- Impact of solvent on Co/SiO2 activity and selectivity for the synthesis of n-butylamine from butyronitrile hydrogenation
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The impact of solvent on Co(9.8%)/SiO2 activity and selectivity for the synthesis of n-butylamine from butyronitrile hydrogenation was investigated using methanol, benzene, toluene and cyclohexane as solvents. In non-polar solvents, the yield of n-butylamine increased from 60% to 79% following the order cyclohexane toluene benzene. Nevertheless, the highest n-butylamine yield (91%) was obtained in methanol, a protic solvent. The solvent effect on the catalyst performance was interpreted by considering: i) the solvent-catalyst interaction strength and ii) the solvent polarity and its ability for H-bond formation with n-butylamine.
- Segobia,Trasarti,Apesteguía
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- Kinetics of Amine Addition to Benzylidenemalonodialdehyde in 50percent Me2SO-50percent water
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The kinetics of the reaction of benzylidenemalonodialdehyde with piperidine, morpholine, n-butylamine, 2-methoxyethylamine, glycinamide, glycine ethyl ester, cyanomethylamine, and semicarbazide have been determined in 50percent aqueous Me2SO at 20 deg C.The reaction leads to a zwitterionic adduct, PhCH(RR'NH(1+))C(CHO)2(1-) (TA(+/-)), that is in fast acid-base equilibrium with the anionic adduct, PhCH(RR'N)C(CHO)2(1-) (TA(1-)).With strongly basic amines at high pH there is also attack of the amine on one of the carbonyl groups, which acts as a rapid preequilibrium.Rate constants for the formation of TA(+/-) (k1) and its reverse (k-1), as well as equilibrium constants (K1 = k1/k-1) and the pKa of TA(+/-) were determined for all the amines.Intrinsic rate constants (k0 = k1 = k-1 when K1 = 1) were calculated.The intrinsic rate constants are lower than those for amine addition to benzylidene Meldrum's acid.This is consistent with the greater role played by resonance in stabilizing TA(+/-) derived from benzylidenemalonodialdehyde.However, k0 for piperidine/morpholine addition to benzylidenemalonodialdehyde is much higher than for the reaction of benzylideneacetylacetone with the same amines, indicating that the rate-depressing effect of intramolecular hydrogen bonding in TA(+/-) derived from benzylidenemalonodialdehyde is much smaller than that in TA(+/-) derived from benzylideneacetylacetone.Even though semicarbazide is an α-effect nucleophile, no enhancement of k1 was observed, but K1, estimated on the basis of a structure-reactivity relationship, is larger than expected based on the pKa of the amine.This result is attributed to a low νnucn value.
- Bernasconi, Claude F.,Stronach, Michael W.
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- Dynamic Covalent Switches and Communicating Networks for Tunable Multicolor Luminescent Systems and Vapor-Responsive Materials
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Molecular switches are an intensive area of research, and in particular, the control of multistate switching is challenging. Herein we introduce a general and versatile strategy of dynamic covalent switches and communicating networks, wherein distinct states of reversible covalent systems can induce addressable fluorescence switching. The regulation of intramolecular ring/chain equilibrium, intermolecular dynamic covalent reactions (DCRs) with amines, and both permitted the activation of optical switches. The variation in electron-withdrawing competition between the fluorophore and 2-formylbenzenesulfonyl unit afforded diverse signaling patterns. The combination of switches in situ further enabled the creation of communicating networks for multistate color switching, including white emission, through the delicate control of DCRs in complex mixtures. Finally, reversible and recyclable multiresponsive luminescent materials were achieved with molecular networks on the solid support, allowing visualization of different types of vapors and quantification of primary amine vapors with high sensitivity and wide detection range. The results reported herein should be appealing for future studies of dynamic assemblies, molecular sensing, intelligent materials, and biological labeling.
- Zou, Hanxun,Hai, Yu,Ye, Hebo,You, Lei
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- Biocatalysed synthesis of chiral amines: continuous colorimetric assays for mining amine-transaminases
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In the course of our research aimed at the design of new biocatalytic processes for the enantioselective synthesis of chiral amines, we have developed new continuous assays for the screening of amine-transaminase collections. These assays are based on the use of hypotaurine as an irreversible amine donor. This β-aminosulfinic acid is converted upon transamination into 2-oxoethylsulfinic acid, which instantaneously decomposes into acetaldehyde and sulfite ions that can be easily detected by spectrophotometry using Ellman's reagent. Two complementary assays were developed based on this titration method. Firstly, a direct assay allowed detection of various transaminases able to use hypotaurine as an amino donor. In a second coupled assay,l-alanine is used as a generic donor substrate of amine-transaminases and is regenerated using an auxiliary hypotaurine-transaminase. The powerful and complementary nature of both assays was demonstrated through the screening of a collection of 549 amine-transaminases from biodiversity, thus allowing the discovery of a variety of valuable new biocatalysts for use in synthetic processes.
- Gourbeyre, Léa,Heuson, Egon,Charmantray, Franck,Hélaine, Virgil,Debard, Adrien,Petit, Jean-Louis,de Berardinis, Véronique,Gefflaut, Thierry
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- Kinetic and equilibrium studies of σ-adduct formation and nucleophilic substitution in the reactions of trinitro-activated benzenes with aliphatic amines in acetonitrile
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Rate and equilibrium constants are reported for reactions in acetonitrile of butylamine, pyrrolidine and piperidine with 1,3,5-trinitrobenzene, 1, and with ethyl 2,4,6-trinitrophenyl ether, 4a, and phenyl 2,4,6-trinitrophenyl ether, 4b. Rapid nucleophilic attack at unsubstituted ring-positions may yield anionic σ-adducts via zwitterionic intermediates, while slower attack at the 1-position of 4a and 4b may lead to substitution to give 2,4,6-trinitroaniline derivatives. Base catalysis in the substitution reaction reflects rate-limiting proton transfer which may be from the zwitterionic intermediates to amine in the case of 4b, or from a substituted ammonium ion to the ethoxy leaving group in the case of 4a. Comparisons with values in DMSO indicate that values of overall equilibrium constants for adduct formation are ca. 104 lower in acetonitrile, while rate constants for proton transfer are ca. 104 higher. These differences may reflect strong hydrogen-bonding between DMSO and -NH+ protons in ammonium ions and in zwitterions. In acetonitrile homoconjugation of substituted ammonium ions with free amine is an important factor.
