- Selective, Catalytic, and Dual C(sp3)-H Oxidation of Piperazines and Morpholines under Transition-Metal-Free Conditions
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By using cheap and innocuous reagents, such as NaClO2, NaOCl, and catalytic amounts of TEMPO, a new environmentally friendly protocol for the selective and catalytic TEMPO C(sp3)-H oxidation of piperazines and morpholines to 2,3-diketopiperazines (2,3-DKP) and 3-morpholinones (3-MPs), respectively, has been developed. This novel direct access to 2,3-DKP from piperazines provides significant advantages over the traditional N-monoacylation/intramolecular C-N cyclization procedure. Additionally, by modulating the amounts of TEMPO, 2-alkoxyamino-3-morpholinone can be prepared from morpholine derivatives, which would enable further functionalization at the C2 position of the morpholine skeleton.
- Chamorro-Arenas, Delfino,Osorio-Nieto, Urbano,Quintero, Leticia,Hernández-García, Luís,Sartillo-Piscil, Fernando
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p. 15333 - 15346
(2019/01/03)
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- Mild Hydrogenation of Amides to Amines over a Platinum-Vanadium Bimetallic Catalyst
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Hydrogenation of amides to amines is an important reaction, but the need for high temperatures and H2 pressures is a problem. Catalysts that are effective under mild reaction conditions, that is, lower than 30 bar H2 and 70 °C, have not yet been reported. Here, the mild hydrogenation of amides was achieved for the first time by using a Pt-V bimetallic catalyst. Amide hydrogenation, at either 1 bar H2 at 70 °C or 5 bar H2 at room temperature was achieved using the bimetallic catalyst. The mild reaction conditions enable highly selective hydrogenation of various amides to the corresponding amines, while inhibiting arene hydrogenation. Catalyst characterization showed that the origin of the catalytic activity for the bimetallic catalyst is the oxophilic V-decorated Pt nanoparticles, which are 2 nm in diameter.
- Mitsudome, Takato,Miyagawa, Kazuya,Maeno, Zen,Mizugaki, Tomoo,Jitsukawa, Koichiro,Yamasaki, Jun,Kitagawa, Yasutaka,Kaneda, Kiyotomi
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supporting information
p. 9381 - 9385
(2017/08/01)
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- Carbon dioxide transformation in imidazolium salts: Hydroaminomethylation catalyzed by Ru-complexes
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The catalytic species generated by dissolving Ru3(CO)12 in the ionic liquids 1-n-butyl-3-methyl-imidazolium chloride or 1-n-butyl-2,3-dimethyl-imidazolium chloride are efficient multifunctional catalysts for: (a) reverse water-gas shift, (b) hydroformylation of alkenes, and (c) reductive amination of aldehydes. Thus the reaction of alkenes with primary or secondary amines (alkene/amine, 1:1) under CO2/H2 (1:1) affords the hydroamino-methylations products in high alkene conversions (up to 99%) and selectivities (up to 96%). The reaction proceeds under relatively mild reaction conditions (120 °C, 60 bar = 6 MPa) and affords selectively secondary and tertiary amines. The presence of amine strongly reduces the alkene hydrogenation competitive pathway usually observed in the hydroformylation of terminal alkenes by Ru complexes. The catalytic system is also highly active for the reductive amination of aldehydes and ketones yielding amines in high yields (> 90%).
- Ali, Meher,Gual, Aitor,Ebeling, Gunter,Dupont, Jairton
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p. 2129 - 2134
(2017/07/25)
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- Selective hydroaminomethylation of olefins using simple and efficient Rh-phosphinite complex catalyst
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Hydroaminomethylation of various olefins with primary and secondary amines was carried out using a simple and efficient rhodium-phosphinite complex catalyst. The influence of various reaction parameters including the effects of temperature, pressure, catalyst loading, time and solvents has been investigated. The present protocol is general with wider substrate applicability for the synthesis of an important class of aliphatic amines and arylethylamines. High activity and selectivity for amines was achieved with a very good substrate/catalyst molar ratio (turnover number 2500) under mild reaction conditions. Copyright
- Khan, Shoeb R.,Bhanage, Bhalchandra M.
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p. 711 - 715
(2013/12/04)
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- Aminomethylation of organic halides promoted by zinc in protic medium
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Organic halides undergo smooth aminomethylation by secondary amines and aqueous formaldehyde promoted by metallic zinc under copper(I) catalysis. Good to excellent yields are obtained with primary, secondary, and tertiary iodides, allylic, propargylic, and benzylic bromides and with α-bromoesters. In most cases, DMSO is the best solvent, but dioxane is preferable for some more reactive halides. Additional experiments with radical quenchers and promoters and the use of 'radical clocks' indicate a stepwise reaction mechanism initiated by the attack of an alkyl radical to iminium ion.
- Estevam, Idália H. S.,Da Silva, Margarete F.,Bieber, Lothar W.
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p. 7601 - 7604
(2007/10/03)
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- Catalytic amination of aldehydes to amides
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Aldehydes react in a disproportionation reaction in the presence of rhodium catalysts to yield amines and amides. By adding N-methylmorpholine N-oxide as an oxidant in the presence of catalytic amounts of rhodium, the oxidative amination of aldehydes proceeds selectively to give the corresponding amide. Both aliphatic and aromatic aldehydes react with secondary amines to yield carboxylic acid amides in good to excellent yields.
- Tillack, Annegret,Rudloff, Ivo,Beller, Matthias
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p. 523 - 528
(2007/10/03)
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- N-Arylsulfonylamidines; Part 1. Synthesis of Tertiary Amines via Lithium Aluminium Hydride Reduction of N-Tosylamidines
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Tertiary N-tosylamidines are readily reduced by an equimolar amount of lithium aluminium hydride to the corresponding tertiary amines.
- Clerici, Francesca,Mare, Anna Di,Gelmi, Maria Luisa,Pocar, Donato
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p. 719 - 720
(2007/10/02)
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