- Impact of sulfur heteroatoms on the activity of quaternary ammonium salts as phase transfer catalysts for nucleophilic displacement reactions
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The application of a new class of alkylammonium salts as phase-transfer catalysts was investigated. These salts are tetra(4-thiaalkyl) ammonium bromides, and the key questions of the study focus on how the incorporation of a sulfur atom in the alkyl chains affects the efficacy of the salts as phase-transfer catalysts. Employing the nucleophilic substitution of cyanide for bromide on 1-bromopentane as a model reaction, reaction rate constants and activation energies are evaluated. The kinetic parameters obtained using the tetrathiaalkylammonium salts are compared to those obtained using their tetraalkylammonium analogs. The general trend is that the presence of sulfur in the alkyl chains reduces the reaction rates and increases activation energies. This trend is analyzed both in terms of computational modeling and experimental distribution coefficients to determine the cause of the slower reaction rates. Thiaquats are shown to distribute more into the aqueous phase than traditional quat salts of similar chain length, resulting in lower organic phase concentrations. Quantum calculations indicate stronger ion pairing for the thiaquats, increasing activation energies and slowing reaction rates. Thus, differences in rate enhancements are attributable both to phase distribution and ion pairing effects.
- West, Christy Wheeler,O'Brien, Richard A.,Salter, E. Alan,Hollingsworth, Brian E.,Huynh, Thai L.,Sweat, Rachel E.,Griffin, Nathan J.,Wierzbicki, Andrzej,Davis, James H.
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Read Online
- A simple and rapid route to novel tetra(4-thiaalkyl)ammonium bromides
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A simple approach for the preparation of symmetrical quaternary ammonium bromides employing thiol-ene click chemistry is used to synthesize tetra(4-thiaalkyl)ammonium bromides. This approach allows the incorporation of a variety of alkyl moieties onto the nitrogen center with a one-step synthesis involving easy work-up, no side reactions and environmentally friendly reagents. To elucidate information regarding the behaviour of this novel class of compounds, comparisons to tetraalkylammonium analogues have been made. These include melting points, activity as phase-transfer catalysts, and conformational predictions from computational modelling. All results are consistent in indicating stronger bonding between the quaternary cation and the anion for the salts with 4-thiaalkyl chains as compared to those with n-alkyl chains.
- O'Brien, Richard A.,West, Christy Wheeler,Hollingsworth, Brian E.,Stenson, Alexandra C.,Henderson, Codey B.,Mirjafari, Arsalan,Mobarrez, Niloufar,West, Kevin N.,Mattson, Kaila M.,Salter, E. Alan,Wierzbicki, Andrzej,Davis Jr., James H.
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Read Online
- Chemoenzymatic one-pot reaction from carboxylic acid to nitrile: Via oxime
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We report a new chemoenzymatic cascade starting with aldehyde synthesis by carboxylic acid reductase (CAR) followed by chemical in situ oxime formation. The final step to the nitrile is catalyzed by aldoxime dehydratase (Oxd). Full conversions of phenylacetic acid and hexanoic acid were achieved in a two-phase mode.
- Hecko, Sebastian,Horvat, Melissa,Klempier, Norbert,Martínková, Ludmila,Pátek, Miroslav,R?disch, Robert,Rudroff, Florian,Schiefer, Astrid,Weilch, Victoria,Wilding, Birgit,Winkler, Margit
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- Method for dehydrating primary amide into nitriles under catalysis of cobalt
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The invention provides a method for dehydrating primary amide into nitrile. The method comprises the following steps: mixing primary amide (II), silane, sodium triethylborohydride, aminopyridine imine tridentate nitrogen ligand cobalt complex (I) and a reaction solvent under the protection of inert gas, carrying out reacting at 60-100 DEG C for 6-24 hours, and post-treating reaction liquid to obtain a nitrile compound (III). According to the invention, an effective method for preparing nitrile compounds by cobalt-catalyzed primary amide dehydration reaction by using the novel aminopyridine imine tridentate nitrogen ligand cobalt complex catalyst is provided; and compared with existing methods, the method has the advantages of simple operation, mild reaction conditions, wide application range of reaction substrates, high selectivity, stable catalyst, high efficiency, and relatively high practical application value in synthesis.
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Paragraph 0099-0101
(2021/06/21)
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- METHOD FOR PRODUCING NITRILE
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The present invention provides a method of producing a nitrile from a primary amide, characterized in that the primary amide is subjected to a dehydration reaction in a supercritical fluid in the presence of an acid catalyst. The present invention achieves the object of reducing the corrosion of a reactor and the thermal decomposition of raw materials, as well as provides the effect of improving the reaction rate and nitrile selectivity.
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Paragraph 0080; 0084; 0095-0099
(2021/02/05)
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- Chemoselective Hydrogenation of Olefins Using a Nanostructured Nickel Catalyst
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The selective hydrogenation of functionalized olefins is of great importance in the chemical and pharmaceutical industry. Here, we report on a nanostructured nickel catalyst that enables the selective hydrogenation of purely aliphatic and functionalized olefins under mild conditions. The earth-abundant metal catalyst allows the selective hydrogenation of sterically protected olefins and further tolerates functional groups such as carbonyls, esters, ethers and nitriles. The characterization of our catalyst revealed the formation of surface oxidized metallic nickel nanoparticles stabilized by a N-doped carbon layer on the active carbon support.
- Klarner, Mara,Bieger, Sandra,Drechsler, Markus,Kempe, Rhett
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supporting information
p. 2157 - 2161
(2021/05/21)
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- A new reagent for efficient synthesis of nitriles from aldoximes using methoxymethyl bromide
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This study outlines an efficient, high-yielding, and rapid method by which to access diverse nitriles from aldoximes with methoxymethyl bromide (MOM-Br) in THF. It represents the first application of MOM-Br as a deoximation reagent to synthesize nitriles. The reaction was performed at reflux to ensure excellent yield (79-96%) of the nitriles within 20-45 minutes. Furthermore, this method has been successfully applied to the synthesis of the synthesis precursor of aromatic, heteroaromatic, cyclic, and acyclic aliphatic.