- Crampton, Michael R.,Lord, Simon D.
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- SOLVATION OF PRIMARY AMINES: SHORT-RANGE SOLVATION OF PROTON TRANSFER COMPLEXES OF 2,4-DINITROPHENOL, AND n-BUTYLAMINE
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The short range solvation of the proton-transfer complex formed between 2,4-dinitrophenol and n-butylamine was studied in benzene solution containing small amounts of three ethers: n-propylether, tetrahydropyran, and dioxane.In all cases a pattern is observed in which solvation by the ether causes an increase in the equilibrium constant for the formation of the proton transfer complex until a plateau value is reached.This is followed on further increase of the ether concentration by a second rise followed by a second plateau.The equilibrium constants for each of thesolvation events and the number of solvent molecules reacting per amine molecule were calculated.The first step involves two solvent molecules per amine, and the second step involves a larger number.
- Guo, Shuqiong,Scott, Ronald M.
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- Charged states of proteins. Reactions of doubly protonated alkyldiamines with NH3: Solvation or deprotonation. Extension of two proton cases to multiply protonated globular proteins observed in the gas phase
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The apparent gas-phase basicities (GBapp'S) of basic sites in multiply protonated molecules, such as proteins, can be approximately predicted. An approach used by Williams and co-workers was to develop an equation for a diprotonated system, NH
- Peschke, Michael,Blades, Arthur,Kebarle, Paul
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- A new supported rhodium catalyst for selective hydrogenation of nitriles to primary amines
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Nitriles are converted to primary amines with high selectivity using a newly developed alumina-supported rhodium catalyst. The high selectivity is obtained without any additives, which are often used to prevent the formation of higher amines. The catalyst is active under mild conditions In various solvents, which makes it specifically suitable for use in pharmaceutical applications or for other substrates that can react with additives like strong acids or bases.
- Witte, Peter T.
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- Electron Spin Resonance Monitoring of Ligand Ejection Reactions Following Solid-State Reduction of Cobalt Globin and Cobalt Protoporphyrin Complexes
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Cobaltihemoglobin, isolated α and β chains, and cobaltimyoglobin in aqueous solution at neutral pH were irradiated at 77 K with 3 Mrd of 60Co γ-rays.These diamagnetic Co(III) species are converted to paramagnetic Co(II) species in high yield.The EPR spectra are identical with those of authentic six-coordinate cobalt(II) porphyrins.Upon partial annealing of the species, the EPR spectrum transforms irreversibly to that of a five-coordinate species, indicating that at 77 K these cobaltiglobins are cobaltichromes in analogy to the hemichromes of the native iron species.Differences are seen among all of the six-coordinate, reduced protein ligated species.This ejection of the sixth ligand with thermal annealing after addition of one electron to the dz2 orbital of the cobalt porphyrin also occurs in aqueous glasses of cobalt protoporphyrin IX in pyridine, n-butylamine, or quinuclidine.The five-coordinate species in aqueous media are stable with annealing to room temperature.
- Dickinson, L. Charles,Symons, M. C. R.
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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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- Conversion of alcohols to enantiopure amines through dual-enzyme hydrogen-borrowing cascades
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α-Chiral amines are key intermediates for the synthesis of a plethora of chemical compounds at industrial scale. We present a biocatalytic hydrogen-borrowing amination of primary and secondary alcohols that allows for the efficient and environmentally benign production of enantiopure amines. The method relies on a combination of two enzymes: an alcohol dehydrogenase (from Aromatoleum sp., Lactobacillus sp., or Bacillus sp.) operating in tandem with an amine dehydrogenase (engineered from Bacillus sp.) to aminate a structurally diverse range of aromatic and aliphatic alcohols, yielding up to 96% conversion and 99% enantiomeric excess. Primary alcohols were aminated with high conversion (up to 99%). This redox self-sufficient cascade possesses high atom efficiency, sourcing nitrogen from ammonium and generating water as the sole by-product.
- Mutti, Francesco G.,Knaus, Tanja,Scrutton, Nigel S.,Breuer, Michael,Turner, Nicholas J.
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- Amination of ω-Functionalized Aliphatic Primary Alcohols by a Biocatalytic Oxidation-Transamination Cascade
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Amination of non-activated aliphatic fatty alcohols to the corresponding primary amines was achieved through a five-enzyme cascade reaction by coupling a long-chain alcohol oxidase from Aspergillus fumigatus (LCAO-Af) with a ω-transaminase from Chromobacterium violaceum (ω-TA-Cv). The alcohol was oxidized at the expense of molecular oxygen to yield the corresponding aldehyde, which was subsequently aminated by the PLP-dependent ω-TA to yield the final primary amine product. The overall cascade was optimized with respect to pH, O2 pressure, substrate concentration, decomposition of H2O2 (derived from alcohol oxidation), NADH regeneration, and biocatalyst ratio. The substrate scope of this concept was investigated under optimized conditions by using terminally functionalized C4-C11 fatty primary alcohols bearing halogen, alkyne, amino, hydroxy, thiol, and nitrile groups.
