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11.
Microemulsion of Tween‐80/n‐butylalcohol/H2O system was prepared, and the microemulsion region as well as the influence of temperature and concentration of NaCl on the region were determined with ternary diagrams. The O/W, W/O, and B.C. regions were divided by the conductance method. The particle diameters of microemulsions with different NaCl concentrations or microemulsion‐enveloping all‐trans retinoic acid (ATRA) were measured with dynamic light scattering in O/W region. The release rate of ATRA was studied with dialysis a bag‐ultraviolet spectrophotometers and the anticancer activity of ATRA in microemulsion was investigated with cancer cells H446. Results showed that O/W microemulsion forms when water content is over 64% in the mixture. The influences of temperature and salinity on microemulsion region were very slight, and even the particle diameter decreased very little with increasing salt and ATRA concentrations. The microemulsion‐enveloping ATRA possessed eminent sustaining release efficiencys and the efficiency was further confirmed with the growth inhibitory effect test on human cancer cells H446. 相似文献
12.
Ksenia Parkhomenko Jean-Baptiste Sortais Jean-Pierre Djukic Michel Pfeffer 《Tetrahedron letters》2010,51(5):822-825
Various cycloruthenated complexes were used as homogeneous catalysts for the atom-transfer radical addition of polyhalogenated compounds to several olefinic substrates. Yields obtained through conventional or microwave heating could reach high values (up to 98% with CBrCl3 and 88% with CCl4). 相似文献
13.
Transition metal-catalyzed atom transfer radical addition (ATRA) reactions are an effective and versatile strategy for constructing carbon–carbon bonds in organic synthesis. Typically, the metal center in this metal-assisted radical transformation undergoes a reversible redox process. In this work, a quintuply-bonded dinuclear complex, Mo2(N∧N)2 {N∧N = μ-κ2-CH[N(2,6-iPr2C6H3)]2}, has been investigated as potential catalyst for radical addition of CCl4 to 1-hexene by performing density functional theory (DFT) calculations. The study shows that the Mo2(N∧N)2-mediated radical addition reaction is computationally predicted to occur with acceptable activation energies, indicating that the Mo-Mo quintuple bond can be applied as an effective catalyst for this transformation under mild conditions. The whole reaction involves 3 steps, two of which are metal-mediated. Firstly, the C-Cl bond activiation catalyzed by Mo2(N∧N)2 to obtain Mo2(N∧N)2Cl and ·CCl3 radical; Then the ·CCl3 radical interacts with 1-hexene to get an addition, the addition product reacts with the Mo2(N∧N)2Cl to get the last product and regenerate the catalyst Mo2(N∧N)2. Both the thermodynamic and kinetic study show that the second step is the rate-determine step. When coordinating solvent pyridine is added to the catalytic reaction, the reaction is suppressed due to their high energies barriers, which is consistent with experimental results. 相似文献
14.
Kazuki Matsuo Tadashi Yoshitake Eiji Yamaguchi Akichika Itoh 《Molecules (Basel, Switzerland)》2021,26(22)
We have developed a photochemical ATRA/ATRC reaction that is mediated by halogen bonding interactions. This reaction is caused by the reaction of malonic acid ester derivatives containing bromine or iodine with unsaturated compounds such as alkenes and alkynes in the presence of diisopropylethylamine under visible light irradiation. As a result of various control experiments, it was found that the formation of complexes between amines and halogens by halogen-bonding interaction occurs in the reaction system, followed by the cleavage of the carbon–halogen bonds by visible light, resulting in the formation of carbon radicals. In this reaction, a variety of substrates can be used, and the products, cyclopentenes and cyclopentanes, were obtained by intermolecular addition and intramolecular cyclization. 相似文献
15.
Trifluoromethylchlorosulfonylation of Alkenes: Evidence for an Inner‐Sphere Mechanism by a Copper Phenanthroline Photoredox Catalyst 下载免费PDF全文
Dattatraya B. Bagal Dr. Georgiy Kachkovskyi Matthias Knorn Thomas Rawner Prof. Dr. Bhalchandra M. Bhanage Prof. Dr. Oliver Reiser 《Angewandte Chemie (International ed. in English)》2015,54(24):6999-7002
A visible‐light‐mediated procedure for the unprecedented trifluoromethylchlorosulfonylation of unactivated alkenes is presented. It uses [Cu(dap)2]Cl as catalyst, and contrasts with [Ru(bpy)3]Cl2, [Ir(ppy)2(dtbbpy)]PF6, or eosin Y that exclusively give rise to trifluoromethylchlorination of the same alkenes. It is assumed that [Cu(dap)2]Cl plays a dual role, that is, acting both as an electron transfer reagent as well as coordinating the reactants in the bond forming processes. 相似文献
16.
Malte Gallhof Lukas Kell Prof. Malte Brasholz 《Chemistry (Weinheim an der Bergstrasse, Germany)》2020,26(8):1772-1775
Ruthenium(II) alkylidene complexes such as the Grubbs’ 1st and 2nd generation catalysts undergo a ligand substitution with 2,2′-bipyridine, which readily leads to the common photoredox catalyst Ru(bpy)32+. The application of this catalyst transformation in sequential olefin metathesis/photoredox catalysis is demonstrated by way of ring-closing metathesis (RCM)/photoredox ATRA reactions. 相似文献