- ULUDAG, Nesimi,GIDEN, Ozge NUR
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p. 993 - 998
(2021/02/05)
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- Atomically Dispersed Ru on Manganese Oxide Catalyst Boosts Oxidative Cyanation
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There is a strong incentive for environmentally benign and sustainable production of organic nitriles to avoid the use of toxic cyanides. Here we report that manganese oxide nanorod-supported single-site Ru catalysts are active, selective, and stable for oxidative cyanation of various alcohols to give the corresponding nitriles with molecular oxygen and ammonia as the reactants. The very low amount of Ru (0.1 wt %) with atomic dispersion boosts the catalytic performance of manganese oxides. Experimental and theoretical results show how the Ru sites enhance the ammonia resistance of the catalyst, bolstering its performance in alcohol dehydrogenation and oxygen activation, the key steps in the oxidative cyanation. This investigation demonstrates the high efficiency of a single-site Ru catalyst for nitrile production.
- Gates, Bruce C.,Guan, Erjia,Meng, Xiangju,Wang, Chengtao,Wang, Hai,Wang, Liang,Wang, Sai,Xiao, Feng-Shou,Xu, Dongyang,Xu, Hua,Yang, Bo,Zhang, Jian
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p. 6299 - 6308
(2020/07/21)
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- An Air-Stable N-Heterocyclic [PSiP] Pincer Iron Hydride and an Analogous Nitrogen Iron Hydride: Synthesis and Catalytic Dehydration of Primary Amides to Nitriles
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An air-stable N-heterocyclic PSiP pincer iron hydride FeH(PMe3)2(SiPh(NCH2PPh2)2C6H4) (4) was synthesized by Si-H activation of a Ph-substituted [PSiP] pincer ligand. The analogous strong electron-donating iPr-substituted [PSiP] pincer ligand was prepared and introduced into iron complex to give an iron nitrogen complex FeH(N2)(PMe3)(SiPh(NCH2PiPr2)2C6H4) (6). Both 4 and 6 showed similar high efficiency for catalytic dehydration of primary amides to nitriles. Air-stable iron hydride 4 was the best catalyst for its stabilization and convenient preparation. A diverse range of cyano compounds including aromatic and aliphatic species was obtained in moderate to excellent yields. A plausible catalytic reaction mechanism was proposed.
- Fenske, Dieter,Fuhr, Olaf,Li, Xiaoyan,Sun, Hongjian,Wang, Yajie,Xie, Shangqing,Zhang, Hua
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- Method for continuous preparation of nitriles by amides (by machine translation)
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The method comprises the following steps: preparing a lead salt supported by a molecular sieve by a lead salt and a molecular sieve through an impregnation method; and filling a molecular sieve-loaded lead catalyst into a fixed bed reactor. The amide or amide solution is sent into a fixed bed reactor from the top of the fixed bed to be subjected to catalytic dehydration, and the obtained reaction product is led out from the bottom of the fixed bed. The reaction product is separated to obtain the crude product of the nitrile corresponding to the amide. A fixed bed continuous production process is adopted, the reaction process is simple, the production efficiency is high, the product post-treatment is simple, and industrial production is easy to realize. (by machine translation)
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Paragraph 0033-0054; 0061-0066
(2020/12/15)
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- Photocatalytic selective aerobic oxidation of amines to nitriles over Ru/γ-Al2O3: The role of the support surface and the strong imine intermediate adsorption
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Hydroxyl coordinated ruthenium dispersed on the surface of γ-Al2O3 can be applied to the selective oxidation of amines with light irradiation and an atmospheric pressure of O2 at room temperature. Sunlight is also an effective light source for the selective aerobic oxidation of primary amines to corresponding nitriles. The high photocatalytic activity and selectivity over Ru/γ-Al2O3 originate from the adsorption of amines and imine intermediates on the abundant surface OH groups of the photocatalyst and further formation of Ru-amide species by ligand exchange of adsorbed amines and imine intermediates with adjacent exposed active Ru sites. Light is introduced to the system successfully via the formation of Ru-amide species, which are used as the light absorption sites of the photocatalytic selective oxidation of amines. Primary amines are directly converted to corresponding nitriles via a two-step oxidative dehydrogenation process.
- Zhu, Pengqi,Zhang, Jin,Wang, Jie,Kong, Peng,Wang, Yunwei,Zheng, Zhanfeng
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p. 440 - 449
(2020/02/04)
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- Synthesis, characterization, catalytic and biological application of half-sandwich ruthenium complexes bearing hemilabile (κ2-: C, S)-thioether-functionalised NHC ligands
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A series of cationic Ru(ii)(η6-p-cymene) complexes with thioether-functionalised N-heterocyclic carbene ligands have been prepared and fully characterized. Steric and electronic influence of the R thioether substituent on the coordination of the sulfur atom was investigated. The molecular structure of three of them has been determined by means of X-ray diffractrometry and confirmed the bidentate (κ2-C,S) coordination mode of the ligand. Interestingly, only a single diastereomer, as an enantiomeric couple, was observed in the solid state for complexes 1c, 1i and 1j. DFT calculations established a low energy inversion barrier between the two diastereomers through a sulfur pyramidal inversion pathway with R donating group while a dissociative/associative mechanism is more likely with R substituents that contain electron withdrawing group, thus suggesting that the only species observed by the 1H-NMR correspond to an average resonance position of a fluxional mixtures of isomers. All these complexes were found to catalyse the oxydant-free double dehydrogenation of primary amine into nitrile. Ru complex bearing NHC-functionalised S-tBu group was further investigated in a wide range of amines and was found more selective for alkyl amine substrates than for benzylamine derivatives. Finally, preliminary results of the biological effects on various human cancer cells of four selected Ru complexes are reported.
- Achard, Thierry,Bellemin-Laponnaz, Stéphane,Chen, Weiguang,Egly, Julien,Maisse-Francois, Aline,Poblador-Bahamonde, Amalia I.
