- Hydrogenation Properties of Nanostructured Tungsten Carbide Catalysts in a Continuous-Flow Reactor
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Tungsten monocarbide (WC) obtained through a urea glass route showed a high activity and chemoselectivity for the continuous-flow reduction of a variety of nitro compounds under milder conditions than those reported previously. The favorable effect of the nanostructure was shown by comparison with other commercially available WC materials. Moreover, WC functioned as an efficient support for Ni nanoparticles. This expanded its range of applicability and led to a bimetallic Ni@WC composite characterized by a high activity for the hydrogenation of cardanol, a phenolic lipid obtained from cashew nut shells.
- Braun, Max,Esposito, Davide
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- Nanopalladium on amino-functionalized mesocellular foam as an efficient and recyclable catalyst for the selective transfer hydrogenation of nitroarenes to anilines
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Herein, we report on the use of nanopalladium on amino-functionalized siliceous mesocellular foam as an efficient heterogeneous catalyst for the transfer hydrogenation of nitroarenes to anilines. In all cases, the protocol proved to be highly selective and favored the formation of the desired aniline as the single product in high yields with short reaction times if naturally occurring and renewable γ-terpinene was employed as the hydrogen donor. Furthermore, the catalyst displayed excellent recyclability over five cycles and negligible leaching of metal into solution, which makes it an eco-friendly and economic catalyst to perform this transformation. The scalability of the protocol was demonstrated with the reduction of 4-nitroanisole on a 2 g scale, in which p-anisidine was isolated in 98 % yield. Copyright
- Verho, Oscar,Nagendiran, Anuja,Tai, Cheuk-Wai,Johnston, Eric V.,Baeckvall, Jan-E.
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- N-doped carbon supported Pd catalysts for N-formylation of amines with CO2/H2
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Using mesoporous N-doped carbons (NCs) derived from glucose and melamine as the supports, a series of Pd/NC catalysts were prepared, in which Pd nanoparticles with average size2 and H2 in ethanol without any additives. Especially, the catalyst Pd/NC-800-6.9% containing quaternary N showed the best performance, affording a series of formylamides in good or even excellent yields. Further investigation reveals that the interaction between the Pd nanoparticles and quaternary nitrogen in the NC support was responsible for the good performance of the catalyst.
- Luo, Xiaoying,Zhang, Hongye,Ke, Zhengang,Wu, Cailing,Guo, Shien,Wu, Yunyan,Yu, Bo,Liu, Zhimin
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- Fe3O4 nanoparticles: A conveniently reusable catalyst for the reduction of nitroarenes using hydrazine hydrate
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A magnetic personality: Commercially available Fe3O4 nanoparticles were utilized for efficient nitroarene reductions, and could be recycled up to 10 times using magnetic separation, whilst retaining activity (99 % aniline yield in each case without any side-products). Excellent chemoselectivity for reduction of the nitro versus other functional groups, such as halogen, ester, O-benzyl, and N-Cbz groups, was observed.
- Kim, Seyoung,Kim, Eunsuk,Kim, B. Moon
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- The chemistry of N,N-bis(trialkylsilyloxy)enamines 2. Alkylation of primary amines with N,N-bis(trimethylsilyloxy)enamines
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The reactions of primary amines with N,N-bis(trimethylsilyloxy)enamines can give products of both mono- and bis-α-oximinoalkylation of primary amines. The steric restrictions in both reactants substantially retard bis-α-oximinoalkylation. A general method for the synthesis of α-amino-substituted oximes from primary amines and bis-silyl derivatives of aliphatic nitro compounds was developed.
- Makarenkova,Bliznets,Ioffe,Strelenko,Tartakovsky
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- PHOTODETOSYLATION OF SULFONAMIDES INITIATED BY ELECTRON TRANSFER FROM AN ANIONIC SENSITIZER
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A new and efficient photosensitized process for the detosylation of a wide variety of sulfonamides is presented.The excited β-naphthoxide anion is used as sensitizer, in methanol as solvent.Electron transfer from the excited naphthoxide anion to the electron-accepting sulfonamide leads, in the presence of sodium borohydride, to the recovering of amines after cleavage of the radical anion.
- Art, J. F.,Kestemont, J. P.,Soumillion, J. Ph.
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- A biocatalytic cascade for the conversion of fatty acids to fatty amines
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Fatty amine synthesis from renewable sources is an energetically-demanding process involving toxic metal catalysts and harsh reaction conditions as well as selectivity problems. Herein we present a mild, biocatalytic alternative to the conventional amination of fatty acids through a one-pot tandem cascade performed by a carboxylic acid reductase (CAR) and a transaminase (ω-TA). Saturated and unsaturated fatty acids, with carbon chain lengths ranging from C6 to C18, were successfully aminated obtaining conversions of up to 96%.
- Citoler, Joan,Derrington, Sasha R.,Galman, James L.,Bevinakatti, Han,Turner, Nicholas J.
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- Depolymerization of Technical-Grade Polyamide 66 and Polyurethane Materials through Hydrogenation
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Chemical recycling provides a promising solution to utilize plastic waste. Here, a catalytic hydrogenative depolymerization of polyamide 66 (PA 66) and polyurethane (PU) was developed. The system employed Ru pincer complexes at high temperature (200 °C) in THF solution, and even technical-grade polymers could be hydrogenated with satisfactory yields under these conditions. A comparison of the system with some known heterogeneous catalysts as well as catalyst poisoning tests supported the homogeneity of the system. These results demonstrate the potential of chemical recycling to regain building blocks for polymers and will be interesting for the further development of polymer hydrogenation.
- Zhou, Wei,Neumann, Paul,Al Batal, Mona,Rominger, Frank,Hashmi, A. Stephen K.,Schaub, Thomas
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- Elucidation of reaction scheme describing malondialdehyde - Acetaldehyde - Protein adduct formation
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Malondialdehyde and acetaldehyde react together with proteins and form hybrid protein conjugates designated as MAA adducts, which have been detected in livers of ethanol-fed animals. Our previous studies have shown that MAA adducts are comprised of two distinct products. One adduct is composed of two molecules of malondialdehyde and one molecule of acetaldehyde and was identified as the 4-methyl-1,4-dihydropyridine-3,5-dicarbaldehyde derivative of an amino group (MDHDC adduct). The other adduct is a 1:1 adduct of malondialdehyde and acetaldehyde and was identified as the 2-formyl-3-(alkylamino)butanal derivative of an amino group (FAAB adduct). In this study, information on the mechanism of MAA adduct formation was obtained, focusing on whether the FAAB adduct serves as a precursor for the MDHDC adduct. Upon the basis of chemical analysis and NMR spectroscopy, two initial reaction steps appear to be a prerequisite for MDHDC formation. One step involves the reaction of one molecule of malondialdehyde and one of acetaldehyde with an amino group of a protein to form the FAAB product, while the other step involves the generation of a malondialdehyde - enamine. It appears that generation of the MDHDC adduct requires the FAAB moiety to be transferred to the nitrogen of the MDA - enamine. For efficient reaction of FAAB with the enamine to take place, additional experiments indicated that these two intermediates likely must be in positions on the protein of close proximity to each other. Further studies showed that the incubation of liver proteins from ethanol-fed rats with MDA resulted in a marked generation of MDHDC adducts, indicating the presence of a pool of FAAB adducts in the liver of ethanol-fed animals. Overall, these findings show that MDHDC - protein adduct formation occurs via the reaction of the FAAB moiety with a malondialdehyde - enamine, and further suggest that a similar mechanism may be operative in vivo in the liver during prolonged ethanol consumption.
