排序方式: 共有23条查询结果,搜索用时 15 毫秒
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Dr. Pavel Ryabchuk Thomas Leischner Dr. Carsten Kreyenschulte Dr. Anke Spannenberg Dr. Kathrin Junge Prof. Dr. Matthias Beller 《Angewandte Chemie (Weinheim an der Bergstrasse, Germany)》2020,132(42):18838-18844
A bifunctional 3d-metal catalyst for the cascade synthesis of diverse pyrroles from nitroarenes is presented. The optimal catalytic system Co/NGr-C@SiO2-L is obtained by pyrolysis of a cobalt-impregnated composite followed by subsequent selective leaching. In the presence of this material, (transfer) hydrogenation of easily available nitroarenes and subsequent Paal–Knorr/Clauson-Kass condensation provides >40 pyrroles in good to high yields using dihydrogen, formic acid, or a CO/H2O mixture (WGSR conditions) as reductant. In addition to the favorable step economy, this straightforward domino process does not require any solvents or external co-catalysts. The general synthetic utility of this methodology was demonstrated on a variety of functionalized substrates including the preparation of biologically active and pharmaceutically relevant compounds, for example, (+)-Isamoltane. 相似文献
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Dilip K. Dutta 《合成通讯》2013,43(13):1903-1906
Azoxy compounds have been prepared in good yields by reductive coupling of aromatic nitro compounds with manganese and a catalytic amount of acetic acid in aqueous conditions. 相似文献
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Wei-Guo Jia Zhi-Bao Wang Xue-Ting Zhi Jia-Qin Han Ying Sun 《Journal of Coordination Chemistry》2017,70(5):848-858
Four ruthenium(II) p-cymene complexes with naphthalene-based Schiff base ligands [Ru(p-cymene)LCl] (2a–2d) have been synthesized and characterized. The half-sandwich ruthenium complexes were characterized by 1H and 13C NMR spectra, elemental analyses, and infrared spectrometry. The molecular structures of 2a, 2b, and 2c were confirmed by single-crystal X-ray diffraction. Furthermore, these half-sandwich ruthenium complexes are highly active catalysts for the hydrogenation of nitroarenes to anilines using NaBH4 as the reducing agent in ethanol at room temperature. 相似文献
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Synthesis of diaryl sulfides via nickel ferrite‐catalysed C─S bond formation in green media 下载免费PDF全文
NiFe2O4 magnetic nanoparticles (MNPs) were synthesized, characterized and applied as an air‐stable, inexpensive and magnetically separable nanocatalyst for the synthesis of structurally diverse sulfides. Efficient methodologies were developed for the synthesis of unsymmetric diaryl sulfides via odourless and one‐pot reactions of triphenyltin chloride/S8 or arylboronic acid/S8 as thiolating agents with aryl halides or nitroarenes as starting materials in the presence of base (K2CO3 or NaOH) and NiFe2O4 MNPs as a catalyst in water or poly (ethylene glycol) as solvent at 80–110 °C. Free from ligand and the unpleasant smell of thiols and with the use of magnetically reusable nanocatalyst, green solvents and commercially available and cheap sulfur source and starting materials, these methods are more eco‐friendly and practical than available protocols for the synthesis of sulfides. 相似文献
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Changlong Wang Dr. Roberto Ciganda Dr. Lionel Salmon Dr. Danijela Gregurec Dr. Joseba Irigoyen Dr. Sergio Moya Dr. Jaime Ruiz Prof. Didier Astruc 《Angewandte Chemie (International ed. in English)》2016,55(9):3091-3095
A ligand design is proposed for transition metal nanoparticle (TMNP) catalysts in aqueous solution. Thus, a tris(triazolyl)‐polyethylene glycol (tris‐trz‐PEG) amphiphilic ligand, 2 , is used for the synthesis of very small TMNPs with Fe, Co, Ni, Cu, Ru, Pd, Ag, Pt, and Au. These TMNP‐ 2 catalysts were evaluated and compared for the model 4‐nitrophenol reduction, and proved to be extremely efficient. High catalytic efficiencies involving the use of only a few ppm metal of PdNPs, RuNPs, and CuNPs were also exemplified in Suzuki–Miyaura, transfer hydrogenation, and click reactions, respectively. 相似文献
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开发了一种温和高效的以甲醇为氢源,以Ru-Fe双金属催化剂催化的硝基芳烃连续化转移加氢方法。采用浸渍法制备Ru-Fe双金属催化剂,通过电感耦合等离子体-质谱(ICP-MS)、透射电子显微镜(TEM)、X射线衍射(XRD)、氢气程序升温还原(H2-TPR)对催化剂进行表征。结果表明催化剂具有较小的粒径和较好的分散性。在Ru-Fe双金属催化剂上,成功实现了硝基芳烃与甲醇在无外加氢源条件下的连续化转移加氢合成芳胺。通过对反应条件的调控,成功得到了一系列产率较高的胺类化合物。特别地,该方法对不饱和基团(醛基、羰基或炔基)取代的硝基芳烃的加氢表现出优异的选择性和转化率。 相似文献
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In this study, magnetically nanoparticles of CuFe2O4@SiO2@PTMS@Tu@Ni(II) as novel and reusable catalyst were prepared. Synthesis of the Ni (II)‐nanocatalyst was carried out through the complexation of Ni(OAc)2·4H2O with the immobilized thiourea on silica‐layered CuFe2O4. The prepared nanocomposite system was then characterized using SEM, EDX, XRD, VSM, ICP‐OES, Raman, UV–Vis and FT‐IR analyses. Catalytic activity of the Ni(II)‐CuFe2O4 system was investigated towards rapid reduction of aromatic nitro compounds to arylamines with sodium borohydride as well as one‐pot reductive‐acetylation of nitroarenes to acetanilides with NaBH4/Ac2O system without the isolation of intermediate arylamines. All reactions were carried out in H2O within 3–7 min to afford the products arylamines/acetanilides in high to excellent yields. Reusability of the Ni(II)‐nanocatalyst was examined for seven consecutive cycles without the significant loss of the catalytic activity. 相似文献
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A dipalladium complex [Pd2( L )Cl2](PF6)2 ( 2 ), via the substitution of (PhCN)2PdCl2 with 5‐phenyl‐2,8‐bis(6′‐bipyridinyl)‐1,9,10‐anthyridine ( L ) followed by the anion exchange, was found to be a good pre‐catalyst for the reduction of nitroarenes to yield the corresponding anilines under atmospheric pressure of hydrogen in methanol. This method provides a straightforward access to a diverse array of functionalized anilines, exhibiting a possible application in synthetic chemistry. The catalytic activity of this complex is enhanced by the di‐metallic system via the synergistic effect. 相似文献