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supporting information
p. 3243 - 3252
(2020/03/19)
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- Nitrile Synthesis by Aerobic Oxidation of Primary Amines and in situ Generated Imines from Aldehydes and Ammonium Salt with Grubbs Catalyst
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Herein, a Grubbs-catalyzed route for the synthesis of nitriles via the aerobic oxidation of primary amines is reported. This reaction accommodates a variety of substrates, including simple primary amines, sterically hindered β,β-disubstituted amines, allylamine, benzylamines, and α-amino esters. Reaction compatibility with various functionalities is also noted, particularly with alkenes, alkynes, halogens, esters, silyl ethers, and free hydroxyl groups. The nitriles were also synthesized via the oxidation of imines generated from aldehydes and NH4OAc in situ. (Figure presented.).
- Utsumi, Tatsuki,Noda, Kenta,Kawauchi, Daichi,Ueda, Hirofumi,Tokuyama, Hidetoshi
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supporting information
p. 3583 - 3588
(2020/08/05)
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- Method for continuous preparation of nitriles in a pipelined reactor (by machine translation)
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The method comprises the following steps that a tin catalyst is coated on the inner wall of the pipeline reactor; and the method comprises the following steps: coating a tin catalyst on the inner wall of the pipeline reactor. The amide solution and the catalytic auxiliary agent are mixed and then sent to a pipeline reactor, and the amide is dehydrated to generate nitrile at the reaction pressure of 0.1 - 2.0 mpa and 100 - 200 °C reaction temperature. The resulting reaction product was separated to give the crude product of the nitrile to which the amide corresponded. In the pipeline reactor, the corresponding nitrile is continuously prepared under the action of the tin catalyst, a dehydrating agent is not needed, byproducts only are water, and three wastes are reduced. (by machine translation)
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Paragraph 0036-0047; 0056; 0058
(2020/12/14)
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- Oxidant free conversion of alcohols to nitriles over Ni-based catalysts
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Organic nitriles are significant and versatile industrial feedstocks, but their conventional synthetic protocols require hazardous starting materials and/or harsh reaction conditions posing environmental and health risks. Herein, we established a Ni-based catalytic system to convert primary alcohols to nitriles with ammonia gas as the sole nitrogen source under oxidant-free conditions at merely 190-230 °C. Based on isotope labelling experiments, in situ DRIFTS and control experiments, the reaction pathway was identified to follow a dehydrogenation-imination-dehydrogenation sequence, with α-carbon C-H bond breakage as the rate determining step. Ni is superior to all noble metal catalysts tested, due to its excellent dehydrogenation ability that is not inhibited by NH3. The support plays an auxiliary role, promoting the reaction between aldehyde and ammonia to form imine as a critical intermediate. Ni/Al2O3 catalyst prepared via a deposition-precipitation method, featuring both excellent dispersion of metallic Ni and suitable acid sites, enabled alcohol transformation into nitrile under unprecedented low temperature. Various alcohols were converted into their corresponding nitriles in high conversions and yields (both up to 99%), while the catalyst kept 90% of its original activity after 48 hours in the stability test, highlighting the wide applicability and the robustness of the catalytic system.
- Wang, Yunzhu,Furukawa, Shinya,Zhang, Zhang,Torrente-Murciano, Laura,Khan, Saif A.,Yan, Ning
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- Identification of an Active NiCu Catalyst for Nitrile Synthesis from Alcohol
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Development of heterogeneous catalysts for alcohol transformation into nitriles under oxidant-free conditions is a challenge. Considering the C-H activation on α-carbon of primary alcohols is the rate-determining step, decreasing the activation energy of C-H activation is critical in order to enhance the catalytic activity. Several NiM/Al2O3 bimetallic catalysts were synthesized and scrutinized in catalytic transformation of 1-butanol to butyronitrile. Ni-Cu was identified as a suitable combination with the optimized Ni0.5Cu0.5/Al2O3 catalyst exhibiting 10 times higher turnover frequency than Ni/Al2O3 catalyst. X-ray absorption spectroscopy (XAS) and high angle annular dark field scanning transmission electron microscopy (HAADF-STEM) revealed that the NiCu particles in the catalyst exist in the form of homogeneous alloys with an average size of 8.3 nm, providing an experimental foundation to build up a catalyst model for further density functional theory (DFT) calculations. Calculations were done over a series of NiM catalysts, and the experimentally observed activity trend could be rationalized by the Br?nsted-Evans-Polanyi (BEP) principle, i.e., catalysts that afford reduced reaction energy also feature lower activation barriers. The calculated activation energy (Ea) for C-H activation with coadsorbed NH3 dropped from 63.4 kJ/mol on pure Ni catalyst to 49.9 kJ/mol on the most active NiCu-2 site in NiCu bimetallic catalyst, in good agreement with the experimentally measured activation energy values. The Ni0.5Cu0.5/Al2O3 catalyst was further employed to convert 11 primary alcohols into nitriles with high to near-quantitative yields, at a Ni loading 10 times less than that of the conventional Ni/Al2O3 catalyst.
- Wang, Yunzhu,Furukawa, Shinya,Yan, Ning
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p. 6681 - 6691
(2019/07/12)
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- A BEt3-Base catalyst for amide reduction with silane
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Reported herein is the development of a simple but practical catalytic system for the selective reduction of amides with hydrosilane or hydrosiloxane. Low-cost and readily available triethylborane (1.0 M in THF), in combination with a catalytic amount of an alkali metal base, was found to catalyze the reduction of all three amide classes (tertiary, secondary, and primary amides) to form amines under mild conditions. In addition, the selective transformation of secondary amides to aldimines and primary amides to nitriles can also be achieved by using a proper combination of BEt3 and base. The scope of these BEt3-base-catalyzed amide hydrosilylation reactions has been explored in depth. Preliminary results of mechanistic studies suggest a modified Piers' silane Si-H···B activation mode wherein the hydride abstraction by BEt3 is promoted by the coordination of an alkoxide or hydroxide anion to the Si center.