- Tuma,Kearley,Thiele,Worrall,Haver,Klassen,Sorrell
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- REDUCTION D'AZIDES EN AMINES PAR LE FORMIATE D'AMMONIUM PAR "TRANSFERT D'HYDROGENE CATALYSE" (CTH)
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The azides are reduced to amines in very good yields by "Catalytic Transfer Hydrogenation" (CTH) using ammonium formate.
- Gartiser, T.,Selve, C.,Delpuech, J.-J.
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- Method for preparing primary amine by catalytically reducing nitrile compounds through nano-porous palladium catalyst
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The invention belongs to the technical field of heterogeneous catalysis, and provides a method for preparing primary amine by catalytically reducing nitrile compounds with a nano-porous palladium catalyst. According to the invention, aromatic and aliphatic nitrile compounds are adopted as raw materials, nano-porous palladium is adopted as a catalyst, ammonia borane is adopted as a hydrogen source, no additional additive is added, and selective hydrogenation is performed to prepare the corresponding primary amine. The method provided by the invention has the beneficial effects of mild reaction conditions, no additive, environmental protection, no need of hydrogen, simple operation, stable hydrogen source, safety, harmlessness, high conversion rate, high selectivity and good catalyst stability, and makes industrialization possible.
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Paragraph 0101-0104
(2021/05/29)
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- Indirect reduction of CO2and recycling of polymers by manganese-catalyzed transfer hydrogenation of amides, carbamates, urea derivatives, and polyurethanes
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The reduction of polar bonds, in particular carbonyl groups, is of fundamental importance in organic chemistry and biology. Herein, we report a manganese pincer complex as a versatile catalyst for the transfer hydrogenation of amides, carbamates, urea derivatives, and even polyurethanes leading to the corresponding alcohols, amines, and methanol as products. Since these compound classes can be prepared using CO2as a C1 building block the reported reaction represents an approach to the indirect reduction of CO2. Notably, these are the first examples on the reduction of carbamates and urea derivatives as well as on the C-N bond cleavage in amides by transfer hydrogenation. The general applicability of this methodology is highlighted by the successful reduction of 12 urea derivatives, 26 carbamates and 11 amides. The corresponding amines, alcohols and methanol were obtained in good to excellent yields up to 97%. Furthermore, polyurethanes were successfully converted which represents a viable strategy towards a circular economy. Based on control experiments and the observed intermediates a feasible mechanism is proposed.
- Liu, Xin,Werner, Thomas
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p. 10590 - 10597
(2021/08/20)
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- Method for preparing amine through catalytic reduction of nitro compound by cyclic (alkyl) (amino) carbene chromium complex
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The cyclic (alkyl) (amino) carbene chromium complex is prepared from corresponding ligand salt, alkali and CrCl3 and used for catalyzing pinacol borane to reduce nitro compounds in an ether solvent under mild conditions to generate corresponding amine. The method for preparing amine has the advantages of cheap and accessible raw materials, mild reaction conditions, wide substrate application range, high selectivity and the like, and is simple to operate.
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Paragraph 0015
(2021/04/17)
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- Zirconium-hydride-catalyzed site-selective hydroboration of amides for the synthesis of amines: Mechanism, scope, and application
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Developing mild and efficient catalytic methods for the selective synthesis of amines is a longstanding research objective. In this respect, catalytic deoxygenative amide reduction has proven to be promising but challenging, as this approach necessitates selective C–O bond cleavage. Herein, we report the selective hydroboration of primary, secondary, and tertiary amides at room temperature catalyzed by an earth-abundant-metal catalyst, Zr-H, for accessing diverse amines. Various readily reducible functional groups, such as esters, alkynes, and alkenes, were well tolerated. Furthermore, the methodology was extended to the synthesis of bio- and drug-derived amines. Detailed mechanistic studies revealed a reaction pathway entailing aldehyde and amido complex formation via an unusual C–N bond cleavage-reformation process, followed by C–O bond cleavage.
- Han, Bo,Jiao, Haijun,Wu, Lipeng,Zhang, Jiong
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p. 2059 - 2067
(2021/09/02)
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- Highly selective synthesis of primary amines from amide over Ru-Nb2O5 catalysts
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Amines are an important class of compounds in natural products and medicines. The universal availability of amides provides a potential way for the synthesis of amines. Herein, Ru/Nb2O5 catalyst is demonstrated to be highly efficient and stable for the selective hydrogenation of propionamide to propylamine (as a model reaction), with up to 91.4% yield of propylamine under relatively mild conditions. Results from XPS analyses, CO chemisorption, TEM images and DRIFTS spectra revealed that the unique properties of Nb2O5 can effectively activate the C=O group of amides, and the smaller Ru particles on Nb2O5 could further promote the activation, leading to superior catalytic performance of Ru/Nb2O5 for amide hydrogenation. Meanwhile, reducing the surface acidity of Nb2O5 can greatly inhibit the side reactions to by-products, and further enhance the selectivity to amine. Moreover, this catalytic system is also applicable for the hydrogenation of a variety of amides and provides high potential for the industrial production of primary amines from amides.
- Guo, Wanjun,Guo, Yong,Jia, Hongyan,Liu, Xiaohui,Pan, Hu,Wang, Yangang,Wang, Yanqin,Xia, Qineng
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- Deoxygenative hydroboration of primary, secondary, and tertiary amides: Catalyst-free synthesis of various substituted amines
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Transformation of relatively less reactive functional groups under catalyst-free conditions is an interesting aspect and requires a typical protocol. Herein, we report the synthesis of various primary, secondary, and tertiary amines through hydroboration of amides using pinacolborane under catalyst-free and solvent-free conditions. The deoxygenative hydroboration of primary and secondary amides proceeded with excellent conversions. The comparatively less reactive tertiary amides were also converted to the corresponding N,N-diamines in moderate yields under catalyst-free conditions, although alcohols were obtained as a minor product.