- Pickl, Mathias,Fuchs, Michael,Glueck, Silvia M.,Faber, Kurt
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- N,N-Chelate nickel(II) complexes bearing Schiff base ligands as efficient hydrogenation catalysts for amine synthesis
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Five N, N-chelate nickel (II) complexes bearing N-(2-pyridinylmethylene)-benzylamine ligands with different substituent groups were synthesized in good yields. The nickel complexes exhibited prominent catalytic efficiency toward amine synthesis from nitro compounds by using NaBH4 or H2 as hydrogen source through two catalytic systems. Various amines with different substituents were obtained in moderate to excellent yields. All substrates with electron-donating and electron-withdrawing properties were tolerated in the two reduction systems. Given the efficient catalytic activity, broad substance scope, and mild reduction conditions, the nickel catalysts have potential applications in industrial production.
- Xu, Mengyin,Wang, Yang,Zhou, Yifeng,Yao, Zi-Jian
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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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- Synthesis, Structure, and Catalytic Hydrogenation Activity of [NO]-Chelate Half-Sandwich Iridium Complexes with Schiff Base Ligands
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A series of N,O-coordinate iridium(III) complexes with a half-sandwich motif bearing Schiff base ligands for catalytic hydrogenation of nitro and carbonyl substrates have been synthesized. All iridium complexes showed efficient catalytic activity for the hydrogenation of ketones, aldehydes, and nitro-containing compounds using clean H2 as reducing reagent. The iridium catalyst displayed the highest TON values of 960 and 950 in the hydrogenation of carbonyl and nitro substrates, respectively. Various types of substrates with different substituted groups afforded corresponding products in excellent yields. All N,O-coordinate iridium(III) complexes 1-4 were well characterized by IR, NMR, HRMS, and elemental analysis. The molecular structure of complex 1 was further characterized by single-crystal X-ray determination.
- Lv, Wen-Rui,Li, Rong-Jian,Liu, Zhen-Jiang,Jin, Yan,Yao, Zi-Jian
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p. 8181 - 8188
(2021/05/26)
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- Half-sandwiched ruthenium complex containing carborane schiff base ligand and preparation and application thereof
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The invention relates to a half-sandwiched ruthenium complex containing a carborane schiff base ligand and a preparation and an application thereof. The preparation method specifically comprises the following steps; i) dissolving o-carborane formaldehyde and aromatic amine in an organic solvent, carrying out reaction at 60-100 DEG C for 8-12h, cooling to room temperature after the reaction; ii) adding n-butyllithium, carrying out reaction at room temperature for 1.5-2.5h; ii) adding phellandrene ruthenium chloride dimer, carrying out reaction at room temperature for 3-6h, and obtaining the half-sandwiched ruthenium complex through separation. The half-sandwiched ruthenium complex is applied to catalyze transfer hydrogenation reaction of nitrile compounds. Compared with the prior art, the complex of the present invention is not sensitive to air and water, has stable properties, and shows high-efficiency catalytic activity in catalyzing the transfer hydrogenation reaction of nitrile compounds. The preparation method of the complex is simple and green, high in yield, mild in reaction conditions and good in universality.
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Paragraph 0067-0071
(2020/12/09)
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- PROCESS FOR PREPARING PRIMARY AMINES FROM ALCOHOLS
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A process for preparing a primary amine by reacting an alcohol with ammonia in the present of a metal catalyst comprising metal nanoparticles, wherein the metal nano-particles comprises at least one transition metal in elemental form and/or at least one transition metal compound and carbonaceous species are deposited on the metal nan-oparticles.
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Page/Page column 13
(2020/06/10)
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- Ambient-Temperature Synthesis of Primary Amines via Reductive Amination of Carbonyl Compounds
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Efficient synthesis of primary amines via low-temperature reductive amination of carbonyl compounds using NH3 and H2 as the nitrogen and hydrogen resources is highly desired and challenging in the chemistry community. Herein, we employed naturally occurring phytic acid as a renewable precursor to fabricate titanium phosphate (TiP)-supported Ru nanocatalysts with different reduction degrees of RuO2 (Ru/TiP-x, x represents the reduction temperature) by combining ball milling and molten-salt processes. Very interestingly, the obtained Ru/TiP-100 had good catalytic performance for the reductive amination of carbonyl compounds at ambient temperature, resulting from the synergistic cooperation of the support (TiP) and the Ru/RuO2 with a suitable proportion of Ru0 (52%). Various carbonyl compounds could be efficiently converted into the corresponding primary amines with high yields. More importantly, the conversion of other substrates with reducible groups could also be achieved at ambient temperature. Detailed investigations indicated that the partially reduced Ru and the support (TiP) were indispensable. The high activity and selectivity of Ru/TiP-100 catalyst originates from the relatively high acidity and the suitable electron density of metallic Ru0.
- Xie, Chao,Song, Jinliang,Hua, Manli,Hu, Yue,Huang, Xin,Wu, Haoran,Yang, Guanying,Han, Buxing
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p. 7763 - 7772
(2020/08/21)
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- Rice husk-SiO2supported bimetallic Fe-Ni nanoparticles: as a new, powerful magnetic nanocomposite for the aqueous reduction of nitro compounds to amines
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This paper reports a novel green procedure for immobilization of bimetallic Fe/Ni on amorphous silica nanoparticles extracted from rice husk (RH-SiO2). The heterogeneous nanocomposite (Fe/Ni?RH-SiO2) was identified using SEM, EDX, TEM, BET, H2-TPR, TGA, XRD, VSM, ICP-OES, and FT-IR analyses. The Fe/Ni?RH-SiO2nanocomposite was applied as a powerful catalyst for the reduction of structurally diverse nitro compounds with sodium borohydride (NaBH4) in green conditions. This procedure suggests some benefits such as green chemistry-based properties, short reaction times, non-explosive materials, easy to handle, fast separation and simple work-up method. The catalyst was separated by an external magnet from the reaction mixture and was reused for 9 successive cycles with no detectable changes of its catalytic efficiency.
