- General and selective synthesis of primary amines using Ni-based homogeneous catalysts
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The development of base metal catalysts for industrially relevant amination and hydrogenation reactions by applying abundant and atom economical reagents continues to be important for the cost-effective and sustainable synthesis of amines which represent highly essential chemicals. In particular, the synthesis of primary amines is of central importance because these compounds serve as key precursors and central intermediates to produce value-added fine and bulk chemicals as well as pharmaceuticals, agrochemicals and materials. Here we report a Ni-triphos complex as the first Ni-based homogeneous catalyst for both reductive amination of carbonyl compounds with ammonia and hydrogenation of nitroarenes to prepare all kinds of primary amines. Remarkably, this Ni-complex enabled the synthesis of functionalized and structurally diverse benzylic, heterocyclic and aliphatic linear and branched primary amines as well as aromatic primary amines starting from inexpensive and easily accessible carbonyl compounds (aldehydes and ketones) and nitroarenes using ammonia and molecular hydrogen. This Ni-catalyzed reductive amination methodology has been applied for the amination of more complex pharmaceuticals and steroid derivatives. Detailed DFT computations have been performed for the Ni-triphos based reductive amination reaction, and they revealed that the overall reaction has an inner-sphere mechanism with H2metathesis as the rate-determining step.
- Beller, Matthias,Chandrashekhar, Vishwas G.,Jagadeesh, Rajenahally V.,Jiao, Haijun,Murugesan, Kathiravan,Wei, Zhihong
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p. 4332 - 4339
(2020/05/18)
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- Ultra-small cobalt nanoparticles from molecularly-defined Co-salen complexes for catalytic synthesis of amines
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We report the synthesis of in situ generated cobalt nanoparticles from molecularly defined complexes as efficient and selective catalysts for reductive amination reactions. In the presence of ammonia and hydrogen, cobalt-salen complexes such as cobalt(ii)-N,N′-bis(salicylidene)-1,2-phenylenediamine produce ultra-small (2-4 nm) cobalt-nanoparticles embedded in a carbon-nitrogen framework. The resulting materials constitute stable, reusable and magnetically separable catalysts, which enable the synthesis of linear and branched benzylic, heterocyclic and aliphatic primary amines from carbonyl compounds and ammonia. The isolated nanoparticles also represent excellent catalysts for the synthesis of primary, secondary as well as tertiary amines including biologically relevant N-methyl amines.
- Beller, Matthias,Chandrashekhar, Vishwas G.,Gawande, Manoj B.,Jagadeesh, Rajenahally V.,Kalevaru, Narayana V.,Kamer, Paul C. J.,Senthamarai, Thirusangumurugan,Zbo?il, Radek
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p. 2973 - 2981
(2020/03/27)
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- The Rhodium Catalysed Direct Conversion of Phenols to Primary Cyclohexylamines
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Cyclohexylamines are important intermediates in chemical industry, which are currently produced from petrochemical sources. Phenols, however, are an attractive sustainable feedstock. We here demonstrate the transformation of phenols with ammonia to primary cyclohexylamines. In contrast to previously reported chemistry which used palladium catalysts, we here show that rhodium is an excellent catalyst for the formation of primary cyclohexylamines. Different parameters were studied and it was shown that the reaction is applicable to a scope of phenolic compounds providing high selectivity.
- Tomkins, Patrick,Valgaeren, Carlot,Adriaensen, Koen,Cuypers, Thomas,Vos, Dirk E. De
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p. 3689 - 3693
(2018/07/31)
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- 2-aminobenzoxazole derivatives and combinatorial libraries thereof
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The present invention relates to novel 2-aminobenzoxazole derivative compounds of the following formula: wherein R1 to R4 and Z have the meanings provided herein. The invention further relates to combinatorial libraries containing two or more such compounds, as well as methods of preparing 2-aminobenzoxazole derivative compounds.
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- Synthesis of N-[4-(alkyl)cyclohexyl]-substituted benzamides with anti-inflammatory and analgesic activities
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Two series of N-[4-(alkyl)cyclohexyl]-substituted benzamides, i.e. a series of N-[4-(tert-butyl)cyclohexyl]-substituted benzamides and a series of N-[4-(ethyl)cyclohexyl]-substituted benzamides, were synthesised and evaluated for their anti-inflammatory and analgesic potencies, and gastrointestinal irritation liability. Copyright (C) 1999 Elsevier Science S.A.
- Pau, Amedeo,Boatto, Gianpiero,Palomba, Michele,Asproni, Battistina,Cerri, Riccardo,Palagiano, Francesco,Filippelli, Walter,Falcone, Giuseppe,Motola, Giulia
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p. 524 - 532
(2007/10/03)
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- Zirconium-Catalyzed Oxidation of Primary Aliphatic Amines to Nitro Compounds with tert-Butyl Hydroperoxide
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Primary aliphatic amines are oxidized with tert-butyl hydroperoxide to the corresponding nitro compounds in 50-98% yield using Zr(Ot-Bu)4 as the catalyst. The CH-acidic nitro compounds are not epimerized under these reaction conditions.
- Krohn, Karsten,Kuepke, Jochen
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p. 679 - 682
(2007/10/03)
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- Substituted pyrimidines, process for their preparation, and their use as pesticides and fungicides
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The invention relates to compounds of the formula STR1 in which R1, R2, R3 and Q are as defined in the description, X is NH or oxygen and E is a bond or a 1- to 4-membered carbon chain, to a process for their preparation, to agents containing them, and to their use in the control of pests and as fungicides.
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- Tetraalkylated biscyclohexylamine derivatives
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New biscyclohexylamine derivatives represented by the following formula STR1 wherein R1 to R4 represent identical or different alkyl groups having 1 to 6 carbon atoms; X is a single bond, a divalent aliphatic straight-chain or branched-chain group having from 2 to 10 carbon atoms, a methylene group, when at least one of the substituents R1 to R4 has more than 1 carbon atom, a divalent cycloaliphatic group having from 6 to 12 carbon atoms, a divalent aliphatic straight-chain or branched-chain group with cycloaliphatic substituents having from 6 to 8 carbon atoms, a divalent straight-chain or branched-chain dialkyl cyclohexane group having from 8 to 12 carbon atoms and a divalent straight-chain or branched-chain dialkyl benzene group having from 8 to 12 carbon atoms.
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