- Yao, Wubing,Fang, Huaquan,He, Qiaoxing,Peng, Dongjie,Liu, Guixia,Huang, Zheng
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- Method for preparing nitrile from primary amide
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The invention relates to a method for preparing nitrile from primary amide, which has a structural formula as shown in the specification. The method comprises the following steps: sequentially addingdimethyl sulfoxide (0.01 equiv), primary amide (1.0 equiv) and triethylamine (2.5 equiv) into acetonitrile at room temperature; dropwise adding oxalyl chloride (1.2 equiv) into the acetonitrile solution, and reacting for 40-60 minutes to obtain a corresponding nitrile compound having the yield of 80-96 percent.
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Paragraph 0014; 0015
(2019/01/21)
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- A BEt3-Base Catalyst for Amide Reduction with Silane
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Reported herein is the development of a simple but practical catalytic system for the selective reduction of amides with hydrosilane or hydrosiloxane. Low-cost and readily available triethylborane (1.0 M in THF), in combination with a catalytic amount of an alkali metal base, was found to catalyze the reduction of all three amide classes (tertiary, secondary, and primary amides) to form amines under mild conditions. In addition, the selective transformation of secondary amides to aldimines and primary amides to nitriles can also be achieved by using a proper combination of BEt3 and base. The scope of these BEt3-base-catalyzed amide hydrosilylation reactions has been explored in depth. Preliminary results of mechanistic studies suggest a modified Piers' silane Si-H···B activation mode wherein the hydride abstraction by BEt3 is promoted by the coordination of an alkoxide or hydroxide anion to the Si center.
- Yao, Wubing,Fang, Huaquan,He, Qiaoxing,Peng, Dongjie,Liu, Guixia,Huang, Zheng
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p. 6084 - 6093
(2019/05/24)
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- Green synthesis of benzonitrile using ionic liquid with multiple roles as the recycling agent
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Preparation of benzonitrile from benzaldehyde and hydroxylamine hydrochloride is one of the most advantageous approaches. Nevertheless, it suffers from various constraints such as longer reaction time, corrosion and recovery of hydrochloric acid, the use of metal salt catalysts and their separation. For these reasons, a novel green benzonitrile synthetic route was proposed with ionic liquid as the recycling agent in this study. The results indicated that hydroxylamine 1-sulfobutyl pyridine hydrosulfate salt ((NH2OH)2·[HSO3-b-Py]·HSO4) was an expert alternative to hydroxylamine hydrochloride. Meanwhile, the ionic liquid [HSO3-b-Py]·HSO4 exhibited the multiple roles of co-solvent, catalysis and phase separation, thus the use of metal salt catalyst was eliminated, and no additional catalyst was needed. Hence, the separation process was greatly simplified. When the molar ratio of benzaldehyde to (NH2OH)2·[HSO3-b-Py]·HSO4 was 1:1.5, the volume ratio of paraxylene to [HSO3-b-Py]·HSO4 was 2:1, the benzaldehyde conversion and benzonitrile yield were both 100% at 120 °C in 2 h. Even better, the ionic liquid could be recovered easily by phase separation, and recycled directly after reaction. Additionally, this novel route is applicable to the green synthesis of a variety of aromatic, heteroaromatic and aliphatic nitriles with excellent yields.
- Li, Zhihui,Wang, Tingting,Qi, Xudong,Yang, Qiusheng,Gao, Liya,Zhang, Dongsheng,Zhao, Xinqiang,Wang, Yanji
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p. 17631 - 17638
(2019/06/24)
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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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- A method of synthesizing fatty nitrile by the aliphatic aldehyde
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The invention relates to a method of synthesizing fatty nitrile by the aliphatic aldehyde. The method comprises the following steps: the aliphatic aldehyde, ionic liquid regenerating and ionic liquid in the reactor, to join the two toluene, stirring, of the reflux condensation, in the normal pressure, 90 - 120 °C reaction under 0.5 - 2 h, to obtain the product fatty nitrile; wherein said ionic liquid is 1 - sulfobutyl pyridine bisulphate ionic liquid; ion liquid hydroxylamine salt is 1 - sulfobutyl pyridine bisulphate ion liquid hydroxylamine salt. The invention in one reactor to achieve the fat [...] and fat aldoxime dehydration integrated two-step reaction, the process is simple, easy to operate; to ionic liquid as catalyst and a co-solvent, without the addition of metal salt catalyst and corrosive solvent, environment-friendly.
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Paragraph 0027; 0028; 0045; 0046
(2019/05/28)
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- Enzymatic Synthesis of Aliphatic Nitriles at a Substrate Loading of up to 1.4 kg/L: A Biocatalytic Record Achieved with a Heme Protein
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A biocatalytic approach toward linear aliphatic nitriles being widely used as industrial bulk chemicals has been developed that runs at high substrate loadings of up to 1.4 kg/L as demonstrated for the synthesis of n-octanenitrile. This substrate loading is one of the highest ever reported in biocatalysis and to best of our knowledge the highest obtained for a water-immiscible product in aqueous medium. It is noteworthy that the biotransformation at such a high substrate loading was achieved by means of a metalloprotein bearing an iron-containing heme subunit in the active site. In detail, an aldoxime dehydratase from Bacillus sp. OxB-1 was used as a biocatalyst for a dehydration of aldoximes as readily available starting materials due to their easy preparation from aliphatic aldehydes through spontaneous condensation with hydroxylamine as bulk chemical. Excellent conversions toward the nitriles in the two-phase system were achieved and the products are easily separated from the reaction mixture without the need for further purification. Aliphatic nitriles are used in industry as solvents and intermediates for the production of surfactants and life sciences products.