- Ghadermazi, Mohammad,Moradi, Setareh,Mozafari, Roya
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p. 33389 - 33400
(2020/09/21)
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- Modulation of imine chemistry with intramolecular hydrogen bonding: Effects from ortho-OH to NH
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Salicylaldehyde derivatives and their imines are important building blocks in organic and supramolecular chemistry. In an effort to expand structural diversity in the current work we changed ortho-OH in salicylaldehyde to NH of amide/sulfonamide and investigated the effect of resulting intramolecular hydrogen bonds on imine dynamic covalent chemistry (DCC). A suite of ortho-aminobenzaldehydes were readily synthesized, and X-ray and NMR data validated the existence of NH?O intramolecular hydrogen bonds. The formation and exchange of imines were then studied in acetonitrile, and the acidity of OH/NH significantly influenced the thermodynamics and kinetics of imine reactions. Furthermore, the role of OH/NH?N hydrogen bonds on imines was elucidated by the shift of aldehyde exchange equilibrium. Finally, the formation of imines was achieved in aqueous solutions. The mechanistic insights could pave the way for future applications in assembly and labelling.
- Chen, Hang,Feng, Zelin,Jia, Shuaipeng,You, Lei
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supporting information
(2020/03/24)
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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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- Environmentally responsible, safe, and chemoselective catalytic hydrogenation of olefins: ppm level Pd catalysis in recyclable water at room temperature
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Textbook catalytic hydrogenations are typically presented as reactions done in organic solvents and oftentimes under varying pressures of hydrogen using specialized equipment. Catalysts new and old are all used under similar conditions that no longer reflect the times. By definition, such reactions are both environmentally irresponsible and dangerous, especially at industrial scales. We now report on a general method for chemoselective and safe hydrogenation of olefins in water using ppm loadings of palladium from commercially available, inexpensive, and recyclable Pd/C, together with hydrogen gas utilized at 1 atmosphere. A variety of alkenes is amenable to reduction, including terminal, highly substituted internal, and variously conjugated arrays. In most cases, only 500 ppm of heterogeneous Pd/C is sufficient, enabled by micellar catalysis used in recyclable water at room temperature. Comparison with several newly introduced catalysts featuring base metals illustrates the superiority of chemistry in water.
- Gallou, Fabrice,Gao, Eugene S.,Lipshutz, Bruce H.,Takale, Balaram S.,Thakore, Ruchita R.
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supporting information
p. 6055 - 6061
(2020/10/14)
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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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- Metal-free nitrogen -doped carbon nanosheets: A catalyst for the direct synthesis of imines under mild conditions
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Herein, a highly stable, porous, multifunctional and metal-free catalyst was developed, which exhibited significant catalytic performance in the oxidation of amines and transfer hydrogenation of nitriles under mild conditions; this could be attributed to the presence of numerous active sites and their outstanding BET surface area. The obtained results showed that most of the yields of imines exceeded 90%, and the cycling performance of the catalyst could be at least seven runs without any decay in the reaction activity, which could be comparable to those of metal catalysts. Subsequently, a kinetic study has demonstrated that the apparent activation energy for the direct synthesis of imines from amines is 67.39 kJ mol-1, which has been performed to testify that the catalytic performances are rational. Via catalyst characterizations and experimental data, graphitic-N has been proven to be the active site of the catalyst. Hence, this study is beneficial to comprehend the mechanism of action of a metal-free N-doped carbon catalyst in the formation of imines.
- Wang, Kaizhi,Jiang, Pengbo,Yang, Ming,Ma, Ping,Qin, Jiaheng,Huang, Xiaokang,Ma, Lei,Li, Rong
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p. 2448 - 2461
(2019/05/17)
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- Mild palladium-catalysed highly efficient hydrogenation of CN, C-NO2, and CO bonds using H2 of 1 atm in H2O
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Here we present the first example of a mild and high-efficiency protocol enabling a process in water using 1 atm of H2 for the efficient and selective hydrogenation of nitriles, nitro compounds, ketones, and aldehydes to yield primary amines and alcohols with satisfactory yields of up to >99%. Several palladium-based nanoparticle catalysts were prepared from K2PdCl4 and ligands, and one of them was found to be the best and most suitable for the hydrogenation of CN, C-NO2, and CO bonds. In addition, the catalyst Pd-NPs can be easily recycled and reused without losing their activity and selectivity. A plausible mechanism for the hydrogenation of a CN bond was also proposed, representing the first example that possesses great potential for sustainable industrial purposes.
- Liu, Yaxu,He, Shaopo,Quan, Ziyi,Cai, Huizhuo,Zhao, Yang,Wang, Bo
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supporting information
p. 830 - 838
(2019/02/27)
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- PROCESS FOR PRODUCING AN AMINE IN A SOLVENT SYSTEM CONTAINING WATER
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The present invention pertains to a process for producing an amine from an aldehyde or a precursor thereof, or a ketone in a solvent system containing water. The process is more environmentally friendly and permits to obtain an amine compound under mild reaction conditions.
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Page/Page column 17-18
(2019/10/04)
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- Effect of the catalyst preparation method on the performance of Ni-supported catalysts for the synthesis of saturated amines from nitrile hydrogenation
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The liquid-phase hydrogenation of butyronitrile to saturated amines was studied on silica-supported Ni catalysts prepared by either incipient-wetness impregnation (Ni/SiO2-I) or ammonia (Ni/SiO2-A) methods. A Ni/SiO2-Al2O3-I sample was also used. Ni/SiO2-I was a non-acidic catalyst containing large Ni0 particles of low interaction with the support, while Ni/SiO2-A was an acidic catalyst due to the presence of Ni2+ species in Ni phyllosilicates of low reducibility. Ni/SiO2-I formed essentially butylamine (80%), and dibutylamine as the only byproduct. In contrast, Ni/SiO2-A yielded a mixture of dibutylamine (49%) and tributylamine (45%), being the formation of butylamine almost completely suppressed. The selective formation of secondary and tertiary amines on Ni/SiO2-A was explained by considering that butylamine is not release to the liquid phase during the reaction because it is strongly adsorbed on surface acid sites contiguous to Ni0 atoms, thereby favoring the butylimine/butylamine condensation to higher amines between adsorbed species.
