Organometallic Osmium(II) Arene Anticancer Complexes Containing Picolinate Derivatives was written by van Rijt, Sabine H.;Peacock, Anna F. A.;Johnstone, Russell D. L.;Parsons, Simon;Sadler, Peter J.. And the article was included in Inorganic Chemistry in 2009.Quality Control of 4-Methylpicolinonitrile This article mentions the following:
Chlorido Os(II) arene [(η6-biphenyl)OsII(X-pico)Cl] complexes containing X = Br (1), OH (2), and Me (3) as ortho, or X = Cl (4), CO2H (5), and Me (6) as para substituents on the picolinate (pico) ring were synthesized and characterized. The x-ray crystal structures of 1 and 6 show typical piano-stool geometry with intermol. π-π stacking of the biphenyl outer rings of 6. At 288 K the hydrolysis rates follow the order 2 ≫ 6 > 4 > 3 > 5 ≫ 1 with half-lives ranging from minutes to 4.4 h illustrating the influence of both electronic and steric effects of the substituents. The pKa values of the aqua adducts 3A, 4A, 5A, and 6A were all at 6.3-6.6. The para-substituted pico complexes 4–6 readily formed adducts with both 9-Et guanine (9EtG) and 9-Et adenine (9EtA), but these were less favored for the ortho-substituted complexes 1 and 3 showing little reaction with 9EtG and 9EtA, resp. D.-functional theory calculations confirmed the observed preferences for nucleobase binding for complex 1. In cytotoxicity assays with A2780, cisplatin-resistant A2780cis human ovarian, A549 human lung, and HCT116 colon cancer cells, only complexes 4 (p-Cl) and 6 (p-Me) exhibited significant activity (IC50 values < 25 μM). Both of these complexes were as active as cisplatin in A2780 (ovarian) and HCT116 (colon) cell lines, and even overcome cisplatin resistance in the A2780cis (ovarian) cell line. The inactivity of 5 is attributed to the neg. charge on its para carboxylate substituent. These data illustrate how the chem. reactivity and cancer cell cytotoxicity of Os arene complexes can be controlled and fine-tuned using steric and electronic effects of substituents on a chelating ligand to give Os(II) arene complexes which are as active as cisplatin but have a different mechanism of action. In the experiment, the researchers used many compounds, for example, 4-Methylpicolinonitrile (cas: 1620-76-4Quality Control of 4-Methylpicolinonitrile).
4-Methylpicolinonitrile (cas: 1620-76-4) belongs to pyridine derivatives. Pyridines are an important class of heterocycles and occur in polysubstituted forms in many naturally occurring biologically active compounds, drug molecules and chiral ligands. Pyridine groups exist in countless molecules, and their applications include catalysis, drug design, molecular recognition, and natural product synthesis.Quality Control of 4-Methylpicolinonitrile