- Hinzmann, Alessa,Glinski, Sylvia,Worm, Marion,Gr?ger, Harald
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supporting information
p. 4867 - 4872
(2019/05/09)
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- A new reagent for efficient synthesis of nitriles from aldoximes using methoxymethyl bromide
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This study outlines an efficient, high-yielding, and rapid method by which to access diverse nitriles from aldoximes with methoxymethyl bromide (MOM-Br) in THF. It represents the first application of MOM-Br as a deoximation reagent to synthesize nitriles. The reaction was performed at reflux to ensure excellent yield (79-96percent) of the nitriles within 20-45 minutes. Furthermore, this method has been successfully applied to the synthesis of the synthesis precursor of aromatic, heteroaromatic, cyclic, and acyclic aliphatic.
- Uludag, Nesimi,Nur Giden, Ozge
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p. 993 - 998
(2020/06/27)
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- Direct Synthesis of Nitriles from Carboxylic Acids Using Indium-Catalyzed Transnitrilation: Mechanistic and Kinetic Study
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Aliphatic and aromatic carboxylic acids can be quantitatively converted to the corresponding nitriles in the presence of catalysts using acetonitrile both as a solvent and reactant at 200 °C. This transformation is based on the acid-nitrile exchange (i.e., transnitrilation) and uses a nontoxic and water resistant catalyst, indium trichloride (InCl3). The mechanism of the transnitrilation was investigated both experimentally and computationally and compared to the previously proposed mechanism. In contrast to the usually assumed formation of amide as an intermediate, transnitrilation is an equilibrium reaction and proceeds via an equilibrated Mumm reaction with the formation of an imide as an intermediate. A simple and reversible mechanism was proposed for this reaction, which was validated by kinetics measurement and by density functional theory calculations of the reaction intermediates and reaction mechanisms.
- Vanoye, Laurent,Hammoud, Ahmad,Gérard, Hélène,Barnes, Alexandra,Philippe, Régis,Fongarland, Pascal,De Bellefon, Claude,Favre-Réguillon, Alain
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p. 9705 - 9714
(2019/10/14)
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- Synthesis of Nitriles from Primary Amides or Aldoximes under Conditions of a Catalytic Swern Oxidation
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The preparation of nitriles from primary amides or aldoximes was achieved by using oxalyl chloride with a catalytic amount of dimethyl sulfoxide in the presence of Et3N. The reactions were complete within 1 h after addition at room temperature. A diverse range of cyano compounds were obtained in good to excellent yields, including aromatic, heteroaromatic, cyclic, and acyclic aliphatic species.
- Ding, Rui,Liu, Yongguo,Han, Mengru,Jiao, Wenyi,Li, Jiaqi,Tian, Hongyu,Sun, Baoguo
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p. 12939 - 12944
(2018/10/20)
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- Synthesis of silyl iron hydride: Via Si-H activation and its dual catalytic application in the hydrosilylation of carbonyl compounds and dehydration of benzamides
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The hydrido silyl iron complex (o-Ph2PC6H4SiMe2)Fe(PMe3)3H (2) was obtained via the activation of the Si-H bond of the bidentate silyl ligand o-Ph2P(C6H4)SiMe2H (1) by Fe(PMe3)4. 2 showed good to excellent catalytic activity in both the reduction of aldehydes/ketones and the dehydration of benzamide. In addition, with complex 2 as a catalyst, α,β-unsaturated carbonyls could be selectively reduced to the corresponding α,β-unsaturated alcohols. The mechanisms of the formation of 2 and the catalytic dehydration process are proposed and partly experimentally verified.
- Ren, Shishuai,Xie, Shangqing,Zheng, Tingting,Wang, Yangyang,Xu, Shilu,Xue, Benjing,Li, Xiaoyan,Sun, Hongjian,Fuhr, Olaf,Fenske, Dieter
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p. 4352 - 4359
(2018/03/26)
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- Stable and reusable nanoscale Fe2O3-catalyzed aerobic oxidation process for the selective synthesis of nitriles and primary amides
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The sustainable introduction of nitrogen moieties in the form of nitrile or amide groups in functionalized molecules is of fundamental interest because nitrogen-containing motifs are found in a large number of life science molecules, natural products and materials. Hence, the synthesis and functionalization of nitriles and amides from easily available starting materials using cost-effective catalysts and green reagents is highly desired. In this regard, herein we report the nanoscale iron oxide-catalyzed environmentally benign synthesis of nitriles and primary amides from aldehydes and aqueous ammonia in the presence of 1 bar O2 or air. Under mild reaction conditions, this iron-catalyzed aerobic oxidation process proceeds to synthesise functionalized and structurally diverse aromatic, aliphatic and heterocyclic nitriles. Additionally, applying this iron-based protocol, primary amides have also been prepared in a water medium.
- Murugesan, Kathiravan,Senthamarai, Thirusangumurugan,Sohail, Manzar,Sharif, Muhammad,Kalevaru, Narayana V.,Jagadeesh, Rajenahally V.
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supporting information
p. 266 - 273
(2018/01/12)
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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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- Facile and efficient preparation of nitriles through FeCl4–IL–SiO2-catalyzed direct oxidation of alcohols with hydrogen peroxide
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Abstract: A series of silica-supported functionalized ionic liquids catalysts have been prepared and tested in the oxidative conversion of alcohols to nitriles with H2O2 as the oxidant. The features of this heterogeneous reaction system were studied by tuning various reaction parameters including catalyst selection, amount of the catalyst, and effect of solvents. Among the catalysts, FeCl4–IL–SiO2 exhibited the highest efficiency in direct oxidation of alcohols to nitriles under the optimized condition along with good recycle performance. Also, a possible catalytic mechanism is provided. Graphical abstract: [Figure not available: see fulltext.]
- Hu, Yu-Lin,Wang, Bing Tong,Fang, Dong
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p. 233 - 243
(2017/01/05)
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- Ligand controlled switchable selectivity in ruthenium catalyzed aerobic oxidation of primary amines
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A ligand controlled catalytic system for the aerobic oxidation of 1° amines to nitriles and imines has been developed where the varying π-acidic feature of BIAN versus phen in the frameworks of ruthenium catalysts facilitates switchable selectivity.
