3099-31-8Relevant articles and documents
Improved Electrocatalytic CO2 Reduction with Palladium bis(NHC) Pincer Complexes Bearing Cationic Side Chains
Deluca, Emile E.,Xu, Zhen,Lam, Jasper,Wolf, Michael O.
supporting information, p. 1330 - 1343 (2019/03/28)
Stabilizing interactions between charged electrocatalytic intermediates and a series of cationic residues were explored through the synthesis and characterization of six palladium bis(N-heterocyclic carbene) (NHC) complexes bearing unique onium functionalities. The presence of a positively charged, pendant substituent was found to mediate electrode kinetics and facilitate CO2 coordination to the catalytic center in a systematic fashion. The introduction of cationic moieties into this system is shown to enhance catalytic selectivity for the conversion of CO2 to CO by as much as 5 times that of an alkyl-bearing analog. A combination of electrochemical experiments and computational analysis demonstrates that catalyst performance benefits most from a bulky onium unit tethered to the catalyst through a flexible linker. This behavior was interpreted as a preference for a wide, hydrophobic reaction pocket that allows for the unhindered formation of catalytic intermediates and mediated interaction with the solution.
Synthesis and antitumor activity of novel pyridinium fullerene derivatives
Yasuno, Takumi,Ohe, Tomoyuki,Ikeda, Hitomi,Takahashi, Kyoko,Nakamura, Shigeo,Mashino, Tadahiko
, p. 6325 - 6337 (2019/08/28)
Purpose: We have previously reported that some cationic fullerene derivatives exhibited anticancer activity, and they are expected to be a potential lead compound for an anti-drug resistant cancer agent. However, they are bis-adducts and a mixture of multiple regioisomers, which cannot be readily separated due to the variability of substituent positions on the fullerene cage. To overcome this issue, we evaluated the antiproliferative activities of a set of mono-adduct derivatives and examined their structure-activity relationship. In addition, the in vivo antitumor activity of selected derivatives was also examined. Methods: Nineteen pyridinium fullerene derivatives were newly designed and synthesized in this study. Their antiproliferative activities were evaluated using several cancer cell lines including drug-resistant cells. Furthermore, in vivo antitumor activity of several derivatives was investigated in mouse xenograft model of human lung cancer. Results: The derivatives inhibited the proliferation of cancer cell lines, including cisplatin-resistant cells and doxorubicin-resistant cells. It was also shown that compound 10 (10 μM), 13 (10 μM) and cis-14 (10 μM) induced the intracellular oxidative stress. In addition, compound 13 (20 mg/kg) and cis-14 (15 mg/kg) significantly exhibited antitumor activity in mouse xenograft model of human lung cancer. Conclusion: We synthesized a novel set of mono-adduct fullerene derivatives functionalized with pyridinium groups and found that most of them show potent antiproliferative activities against cancer cell lines and some of them show significant antitumor activities in vivo. We propose that these fullerene derivatives serve as the lead compounds for a novel type of antitumor agents.
Potent and Selective Human Neuronal Nitric Oxide Synthase Inhibition by Optimization of the 2-Aminopyridine-Based Scaffold with a Pyridine Linker
Wang, Heng-Yen,Qin, Yajuan,Li, Huiying,Roman, Linda J.,Martásek, Pavel,Poulos, Thomas L.,Silverman, Richard B.
supporting information, p. 4913 - 4925 (2016/06/13)
Neuronal nitric oxide synthase (nNOS) is an important therapeutic target for the treatment of various neurodegenerative disorders. A major challenge in the design of nNOS inhibitors focuses on potency in humans and selectivity over other NOS isoforms. Here we report potent and selective human nNOS inhibitors based on the 2-aminopyridine scaffold with a central pyridine linker. Compound 14j, the most promising inhibitor in this study, exhibits excellent potency for rat nNOS (Ki = 16 nM) with 828-fold n/e and 118-fold n/i selectivity with a Ki value of 13 nM against human nNOS with 1761-fold human n/e selectivity. Compound 14j also displayed good metabolic stability in human liver microsomes, low plasma protein binding, and minimal binding to cytochromes P450 (CYPs), although it had little to no Caco-2 permeability.
