Stoichiometry [Ru(p-Cymene)Cl2L] and Their Cytotoxicity against HeLa-Type Cancer Cells

“…Some years ago, our research group described the synthesis of the compound [Ru( p -cymene)Cl(o-phen)]PF 6 , (o-phen = o-phenylenediamine) [ 18 ], which has shown to be an excellent antitumor agent [ 19 , 20 ]. Moreover, complexes [Ru( p -cymene)Cl 2 L], L being one of the following substituted pyridines: 2-fluoro-5-aminopyridine, 5-amino-2-chloropyridine and 2-bromo-5-aminopyridine, have been isolated and characterized and have shown moderate cytotoxicity against lung carcinoma A549 and breast cancer MCF-7 cell lines [ 21 ]. Recently, J. Ruiz et al [ 22 ] have described a set of ruthenium (II) complexes containing p -cymene, and a C-N ligand with a non-coordinated CHO group, capable of exhibiting anticancer properties towards several human cancer cell lines, including cells of the epithelial ovarian carcinoma A2780, CDDP-resistant ovarian cancer A2780cisR and breast cancer MCF-7.…”