- Segobia,Trasarti,Apesteguía
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p. 1693 - 1703
(2019/11/11)
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- B(C6F5)3-Catalyzed Deoxygenative Reduction of Amides to Amines with Ammonia Borane
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The first B(C6F5)3-catalyzed deoxygenative reduction of amides into the corresponding amines with readily accessible and stable ammonia borane (AB) as a reducing agent under mild reaction conditions is reported. This metal-free protocol provides facile access to a wide range of structurally diverse amine products in good to excellent yields, and various functional groups including those that are reduction-sensitive were well tolerated. This new method is also applicable to chiral amide substrates without erosion of the enantiomeric purity. The role of BF3 ? OEt2 co-catalyst in this reaction is to activate the amide carbonyl group via the in situ formation of an amide-boron adduct. (Figure presented.).
- Pan, Yixiao,Luo, Zhenli,Han, Jiahong,Xu, Xin,Chen, Changjun,Zhao, Haoqiang,Xu, Lijin,Fan, Qinghua,Xiao, Jianliang
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supporting information
p. 2301 - 2308
(2019/01/30)
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- 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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- Selective one-pot synthesis of asymmetric secondary amines via N-alkylation of nitriles with alcohols
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The synthesis of asymmetric secondary amines (ASA) is commonly achieved by N-alkylation of primary amines with alcohols. Here, we investigated the ASA synthesis via the direct amination of alcohols with nitriles, which avoids the synthesis, separation and purification of the primary amines in a first step. Specifically, the ASA synthesis via N-alkylation of butyronitrile (BN) with primary (n-propanol, iso-butanol and n-octanol) and secondary (2‐propanol, 2‐butanol and 2‐octanol) alcohols was studied on SiO2-supported Co, Ni and Ru catalysts. Competitive BN hydrogenation‐condensation reactions formed dibutylamine (the symmetric secondary amine) and tertiary amines as main secondary products. On Co/SiO2, the ASA selectivities for BN/primary alcohol reactions were between 49 and 58% at complete BN conversion, forming dibutylamine and tertiary amines as byproducts. For BN/secondary alcohol reactions, Co/SiO2 formed selectively (ASA + dibutylamine) mixtures containing 78–85% of ASA, thereby showing that the alcohol amination with nitriles is an attractive alternative route for the synthesis of valuable asymmetric secondary amines.
- Segobia,Trasarti,Apesteguía
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p. 178 - 185
(2019/11/13)
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- An amine protecting group deprotectable under nearly neutral oxidative conditions
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The 1,3-dithiane-based dM-Dmoc group was studied for the protection of amino groups. Protection was achieved under mild conditions for aliphatic amines, and under highly reactive conditions for the less reactive arylamines. Moderate to excellent yields were obtained. Deprotection was performed by oxidation followed by treating with a weak base. The yields were good to excellent. The new amino protecting group offers a different dimension of orthogonality in reference to the commonly used amino protecting groups in terms of deprotection conditions. It is expected to allow a collection of transformations to be carried out on the protected substrates that are unattainable using any known protecting groups.
- Shahsavari, Shahien,McNamara, Chase,Sylvester, Mark,Bromley, Emily,Joslin, Savannah,Lu, Bao-Yuan,Fang, Shiyue
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p. 1750 - 1757
(2018/08/21)
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- Benzhydrylamine: An effective aminating agent for the synthesis of primary amines
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Aldehydes, ketones, alkyl toluene-p-sulfonates and halides are converted into the corresponding primary amines with benzhydrylamine as a valuable ammonia synthon in moderate to excellent yields.
- Sun, Quan-Wei,Xing, Jun-De,Qin, Yu-Hong,Yin, Xu-Wen,Zhou, Yi
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p. 181 - 183
(2018/05/26)
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- An Efficient Ruthenium Catalyst Bearing Tetradentate Ligand for Hydrogenations of Carbon Dioxide
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A ruthenium complex with a tetradentate bipyridine ligand was proved to be a highly efficient catalyst for the conversions of CO2. Turnover numbers up to 300 000, 9800, and 2100 were achieved for the hydrogenations of CO2 to formamides, formamides to methanol and amines, and the direct hydrogenation of CO2 to methanol, respectively.
- Zhang, Feng-Hua,Liu, Chong,Li, Wei,Tian, Gui-Long,Xie, Jian-Hua,Zhou, Qi-Lin
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supporting information
p. 1000 - 1002
(2018/09/21)
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- Low-Pressure Hydrogenation of Nitriles to Primary Amines Catalyzed by Ruthenium Pincer Complexes. Scope and mechanism
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The catalytic hydrogenation of nitriles to primary amines constitutes an environmentally benign and atom-economical methodology in synthetic organic chemistry. However, selective hydrogenation can be challenging, and usually elevated pressure and the use of various additives is required. Herein the hydrogenation of aromatic and aliphatic nitriles to form primary amines catalyzed by ruthenium pincer complexes is described. The reactions are conducted at low H2 pressure, low catalytic loadings and, in case of a variety of benzonitriles, under neutral conditions and without any additives. Mechanistic insight is provided.
- Mukherjee, Arup,Srimani, Dipankar,Ben-David, Yehoshoa,Milstein, David
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p. 559 - 563
(2017/02/26)
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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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- An improved and one-pot procedure to the synthesis of symmetric amines by domino reactions of 5-methyl-1,3,4-thiadiazole-2-amine, a new nitrogen atom donor, and alkyl halides
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Abstract: A new one-pot method has been introduced in this work for the synthesis of symmetrical primary, secondary, and tertiary alkyl amines from alkyl halides and 5-methyl-1,3,4-thiadiazole-2-amine as a nitrogen-transfer reagent. In this method, all three types of amines have been successfully prepared after changing the ratio of substrates and base control. In addition to the introduction of a new nitrogen-transfer reagent, other important features of this work include normal atmospheric conditions and excellent yields under mild reaction conditions.
