The reaction of perfluoroalkylcopper with 4-iodophthalonitrile provides a convenient route to fluorinated phthalonitriles which readily form phthalocyanines in the presence of stannous chloride dihydrate.During the course of preparing 4-perfluoroheptylphthalonitrile , a secondary reaction was observed when the reaction time was extended beyond two hours. This reaction involves the interaction of the orthodinitrile with copper and/or cuprous iodide to afford the phthalocyanine nucleus. This coaction is portrayed by the appearance of a green color in the reaction media. 相似文献
In a previous paper (Bagnost et al., J Chromatogr B Analyt Technol Biomed Life Sci 853:38–46, 2007), an arginase chromatographic support was developed to study the association mechanism of arginase (an enzyme which can reduce endothelial dysfunction and blood pressure rising in spontaneously hypertensive rats) with nor-NOHA a potential inhibitor of its activity. In this report mutagenesis experiments associated with this biochromatographic approach confirmed that the active-site residue Hist 141 is protonated as imidazolium cation. Hist 141 could function as a general acid to protonate the leaving amino group of l-ornithine during catalysis. 相似文献
Recently, we reported a significant solvent effect on the phosphorus hyperfine coupling constant aP in β-phosphorylated 6-membered ring nitroxides (?aP = 24 G in Org. Biomol. Chem. 2015). Thus, it led us to investigate the effect of solvent for several 6-membered ring nitroxides. Although smaller than mentioned above, a change of 5–7 G in aP with the polarity of solvent was still observed for these nitroxides. As for other β-phosphorylated nitroxides, aN increases with the polarity/polarizability π* and the Hydrogen Bond Donating α properties of the solvent whereas aP exhibits the reverse trends. The change of aP with the solvent depends a lot on a subtle interplay between the destabilizing steric hindrance due to the bulkiness of the substituents and the stabilizing hyperconjugation interactions SOMO → σ*C–P between the anti-bonding orbitals of the C–P bond and the SOMO. 相似文献
ATP-binding cassette transporter A1 (ABCA1) mediates the lipidation of exchangeable apolipoproteins, the rate-limiting step
in the formation of high density lipoproteins (HDL). We previously demonstrated that HDL oxidized ex vivo by peroxidase-generated
tyrosyl radical (tyrosylated HDL, tyrHDL) increases the availability of cellular cholesterol for efflux and reduces the development
of atherosclerosis when administered to apolipoprotein E-deficient mice as compared to treatment with control HDL. 相似文献
Nowadays, scientists are increasingly asked to investigate problems, which require the analysis of irregular, chaotic, non-stationary and corrupted time series. Assessing the causal relations between such signals is particularly challenging and, in many instances, interventions and experiments are impossible or impractical. The present work is a contribution to the development of indicators to quantify the mutual influences between time series. The criterion is called Cross Markov Matrix and belongs to the strand of techniques based on the conversion of time series into complex networks and the subsequent analysis of their topological properties. The proposed indicator is quite competitive with the available tools and can complement them very effectively. Indeed, all techniques have their strong and weak points and therefore corroborating the conclusions with mathematically independent methods is a recommended practice. The properties of the Cross Markov Matrix have been investigated with the help of a systematic series of numerical tests using synthetic data. The potential of the approach is then substantiated by the analysis of various real-life examples, ranging from environmental and global climate problems to the mutual influence between media coverage of Brexit and the pound-euro exchange rate.