- An, Duk Keun,Jaladi, Ashok Kumar,Kim, Hyun Tae,Yi, Jaeeun
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- Direct Enzymatic Synthesis of Fatty Amines from Renewable Triglycerides and Oils
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Fatty amines represent an important class of commodity chemicals which have broad applicability in different industries. The synthesis of fatty amines starts from renewable sources such as vegetable oils or animal fats, but the process has multiple drawbacks that compromise the overall effectiveness and efficiency of the synthesis. Herein, we report a proof-of-concept biocatalytic alternative towards the synthesis of primary fatty amines from renewable triglycerides and oils. By coupling a lipase with a carboxylic acid reductase (CAR) and a transaminase (TA), we have accomplished the direct synthesis of multiple medium and long chain primary fatty amines in one pot with analytical yields as high as 97 %. We have also performed a 75 mL preparative scale reaction for the synthesis of laurylamine from trilaurin, obtaining 73 % isolated yield.
- Bevinakatti, Han,Citoler, Joan,Finnigan, William,Turner, Nicholas J.
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- Recurrent Approximation of Retention Parameters of N-Substituted p-Toluenesulfonamides in Reversed-Phase High Performance Liquid Chromatography for Revealing the Formation of Their Hydrates
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Abstract: Recurrent approximation of retention times in reversed-phase high performance liquid chromatography (RP-HPLC), tR(C + ΔC) = atR(C) + b, where C is the acetonitrile concentration in the eluent, and ΔC is the constant “step” of its variation, for six specially synthesized N-substituted p-toluenesulfonamides confirmed the presence of anomalies previously revealed for some complex polyfunctional organic compounds. The reason for these anomalies is the presence of sulfonamide –SO2–NH fragments in the molecules, which leads to hydration of sorbates in aqueous solutions, or, more precisely, to a change in the ratio of their non-hydrated and hydrated forms because of a shift in the equilibrium Х + Н2О $$ rightleftarrows $$ Х·Н2О (*) as a result of a change in the eluent composition. The same effect is indicated by the strong antibatic dependence of the retention indices RI(C) of all sulfonamides under study; the coefficients dRI/dC vary from –1.9 to –4.0, these values being much higher in magnitude than for compounds that do not form hydrates. Further independent evidence in favor of the transformation of sorbates due to variation of the eluent composition is the dependence of the relative absorbance Arel = A(254)/A(220) on the acetonitrile content in the eluent. This suggests changes in the chemical nature of chromophores in sulfonamide molecules depending on the equilibrium state (*).
- Kornilova, T. A.,Nikitina, D. A.,Zenkevich, I. G.
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p. 1931 - 1941
(2021/09/15)
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- A cobalt phosphide catalyst for the hydrogenation of nitriles
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The study of metal phosphide catalysts for organic synthesis is rare. We present, for the first time, a well-defined nano-cobalt phosphide (nano-Co2P) that can serve as a new class of catalysts for the hydrogenation of nitriles to primary amines. While earth-abundant metal catalysts for nitrile hydrogenation generally suffer from air-instability (pyrophoricity), low activity and the need for harsh reaction conditions, nano-Co2P shows both air-stability and remarkably high activity for the hydrogenation of valeronitrile with an excellent turnover number exceeding 58000, which is over 20- to 500-fold greater than that of those previously reported. Moreover, nano-Co2P efficiently promotes the hydrogenation of a wide range of nitriles, which include di- and tetra-nitriles, to the corresponding primary amines even under just 1 bar of H2 pressure, far milder than the conventional reaction conditions. Detailed spectroscopic studies reveal that the high performance of nano-Co2P is attributed to its air-stable metallic nature and the increase of the d-electron density of Co near the Fermi level by the phosphidation of Co, which thus leads to the accelerated activation of both nitrile and H2. Such a phosphidation provides a promising method for the design of an advanced catalyst with high activity and stability in highly efficient and environmentally benign hydrogenations. This journal is
- Jitsukawa, Koichiro,Mitsudome, Takato,Mizugaki, Tomoo,Nakata, Ayako,Sheng, Min,Yamasaki, Jun
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p. 6682 - 6689
(2020/08/24)
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- Selective Room-Temperature Hydrogenation of Amides to Amines and Alcohols Catalyzed by a Ruthenium Pincer Complex and Mechanistic Insight
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We report a room-temperature protocol for the hydrogenation of various amides to produce amines and alcohols. Compared with most previous reports for this transformation, which use high temperatures (typically, 100-200 °C) and H2 pressures (10-100 bar), this system proceeds under extremely mild conditions (RT, 5-10 bar of H2). The hydrogenation is catalyzed by well-defined ruthenium-PNNH pincer complexes (0.5 mol %) with potential dual modes of metal-ligand cooperation. An unusual Ru-amidate complex was formed and crystallographically characterized. Mechanistic investigations indicate that the room-temperature hydrogenation proceeds predominantly via the Ru-N amido/amine metal-ligand cooperation.
- Ben-David, Yehoshoa,Kar, Sayan,Kumar, Amit,Leitus, Gregory,Milstein, David,Rauch, Michael
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p. 5511 - 5515
(2020/07/21)
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- Synthesis of oxalamides by acceptorless dehydrogenative coupling of ethylene glycol and amines and the reverse hydrogenation catalyzed by ruthenium
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A sustainable, new synthesis of oxalamides, by acceptorless dehydrogenative coupling of ethylene glycol with amines, generating H2, homogeneously catalyzed by a ruthenium pincer complex, is presented. The reverse hydrogenation reaction is also accomplished using the same catalyst. A plausible reaction mechanism is proposed based on stoichiometric reactions, NMR studies, X-ray crystallography as well as observation of plausible intermediates.
- Ben-David, Yehoshoa,Diskin-Posner, Yael,Milstein, David,Zhou, Quan-Quan,Zou, You-Quan
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p. 7188 - 7193
(2020/07/23)
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- One-pot reductive amination of carboxylic acids: a sustainable method for primary amine synthesis
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The reductive amination of carboxylic acids is a very green, efficient and sustainable method for the production of (bio-based) amines. However, with current technology, this reaction requires two to three reaction steps. Here, we report the first (heterogeneous) catalytic system for the one-pot reductive amination of carboxylic acids to amines, with solely H2 and NH3 as the reactants. This reaction can be performed with relatively cheap ruthenium-tungsten bimetallic catalysts in the green and benign solvent cyclopentyl methyl ether (CPME). Selectivities of up to 99% for the primary amine could be achieved at high conversions. Additionally, the catalyst is recyclable and tolerant for common impurities such as water and cations (e.g. sodium carboxylate).