- Soleiman-Beigi, Mohammad,Mohammadi, Fariba
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p. 2123 - 2128
(2017/10/26)
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- A metagenomics approach for new biocatalyst discovery: Application to transaminases and the synthesis of allylic amines
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Transaminase enzymes have significant potential for the sustainable synthesis of amines using mild aqueous reaction conditions. Here a metagenomics mining strategy has been used for new transaminase enzyme discovery. Starting from oral cavity microbiome samples, DNA sequencing and bioinformatics analyses were performed. Subsequent in silico mining of a library of contiguous reads built from the sequencing data identified 11 putative Class III transaminases which were cloned and overexpressed. Several screening protocols were used and three enzymes selected of interest due to activities towards substrates covering a wide structural diversity. Transamination of functionalized cinnamaldehydes was then investigated for the production of valuable amine building blocks.
- Baud, Damien,Jeffries, Jack W. E.,Moody, Thomas S.,Ward, John M.,Hailes, Helen C.
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p. 1134 - 1143
(2017/08/14)
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- Production of Primary Amines by Reductive Amination of Biomass-Derived Aldehydes/Ketones
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Transformation of biomass into valuable nitrogen-containing compounds is highly desired, yet limited success has been achieved. Here we report an efficient catalyst system, partially reduced Ru/ZrO2, which could catalyze the reductive amination of a variety of biomass-derived aldehydes/ketones in aqueous ammonia. With this approach, a spectrum of renewable primary amines was produced in good to excellent yields. Moreover, we have demonstrated a two-step approach for production of ethanolamine, a large-market nitrogen-containing chemical, from lignocellulose in an overall yield of 10 %. Extensive characterizations showed that Ru/ZrO2-containing multivalence Ru association species worked as a bifunctional catalyst, with RuO2 as acidic promoter to facilitate the activation of carbonyl groups and Ru as active sites for the subsequent imine hydrogenation.
- Liang, Guanfeng,Wang, Aiqin,Li, Lin,Xu, Gang,Yan, Ning,Zhang, Tao
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supporting information
p. 3050 - 3054
(2017/03/14)
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- Direct Catalytic Hydrogenation of Simple Amides: A Highly Efficient Approach from Amides to Amines and Alcohols
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A highly chemoselective and reactive direct catalytic reduction of various amides to amines and alcohols was developed by using a tetradentate ruthenium complex. The catalytic system showed excellent activity (turnover numbers up to 19 600) and great functional group tolerance under mild reaction conditions, compared to several bidentate and tridentate ruthenium-catalyzed systems.
- Shi, Liyang,Tan, Xuefeng,Long, Jiao,Xiong, Xiong,Yang, Song,Xue, Peng,Lv, Hui,Zhang, Xumu
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supporting information
p. 546 - 548
(2017/01/18)
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- Versatile Dynamic Covalent Assemblies for Probing π-Stacking and Chirality Induction from Homotopic Faces
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Herein we report for the first time the use of dynamic covalent reactions (DCRs) for building a π-stacking model system and further quantifying its substituent effects (SEs), which remain a topic of debate despite the rich history of stacking. A general DCR between 10-methylacridinium ion and primary amines was discovered, in which π-stacking played a stabilizing role. Facile quantification of SEs with in situ competing π-stacking systems was next achieved in the form of amine exchange exhibiting structural diversity by simply varying components. The linear correlation with σm in Hammett plots indicates the dominance of purely electrostatic SEs, and the additivity of SEs is in line with the direct interaction model. With α-chiral amines π-stacking within the adduct enabled chirality transfer from homotopic faces. The strategy of dynamic covalent assembly should be appealing to future research of probing weak interactions and manipulating chirality.
- Ye, Hebo,Hai, Yu,Ren, Yulong,You, Lei
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supporting information
p. 3804 - 3809
(2017/03/27)
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- Tris(2-carboxyethyl)phosphine promotes hydrolysis of iminoboronates
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Iminoboronates are stable and formed fast. Their B[sbnd]N bonds could be reverted by some endogenous biological molecules. The reversible characteristic attracts significant attention in biological and chemical fields. Although synthesis of iminoboronates is well-studied, less efforts have been devoted to disconnecting the units. Here, a series of selected compounds were screened to evaluate their hydrolytic capability of iminoboronates by 1H NMR or 11B NMR detection. Tris(2-carboxyethyl)phosphine (TCEP), was emerged as an excellent reagent, which decomposed most iminoboronates in short time with high yields. In addition, TCEP is also able to hydrolyze hydrazones and oximes with moderate yields.
- Liu, Xiaoyu,Li, Zhihong,Xu, Hongtao,Zhan, Yuexiong,Ma, Peixiang,Chen, Hongli,Jiang, Biao
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p. 3101 - 3106
(2017/07/18)
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- Efficient Reduction of C–N Multiple Bonds Catalyzed by Magnetically Retrievable Magnetite Nanoparticles with Sodium Borohydride
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Abstract: A simple, rapid and efficient methodology has been developed for the reductive transformation of the compounds bearing C–N multiple bonds such as oximes and nitriles to the corresponding amines by sodium borohydride catalyzed by highly active solid Fe3O4 nanoparticles. The catalyst was easily recovered using external magnet and reused five times without losing its catalytic activity. Graphical Abstract: A simple, rapid, efficient and reusable heterogeneous catalytic system has been developed for the reductive transformation of oximes and nitriles into corresponding amines by sodium borohydride in presence of Fe3O4 nanoparticles.[Figure not available: see fulltext.]