- Ray, Ritwika,Chandra, Shubhadeep,Yadav, Vishal,Mondal, Prasenjit,Maiti, Debabrata,Lahiri, Goutam Kumar
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supporting information
p. 4006 - 4009
(2017/04/11)
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- Synthesis of nitriles from aerobic oxidation of amines catalyzed by ruthenium supported on activated carbon
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Nitriles were synthesized from the aerobic oxidation of amines over commercially available catalysts, which were activated carbon-supported ruthenium catalysts (Ru/AC). The 5%Ru/AC catalyst can tolerate a wide range of substrates, such as aromatic, aliphatic, and heterocyclic amines, and afford the target nitriles in good-to-excellent yields. The 5%Ru/AC catalyst was easily recovered and no ruthenium leaking took place in the catalytic run.
- Niu, Baoqiang,Lu, Fei,Zhang, Hong-Yu,Zhang, Yuecheng,Zhao, Jiquan
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supporting information
p. 330 - 333
(2017/02/23)
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- Direct synthesis of nitriles from aldehydes and hydroxylamine hydrochloride catalyzed by a HAP@AEPH2-SO3H Nanocatalyst
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We describe an efficient method for the direct preparation of nitriles from aldehydes and hydroxylamine hydrochloride catalyzed by sulfonated nanohydroxyapatite functionalized by 2-aminoethyl dihydrogen phosphate (HAP@AEPH2-SO3H) as an eco-friendly and recyclable solid acid nanocatalyst. In this protocol the use of a solid acid nanocatalyst provides a green, useful, and rapid method for the preparation of nitriles in excellent yields. In addition, the notable feature of this methodolgy is that the synthesized nanocatalyst can be recovered and reused five times without any noticeable loss of efficiency.
- Masjed, Samane Memar,Akhlaghinia, Batool,Zarghani, Monireh,Razavi, Nasrin
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- Cobalt-Porphyrin-Catalysed Intramolecular Ring-Closing C?H Amination of Aliphatic Azides: A Nitrene-Radical Approach to Saturated Heterocycles
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Cobalt-porphyrin-catalysed intramolecular ring-closing C?H bond amination enables direct synthesis of various N-heterocycles from aliphatic azides. Pyrrolidines, oxazolidines, imidazolidines, isoindolines and tetrahydroisoquinoline can be obtained in good to excellent yields in a single reaction step with an air- and moisture-stable catalyst. Kinetic studies of the reaction in combination with DFT calculations reveal a metallo-radical-type mechanism involving rate-limiting azide activation to form the key cobalt(III)-nitrene radical intermediate. A subsequent low barrier intramolecular hydrogen-atom transfer from a benzylic C?H bond to the nitrene-radical intermediate followed by a radical rebound step leads to formation of the desired N-heterocyclic ring products. Kinetic isotope competition experiments are in agreement with a radical-type C?H bond-activation step (intramolecular KIE=7), which occurs after the rate-limiting azide activation step. The use of di-tert-butyldicarbonate (Boc2O) significantly enhances the reaction rate by preventing competitive binding of the formed amine product. Under these conditions, the reaction shows clean first-order kinetics in both the [catalyst] and the [azide substrate], and is zero-order in [Boc2O]. Modest enantioselectivities (29–46 % ee in the temperature range of 100–80 °C) could be achieved in the ring closure of (4-azidobutyl)benzene using a new chiral cobalt-porphyrin catalyst equipped with four (1S)-(?)-camphanic-ester groups.
- Kuijpers, Petrus F.,Tiekink, Martijn J.,Breukelaar, Willem B.,Broere, Dani?l L. J.,van Leest, Nicolaas P.,van der Vlugt, Jarl Ivar,Reek, Joost N. H.,de Bruin, Bas
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supporting information
p. 7945 - 7952
(2017/06/19)
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- Efficient reductive dehydration of primary amides to nitriles catalyzed by hydrido thiophenolato iron(II) complexes under hydrosilation conditions
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The reductive dehydration of amides to nitriles under hydrosilation conditions with hydrido thiophenolato iron(II) complexes [cis-Fe(H)(SAr)(PMe3)4] (1–4) as catalysts is reported using (EtO)3SiH as an efficient reducing agent in the yields up to 93%. The merits of this catalytic system, the low catalyst loadings (2?mol%) and the amount of efficient reducing agent (EtO)3SiH, make this method more attractive.
- Xue, Benjing,Sun, Hongjian,Wang, Yan,Zheng, Tingting,Li, Xiaoyan,Fuhr, Olaf,Fenske, Dieter
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p. 148 - 150
(2016/09/07)
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- Synthesis of nitriles from amines using nanoscale Co3O4-based catalysts via sustainable aerobic oxidation
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The selective oxidation of amines for the benign synthesis of nitriles under mild conditions is described. Key to success for this transformation is the application of reusable cobalt oxide-based nanocatalysts. The resulting nitriles constitute key precursors and central intermediates in organic synthesis.
- Natte, Kishore,Jagadeesh, Rajenahally V.,Sharif, Muhammad,Neumann, Helfried,Beller, Matthias
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supporting information
p. 3356 - 3359
(2016/04/09)
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- Tin or gallium-catalyzed cyanide-transition metal-free synthesis of nitriles from aldehydes or oximes
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Tin or gallium chloride catalyzed transformation of oximes or aldehydes to nitriles is described. Various nitriles were obtained in up to 99% of yields. The gram-scale reaction or the optically active dinitrile was also available. This synthetically useful method has avoided toxic organic or inorganic cyanides as well as transition or noble metal catalysts.
- Zhuang, Yan-Jun,Liu, Jie,Kang, Yan-Biao
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supporting information
p. 5700 - 5702
(2016/11/28)
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- A ruthenium racemisation catalyst for the synthesis of primary amines from secondary amines
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A Ru-based half sandwich complex used in amine and alcohol racemization reactions was found to be active in the splitting of secondary amines to primary amines using NH3. Conversions up to 80% along with very high selectivities were achieved. However, after about 80% conversion the catalyst lost activity. Similar to Shvo's catalyst, the complex might deactivate under the influence of ammonia. It was revealed that not NH3 but mainly the primary amine is responsible for the deactivation.
