- Cobalt encapsulated in N?doped graphene sheet for one-pot reductive amination to synthesize secondary amines
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To develop an efficient base-metal reductive amination catalyst for synthesis of secondary amines is still a major challenge. In this study, an efficient N-doped graphene sheet-coated cobalt catalyst (Co@CN-800) was developed through a simple pyrolysis process, which could gave 99.5 % yield of N-benzylaniline by one-pot reductive amination of nitrobenzene with benzaldehyde during at least 5 cycles. Catalyst characterization and control experiments confirmed that the robust catalytic performance of the catalyst is probably due to the synergy effect of in situ generated Co-Nx encapsulated in N?doped graphene layer and appropriate meso-pore structure. Additionally, The substrate adaptability of the catalyst was proved since a variety of corresponding secondary amines were smoothly obtained under relatively mild conditions, which makes the secondary amine synthesis strategy based on Co@CN-800 shows excellent application prospect.
- Liu, Lin,Li, Wenxiu,Qi, Ran,Zhu, Qingqing,Li, Jing,Fang, Yuzhen,Kong, Xiangjin
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- Ruthenium(ii) complexes with N-heterocyclic carbene-phosphine ligands for theN-alkylation of amines with alcohols
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Metal hydride complexes are key intermediates forN-alkylation of amines with alcohols by the borrowing hydrogen/hydrogen autotransfer (BH/HA) strategy. Reactivity tuning of metal hydride complexes could adjust the dehydrogenation of alcohols and the hydrogenation of imines. Herein we report ruthenium(ii) complexes with hetero-bidentate N-heterocyclic carbene (NHC)-phosphine ligands, which realize smart pathway selection in theN-alkylated reactionviareactivity tuning of [Ru-H] species by hetero-bidentate ligands. In particular, complex6cbwith a phenyl wingtip group and BArF?counter anion, is shown to be one of the most efficient pre-catalysts for this transformation (temperature is as low as 70 °C, neat conditions and catalyst loading is as low as 0.25 mol%). A large variety of (hetero)aromatic amines and primary alcohols were efficiently converted into mono-N-alkylated amines in good to excellent isolated yields. Notably, aliphatic amines, challenging methanol and diamines could also be transformed into the desired products. Detailed control experiments and density functional theory (DFT) calculations provide insights to understand the mechanism and the smart pathway selectionvia[Ru-H] species in this process.
- Huang, Ming,Li, Yinwu,Lan, Xiao-Bing,Liu, Jiahao,Zhao, Cunyuan,Liu, Yan,Ke, Zhuofeng
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supporting information
p. 3451 - 3461
(2021/05/03)
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- Reductive amination of ketones/aldehydes with amines using BH3N(C2H5)3as a reductant
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Herein, we report the first example of efficient reductive amination of ketones/aldehydes with amines using BH3N(C2H5)3 as a catalyst and a reductant under mild conditions, affording various tertiary and secondary amines in excellent yields. A mechanistic study indicates that BH3N(C2H5)3 plays a dual function role of promoting imine and iminium formation and serving as a reductant in reductive amination. This journal is
- Zou, Qizhuang,Liu, Fei,Zhao, Tianxiang,Hu, Xingbang
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supporting information
p. 8588 - 8591
(2021/09/04)
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- Linear Hydroaminoalkylation Products from Alkyl-Substituted Alkenes
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The regioselective conversion of alkyl-substituted alkenes into linear hydroaminoalkylation products represents a strongly desirable synthetic transformation. In particular, such conversions of N-methylamine derivatives are of great scientific interest, because they would give direct access to important amines with unbranched alkyl chains. Herein, we present a new one-pot procedure that includes an initial alkene hydroaminoalkylation with an α-silylated amine substrate and a subsequent protodesilylation reaction that delivers linear hydroaminoalkylation products with high selectivity from simple alkyl-substituted alkenes. For that purpose, new titanium catalysts have been developed, which are able to activate the α-C?H bond of more challenging α-silylated amine substrates. In addition, a direct relationship between the ligand structure of the new catalysts and the obtained regioselectivity is described.
- Warsitz, Michael,Doye, Sven
-
supporting information
p. 15121 - 15125
(2020/10/23)
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- Direct N-Alkylation/Fluoroalkylation of Amines Using Carboxylic Acids via Transition-Metal-Free Catalysis
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A scalable protocol of direct N-mono/di-alkyl/fluoroalkylation of primary/secondary amines has been constructed with various carboxylic acids as coupling agents under the catalysis of a simple air-tolerant inorganic salt, K3PO4. Advantageous features include 100 examples, 10 drugs and drug-like amines, fluorinated complex tertiary amines, gram-scale synthesis and isotope-labelling amine, thus demonstrating the potential applicability in industry of this methodology. The involvement of relatively less reactive silicon-hydride compared with the traditional reactive metal-hydride or boron-hydride species required to reduce the amide intermediates presumably contributes to the remarkable functional group compatibility. (Figure presented.).