- Coeck, Robin,De Vos, Dirk E.
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supporting information
p. 5105 - 5114
(2020/08/25)
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- Cerium-Catalyzed C-H Functionalizations of Alkanes Utilizing Alcohols as Hydrogen Atom Transfer Agents
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Modern photoredox catalysis has traditionally relied upon metal-to-ligand charge-transfer (MLCT) excitation of metal polypyridyl complexes for the utilization of light energy for the activation of organic substrates. Here, we demonstrate the catalytic application of ligand-to-metal charge-transfer (LMCT) excitation of cerium alkoxide complexes for the facile activation of alkanes utilizing abundant and inexpensive cerium trichloride as the catalyst. As demonstrated by cerium-catalyzed C-H amination and the alkylation of hydrocarbons, this reaction manifold has enabled the facile use of abundant alcohols as practical and selective hydrogen atom transfer (HAT) agents via the direct access of energetically challenging alkoxy radicals. Furthermore, the LMCT excitation event has been investigated through a series of spectroscopic experiments, revealing a rapid bond homolysis process and an effective production of alkoxy radicals, collectively ruling out the LMCT/homolysis event as the rate-determining step of this C-H functionalization.
- An, Qing,Chen, Yuegang,Liu, Weimin,Pan, Hui,Wang, Xin,Wang, Ziyu,Zhang, Kaining,Zuo, Zhiwei
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supporting information
p. 6216 - 6226
(2020/04/27)
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- Manganese catalyzed selective hydrogenation of cyclic imides to diols and amines
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Herein we report the selective hydrogenation of cyclic imides to diols and amines, homogeneously catalyzed for the first time by a complex of an earth-abundant metal, a manganese pincer complex. A plausible catalytic cycle is proposed based on informative mechanistic experiments.
- Das, Uttam Kumar,Janes, Trevor,Kumar, Amit,Milstein, David
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supporting information
p. 3079 - 3082
(2020/06/19)
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- Amination of aliphatic alcohols with urea catalyzed by ruthenium complexes: effect of supporting ligands
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In the present study, ruthenium-catalyzed amination of alcohols by urea as a convenient ammonia carrier in the presence of free diphosphine ligands has been described. A number of ruthenium-phosphine complexes have been studied among which, [(Cp)RuCl(dppe)] was found as an efficient catalyst for alcohol amination reaction. The crystal structures of two new half-sandwich ruthenium complexes, [(Cp)RuCl(dppe)] and [(C6H6)RuCl2(PHEt2)], were determined by X-ray crystallographic analysis. Also the effect of using different supporting phosphines, ratio of raw materials and reaction temperature on conversion and selectivity was investigated. Under optimum reaction conditions high conversion (98percent) and chemo-selectivity toward secondary amines were obtained.
- Dindar, Sara,Nemati Kharat, Ali
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- Method for preparing primary amine by catalyzing reductive amination of aldehyde ketone compounds
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The invention discloses a method for preparing primary amine by catalyzing reductive amination of aldehyde ketone compounds. The method comprises the following steps: 1) mixing nickel nitrate hexahydrate, citric acid and an organic solvent, carrying out heating and stirring until a colloidal material is obtained, drying the colloidal material, roasting the colloidal material in a protective atmosphere, pickling, washing and drying a roasted product, and performing a partial oxidation reaction on a dried product in an oxygen-nitrogen mixed atmosphere to obtain a catalyst for a reductive amination reaction; and 2) mixing aldehyde or ketone compounds, a methanol solution of ammonia and the reductive amination reaction catalyst, introducing hydrogen, and carrying out a reductive amination reaction. The method has the advantages of high primary amine yield, high selectivity, wide aldehyde ketone substrate range, short reaction time, mild reaction conditions, low cost, greenness, economicalperformance and the like; the used reductive amination reaction catalyst can be recycled more than 10 times, and the catalytic activity of the catalyst is not obviously changed in gram-level reactions; and the method is suitable for large-scale application.
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Paragraph 0027-0030; 0051-0055
(2020/05/30)
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- Anti-Markovnikov Hydroamination of Alkenes with Aqueous Ammonia by Metal-Loaded Titanium Oxide Photocatalyst
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A completely new route was established to synthesize valuable primary amines from alkenes by using aqueous ammonia, that is, a simple photocatalytic hydroamination of alkenes using aqueous ammonia with a metal-loaded TiO2 photocatalyst. Although the photochemical hydroamination prefers to form amines according to the Markovnikov rule, the new photocatalytic hydroamination gives anti-Markovnikov products predominantly. With an Au-loaded TiO2 photocatalyst, the amine yield reached up to 93% and the regioselectivity of anti-Markovnikov products was above 98%. The reaction mechanism was proposed for the new photocatalytic hydroamination.
- Park, Soyeong,Jeong, Jaeyoung,Fujita, Ken-Ichi,Yamamoto, Akira,Yoshida, Hisao
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supporting information
p. 12708 - 12714
(2020/08/21)
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- Facile synthesis of controllable graphene-co-shelled reusable Ni/NiO nanoparticles and their application in the synthesis of amines under mild conditions
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The primary objective of many researchers in chemical synthesis is the development of recyclable and easily accessible catalysts. These catalysts should preferably be made from Earth-abundant metals and have the ability to be utilised in the synthesis of pharmaceutically important compounds. Amines are classified as privileged compounds, and are used extensively in the fine and bulk chemical industries, as well as in pharmaceutical and materials research. In many laboratories and in industry, transition metal catalysed reductive amination of carbonyl compounds is performed using predominantly ammonia and H2. However, these reactions usually require precious metal-based catalysts or RANEY nickel, and require harsh reaction conditions and yield low selectivity for the desired products. Herein, we describe a simple and environmentally friendly method for the preparation of thin graphene spheres that encapsulate uniform Ni/NiO nanoalloy catalysts (Ni/NiO?C) using nickel citrate as the precursor. The resulting catalysts are stable and reusable and were successfully used for the synthesis of primary, secondary, tertiary, and N-methylamines (more than 62 examples). The reaction couples easily accessible carbonyl compounds (aldehydes and ketones) with ammonia, amines, and H2 under very mild industrially viable and scalable conditions (80 °C and 1 MPa H2 pressure, 4 h), offering cost-effective access to numerous functionalized, structurally diverse linear and branched benzylic, heterocyclic, and aliphatic amines including drugs and steroid derivatives. We have also demonstrated the scale-up of the heterogeneous amination protocol to gram-scale synthesis. Furthermore, the catalyst can be immobilized on a magnetic stirring bar and be conveniently recycled up to five times without any significant loss of catalytic activity and selectivity for the product.