- Pingen, Dennis,Altinta?, ?i?dem,Rudolf Schaller, Max,Vogt, Dieter
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p. 11765 - 11771
(2016/07/28)
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- Half-Sandwich Guanidinate-Osmium(II) Complexes: Synthesis and Application in the Selective Dehydration of Aldoximes
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The novel guanidinate-osmium(II) complexes [OsCl{κ2-(N,N′)-C(NR)(NiPr)NHiPr}(η6-p-cymene)] [R = Ph (3a), 4-C6H4F (3b), 4-C6H4Cl (3c), 4-C6H4CF3 (3d), 3-C6H4CF3 (3e), 3,5-C6H3(CF3)2 (3f), 4-C6H4CN (3g), 4-C6H4Me (3h), 3-C6H4Me (3i), 2-C6H4Me (3j), 4-C6H4tBu (3k), 2,6-C6H3iPr2 (3l), 2,4,6-C6H2Me3 (3m)] have been synthesized in high yields (70-88 %) by treatment of THF solutions of the dimeric precursor [{OsCl(μ-Cl)(η6-p-cymene)}2] (1) with 4 equivalents of the corresponding guanidine (iPrHN)2C=NR (2a-m) at room temperature. The easily separable guanidinium chloride salts [(iPrHN)2C(NHR)]Cl (4a-m) were also formed in these reactions. The structures of 3a, 3d, and 3h were unequivocally confirmed by X-ray diffraction methods. Complexes 3a-m proved to be active in the catalytic dehydration of aldoximes. The best results were obtained with [OsCl{κ2-(N,N′)-C(N-4-C6H4CF3)(NiPr)NHiPr}(η6-p-cymene)] (3d; 5 mol-%), which, in acetonitrile at 80C, was able to convert selectively a large variety of aromatic, heteroaromatic, α,β-unsaturated, and aliphatic aldoximes into the corresponding nitriles in high yields and short reaction times. Novel osmium(II)-guanidinate complexes of general composition [OsCl{κ2-(N,N′)-C(NR)(NiPr)NHiPr}(η6-p-cymene)] (R = Ar) have been synthesized and successfully employed as catalysts for the selective conversion of aldoximes into nitriles.
- Francos, Javier,González-Liste, Pedro J.,Menéndez-Rodríguez, Lucía,Crochet, Pascale,Cadierno, Victorio,Borge, Javier,Anti?olo, Antonio,Fernández-Galán, Rafael,Carrillo-Hermosilla, Fernando
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p. 393 - 402
(2016/02/03)
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- "Nanorust"-catalyzed benign oxidation of amines for selective synthesis of nitriles
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Organic nitriles constitute key precursors and central intermediates in organic synthesis. In addition, nitriles represent a versatile motif found in numerous medicinally and biologically important compounds. Generally, these nitriles are synthesized by traditional cyanation procedures using toxic cyanides. Herein, we report the selective and environmentally benign oxidative conversion of primary amines for the synthesis of structurally diverse aromatic, aliphatic and heterocyclic nitriles using a reusable "nanorust" (nanoscale Fe2O3)-based catalysts applying molecular oxygen.
- Jagadeesh, Rajenahally V.,Junge, Henrik,Beller, Matthias
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- Ru(II)-triphos catalyzed amination of alcohols with ammonia via ionic species
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An active and selective system for the amination of primary alcohols to primary amines with ammonia based on ruthenium and triphos as the tridentate phosphine ligand was developed. On the basis of detailed mechanistic studies, we propose that the active catalyst is, unlike the previously reported systems on this reaction, a cationic ruthenium complex. The experimental findings are supported by detailed density functional theory (DFT) calculations on the catalytic cycle. Because of the cationic nature of the active catalyst, strong anion and solvent effects were observed in the catalytic amination reaction when using the ruthenium triphos complexes. Therefore, a higher activity could be achieved when the nonpolar solvent toluene is used in this amination instead of tetrahydrofuran. Our findings can help to develop and optimize the system systematically for an application to relevant target molecules.
- Derrah, Eric J.,Hanauer, Matthias,Plessow, Philipp N.,Schelwies, Mathias,Da Silva, Marion K.,Schaub, Thomas
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p. 1872 - 1881
(2015/06/08)
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- A highly efficient electrochemical route for the conversion of aldehydes to nitriles
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Using NH4I as the supporting electrolyte as well as the precursor of an I2 promoter and nitrogen source, a highly efficient electrochemical route was developed to convert aldehydes to nitriles with excellent yields under mild reaction conditions. This electrochemical process could effectively avoid the direct use of NH3 gas, molecular iodine, and oxidants.
- Qu, Qinghui,Gao, Xiaofang,Gao, Jian,Yuan, Gaoqing
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p. 747 - 750
(2015/04/14)
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- Palladium(II) complexes with a phosphino-oxime ligand: Synthesis, structure and applications to the catalytic rearrangement and dehydration of aldoximes
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The treatment of [PdCl2(COD)] (COD = 1,5-cyclooctadiene) with 1 and 2 equivalents of 2-(diphenylphosphino)benzaldehyde oxime in dichloromethane at room temperature led to the selective formation of [PdCl2{κ2-(P,N)-2-Ph2PC6H4CHNOH}] (1) and [Pd{κ2-(P,N)-2-Ph2PC6H4CHNOH}2][Cl]2 (2), respectively, which represent the first examples of Pd(II) complexes containing a phosphino-oxime ligand. These compounds, whose structures were fully confirmed by X-ray diffraction methods, were active in the catalytic rearrangement of aldoximes. In particular, using 5 mol% complex 1, a large variety of aldoximes could be cleanly converted into the corresponding primary amides at 100 °C, employing water as solvent and without the assistance of any cocatalyst. Palladium nanoparticles are the active species in the rearrangement process. In addition, when the same reactions were performed employing acetonitrile as solvent, selective dehydration of the aldoximes to form the respective nitriles was observed. For comparative purposes, the catalytic behaviour of an oxime-derived palladacyclic complex has also been briefly evaluated.