- Lu, Chunlei,Qiu, Zetian,Xuan, Maojie,Huang, Yan,Lou, Yongjia,Zhu, Yiling,Shen, Hao,Lin, Bo-Lin
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supporting information
p. 4151 - 4158
(2020/08/21)
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- MOF-derived Ni?NC catalyst: Synthesis, characterization, and application in one-pot hydrogenation and reductive amination
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MOF-derived catalysts with nickel nanoparticles (NPs) uniformly embedded in nitrogen doped carbon shells were developed by pyrolysis of nickel-based metal-organic frameworks (MOFs), in which amino groups were introduced to act as the nitrogen source and possible anchoring sites for Ni NPs. The resulting materials were characterized systematically. In the architecture of the catalysts, a core-shell structure was discovered, in which Ni NPs with a diameter of 6-7 nm were surrounded by N doped graphitic layers, indicating that the introduction of amino groups into precursors is beneficial to the dispersion of NPs. One-step hydrogenation and reductive amination (OHRA) is a promising route to produce secondary amines, which avoids tedious separation of intermediates. Accordingly, we applied the prepared composites as catalysts to OHRA of benzaldehyde with nitrobenzene. Among them, the catalyst pyrolyzed at 600 °C for 1.5 h exhibited the best catalytic performance (conversion: >99%, selectivity for N-benzylaniline: 97.96%) and excellent recyclability. N-doping remarkably promotes the dispersion and stability of Ni NPs, thus improving their catalytic activity and selectivity. Furthermore, the Ni-N species as well as synergism of Ni NPs and adjacent pyridinic N may also facilitate the activation of H2. And its excellent stability and recyclability can be attributed to the core-shell structure. The achieved success in MOF-derived nanocomposites may pave the way for further industrial applications.
- Li, Jiayi,Wang, Bowei,Qin, Yutian,Tao, Qin,Chen, Ligong
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p. 3726 - 3734
(2019/07/22)
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- Colloidal and Nanosized Catalysts in Organic Synthesis: XXIII. Reductive Amination of Carbonyl Compounds Catalyzed by Nickel Nanoparticles in a Plug-Flow Reactor
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Reductive amination of aldehydes and ketones with primary and secondary amines under catalysis with nickel nanoparticles supported on zeolite X, MgO, or activated carbon in the gas phase or in the gas-liquid system in a plug-flow reactor proceeds at atmospheric pressure of hydrogen with the formation of secondary or tertiary amines in high yield.
- Mokhov, V. M.,Nebykov, D. N.,Paputina, A. N.,Popov, Yu. V.,Shishkin, E. V.
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p. 2333 - 2340
(2020/02/25)
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- B(C6F5)3-Catalyzed Deoxygenative Reduction of Amides to Amines with Ammonia Borane
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The first B(C6F5)3-catalyzed deoxygenative reduction of amides into the corresponding amines with readily accessible and stable ammonia borane (AB) as a reducing agent under mild reaction conditions is reported. This metal-free protocol provides facile access to a wide range of structurally diverse amine products in good to excellent yields, and various functional groups including those that are reduction-sensitive were well tolerated. This new method is also applicable to chiral amide substrates without erosion of the enantiomeric purity. The role of BF3 ? OEt2 co-catalyst in this reaction is to activate the amide carbonyl group via the in situ formation of an amide-boron adduct. (Figure presented.).
- Pan, Yixiao,Luo, Zhenli,Han, Jiahong,Xu, Xin,Chen, Changjun,Zhao, Haoqiang,Xu, Lijin,Fan, Qinghua,Xiao, Jianliang
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supporting information
p. 2301 - 2308
(2019/01/30)
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- Ru-Catalyzed Deoxygenative Transfer Hydrogenation of Amides to Amines with Formic Acid/Triethylamine
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A ruthenium(II)-catalyzed deoxygenative transfer hydrogenation of amides to amines using HCO2H/NEt3 as the reducing agent is reported for the first time. The catalyst system consisting of [Ru(2-methylallyl)2(COD)], 1,1,1-tris(diphenylphosphinomethyl) ethane (triphos) and Bis(trifluoromethane sulfonimide) (HNTf2) performed well for deoxygenative reduction of various secondary and tertiary amides into the corresponding amines in high yields with excellent selectivities, and exhibits high tolerance toward functional groups including those that are reduction-sensitive. The choice of hydrogen source and acid co-catalyst is critical for catalysis. Mechanistic studies suggest that the reductive amination of the in situ generated alcohol and amine via borrowing hydrogen is the dominant pathway. (Figure presented.).
- Pan, Yixiao,Luo, Zhenli,Xu, Xin,Zhao, Haoqiang,Han, Jiahong,Xu, Lijin,Fan, Qinghua,Xiao, Jianliang
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supporting information
p. 3800 - 3806
(2019/07/12)
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- Borrowing Hydrogen-Mediated N-Alkylation Reactions by a Well-Defined Homogeneous Nickel Catalyst
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We report herein a well-defined and bench-stable azo-phenolate ligand-coordinated nickel catalyst which can efficiently execute N-alkylation of a variety of anilines by alcohol. We demonstrate that the redox-active azo ligand can store hydrogen generated during alcohol oxidation and redelivers the same to an in-situ-generated imine bond to result in N-alkylation of amines. The reaction has wide scope, and a large array of alcohols can directly couple to a variety of anilines. Mechanistic studies including deuterium labeling to the substrate establishes the borrowing hydrogen method from alcohols and pinpoints the crucial role of the redox-active azo moiety present on the ligand backbone. Isolation of the ketyl intermediate in its trapped form with a radical quencher and higher kH/kD for the alcohol oxidation step suggest altogether a hydrogen-atom transfer (HAT) to the reduced azo backbone to pave alcohol oxidation as opposed to the conventional metal-ligand bifunctional mechanism. This example clearly demonstrates that an inexpensive base metal catalyst can accomplish an important coupling reaction with the help of a redox-active ligand backbone.
- Bains, Amreen K.,Kundu, Abhishek,Yadav, Sudha,Adhikari, Debashis
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p. 9051 - 9059
(2019/10/02)
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- A bifunctional strategy for N-heterocyclic carbene-stabilized iridium complex-catalyzed: N -alkylation of amines with alcohols in aqueous media
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Through the strategy of combining bifunctional 2-hydroxypyridine and a thermally stable N-heterocyclic carbene ligand, an Ir-catalyzed N-monoalkylation reaction has been developed in aqueous media under base-free conditions. This reaction proceeds smoothly with high yields of various aromatic amines and sulfonamides with a wide range of primary alcohols. Experimental and computational studies revealed a metal-ligand cooperative mechanism and its thermal stability during the bifunctional catalysis in aqueous media.