- Cui, Zhibing,Liu, Jianguo,Liu, Qiying,Ma, Longlong,Singh, Thishana,Wang, Chenguang,Wang, Nan,Zhu, Yuting
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supporting information
p. 7387 - 7397
(2020/11/19)
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- Method for preparing substituted primary aliphatic amine
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The invention belongs to the fields of medicinal and natural compound chemical intermediates and related chemical technologies, and relates to a preparation method of substituted primary amine. The method adopts benzonitrile and its derivative as raw materials, takes nanoporous palladium as a catalyst, takes hydrogen as a hydrogen source, and performs selective hydrogenation to prepare the substituted primary amine. The molar concentration of benzonitrile and its derivative in a solvent is 0.01-2 mmol/mL, and the molar ratio of benzonitrile and its derivative to the catalyst is 1:0.01-1:0.5; the size pore skeleton of the nanoporous palladium is 1 nm to 50 nm; and the pressure of hydrogen gas is 0.1 to 20.0 MPa. The method has the beneficial effects that the obtained product has high selectivity, the reaction condition is very mild, no additives is needed, the operation and the post-treatment are simple, the catalyst reproducibility is good, the multi-time catalytic effect with repeateduse is not significantly reduced, and the method provides possibility for industrialization.
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Paragraph 0056-0064
(2019/01/21)
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- Continuous-Flow Hydrogenation and Reductive Deuteration of Nitriles: a Simple Access to α,α-Dideutero Amines
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A simple and efficient continuous flow methodology has been developed for hydrogenation and reductive deuteration of nitriles to yield primary amines and also valuable α,α-dideutero analogues. Raney nickel proved to be a useful catalyst for the transformation of a wide range of nitriles under reasonably mild conditions with excellent deuterium incorporation (>90 %) and quantitative conversion. Among known model compounds, three new deuterated primary amines were prepared. The large-scale synthesis of deuterated tryptamine was also carried out to deliver 1.1 g product under flow conditions.
- Mészáros, Rebeka,Peng, Bai-Jing,?tv?s, Sándor B.,Yang, Shyh-Chyun,Fül?p, Ferenc
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p. 1508 - 1511
(2019/11/03)
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- Green and convenient protocols for the efficient reduction of nitriles and nitro compounds to corresponding amines with NaBH4 in water catalyzed by magnetically retrievable CuFe2O4 nanoparticles
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Abstract: In this study, firstly, CuFe2O4 nanoparticles were prepared by a simple operation. The structure of the mentioned nanoparticles was characterized by Fourier transform infrared spectroscopy, X-ray diffraction, scanning electron microscopy, transmission electron microscopy, energy-dispersive X-ray spectroscopy, inductively coupled plasma-optical emission spectrometry, vibrating sample magnetometer and also Brunauer–Emmett–Teller and Barrett–Joyner–Halenda analyses. The prepared magnetically copper ferrite nanocomposite was successfully applied as a simple, cost-effective, practicable, and recoverable catalyst on the green, highly efficient, fast, base-free, and ligand-free reduction of nitriles and also on the affordable and eco-friendly reduction of nitro compounds with the broad substrate scope to the corresponding amines with NaBH4 in water at reflux in high to excellent yields. Graphical abstract: [Figure not available: see fulltext.].
- Zeynizadeh, Behzad,Mohammad Aminzadeh, Farkhondeh,Mousavi, Hossein
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- Cobalt nanoparticles anchoring on nitrogen doped carbon with excellent performances for transfer hydrogenation of nitrocompounds to primary amines and N-substituted formamides with formic acid
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Cobalt nanoparticles anchoring on nitrogen doped carbon derived from pyrolysis of a cobalt complex and chitosan were developed for reduction of nitrocompounds with neat formic acid to their corresponding amines or N-substituted formamides by switch of solvents. Characterization results revealed that most of the nitrogen atoms are present as graphitic N and pyridinic N as anchoring sites, and the cobalt nanoparticles are wrapped by nitrogen doped carbon layers, endowing the catalyst with excellent activity and superior reusability.
- Zhang, Yuecheng,Cao, Pengwei,Zhang, Hong-Yu,Yin, Guohui,Zhao, Jiquan
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- Manganese catalyzed hydrogenation of carbamates and urea derivatives
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We report the hydrogenation of carbamates and urea derivatives, two of the most challenging carbonyl compounds to be hydrogenated, catalyzed for the first time by a complex of an earth-abundant metal. The hydrogenation reaction of these CO2-derived compounds, catalyzed by a manganese pincer complex, yields methanol in addition to amine and alcohol, which makes this methodology a sustainable alternative route for the conversion of CO2 to methanol, involving a base-metal catalyst. Moreover, the hydrogenation proceeds under mild pressure (20 bar). Our observations support a hydrogenation mechanism involving the Mn-H complex. A plausible catalytic cycle is proposed based on informative mechanistic experiments.
- Das, Uttam Kumar,Kumar, Amit,Ben-David, Yehoshoa,Iron, Mark A.,Milstein, David
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supporting information
p. 12962 - 12966
(2019/08/26)
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- Sustainable hydrogenation of aliphatic acyclic primary amides to primary amines with recyclable heterogeneous ruthenium-tungsten catalysts
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The hydrogenation of amides is a straightforward method to produce (possibly bio-based) amines. However current amide hydrogenation catalysts have only been validated in a rather limited range of toxic solvents and the hydrogenation of aliphatic (acyclic) primary amides has rarely been investigated. Here, we report the use of a new and relatively cheap ruthenium-tungsten bimetallic catalyst in the green and benign solvent cyclopentyl methyl ether (CPME). Besides the effect of the Lewis acid promotor, NH3 partial pressure is identified as the key parameter leading to high primary amine yields. In our model reaction with hexanamide, yields of up to 83% hexylamine could be achieved. Beside the NH3 partial pressure, we investigated the effect of the catalyst support, PGM-Lewis acid ratio, H2 pressure, temperature, solvent tolerance and product stability. Finally, the catalyst was characterized and proven to be very stable and highly suitable for the hydrogenation of a broad range of amides.
- Coeck, Robin,Berden, Sarah,De Vos, Dirk E.
