Synthesis, Characterization and Anti-Proliferative Activity of an Imidazolium Salt and its Silver Carbene Complex: Utilization of Picolyl and Quinolylmethyl Substituents

The imidazolium salt (IS) and silver carbene complex (SCC) studied in this report are 3-(pyridin-2-ylmethyl)-1-(quinolin-2-ylmethyl)imidazolium chloride (1) and 3-(pyridin-2-ylmethyl)-1-(quinolin-2-ylmethyl)imidazole – silver acetate complex (2). It was anticipated that the anti-proliferative activity of 1 and 2 would be similar to other characterized ISs while having increased solubility. The SCC (2) was synthesized in order to simulate the ligand-metal coordination similar to that of cisplatin. The success of the synthetic processes of 1 and 2 were determined by 1H NMR (300 MHz) spectroscopy. In addition, 1 was also characterized by 1H NMR (500 MHz) and 13C NMR (500 MHz) spectroscopy and mass spectrometry. The anti-proliferative activity of 1 was determined via MTT assay. 2-(Chloromethyl)pyridine and 1-(quinolin-2-ylmethyl)imidazole were dissolved in acetonitrile and successfully combined under reflux conditions to form 1. However, 1 exhibited limited anti-proliferative activity; an IC50 value of greater than 30 μM was obtained for both NCI-H460 and A549 cell lines. Likewise, 1 and silver acetate were dissolved in methylene chloride and successfully combined under anaerobic conditions to form 2. Compound 2, like 1, exhibited hygroscopic behavior. Because 1 lacks anti-proliferative activity, further research should be focused on substituent families that have greater structural similarity to the ISs previously determined, via research, to exhibit great activity