- Huang, Ming,Li, Yinwu,Liu, Jiahao,Lan, Xiao-Bing,Liu, Yan,Zhao, Cunyuan,Ke, Zhuofeng
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supporting information
p. 219 - 224
(2019/01/28)
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- Catalytic Selective Oxidative Coupling of Secondary N-Alkylanilines: An Approach to Azoxyarene
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Azoxyarenes are among important scaffolds in organic molecules. Direct oxidative coupling of primary anilines provides a concise fashion to construct them. However, whether these scaffolds can be prepared from secondary N-alkylanilines is not well explored. Here, we present a catalytic selective oxidative coupling of secondary N-alkylaniline to afford azoxyarene with tungsten catalyst under mild conditions. In addition, azoxy can be viewed as a bioisostere of alkene and amide. Several "azoxyarene analogues" of the corresponding bioactive alkenes and amides showed comparable promising anticancer activities.
- Ke, Lei,Zhu, Guirong,Qian, Hui,Xiang, Guangya,Chen, Qin,Chen, Zhilong
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supporting information
p. 4008 - 4013
(2019/06/04)
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- Cu-mediated selective bromination of aniline derivatives and preliminary mechanism study
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A simple and efficient bromination of aniline, aniline derivatives, and analogs have been developed. Forty three examples were given and the highest yield reached was 98%. Different substrates including substituted aniline, pyridin-amine, N-substituted aniline, N,N-disubstituted aniline, N-phenyl-amide, N-phenyl-sulfonamide, and nitrogen-containing heterocycles were all reactive and selectively generated desired bromo-products. The method can be applied to synthesize drug intermediate and quinoxaline derivatives.
- Zhao, Hong-Yi,Yang, Xue-Yan,Lei, Hao,Xin, Minhang,Zhang, San-Qi
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supporting information
p. 1406 - 1415
(2019/05/01)
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- AuPd?Fe3O4 Nanoparticle Catalysts for Highly Selective, One-Pot Cascade Nitro-Reduction and Reductive Amination
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Exceedingly chemoselective preparation of secondary amines from the cascade reaction of nitro reduction followed by reductive amination of the resulting amine with an aldehyde through the use of bimetallic AuPd alloy nanoparticle catalyst is described. We prepared a AuPd alloy nanocatalyst supported on Fe3O4 in gram scale without calcination. One pot synthesis of a number of secondary amines was achieved from a variety of nitroarenes and aryl or alkyl aldehydes under 1 atm of H2 at room temperature. No N-debenzylation was observed in the case of the reactions involving aryl aldehydes, which is often observed in the reductive amination catalysed by a transition metal catalyst such as palladium. We also accomplished efficient one-pot synthesis of a number of N-aryl substituted isoindolinone derivatives from 1-formylbenzoic acid and several nitroarenes using the same reaction conditions. Furthermore, thanks to the magnetic property of the Fe3O4 support, the AuPd?Fe3O4 NPs could be easily separated and reused up to 20 times without the loss of its catalytic activity. (Figure presented.).
- Cho, Ahra,Byun, Sangmoon,Kim, B. Moon
-
supporting information
p. 1253 - 1261
(2018/02/21)
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- Highly Selective, Efficient Deoxygenative Hydrogenation of Amides Catalyzed by a Manganese Pincer Complex via Metal-Ligand Cooperation
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Deoxygenative hydrogenation of amides to amines homogeneously catalyzed by a complex of an Earth-abundant metal is presented. This manganese-catalyzed reaction features high efficiency and selectivity. A plausible reaction mechanism, involving metal-ligand cooperation of the manganese pincer complex, is proposed based on NMR studies and relevant stoichiometric reactions.
- Zou, You-Quan,Chakraborty, Subrata,Nerush, Alexander,Oren, Dror,Diskin-Posner, Yael,Ben-David, Yehoshoa,Milstein, David
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p. 8014 - 8019
(2018/09/06)
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- Reductive Amination by Photoredox Catalysis and Polarity-Matched Hydrogen Atom Transfer
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The excitation of a RuII photosensitizer in the presence of ascorbic acid leads to the reduction of iminium ions to electron-rich α-aminoalkyl radical intermediates, which are rapidly converted into reductive amination products by thiol-mediated hydrogen atom transfer (HAT). As a result, the reductive amination of carbonyl compounds with amines by photoredox catalysis proceeds in good to excellent yields and with broad substrate scope and good functional group tolerance. The three key features of this work are 1) the rapid interception of electron-rich α-aminoalkyl radical intermediates by polarity-matched HAT in a photoredox reaction, 2) the method of reductive amination by photoredox catalysis itself, and 3) the application of this new method for temporally and spatially controlled reactions on a solid support, as demonstrated by the attachment of a fluorescent dye on an activated cellulose support by photoredox-catalyzed reductive amination.
- Guo, Xingwei,Wenger, Oliver S.
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supporting information
p. 2469 - 2473
(2018/01/27)
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- One-pot Reductive Amination of carbonyl Compounds with Nitro Compounds by Transfer Hydrogenation over Co–Nx as catalyst
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A new method was developed for the synthesis of secondary amines through the one-pot reductive amination of carbonyl compounds with nitro compounds using formic acid as the hydrogen donor over a heterogeneous non-noble-metal catalyst (Co-Nx/C-800-AT, generated by the pyrolysis of the cobalt phthalocyanine/silica composite at 800°C under a N2 atmosphere and subsequent etching by HF). Both nitrogen and cobalt were of considerable importance in the transfer hydrogenation reactions with formic acid.