- Menéndez-Rodríguez, Lucía,Tomás-Mendivil, Eder,Francos, Javier,Nájera, Carmen,Crochet, Pascale,Cadierno, Victorio
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p. 3754 - 3761
(2015/07/01)
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- One-step synthesis of nitriles by the dehydrogenation-amination of fatty primary alcohols over Cu/m-ZrO2
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An effective method for one-step synthesis of nitriles employing C 2-C8 fatty primary alcohols and ammonia over 5%Cu/m-ZrO2 has been found. The conversion of alcohols and selectivity of nitriles obtained are > 96 and > 87 wt.%, respectively, and are obviously influenced by the C2-substitution rather than the chain length of fatty primary alcohols. Cu/m-ZrO2 was characterized by XRD, H 2-TPR, CO2-TPD and NH3-TPD. It is revealed that a substantial amount of Cu species over m-ZrO2 is in highly dispersed CuO. A plausible mechanism is proposed and supported by different experiments, and aldehyde generation is an important step in the reaction mechanism.
- Hu, Yunfeng,Jin, Shuhan,Zhang, Zhichao,Zhang, Likun,Deng, Jun,Zhang, Hongsheng
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- One-step synthesis of nitriles by the dehydrogenation-amination of fatty primary alcohols over Cu/m-ZrO2
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An effective method for one-step synthesis of nitriles employing C2-C8 fatty primary alcohols and ammonia over 5%Cu/m-ZrO2 has been found. The conversion of alcohols and selectivity of nitriles obtained are > 96 and > 87 wt.%, respectively, and are obviously influenced by the C2-substitution rather than the chain length of fatty primary alcohols. Cu/m-ZrO2 was characterized by XRD, H2-TPR, CO2-TPD and NH3-TPD. It is revealed that a substantial amount of Cu species over m-ZrO2 is in highly dispersed CuO. A plausible mechanism is proposed and supported by different experiments, and aldehyde generation is an important step in the reaction mechanism.
- Hu, Yunfeng,Jin, Shuhan,Zhang, Zhichao,Zhang, Likun,Deng, Jun,Zhang, Hongsheng
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- Copper nanoparticles from copper aluminum hydrotalcite: An efficient catalyst for acceptor- and oxidant-free dehydrogenation of amines and alcohols
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An efficient and simple process for the preparation of stable nanocopper(0) on alumina [Cu(0)/Al2O3] from the inorganic composite precursor copper aluminum hydrotalcite (Cu-AlHT) by a chemical reduction method is described. Cu(0)/ Al2O3 was employed as an efficient catalyst in the acceptor- and oxidant-free dehydrogenation of various amines and alcohols to their corresponding dehydrogenated products in good to excellent yields. The stability of Cu(0)/Al2O3 was assessed by studying its recoverability and reusability in the dehydrogenation of amines and alcohols for up to five cycles.
- Damodara, Dandu,Arundhathi, Racha,Likhar, Pravin R.
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supporting information
p. 189 - 198
(2014/03/21)
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- Oxidant-free conversion of primary amines to nitriles
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An amide-derived NNN-Ru(II) hydride complex catalyzes oxidant-free, acceptorless, and chemoselective dehydrogenation of primary and secondary amines to the corresponding nitriles and imines with liberation of dihydrogen. The catalyst system tolerates oxidizable functionality and is selective for the dehydrogenation of primary amines (-CH2NH2) in the presence of amines without α-CH hydrogens.
- Tseng, Kuei-Nin T.,Rizzi, Andrew M.,Szymczak, Nathaniel K.
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supporting information
p. 16352 - 16355
(2013/12/04)
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- Cu/nitroxyl-catalyzed aerobic oxidation of primary amines into nitriles at room temperature
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An efficient catalytic method has been developed for aerobic oxidation of primary amines to the corresponding nitriles. The reactions proceed at room temperature and employ a catalyst consisting of (4,4′-tBu 2bpy)CuI/ABNO (ABNO = 9-azabicyclo[3.3.1]nonan-3-one-N-oxyl). The reactions exhibit excellent functional group compatibility and substrate scope and are effective with benzylic, allylic, and aliphatic amines. Preliminary mechanistic studies suggest that aerobic oxidation of the Cu catalyst is the turnover-limiting step of the reaction.
- Kim, Jinho,Stahl, Shannon S.
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p. 1652 - 1656
(2013/07/26)
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- Novel ruthenium-terpyridyl complex for direct oxidation of amines to nitriles
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High catalytic activity and selectivity has been demonstrated for the oxidation of both aliphatic and aromatic amines to nitriles under benign conditions with dioxygen or air using the Ru2Cl4(az-tpy) 2 complex. The conversion was found to be strongly influenced by the alkyl chain length of the reactant with shorter chain amines found to have lower conversions than those with longer chains. Importantly, by using the ruthenium terpyridine complex functionalized with azulenyl moiety at the 4 position of central pyridine core provided a much higher reactivity catalyst compared with a series of ruthenium terpyridine-based ligand complexes reported. Mechanistic studies using deuterated benzylamine demonstrated the importance of RuOH in this reaction.
- Cristian, Liliana,Nica, Simona,Pavel, Octavian D.,Mihailciuc, Constantin,Almasan, Valer,Coman, Simona M.,Hardacre, Christopher,Parvulescu, Vasile I.
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p. 2646 - 2653
(2013/09/24)
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- A clean and efficient conversion of aldehydes into the corresponding nitriles using ionic supported triphenylphosphine and CBr4
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An ionic supported triphenylphosphine and carbon tetrabromide system has been applied to the clean and efficient conversion of various aromatic and aliphatic aldehydes to the corresponding nitriles.
- Huo, Congde,Wang, Cheng,Hu, Dongcheng,Jia, Xiaodong
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p. 442 - 444
(2013/08/23)
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