- Kumari, Pratibha,Gautam, Renu,Yadav, Harshit,Kushwaha, Vikas,Mishra, Avinash,Gupta, Shilpi,Arora, Veena
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p. 2149 - 2156
(2016/10/18)
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- Process for the preparation of n-butylamine
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The invention discloses a preparation method of n-butylamine, which comprises the following steps: mixing n-butanol, ammonia and hydrogen in a mole ratio of 1:(2-7):(3-7), reacting at 160-220 DEG C under the pressure of 0.3-0.8 MPa at the air speed of 0.15-0.6 h under the action of a catalyst, standing the collected reaction product to stratify to obtain a supernatant organic phase and an understratum water phase, distilling the supernatant organic phase, and collecting the 76-80 DEG C fraction to obtain the n-butylamine. The method for preparing n-butylamine has the technical advantages of technique, mild reaction conditions, high n-butylamine yield, low cost and the like.
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Paragraph 0043-0047
(2017/06/20)
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- Integrated Heterogeneous Metal/Enzymatic Multiple Relay Catalysis for Eco-Friendly and Asymmetric Synthesis
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Organic synthesis is in general performed using stepwise transformations where isolation and purification of key intermediates is often required prior to further reactions. Herein we disclose the concept of integrated heterogeneous metal/enzymatic multiple relay catalysis for eco-friendly and asymmetric synthesis of valuable molecules (e.g., amines and amides) in one-pot using a combination of heterogeneous metal and enzyme catalysts. Here reagents, catalysts, and different conditions can be introduced throughout the one-pot procedure involving multistep catalytic tandem operations. Several novel cocatalytic relay sequences (reductive amination/amidation, aerobic oxidation/reductive amination/amidation, reductive amination/kinetic resolution and reductive amination/dynamic kinetic resolution) were developed. They were next applied to the direct synthesis of various biologically and optically active amines or amides in one-pot from simple aldehydes, ketones, or alcohols, respectively.
- Palo-Nieto, Carlos,Afewerki, Samson,Anderson, Mattias,Tai, Cheuk-Wai,Berglund, Per,Córdova, Armando
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p. 3932 - 3940
(2016/07/06)
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- B(C6F5)3-Catalyzed Reduction of Aromatic and Aliphatic Nitro Groups with Hydrosilanes
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A transition-metal-free method for the hydrosilane reduction of aromatic and aliphatic nitro compounds to the corresponding amines is reported. Et3SiH is found to be the optimal reductant in this B(C6F5)3-catalyzed deoxygenation. The functional-group tolerance is, however, moderate.
- Porwal, Digvijay,Oestreich, Martin
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supporting information
p. 3307 - 3309
(2016/07/23)
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- Quantitative Reactivity Scales for Dynamic Covalent and Systems Chemistry
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Dynamic covalent chemistry (DCC) has become a powerful tool for the creation of molecular assemblies and complex systems in chemistry and materials science. Herein we developed for the first time quantitative reactivity scales capable of correlation and prediction of the equilibrium of dynamic covalent reactions (DCRs). The reference reactions are based upon universal DCRs between imines, one of the most utilized structural motifs in DCC, and a series of O-, N-, and S- mononucleophiles. Aromatic imines derived from pyridine-2-carboxyaldehyde exhibit capability for controlling the equilibrium through distinct substituent effects. Electron-donating groups (EDGs) stabilize the imine through quinoidal resonance, while electron-withdrawing groups (EWGs) stabilize the adduct by enhancing intramolecular hydrogen bonding, resulting in curvature in Hammett analysis. Notably, unique nonlinearity induced by both EDGs and EWGs emerged in Hammett plot when cyclic secondary amines were used. This is the first time such a behavior is observed in a thermodynamically controlled system, to the best of our knowledge. Unified quantitative reactivity scales were proposed for DCC and defined by the correlation log K = SN (RN + RE). Nucleophilicity parameters (RN and SN) and electrophilicity parameters (RE) were then developed from DCRs discovered. Furthermore, the predictive power of those parameters was verified by successful correlation of other DCRs, validating our reactivity scales as a general and useful tool for the evaluation and modeling of DCRs. The reactivity parameters proposed here should be complementary to well-established kinetics based parameters and find applications in many aspects, such as DCR discovery, bioconjugation, and catalysis.
- Zhou, Yuntao,Li, Lijie,Ye, Hebo,Zhang, Ling,You, Lei
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supporting information
p. 381 - 389
(2016/01/26)
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- Selective hydrogenation of nitriles to primary amines catalyzed by a novel iron complex
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Hydrogenation of nitriles to primary amines constitutes an atom-efficient and environmentally benign synthetic reaction. Herein we present a novel complex based on earth-abundant iron, and its application in the catalytic homogeneous hydrogenation of (hetero)aromatic, benzylic, and aliphatic nitriles to selectively form primary amines.
- Chakraborty, Subrata,Leitus, Gregory,Milstein, David
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supporting information
p. 1812 - 1815
(2016/02/05)
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- Colloid and nanosized catalysts in organic synthesis: XIV. Reductive amination and amidation of carbonitriles catalyzed by nickel nanoparticles
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Hydrogenation of carbonitriles catalyzed by nickel nanoparticles in the presence of primary amines led to the predominant formation of unsymmetrical secondary amines. In the presence of secondary amines hydrogenation of nitrites provided enamines as main products. Hydrogenation of nitriles in the presence of formamide or acetamide afforded formyl or acetyl derivatives of primary amines.
- Popov, Yu. V.,Mokhov,Shcherbakova
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p. 798 - 805
(2016/06/13)
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- METHOD OF FORMING CARBONYL COMPOUND AND DEPROTECTION METHOD OF AMIDE-BASED COMPOUND USING A CLEAVAGE REACTION OF CARBON-NITROGEN BOND
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The present invention relates to a preparation method of a carbonyl compound and a method for removing nitrogen-end protective group of an amide-based compound. The carbonyl compound is prepared by having a photocatalytic reaction of an amine-based group using water and an oxidizing agent. Therefore, the preparation method can prepare a carbonyl compound by usefully cutting carbon-nitrogen bonds at mild conditions, and such cutting reaction of carbon-nitrogen bonds can be usefully used for removing a protective group combined to an amide-based compound including amide or sulfonyl amide having carbon-nitrogen bonds.COPYRIGHT KIPO 2016
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Paragraph 0091; 0092; 0097; 0098; 0099
(2016/11/24)
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- Selective Hydrogenation of Nitriles to Primary Amines Catalyzed by a Cobalt Pincer Complex
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The catalytic hydrogenation of nitriles to primary amines represents an atom-efficient and environmentally benign reduction methodology in organic chemistry. This has been accomplished in recent years mainly with precious-metal-based catalysts, with a single exception. Here we report the first homogeneous Co-catalyzed hydrogenation of nitriles to primary amines. Several (hetero)aromatic, benzylic, and aliphatic nitriles undergo hydrogenation to the corresponding primary amines in good to excellent yields under the reaction conditions.