- Zhou, Peng,Zhang, Zehui
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p. 1892 - 1897
(2017/05/16)
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- One-pot reductive amination of carbonyl compounds with nitro compounds with CO/H2O as the hydrogen donor over non-noble cobalt catalyst
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The one-pot reductive amination of carbonyl compounds with nitro compounds over heterogeneous non-noble metal catalysts was developed for the first time by transfer hydrogenation with CO/H2O as the hydrogen donor. Nitrogen-doped carbon supported cobalt nanoparticles were observed to be active toward this reaction, affording structurally-diverse secondary amines with high yields. Kinetic studies revealed that the transfer hydrogenation of imines (C[dbnd]N bonds) was the rate-determining step. Reaction mechanism studies indicated that both nitrogen and cobalt nanoparticles were important for the transfer hydrogenation with CO/H2O to generate the proton (N[sbnd]H+) and hydride (Co[sbnd]H?) as the active species. Furthermore, the heterogeneous cobalt catalyst was highly stable without the loss of its catalytic activity during the recycling experiments.
- Zhou, Peng,Yu, Changlin,Jiang, Liang,Lv, Kangle,Zhang, Zehui
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p. 264 - 273
(2017/06/23)
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- Colloid and nanosized catalysts in organic synthesis: XVII. Reductive amination of carbonitriles in the presence of supported nickel nanoparticles
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Reductive amination of carbonitriles catalyzed by nickel nanoparticles applied onto a solid support in a plug flow reactor in the gas phase or the gas–liquid–solid catalyst system occurs at atmospheric pressure of hydrogen affording the nonsymmetrical secondary or tertiary amines. The effect of the support type on the target product yield and conversion of the substrate has been studied.
- Popov, Yu. V.,Mokhov,Latyshova,Panov,Shirkhanyan
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p. 2546 - 2551
(2017/12/26)
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- Colloid and nanosized catalysts in organic synthesis: XIV. Reductive amination and amidation of carbonitriles catalyzed by nickel nanoparticles
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Hydrogenation of carbonitriles catalyzed by nickel nanoparticles in the presence of primary amines led to the predominant formation of unsymmetrical secondary amines. In the presence of secondary amines hydrogenation of nitrites provided enamines as main products. Hydrogenation of nitriles in the presence of formamide or acetamide afforded formyl or acetyl derivatives of primary amines.
- Popov, Yu. V.,Mokhov,Shcherbakova
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p. 798 - 805
(2016/06/13)
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- Deoxygenative Hydrogenation of Amides Catalyzed by a Well-Defined Iridium Pincer Complex
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The iridium-catalyzed highly chemoselective hydrogenation of amides to amines has been developed. Using a well-defined iridium catalyst bearing a P(O)C(O)P pincer ligand combined with B(C6F5)3, the C-O cleavage products are formed under mild reaction conditions. The reaction provides a new method for the preparation of amines from amides in good yield with high selectivity.
- Yuan, Ming-Lei,Xie, Jian-Hua,Zhu, Shou-Fei,Zhou, Qi-Lin
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p. 3665 - 3669
(2016/07/06)
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- Boron Lewis Acid Promoted Ruthenium-Catalyzed Hydrogenation of Amides: An Efficient Approach to Secondary Amines
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The hydrogenation of amides to amines has been developed by using the catalyst [Ru(H)2(CO)(Triphos)] (Triphos=1,1,1-tri(diphenylphosphinomethyl)ethane) and catalytic boron Lewis acids such as B(C6F5)3 or BF3?Et2O as additives. The reaction provides an efficient method for the preparation of secondary amines from amides in good yields with high selectivity.
- Yuan, Ming-Lei,Xie, Jian-Hua,Zhou, Qi-Lin
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p. 3036 - 3040
(2016/10/11)
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- Cobalt-Catalyzed N-Alkylation of Amines with Alcohols
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A well-defined nonprecious metal cobalt(II) catalyst based on a pincer PNP ligand has been employed for the efficient N-alkylation of both aromatic and aliphatic amines with alcohols. A subtle change of reaction conditions (simply adding 4 ? molecular sieves) was observed to readily switch the resulting products (amines vs imines) with high chemoselectivity. A range of alcohols and amines including both aromatic and aliphatic substrates were efficiently converted to secondary amines in good-to-excellent yields when 2 mol % cobalt catalyst was used. Additional experiments indicate that a hydrogen-borrowing mechanism is responsible for the tandem acceptorless dehydrogenation/condensation/hydrogenation process.
- Zhang, Guoqi,Yin, Zhiwei,Zheng, Shengping
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supporting information
p. 300 - 303
(2016/02/03)
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- Pd/C as an Efficient and Reusable Catalyst for the Selective N-Alkylation of Amines with Alcohols
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An efficient Pd/C-catalyzed synthesis of secondary amines involving C-N bond formation was achieved from amines and alcohols with H2O as the only byproduct. This common, green, commercial, and cheap catalyst was recycled five times in this sustainable, simple, and economic procedure.
- Liu, Xiang,Hermange, Philippe,Ruiz, Jaime,Astruc, Didier
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p. 1043 - 1045
(2016/04/05)
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- AROMATIC COMPOUND
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Provided is a novel aromatic ring compound having a GPR40 agonist activity and a GLP-1 secretagogue action. A compound represented by the formula: wherein each symbol is as described in the DESCRIPTION, or a salt thereof has a GPR40 agonist activity and a GLP-1 secretagogue action, is useful for the prophylaxis or treatment of cancer, obesity, diabetes, hypertension, hyperlipidemia, cardiac failure, diabetic complications, metabolic syndrome, sarcopenia and the like, and affords superior efficacy.