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supporting information
p. 5326 - 5335
(2019/10/11)
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- Selective Transformations of Triglycerides into Fatty Amines, Amides, and Nitriles by using Heterogeneous Catalysis
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The use of triglycerides as an important class of biomass is an effective strategy to realize a more sustainable society. Herein, three heterogeneous catalytic methods are reported for the selective one-pot transformation of triglycerides into value-added chemicals: i) the reductive amination of triglycerides into fatty amines with aqueous NH3 under H2 promoted by ZrO2-supported Pt clusters; ii) the amidation of triglycerides under gaseous NH3 catalyzed by high-silica H-beta (Hβ) zeolite at 180 °C; iii) the Hβ-promoted synthesis of nitriles from triglycerides and gaseous NH3 at 220 °C. These methods are widely applicable to the transformation of various triglycerides (C4–C18 skeletons) into the corresponding amines, amides, and nitriles.
- Jamil, Md. A. R.,Siddiki, S. M. A. Hakim,Touchy, Abeda Sultana,Rashed, Md. Nurnobi,Poly, Sharmin Sultana,Jing, Yuan,Ting, Kah Wei,Toyao, Takashi,Maeno, Zen,Shimizu, Ken-ichi
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p. 3115 - 3125
(2019/04/26)
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- Development of an Improved Route for the Synthesis of an Abemaciclib Intermediate
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A new synthesis for an intermediate of abemaciclib is described. Keys to this route are the use of inexpensive starting materials, biphasic amine alkylation for mild C-N bond formation, anhydrous coupling of a 2-chloropyridine derivative with LiHMDS to avoid a hydroxy impurity, and neutral, fluoride-free conditions to affect desilylation. Scale-up of the optimized conditions are described on a kilogram scale.
- Carroll, Michael P.,Moloney, Harold,Gowran, Olivia,O'Connor, Aoibheann,Wilson, Eoin M.,Murray, Michael M.,Pietz, Mark A.,Kjell, Douglas P.,Held, C. Brad,Frederick, Michael O.
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p. 2549 - 2555
(2019/11/11)
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- Molecular Catalysts for Selective Hydrogenolysis of Amides
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A compound by the name 1,1,1-tris(di(3,5-dimethoxyphenyl)phosphino-methyl)ethane. The compound can be represented by the structure of formula (I): The compound is useful as a ligand for ruthenium to form an organometallic complex. The complex is an active catalyst for the hydrogenolysis of amides to form amines and optionally alcohols.
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Paragraph 0079-0080
(2019/11/22)
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- Synthesis of β-Chiral Amines by Dynamic Kinetic Resolution of α-Branched Aldehydes Applying Imine Reductases
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Imine reductases (IREDs) allow the one-step preparation of optically active secondary and tertiary amines by reductive amination of ketones. Until now, mainly α-chiral amines have been prepared by this route. In this study, we explored the possibility of synthesizing β-chiral amines, a class of compounds which is also frequently found as structural motif in pharmaceuticals but much more challenging to prepare due to the following reasons: (i) The aldehyde substrate already contains the chiral center and needs to be racemized to enable full conversion. (ii) Because the intermediate imine bears the stereo center two carbon atoms remote to the imine nitrogen, it is more challenging to achieve high enantioselectivity compared to α-chiral amine synthesis. For investigating the proof of concept, we first confirmed that different IREDs are able to convert a variety of α-branched aldehydes when combined with five different amine substrates. The IRED from Streptomyces ipomoeae was a suitable enzyme facilitating the dynamic kinetic resolution of 2-phenylpropanal and a substituted 2-methyl-3-phenylpropanal: the corresponding N-methylated β-chiral amines were obtained with '95 % conversion and 78 and 95 %ee. Other amines were formed with low to moderate enantiomeric excess. This exemplifies the potential of IREDs for the one-step synthesis of secondary β-chiral amines, but also the challenge to identify highly selective enzymes for a desired amine product.
- Matzel, Philipp,Wenske, Sebastian,Merdivan, Simon,Günther, Sebastian,H?hne, Matthias
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p. 4281 - 4285
(2019/08/20)
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- Hydrogenation of Nitriles and Ketones Catalyzed by an Air-Stable Bisphosphine Mn(I) Complex
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Efficient hydrogenations of nitriles and ketones with molecular hydrogen catalyzed by a well-defined bench-stable bisphosphine Mn(I) complex are described. These reactions are environmentally benign and atomically economic, implementing an inexpensive, earth-abundant nonprecious metal catalyst. A range of aromatic and aliphatic nitriles and ketones were efficiently converted into primary amines and alcohols, respectively, in good to excellent yields. The hydrogenation of nitriles proceeds at 100 °C with catalyst loading of 2 mol % and 20 mol % base (t-BuOK), while the hydrogenation of ketones takes place already at 50 °C, with a catalyst loading of 1 mol % and 5 mol % of base. In both cases, a hydrogen pressure of 50 bar was applied.
- Weber, Stefan,St?ger, Berthold,Kirchner, Karl
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supporting information
p. 7212 - 7215
(2018/11/25)
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- Cobalt-based nanoparticles prepared from MOF-carbon templates as efficient hydrogenation catalysts
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The development of efficient and selective nanostructured catalysts for industrially relevant hydrogenation reactions continues to be an actual goal of chemical research. In particular, the hydrogenation of nitriles and nitroarenes is of importance for the production of primary amines, which constitute essential feedstocks and key intermediates for advanced chemicals, life science molecules and materials. Herein, we report the preparation of graphene shell encapsulated Co3O4- and Co-nanoparticles supported on carbon by the template synthesis of cobalt-terephthalic acid MOF on carbon and subsequent pyrolysis. The resulting nanoparticles create stable and reusable catalysts for selective hydrogenation of functionalized and structurally diverse aromatic, heterocyclic and aliphatic nitriles, and as well as nitro compounds to primary amines (>65 examples). The synthetic and practical utility of this novel non-noble metal-based hydrogenation protocol is demonstrated by upscaling several reactions to multigram-scale and recycling of the catalyst.
- Murugesan, Kathiravan,Senthamarai, Thirusangumurugan,Sohail, Manzar,Alshammari, Ahmad S.,Pohl, Marga-Martina,Beller, Matthias,Jagadeesh, Rajenahally V.
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p. 8553 - 8560
(2018/11/30)
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- Heterogeneously catalyzed selective hydrogenation of amides to alcohols and amines
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We report the heterogeneously catalyzed hydrogenation of amides to form alcohols and amines. This C-N bond cleavage reaction is catalyzed by silver on γ-alumina, proceeds smoothly in high yields and 100% selectivity, and is effective for both benzamides and aliphatic amides. This is in contrast to amide hydrogenation catalyzed by heterogeneous catalysts, which generally proceeds via C-O bond cleavage. Recycling experiments show that the catalyst Ag/γ-Al2O3 can be easily recovered and regenerated without decrease in catalytic activity.
