- SYNTHESIS OF SOME NEW ARYLINDOLES
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New indole derivatives - 2-ethoxycarbonyl-5-(p-acetylphenyl)indole and para-substituted 2-diphenylindoles - key compounds for synthesis of new bisindoles, were synthesized from 4-acetyl-4'-nitrodiphenyl.
- Gogrichiani, E. O.,Chikvaidze, I. Sh.,Dzhibladze, L. I.,Tsotadze, M. B.,Samsoniya, Sh. A.,Suvorov, N. N.
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- Magnetic chitosan-functionalized cobalt-NHC: Synthesis, characterization and catalytic activity toward Suzuki and Sonogashira cross-coupling reactions of aryl chlorides
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Aryl chlorides are one of the most stable and available electrophiles, however, their coupling with nucleophiles remains a challenge in organic synthesis. Herein, we prepared a Cobalt-NHC (N-Heterocyclic carbene) complex anchored on magnetic chitosan nanoparticles and assayed its catalytic activity for the reactions of substituted phenylboronic acid and also phenlacetylene with derivatives of aryl chlorides. These reactions are of great importance since they are employed for the synthesis of unsymmetrical diarylethynes and biphenyls, which belong to a prime class of building blocks. The synthesized nanocatalyst was found to be highly efficient in Suzuki and Sonogashira coupling in terms of their activity and recyclability in polyethylene glycol (PEG) as a green reaction media under conditions of temperatures (70 and 100 °C) and Co loading (3 and 6 mol%). To the best of our knowledge, this is the first attempt of using cobalt-NHC complex for catalyzing the abovementioned reactions. Moreover, replacing the earth-abundant Cobalt-based catalyst as an alternative to high cost palladium make this approach promising from sustainable chemistry view.
- Hajipour, Abdol R.,Malek, Shaghayegh Sadeghi
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- A new cobalt triangular prism supramolecular flask: Encapsulation of a quinhydrone cofactor for hydrogenation of nitroarenes with high selectivity and efficiency
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A new M6L3 metal-organic triangular prism host Co–L1 was synthesized that contains a sufficiently large cavity for encapsulation of a quinhydrone (QHQ) electron transporter to form charge-transfer complexes for accelerating electron delivery. Through the strong coordinating ability of the ONP chelator, a suitable redox potential was obtained for the combination of light-driven proton reduction with the selective hydrogenation of nitro groups. The experimental results showed that the regulation of redox potential is very beneficial for hydrogen production and that the introduction of QHQ accelerates electron transfer and increases the reaction rate. Control experiments based on an inhibitor and a mononuclear compound resembling the cobalt corner of the triangular prism suggest enzyme-like behaviour. This synthetic platform, in which the supramolecular systems exhibit high activity and stability, provides an alternative strategy to selectively hydrogenate nitroarenes using light as a clean energy source.
- Zheng, Sijia,Zhao, Liang,Wei, Jianwei,He, Cheng,Liu, Guangzhou,Duan, Chunying
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- Structure-activity relationship study of E6 as a novel necroptosis inducer
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Necroptosis inducers represent a promising potential treatment for drug-resistant cancer. We herein describe the structure modification of E6, which was identified recently as a potent and selective necroptosis inducer. The studies described herein demonstrate for the first time that functionalized biphenyl derivatives possess necroptosis inducer activity. Furthermore, these studies have led to the identification of two promising compounds (5h and 5j) that can be used for further optimization studies as well as mechanism of action investigations.
- Mou, Jianfeng,Park, Ann,Cai, Yu,Yuan, Junying,Yuan, Chengye
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supporting information
p. 3057 - 3061
(2015/06/22)
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- Use of "homeopathic" ligand-free palladium as catalyst for aryl-aryl coupling reactions
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We have previously shown that the use of ligand-free palladium employing Pd(OAc)2 as catalyst precursor in the Heck reaction of aryl bromides is possible if low catalyst loadings, typically between 0.01-0.1 mol % are used. We have now tested this phenomenon, which we have dubbed " homeopathic" palladium, in biaryl formation using the Suzuki, the Negishi and the Kumada cross-coupling reactions. The Suzuki reaction of aryl bromides, both activated and deactivated, is possible using 0.02-0.05 mol % of Pd(OAc)2. In this reaction turnover frequencies up to 30,000 have been reached with activated substrates. Even aryl chlorides could be reacted if strongly electron-withdrawing substituents were present. The Negishi coupling with a variety of arylzinc halides was possible on aryl bromides containing electron-withdrawing substituents. The Kumada reaction only gave low yields of products under "homeopathic' conditions.
- Alimardanov, Asaf,Schmieder-Van De Vondervoort, Lizette,De Vries, Andre H. M.,De Vries, Johannes G.
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p. 1812 - 1817
(2007/10/03)
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- Microwave-assisted Suzuki-Miyaura reactions with an insoluble pyridine-aldoxime Pd-catalyst
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The preparation of a solid Pd(II)-precatalyst and its use in microwave-assisted Suzuki-Miyaura reactions in water is described. The precatalyst is obtained by treatment of 4-pyridine-aldoxime with Na 2PdCl4 and is insoluble in organic solvents as well as in water. Its robustness under microwave conditions and its insolubility allows simple reuse in 'teabags'.
- Solodenko, Wladimir,Sch?n, Uwe,Messinger, Josef,Glinschert, Anja,Kirschning, Andreas
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p. 1699 - 1702
(2007/10/03)
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