- -
-
Paragraph 0532; 0533; 0815; 0816
(2016/05/19)
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- Programmed synthesis palladium supported on Fe3O4@C: An efficient and heterogeneous recyclable catalyst for one-pot reductive amination of aldehydes with nitroarenes in aqueous reaction medium
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A highly efficient Pd/Fe3O4@C catalytic system has been developed for direct reductive amination of carbonyl compounds with nitroarenes in aqueous reaction medium. The catalyst was characterized by TEM, XRD, XPS and VSM. It was found that the catalyst showed a high activity for the one-pot direct reductive amination of aldehydes with nitroarenes in the presence of molecular hydrogen at mild temperature. Besides, the catalyst could be recovered in a facile manner from the reaction mixture and recycled six times without obvious loss in activity.
- Zhou, Xingchun,Li, Xinzhe,Jiao, Lixin,Huo, Hongfei,Li, Rong
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p. 1591 - 1599
(2017/05/22)
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- Green synthesis and catalytic properties of palladium nanoparticles for the direct reductive amination of aldehydes and hydrogenation of unsaturated ketones
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This paper reports on the synthesis and use of palladium nanoparticles as heterogeneous catalysts for the reductive amination of aldehydes and hydrogenation of unsaturated ketones. This method has the advantages of high yields, simple methodology and easy work up. The catalyst can be recovered and reused several times without significant loss of catalytic activity. This journal is
- Nasrollahzadeh, Mahmoud
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p. 5544 - 5550
(2014/12/10)
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- Palladium supported on hollow magnetic mesoporous spheres as recoverable catalyst for one-pot reductive amination of aldehydes with nitroarenes under mild conditions
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We described here a method to stabilize Pd(0) on the surface of hollow magnetic mesoporous spheres (HMMS), with Fe3O4 nanoparticles embedded in the mesoporous shell. The catalyst was characterized by TEM, XRD and VSM. It was found that the catalyst showed a high activity for the one-pot direct reductive amination of aldehydes with nitroarenes in the presence of molecular hydrogen in ethanol, even at room temperature. Besides, the catalyst could be recovered in a facile manner from the reaction mixture and recycled six times without loss in activity.
- Zhou, Jinghui,Dong, Zhengping,Wang, Peng,Shi, Zhiqiang,Zhou, Xingchun,Li, Rong
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- Palladium supported on magnetic nanoparticles as recoverable catalyst for one-pot reductive amination of aldehydes with nitroarenes under ambient conditions
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A high-performance palladium-based catalyst has been prepared by the co-precipitation method. The catalyst was characterized by TEM, XRD, VSM and ICP. It was found that the catalyst showed a high activity for the one-pot direct reductive amination of aldehydes with nitroarenes in the presence of molecular hydrogen in ethanol, even at room temperature. Furthermore, the catalyst was easily recovered by applying an external magnet and reused for eight cycles without significant loss of activity.
- Wei, Shuoyun,Dong, Zhengping,Ma, Zongyan,Sun, Jian,Ma, Jiantai
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-
- Use of primary amines for the selective n-alkylation of anilines by a reusable heterogeneous catalyst
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Traditionally, anilines can be alkylated with reactive alkyl halides but now more safe reagents such as alcohols or even amines can be used. To overcome the limits of homogeneous catalysis for aniline N-alkylation, we have developed a protocol that employs simple Pd/C as a heterogeneous catalyst under microwave dielectric heating. The process, based on the easy Pd-mediated oxidation of primary amines to imines followed by aniline addition, is characterized by a high atom economy as ammonia is the only other product of the reaction. This kind of aniline alkylation with amines has been carried out both in ionic liquid medium using [bmim]PF6 or in a more traditional solvent such as THF where the catalyst could be successfully recycled more times. The reusability of the catalyst was further confirmed by using material recycled from the amination in a standard alkene hydrogenation without loss of efficiency. Georg Thieme Verlag Stuttgart New York.
- Linciano, Pasquale,Pizzetti, Marianna,Porcheddu, Andrea,Taddei, Maurizio
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p. 2249 - 2254
(2013/11/06)
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- Synchronizing steric and electronic effects in {RuII(NNNN,P)} complexes: The catalytic dehydrative alkylation of anilines by using alcohols as a case study
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A series of new hexacoordinated {RuII(NNNN,P)} complexes was prepared from [RuCl2(R3P)3]. Their structure was determined by X-ray crystallography. The catalytic potential of this new class of complexes was tested in the alkylation of aniline with benzyl alcohol. In this test reaction, the influence of the counteranion plus electronic influences at the tetradentate ligand and the phosphine ligand were examined. The electrochemistry of all complexes was studied by cyclic voltammetry. Depending on the substituent at the ligand backbone, the complexes showed a different behavior. For all N-benzyl substituted complexes, reversible Ru II/III redox potentials were observed, whereas the N-methyl substituted complex possessed an irreversible oxidation event at small scan rates. Furthermore, the electronic influence of different substituents at the ligand scaffold and at the phosphine on the RuII/III redox potential was investigated. The measured E0 values were correlated to the theoretically determined HOMO energies of the complexes. In addition, these HOMO energies correlated well with the reactivity of the single complexes in the alkylation of aniline with benzyl alcohol. The exact balance of redox potential and reactivity appears to be crucial for synchronizing the multiple hydrogen-transfer events. The optimized catalyst structure was applied in a screening on scope and limitation in the catalytic dehydrative alkylation of anilines by using alcohols.
