- Direct synthesis of nitriles by Cu/DMEDA/TEMPO-catalyzed aerobic oxidation of primary amines with air
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By screening the copper catalysts, ligands, and the reaction conditions, a simple CuCl/DMEDA/TEMPO catalyst system readily available from commercial sources is developed for a direct and selective synthesis of the useful nitriles by an aerobic oxidation reaction of primary amines using air as an advantageous oxidant under mild conditions.
- Ma, Xian-Tao,Xu, Hao,Xiao, Ying-Lin,Su, Chen-Liang,Liu, Jian-Ping,Xu, Qing
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p. 1336 - 1339
(2017/06/21)
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- Hydrogenation of heteroaromatic nitriles and aromatic dinitriles by heterogeneous or homogeneous ruthenium catalysts derived from [Ru3(CO)12]
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The use of the complex [Ru3(CO)12] (1) as a catalyst precursor (0.1?mol%) at 200?°C, 60?psi of H2, along with triphenylphosphine (TPP) generated ruthenium nanoparticles (Ru-Nps); this occurred in the presence of pyridine-nitriles leading to a variety of hydrogenation (secondary amine, imine, or imidazole) products, depending of the pyridine-nitrile used, under similar reaction conditions. This relates to relatively good to modest yields, determined by the substituents in the corresponding pyridine. In sharp contrast, the use of aromatic dinitriles did not generate Ru-Nps at 140?°C, 150?psi of H2 and TPP, but allowed the homogeneous catalytic hydrogenation of the 1,4- and 1,3-dicyanobenzenes, to yield the corresponding CN-substituted secondary amine or imine. The main products were characterized by different analytical methods and spectroscopic techniques.
- García, Juventino J.,Pérez-Lezama, Nora,Arévalo, Alma
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- Heterogeneously catalyzed self-condensation of primary amines to secondary amines by supported copper catalysts
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Self-condensation of primary amines to symmetrically substituted secondary amines could efficiently be promoted by an inexpensive supported copper catalyst, Cu/Al2O3, easily prepared by the reduction of the hydroxide precursor, Cu(OH)x/Al2O3. Various kinds of structurally diverse primary amines including benzylamine, picolylamine, and aliphatic amine derivatives could selectively be converted into the corresponding secondary amines in moderate to excellent yields without any cocatalysts such as bases and stabilizing ligands in 1 atm of Ar or H 2. The reactions in H2 showed higher selectivities to desired secondary amines than those in Ar. The roles of H2 are the promotion of hydrogenation of N-alkylimines and the stabilization of active Cu(0) species. In addition, in the presence of Cu/Al2O3, unsymmetrically substituted secondary amines could efficiently be synthesized by N-alkylation of primary amines with alcohols and reductive amination of aldehydes. The observed catalysis was truly heterogeneous, and the retrieved Cu/Al2O3 catalyst could be reused for self-condensation without a significant loss of its catalytic performance. The reaction mechanism involving dehydrogenation of primary amines and condensation to N-alkylimines followed by hydrogenation, the so-called "borrowing hydrogen pathway", has been proposed. The Royal Society of Chemistry 2013.
- Kim, Insu,Itagaki, Shintaro,Jin, Xiongjie,Yamaguchi, Kazuya,Mizuno, Noritaka
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p. 2397 - 2403
(2013/09/02)
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- Selective cross-coupling of amines by alumina-supported palladium nanocluster catalysts
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Al2O3-supported Pd nanoclusters with an average particle size of 1.8 nm act as a reusable catalyst for the selective cross-coupling of amines. The reaction is a structure-sensitive reaction, demanding coordinatively unsaturated Pd atoms on a metallic nanocluster. The support also affects the activity, an amphoteric oxide (Al2O 3) is most effective. The Royal Society of Chemistry.
- Shimizu, Ken-Ichi,Shimura, Katsuya,Ohshima, Keiichiro,Tamura, Masazumi,Satsuma, Atsushi
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supporting information; experimental part
p. 3096 - 3100
(2011/12/04)
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