- Mukherjee, Arup,Srimani, Dipankar,Chakraborty, Subrata,Ben-David, Yehoshoa,Milstein, David
-
supporting information
p. 8888 - 8891
(2015/08/03)
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- Fabrication of tungsten nanocrystals and silver-tungsten nanonets: A potent reductive catalyst
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This communication reports the first synthesis of well-defined colloidal W nanocrystals, Ag-W heterostructures and their broad plasmon absorbance in the visible to near infrared region. Strong interparticle plasmonic interactions significantly improve the photocatalytic reduction performance of silver-tungsten heterostructures.
- Ghosh, Sirshendu,Khamarui, Saikat,Saha, Manas,De
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p. 38971 - 38976
(2015/05/20)
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- Insight into the mechanism of hydrogenation of amino acids to amino alcohols catalyzed by a heterogeneous MoOx-modified Rh catalyst
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Hydrogenation of amino acids to amino alcohols is a promising utilization of natural amino acids. We found that MoOx-modified Rh/SiO2 (Rh-MoOx/SiO2) is an efficient heterogeneous catalyst for the reaction at low temperature (323 K) and the addition of a small amount of MoOx drastically increases the activity and selectivity. Here, we report the catalytic potential of Rh-MoOx/SiO2 and the results of kinetic and spectroscopic studies to elucidate the reaction mechanism of Rh-MoOx/SiO2 catalyzed hydrogenation of amino acids to amino alcohols. Rh-MoOx/SiO2 is superior to previously reported catalysts in terms of activity and substrate scope. This reaction proceeds by direct formation of an aldehyde intermediate from the carboxylic acid moiety, which is different from the reported reaction mechanism. This mechanism can be attributed to the reactive hydride species and substrate adsorption caused by MoOx modification of Rh metal, which results in high activity, selectivity, and enantioselectivity.
- Tamura, Masazumi,Tamura, Riku,Takeda, Yasuyuki,Nakagawa, Yoshinao,Tomishige, Keiichi
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p. 3097 - 3107
(2015/02/05)
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- Vinylogous urethane vitrimers
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Vitrimers are a new class of polymeric materials with very attractive properties, since they can be reworked to any shape while being at the same time permanently cross-linked. As an alternative to the use of transesterification chemistry, we explore catalyst-free transamination of vinylogous urethanes as an exchange reaction for vitrimers. First, a kinetic study on model compounds reveals the occurrence of transamination of vinylogous urethanes in a good temperature window without side reactions. Next, poly(vinylogous urethane) networks with a storage modulus of ≈2.4 GPa and a glass transition temperature above 80 °C are prepared by bulk polymerization of cyclohexane dimethanol bisacetoacetate, m-xylylene diamine, and tris(2-aminoethyl)amine. The vitrimer nature of these networks is examined by solubility, stress-relaxation, and creep experiments. Relaxation times as short as 85 s at 170 °C are observed without making use of any catalyst. In addition, the networks are recyclable up to four times by consecutive grinding/compression molding cycles without significant mechanical or chemical degradation. Catalyst-free vitrimers based on the transamination of vinylogous urethanes are prepared from readily accessible chemicals. These high Tg, cross-linked materials exhibit excellent mechanical properties, while the exchangeable bonds enable full stress-relaxation on short time scales and recycling over many cycles.
- Denissen, Wim,Winne, Johan M.,Du Prez, Filip E.,Rivero, Guadalupe,Nicola, Renaud,Leibler, Ludwik
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p. 2451 - 2457
(2015/09/08)
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- Lamellar Ni/Al-SBA-15 fibers: Preparation, characterization, and applications as highly efficient catalysts for amine and imine syntheses
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A novel Ni/Al-SBA-15 fiber catalyst with a lamellar structure was prepared by the urea precipitation method and successfully utilized in the environmental-friendly reduction of nitro functionality. The applications of the catalyst in highly efficient one-pot amine and imine syntheses were developed; the physicochemical properties of the samples were evaluated with ICP-OES, N2 adsorption, XRD, HRTEM, and EDX. This new catalyst highlights potent catalytic activities and a simple recycling process as an important environmentally-friendly feature.
- Ren, Ren,Ma, Jiantai
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p. 74802 - 74810
(2015/09/21)
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- Synthesis of pyrrolo-/indolo[1,2-a ]quinolines and naphtho[2,1- b ]thiophenes from gem -dibromovinyls and sulphonamides
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A highly efficient and simple route for the synthesis of pyrrolo-/indolo[1,2-a]quinolines and naphtho[2,1-b]thiophenes from gem-dibromovinyls and sulphonamides is reported. The noteworthy feature of this report is that the methodology involves a two-step protocol to synthesize tri- and tetracyclic heterocycles in a one-pot fashion through the Cu(I)-catalyzed formation of ynamide followed by a Ag(I)-assisted intramolecular hydroarylation. The photophysical properties of representative examples of pyrrolo- and indolo[1,2-a]quinolines in solid and solution states have also been studied.
- Kiruthika, Selvarangam E.,Nandakumar, Avanashiappan,Perumal, Paramasivan Thirumalai
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supporting information
p. 4424 - 4427
(2015/02/05)
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