- Weickmann, Daniel,Frey, Wolfgang,Plietker, Bernd
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supporting information
p. 2741 - 2748
(2013/03/14)
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- Selective N-alkylation of amines using nitriles under hydrogenation conditions: Facile synthesis of secondary and tertiary amines
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Nitriles were found to be highly effective alkylating reagents for the selective N-alkylation of amines under catalytic hydrogenation conditions. For the aromatic primary amines, the corresponding secondary amines were selectively obtained under Pd/C-catalyzed hydrogenation conditions. Although the use of electron poor aromatic amines or bulky nitriles showed a lower reactivity toward the reductive alkylation, the addition of NH4OAc enhanced the reactivity to give secondary aromatic amines in good to excellent yields. Under the same reaction conditions, aromatic nitro compounds instead of the aromatic primary amines could be directly transformed into secondary amines via a domino reaction involving the one-pot hydrogenation of the nitro group and the reductive alkylation of the amines. While aliphatic amines were effectively converted to the corresponding tertiary amines under Pd/C-catalyzed conditions, Rh/C was a highly effective catalyst for the N-monoalkylation of aliphatic primary amines without over-alkylation to the tertiary amines. Furthermore, the combination of the Rh/C-catalyzed N-monoalkylation of the aliphatic primary amines and additional Pd/C-catalyzed alkylation of the resulting secondary aliphatic amines could selectively prepare aliphatic tertiary amines possessing three different alkyl groups. According to the mechanistic studies, it seems reasonable to conclude that nitriles were reduced to aldimines before the nucleophilic attack of the amine during the first step of the reaction.
- Ikawa, Takashi,Fujita, Yuki,Mizusaki, Tomoteru,Betsuin, Sae,Takamatsu, Haruki,Maegawa, Tomohiro,Monguchi, Yasunari,Sajiki, Hironao
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supporting information; experimental part
p. 293 - 304
(2012/02/01)
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- Ruthenium(II) picolyl-NHC complexes: Synthesis, characterization, and catalytic activity in amine N-alkylation and transfer hydrogenation reactions
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Ruthenium(II) p-cymene complexes with picolyl-functionalized N-heterocyclic carbenes [(η6-p-cymene)Ru(L)(Cl)][PF6] (L = 3-methyl-1-(2-picolyl)imidazol-2-ylidene (1a), 3-isopropyl-1-(2-picolyl) imidazol-2-ylidene (1b), 3,4,5-trimethyl-1-(2-picolyl)imidazol-2-ylidene (1c), 3-mesityl-1-(2-picolyl)imidazol-2-ylidene (1d), 3-methyl-1-(2-picolyl) benzoimidazol-2-ylidene (1e), 3-methyl-1-(2-picolyl)-4,5-dichloroimidazol-2- ylidene (1f), 3-phenyl-1-(2-picolyl)imidazol-2-ylidene (1g)) have been synthesized and characterized. Compounds 1a-g were recrystallized, and X-ray crystal structures are reported for 1a,f. Furthermore, compounds 1a-f show catalytic activity in transfer hydrogenation of ketones and N-alkylation of amines. Notably, complexes 1a,c,f were found to be very efficient and versatile catalysts toward transfer hydrogenation of a wide range of ketones and imines in addition to N-alkylation of several amines.
- Fernandez, Francys E.,Puerta, M. Carmen,Valerga, Pedro
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p. 6868 - 6879
(2012/11/13)
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- Transition-metal-free electrophilic amination of arylboroxines
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A transition-metal-free strategy to construct C(sp2)-N bonds using arylboroxines and O-benzoyl hydroxylamines as coupling partners has been developed. This transformation provides a useful method to access various aromatic amines.
- Xiao, Qing,Tian, Leiming,Tan, Renchang,Xia, Ying,Qiu, Di,Zhang, Yan,Wang, Jianbo
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p. 4230 - 4233
(2012/09/22)
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- One-pot synthesis of aniline derivatives from nitroarenes under mild conditions promoted by a recyclable polymer-supported palladium catalyst
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This work describes the one-pot direct reductive amination of carbonyl compounds with nitroarenes promoted by a polymer supported palladium catalyst, in the presence of molecular hydrogen as the reductant. This methodology is applicable, with slight differences, to both aliphatic and aromatic aldehydes. The operational simplicity, the mild reaction conditions, the high yields and the good recyclability of the supported catalyst are major advantages of this method. TEM observations of the catalyst showed that the active species are palladium nanoparticles having a size distribution centered at 5 nm within the polymeric support.
- Dell'Anna, Maria Michela,Mastrorilli, Piero,Rizzuti, Antonino,Leonelli, Cristina
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scheme or table
p. 134 - 140
(2012/03/27)
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- Ruthenium-catalyzed reductive amination of allylic alcohols
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Straighforward access to various saturated amines from allylic alcohols and isostructural mixture can now be achieved in the presence of arene ruthenium catalyst featuring phosphinesulfonate ligand and a hydrogen donor.
- Sahli, Zeyneb,Sundararaju, Basker,Achard, Mathieu,Bruneau, Christian
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supporting information; experimental part
p. 3964 - 3967
(2011/09/21)
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- Practical one-pot synthesis of secondary amines by zinc-catalyzed reductive amination
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In the present study, the zinc-catalyzed reductive amination of various aldehydes has been examined in detail. Simple zinc(II) triflate was applied as hydrosilylation catalyst for the reduction of the in situ formed imine by condensation of an aldehyde with an amine. Using a practical Lewis acid catalyst and PMHS [poly(methylhydrosiloxane)] as cheap hydride source excellent yields and a broad functional group tolerance were achieved.