- Xie, Yinjun,Hu, Peng,Bendikov, Tatyana,Milstein, David
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p. 2784 - 2788
(2018/06/18)
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- Magnetically Recyclable Metal–Organic Framework@Fe3O4 Composite-Catalyzed Facile Reduction of Nitroarene Compounds in Aqueous Medium
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A kind of Metal–organic framework (MOF) composite namely Cu-BTC@Fe3O4 (BTC?=?1,3,5-benzenetricarboxylate) was prepared and showed good catalytic activity toward the reduction of nitroarenes. This reaction proceeded smoothly under mild reaction conditions in aqueous medium using sodium borohydride as the reduction agent, affording the corresponding anilines in good to excellent yields. In addition, the catalyst could be easily recovered with an external permanent magnet and be reused for successive six runs with slight decrease in its activity.
- Yang, Sen,Zhang, Zhi-Hui,Chen, Qun,He, Ming-Yang,Wang, Liang
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- Selective synthesis of mono- and di-methylated amines using methanol and sodium azide as C1 and N1 sources
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A Ru(ii) complex mediated synthesis of various N,N-dimethyl and N-monomethyl amines from organic azides using methanol as a methylating agent is reported. This methodology was successfully applied for a one-pot reaction of bromide derivatives and sodium azide in methanol. Notably, by controlling the reaction time several N-monomethylated and N,N-dimethylated amines were synthesized selectively. The practical applicability of this tandem process was revealed by preparative scale reactions with different organic azides and synthesis of an anti-vertigo drug betahistine. Several kinetic experiments and DFT studies were carried out to understand the mechanism of this transformation.
- Chakrabarti, Kaushik,Mishra, Anju,Panja, Dibyajyoti,Paul, Bhaskar,Kundu, Sabuj
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supporting information
p. 3339 - 3345
(2018/07/29)
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- Selective Hydrogenation of Cyclic Imides to Diols and Amines and Its Application in the Development of a Liquid Organic Hydrogen Carrier
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Direct hydrogenation of a broad variety of cyclic imides to diols and amines using a ruthenium catalyst is reported here. We have applied this strategy toward the development of a new liquid organic hydrogen carrier system based on the hydrogenation of bis-cyclic imide that is formed by the dehydrogenative coupling of 1,4-butanediol and ethylenediamine using a new ruthenium catalyst. The rechargeable system has a maximum gravimetric hydrogen storage capacity of 6.66 wt%.
- Kumar, Amit,Janes, Trevor,Espinosa-Jalapa, Noel Angel,Milstein, David
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supporting information
p. 7453 - 7457
(2018/06/08)
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- Chemoselective hydrogenation of nitriles to primary amines catalyzed by water-soluble transition metal catalysts
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The water-soluble rhodium complex generated in situ from [Rh (COD)Cl]2 in aqueous ammonia has been revealed as a highly efficient catalyst for the hydrogenation of aromatic nitriles, to primary amines with excellent yields. The catalyst is also highly selective towards primary amines in the case of sterically hindered aliphatic nitriles. The catalytic system can also be recycled and re-used with no significant loss of activity.
- Nait Ajjou, Abdelaziz,Robichaud, André
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- Amination of 1-hexanol on bimetallic AuPd/TiO2 catalysts
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AuPd/TiO2 catalysts, synthesized using controlled surface reactions, are active for the gas-phase amination of 1-hexanol using ammonia. The bimetallic active sites for these catalysts have been characterized using CO chemisorption and XAS techniques, and the absence of monometallic Pd species in the AuPd catalysts was confirmed using UV-vis and STEM-EDS analysis. The bimetallic catalysts exhibit synergy between Au and Pd, as the rate of hexanol conversion increases from 8.7 μmol ks-1 (μmol total Pd)-1 over Pd/TiO2 to up to 42 μmol ks-1 (μmol total Pd)-1 over AuPd/TiO2 with a Pd/Au atomic ratio of 0.06. The rate of hexanol conversion is also enhanced with respect to Au content, with a 5-fold increase in the total Au-normalized rate from Au/TiO2 to AuPd0.67/TiO2. As Pd is added to Au/TiO2 in increasing quantities, the production rate of primary species (i.e., hexylamine and hexanenitrile) is preferentially increased. The rate of dihexylamine production increases to a lesser extent, while trihexylamine formation remains relatively constant across Pd loadings. Moreover, trihexylamine, which cannot be formed via the condensation of dihexylamine and hexanol, is shown to be produced via the secondary aldimine, N-hexylidene hexylamine. The AuPd bimetallic catalysts also exhibit reduced hydrogenolysis activity compared to monometallic Pd/TiO2.
- Ball, Madelyn R.,Wesley, Thejas S.,Rivera-Dones, Keishla R.,Huber, George W.,Dumesic, James A.
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p. 4695 - 4709
(2018/10/31)
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- Process for producing long chain amino acids and dibasic acids
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There is disclosed a process for the production of long chain amino acid and long chain dibasic acid, comprising: (1) reacting long chain keto fatty acid with hydroxylamine or subjecting keto fatty acid to an ammoximation reaction to yield an oxime fatty acid; (2) subjecting the oxime fatty acid to the Beckmann rearrangement to yield a mixture of two amide fatty acids; (3) hydrolyzing the mixed amide fatty acids to produce long chain amino acid, long chain dibasic acid, short chain alkylamine, and alkanoic acid.
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Page/Page column 9
(2018/09/21)
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- Corresponding amine nitrile and method of manufacturing thereof
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The invention relates to a manufacturing method of nitrile. Compared with the prior art, the manufacturing method has the characteristics of significantly reduced using amount of an ammonia source, low environmental pressure, low energy consumption, low production cost, high purity and yield of a nitrile product and the like, and nitrile with a more complex structure can be obtained. The invention also relates to a method for manufacturing corresponding amine from nitrile.
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Paragraph 0272; 0273
(2018/05/07)
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- Selective Hydrogenation of Nitriles to Primary Amines by using a Cobalt Phosphine Catalyst
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A general procedure for the catalytic hydrogenation of nitriles to primary amines by using a non-noble metal-based system is presented. Co(acac)3 in combination with tris[2-(dicyclohexylphosphino)ethyl]phosphine efficiently catalyzes the selective hydrogenation of a wide range of (hetero)aromatic and aliphatic nitriles to give the corresponding amines.
- Adam, Rosa,Bheeter, Charles Beromeo,Cabrero-Antonino, Jose R.,Junge, Kathrin,Jackstell, Ralf,Beller, Matthias
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p. 842 - 846
(2017/03/17)
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- Cobalt-Catalyzed and Lewis Acid-Assisted Nitrile Hydrogenation to Primary Amines: A Combined Effort
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The selective hydrogenation of nitriles to primary amines using a bench-stable cobalt precatalyst under 4 atm of H2 is reported herein. The catalyst precursor was reduced in situ using NaHBEt3, and the resulting Lewis acid formed, BEt3, was found to be integral to the observed catalysis. Mechanistic insights gleaned from para-hydrogen induced polarization (PHIP) transfer NMR studies revealed that the pairwise hydrogenation of nitriles proceeded through a Co(I/III) redox process.