- Enthaler, Stephan
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experimental part
p. 55 - 61
(2011/10/05)
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- HETEROCYCLIC DERIVATIVE HAVING INHIBITORY ACTIVITY ON TYPE-I 11 -HYDROXYSTEROID DEHYDROGENASE
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Disclosed is a compound which is useful as an 11β-hydroxysteroid dehydrogenase type 1 inhibitor. A compound represented by the formula: its pharmaceutically acceptable salt, or a solvate thereof, wherein X is O or S, a broken line and a wavy line represent the presence or the absence of a bond, (i) when a broken line represents the presence of a bond, a wavy line represents the absence of a bond, R2 and R3 are each independently hydrogen, halogen, cyano, hydroxy, carboxy, optionally substituted alkyl, optionally substituted alkenyl, optionally substituted alkynyl or the like, (ii) when a broken line represents the absence of a bond, a wavy line represents the presence of a bond, R1 and R4 are each independently hydrogen, halogen or the like, R2 and R3 are each independently hydrogen, halogen, cyano, hydroxy, carboxy, optionally substituted alkyl, optionally substituted alkenyl, optionally substituted alkynyl or the like, and R5 and R6 are each independently hydrogen, optionally substituted alkyl, optionally substituted alkenyl, optionally substituted alkynyl or the like.
- -
-
Page/Page column 133-134
(2010/08/07)
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- Regioselective synthesis of heterocycles containing nitrogen neighboring an aromatic ring by reductive ring expansion using diisobutylaluminum hydride and studies on the reaction mechanism
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(Chemical Equation Presented) A systematic investigation of the reductive ring-expansion reaction of cyclic ketoximes fused to aromatic ringswith diisobutylaluminum hydride (DIBALH) is described. This reaction regioselectively afforded a variety of five- to eight-membered bicyclic heterocycles or tricyclic heterocycles containing nitrogen neighboring an aromatic ring, including indoline, 1,2,3,4,5,6-hexahydrobenz[b]azocine, 3,4-dihydro-2H-benzo[b] [1,4]oxazine, 2,3,4,5-tetrahydrobenzo[b][1,4]thiazepine, 1,2,3,4,5,6- hexahydroazepino[3,2-b]-indole, 2,3,4,5-tetrahydro-1H-benzothieno[2,3-b]azepine, 2,3,4,5-tetrahydro-1H-benzothieno[3,2-b]-azepine, 5,6-dihydrophenanthridine, and 5,6,11,12-tetrahydrodibenz[b, f]azocine. The reaction mechanism leading to the rearrangement was investigated on the basis of the restricted Becke three-parameter plus Lee-Yang-Parr (B3LYP) density functional theory (DFT) with the 6-31G (d) basis set. It was found that the reaction proceeds through a three-centered transition state via a stepwise mechanism because the potential energy curve along the intrinsic reaction coordinate (IRC) had twomaxima (saddle points; TS1 and TS2) and the partial phenonium cation intermediate C. In addition to cyclic ketoximes fused to aromatic rings, the reactions of various cyclic and acyclic ketoximeswere examined to investigate preference of migrating group. It was found that themore electron-rich group migrated preferentially to give the corresponding secondary amines.
- Cho, Hidetsura,Iwama, Yusuke,Sugimoto, Kenji,Mori, Seiji,Tokuyama, Hidetoshi
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experimental part
p. 627 - 636
(2010/04/29)
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- Direct one-pot reductive amination of aldehydes with nitroarenes in a domino fashion: Catalysis by gum-acacia-stabilized palladium nanoparticles
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(Figure Presented) This note describes the direct reductive amination of carbonyl compounds with nitroarenes using gum acacia-palladiumnanoparticles, employing molecular hydrogenas the reductant. This methodology is found to be applicable to both aliphatic and aromatic aldehydes and a wide range of nitroarenes. The operational simplicity and the mild reaction conditions add to the value of this method as a practical alternative to the reductive amination of carbonyl compounds.
- Sreedhar,Surendra Reddy,Keerthi Devi
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supporting information; experimental part
p. 8806 - 8809
(2010/03/01)
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- Pentavalent organoantimony compounds as mild N-arylating agents for amines: Cu-mediated ullmann-type N-arylation with tetraarylantimony(V) acetates
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Simple and mild Cu-mediated arylation of various amines by use of tetraarylantimony acetate (Ar4SbOAc) is described. The Ullmann-type condensation of Ar4SbOAc with aliphatic and electron rich aromatic amines proceeded efficiently in
- Qin, Weiwei,Kakusawa, Naoki,Wu, Yichen,Yasuike, Shuji,Kurita, Jyoji
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scheme or table
p. 436 - 438
(2009/12/25)
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- Palladium-catalyzed amination of aryl and heteroaryl tosylates at room temperature
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Mild palladium-catalyzed aminations of aryl tosylates and the first aminations of heteroaryl tosylates are described. In the presence of the combination of L2Pd(0) (L = P(o-tol)3) and the hindered Josiphos ligand CyPF-t-Bu, a variety of primary alkylamines and arylamines react with both aryl and heteroaryl tosylates at room temperature to form the corresponding secondary arylamines in high yields with complete selectivity for the monoarylamine. These reactions at room temperature occur in many cases with catalyst loadings of 0.1 mol % and 0.01 mol % in one case, constituting the most efficient aminations of aryl tosylates by nearly 2 orders of magnitude. This catalyst is made practical by the development of a convenient method to synthesize the L2Pd(0) precursor. This complex is stable to air as a solid. In contrast to conventional relative rates for reactions of aryl sulfonates, the reactions of aryl tosylates are faster than parallel reactions of aryl triflates, and the reactions of aryl tosylates are faster than parallel or competitive reactions of aryl chlorides. Copyright
- Ogata, Tokutaro,Hartwig, John F.
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supporting information; experimental part
p. 13848 - 13849
(2009/02/07)
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- Behaviour of enaminomalonates and enamidomalonates under various reductive conditions: a novel synthetic approach to N-acetyl-N-aryl β-amino acids
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The behaviour of enaminomalonates and their deprotection to amines under various reductive conditions is described. A new synthetic approach to N-aryl-N-acetyl-β-amino acids using heterogeneous catalytic hydrogenation has been discovered.
- Sol?an, Tomá?,Jakubec, Pavol,Prónayová, Nade?da,Milata, Viktor
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p. 2631 - 2633
(2008/09/19)
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- One-pot reductive mono-N-alkylation of aniline and nitroarene derivatives using aldehydes
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(Chemical Equation Presented) One-pot reductive mono-N-alkylation of aniline and nitroarene derivatives using various aldehydes by Pd/C catalyst in aqueous 2-propanol solvent with ammonium formate as in situ hydrogen donor is illustrated. The reaction proceeded smoothly and selectively with excellent yield at room temperature. Our protocol presents a facile, economical, and environmentally benign alternative for reductive amination.
- Byun, Eunyoung,Hong, Bomi,De Castro, Kathlia A.,Lim, Minkyung,Rhee, Hakjune
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p. 9815 - 9817
(2008/03/27)
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- Direct reductive amination of carbonyl compounds using bis(triphenylphosphine) copper(I) tetrahydroborate
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A direct reductive amination protocol for aldehydes/ketones using bis(triphenylphosphine) copper(I) tetrahydroborate as a novel reducing agent in the presence of sulfamic acid has been developed. The reagent chemoselectively reduces the imine moiety and does not affect other reducible functionalities such as chloro, nitro, cyano and methoxy.
- Bhanushali, Mayur J.,Nandurkar, Nitin S.,Bhor, Malhari D.,Bhanage, Bhalchandra M.
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p. 1273 - 1276
(2007/10/03)
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- Copper-catalyzed electrophilic amination of organozinc nucleophiles: Documentation of O-benzoyl hydroxylamines as broadly useful R2N(+) and RHN(+) synthons
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This paper details new copper-catalyzed electrophilic amination reactions of diorganozinc reagents using O-benzoyl hydroxylamines as electrophilic nitrogen sources that may be accessed in one step. Simple and functionalized aryl, heteroaryl-, benzyl, n-alkyl, sec-alkyl, and tert-alkyl nucleophiles couple with R2NOC(O)Ph and RHNOC(O)Ph reagents in the presence of catalytic quantities of copper salts to provide tertiary and secondary amines, respectively, in generally good yields. In many cases, the product may be isolated analytically pure after a simple extractive workup. The amination process is shown to tolerate a significant degree of steric demand. The amination of nominally unreactive Caryl-H bonds via a sequential directed ortho metalation/transmetalation/catalytic amination reaction sequence is detailed. The direct Cu-catalyzed amination of Grignard reagents using cocatalysis by ZnCl2 is described.
- Herman, Ashley M.,Johnson, Jeffrey S.
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p. 219 - 224
(2007/10/03)
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- Synthesis of bulky and electron-rich MOP-type ligands and their applications in palladium-catalyzed C-N bond formation
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A series of 2-dialkylphosphino-2′-alkoxy-1,1′-binaphthyl ligands (6a-c and 8a-c) have been prepared conveniently by a lithium-initiated ring-opening reaction of dinaphthofuran, followed by selective phosphorylation. These compounds displayed a remarkable air and moisture stability, both in solid form and in solution. Application of these phosphine ligands in palladium-catalyzed C-N bond forming reactions revealed the crucial roles of the steric bulk of the substituents on the phosphorus atom governing the catalytic activity. Specifically, 2-di-tert-butylphosphino-2′-isopropoxy-1,1′- binaphthyl (8b) proved to be the most effective for the aminations of aryl halides with primary amines, while the less bulky 2-dicyclohexyl-2′- methoxy-1,1′-binaphthyl (6a) was more effective for the aminations with secondary amines. The steric and electronic effects of the ligands were analyzed to account for these observations.
- Xie, Xiaomin,Zhang, Tony Y.,Zhang, Zhaoguo
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p. 6522 - 6529
(2007/10/03)
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- Highly reactive, general, and long-lived catalysts for coupling heteroaryl and aryl chlorides with primary nitrogen nucleophiles
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Resisting pathways for decomposition followed by palladium complexes of monodentate ligands is one characteristic of the highly reactive but long-lived catalyst generated from the Josiphos ligand L and palladium. It catalyzes under mild conditions the coupling of primary amines with chloropyridines and chloroarenes in high yield with low catalyst loadings (see scheme).
- Shen, Qilong,Shekhar, Shashank,Stambuli, James P.,Hartwig, John F.
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p. 1371 - 1375
(2007/10/03)
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- Microwave-accelerated methodology for the direct reductive amination of aldehydes
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(Chemical Equation Presented) An improved procedure for the direct reductive amination of aldehydes was developed which uses dibutyltin dichloride as catalyst in the presence of phenylsilane as reductant. Rapid reaction is promoted by the use of microwave conditions with anilines, secondary and primary amines being suitable reactants.
- Kangasmetsae, Jussi J.,Johnson, Tony
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p. 5653 - 5655
(2007/10/03)
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- Reductive and catalytic monoalkylation of primary amines using nitriles as an alkylating reagent
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(Chemical Equation Presented) A selective and catalytic mono-N-alkylation method of both aromatic and aliphatic amines using nitriles as an alkylating agent with Pd/C or Rh/C as a catalyst is described. This method is particularly attractive to provide an environmentally benign and applicable alkylation method of amines without using toxic and corrosive alkylating agents such as alkyl halides and carbonyl compounds.
- Sajiki, Hironao,Ikawa, Takashi,Hirota, Kosaku
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p. 4977 - 4980
(2007/10/03)
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