- Tokmic, Kenan,Jackson, Bailey J.,Salazar, Andrea,Woods, Toby J.,Fout, Alison R.
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supporting information
p. 13554 - 13561
(2017/10/05)
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- Synthesis and characterization of magnetically nanoparticles of Fe3O4@APTMS@ZrCp2 as a novel and reusable catalyst for convenient reduction of nitro compounds with glycerol
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The present paper describes the synthesis of magnetically nanoparticles of zirconocene-modified magnetite, Fe3O4@APTMS@ZrCp2, as a new generation in heterogeneous and reusable type nanocatalysts. The prepared zirconocene nanocomposite was characterized using FT-IR, SEM, XRD, EDX, AGFM, ICP–OES, TGA and BET analyses. The core–shell nanocatalyst exhibited an excellent catalytic activity towards glycerol reduction of various nitro compounds to the corresponding amines. All reactions were carried out in H2O at room temperature (40–90?min) to afford amines in high to excellent yields. Reusability of the core–shell zirconocene was examined 5 times without significant loss of its catalytic activity.
- Zeynizadeh, Behzad,Sepehraddin, Farhad
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p. 2649 - 2657
(2017/11/06)
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- Magnetically nano core–shell Fe3O4@Cu(OH)x: a highly efficient and reusable catalyst for rapid and green reduction of nitro compounds
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Magnetically separable nano core–shell Fe3O4@Cu(OH)x with 22?% Cu content was prepared by the addition of sodium hydroxide to a mixture of CuCl2·2H2O and nano Fe3O4 in water. Characterization of the impregnated copper hydroxide was carried out by X-ray fluorescence (XRF), X-ray diffraction (XRD) atomic absorption spectroscopy (AAS), scanning electron microscopy (SEM), value stream mapping (VSM) and Brunauer–Emmett–Teller (BET) analysis. The core–shell nanocatalyst exhibited the excellent catalytic activity toward reduction of various nitro compounds to the corresponding amines with NaBH4. All reactions were carried out in H2O (55–60?°C) within 3–15?min to afford amines in high to excellent yields. Reusability of core–shell Cu(OH)x catalyst was examined 9?times without significant loss of its catalytic activity.
- Shokri, Zahra,Zeynizadeh, Behzad,Hosseini, Seyed Ali,Azizi, Behrooz
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p. 101 - 109
(2017/01/05)
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- Selective Reduction of Nitroarenes with Silanes Catalyzed by Nickel N-Heterocyclic Carbene Complexes
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An efficient catalytic system for the reduction of nitroarenes to amines was developed using a well-defined nickel–NHC (N-heterocyclic carbene) complex as catalyst and phenylsilane as reducing agent. The excellent activity of the catalyst provides access to anilines containing a wide array of reactive functionalities at 20 °C, and without using any base or additive. Notably, the catalytic system allows the reduction of 5,10,15,20-tetra-(nitrophenyl)porphyrin (TNPP) and CuII β-nitroporphyrin to the corresponding aminoporphyrins.
- Lopes, Rita,Pereira, Mariette M.,Royo, Beatriz
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p. 3073 - 3077
(2017/08/15)
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- Two-Enzyme Hydrogen-Borrowing Amination of Alcohols Enabled by a Cofactor-Switched Alcohol Dehydrogenase
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The NADPH-dependent secondary alcohol dehydrogenase from Thermoanaerobacter ethanolicus (TeSADH), displaying broad substrate specificity and low enantioselectivity, was engineered to accept NADH as a cofactor. The engineered TeSADH showed a >10 000-fold switch from NADPH towards NADH compared to the wildtype enzyme. This TeSADH variant was applied to a biocatalytic hydrogen-borrowing system that employed catalytic amounts of NAD+, ammonia, and an amine dehydrogenase, which thereby enabled the conversion a range of alcohols into chiral amines.
- Thompson, Matthew P.,Turner, Nicholas J.
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p. 3833 - 3836
(2017/09/25)
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- A Titanium Dioxide Supported Gold Nanoparticle Catalyst for the Selective N-Formylation of Functionalized Amines with Carbon Dioxide and Hydrogen
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A TiO2-supported, gold nanoparticle catalyst was found to allow the N-formylation of various amines, including normally unreactive anilines, by using CO2 as the carbonyl source under a H2 atmosphere. A series of reducible functional groups, such as olefins, halogens, carbonyls, carbamates, and cyano moieties, were completely retained during the formylation, which proved the highly selective nature of the formylation reaction. The catalyst was also found to be reusable without any loss of activity or selectivity.
- Mitsudome, Takato,Urayama, Teppei,Fujita, Shu,Maeno, Zen,Mizugaki, Tomoo,Jitsukawa, Koichiro,Kaneda, Kiyotomi
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p. 3632 - 3636
(2017/10/16)
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- In vitro biocatalytic pathway design: Orthogonal network for the quantitative and stereospecific amination of alcohols
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The direct and efficient conversion of alcohols into amines is a pivotal transformation in chemistry. Here, we present an artificial, oxidation-reduction, biocatalytic network that employs five enzymes (alcohol dehydrogenase, NADP-oxidase, catalase, amine dehydrogenase and formate dehydrogenase) in two concurrent and orthogonal cycles. The NADP-dependent oxidative cycle converts a diverse range of aromatic and aliphatic alcohol substrates to the carbonyl compound intermediates, whereas the NAD-dependent reductive aminating cycle generates the related amine products with >99% enantiomeric excess (R) and up to >99% conversion. The elevated conversions stem from the favorable thermodynamic equilibrium (K′eq = 1.88 × 1042 and 1.48 × 1041 for the amination of primary and secondary alcohols, respectively). This biocatalytic network possesses elevated atom efficiency, since the reaction buffer (ammonium formate) is both the aminating agent and the source of reducing equivalents. Additionally, only dioxygen is needed, whereas water and carbonate are the by-products. For the oxidative step, we have employed three variants of the NADP-dependent alcohol dehydrogenase from Thermoanaerobacter ethanolicus and we have elucidated the origin of the stereoselective properties of these variants with the aid of in silico computational models.
- Knaus, Tanja,Cariati, Luca,Masman, Marcelo F,Mutti, Francesco G.
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p. 8313 - 8325
(2017/10/19)
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