- Synthesis of N-methylmorpholine from morpholine and dimethyl carbonate
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The synthesis of N-methylmorpholine from morpholine and dimethyl carbonate was investigated. The effects of reaction variables upon the formation of the compounds were also examined. Under the optimized conditions, higher yield of N-methylmorpholine 83 %
- Zhu, Maodian,Liu, Shaoying,Deng, Zhiyong,Wang, Gongying
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- Glycerol as a Building Block for Prochiral Aminoketone, N-Formamide, and N-Methyl Amine Synthesis
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Prochiral aminoketones are key intermediates for the synthesis of optically active amino alcohols, and glycerol is one of the main biomass-based alcohols available in industry. In this work, glycerol was catalytically activated and purposefully converted with amines to generate highly valuable prochiral aminoketones, as well as N-formamides and N-methyl amines, over CuNiAlOx catalyst. The catalyst structure can be anticipated as nano-Ni species on or in CuAlOx via the formation of nano- Cu?Ni alloy particles. This concept may present a novel and valuable methodology for glycerol utilization.
- Dai, Xingchao,Rabeah, Jabor,Yuan, Hangkong,Brückner, Angelika,Cui, Xinjiang,Shi, Feng
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- N-Heterocyclic Carbene-Stabilized Germa-acylium Ion: Reactivity and Utility in Catalytic CO2Functionalizations
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The first acceptor-free heavier germanium analogue of an acylium ion, [RGe(O)(NHC)2]X (R = MesTer = 2,6-(2,4,6-Me3C6H2)2C6H3; NHC = IMe4 = 1,3,4,5-tetramethylimidazol-2-ylidene; X = (Cl or BArF = {(3,5-(CF3)2C6H5)4B}), was isolated by reacting [RGe(NHC)2]X with N2O. Conversion of the germa-acylium ion to the first solely donor-stabilized germanium ester [(NHC)RGe(O)(OSiPh3)] and corresponding heavier analogues ([RGe(S)(NHC)2]X and [RGe(Se)(NHC)2]X) demonstrated its classical acylium-like behavior. The polarized terminal GeO bond in the germa-acylium ion was utilized to activate CO2 and silane, with the former found to be an example of reversible activation of CO2, thus mimicking the behavior of transition metal oxides. Furthermore, its transition-metal-like nature is demonstrated as it was found to be an active catalyst in both CO2 hydrosilylation and reductive N-functionalization of amines using CO2 as the C1 source. Mechanistic studies were undertaken both experimentally and computationally, which revealed that the reaction proceeds via an N-heterocyclic carbene (NHC) siloxygermylene [(NHC)RGe(OSiHPh2)].
- Sarkar, Debotra,Weetman, Catherine,Dutta, Sayan,Schubert, Emeric,Jandl, Christian,Koley, Debasis,Inoue, Shigeyoshi
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- On the chemical interactions of the biomass processing agents γ-valerolactone (GVL) and: N -methylmorpholine- N -oxide (NMMO)
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In new biorefinery processes, NMMO/water is used for the pre-treatment of biomass to increase the efficiency of subsequent digestion processes, while GVL/water is used for organosolv fractionation of biomass. The combination of both methods, GVL digestion after pre-activation by NMMO, appears to be reasonable, but has not been successful. In the present study, we examine the reason for this failure and investigate the chemical processes in the ternary system NMMO/GVL/water and in the quaternary system NMMO/GVL/water/ biomass . The consumption kinetics of NMMO and GVL at different temperatures, water contents and NMMO/GVL ratios were recorded. The respective degradation and reaction products were identified for the first time, by combining nuclear magnetic resonance (NMR) spectroscopy, and gas chromatography-mass spectrometry (GC-MS) techniques and synthesis of authentic compounds for comparison. Decomposition products of NMMO and GVL on their own as well as reaction products of both components together (α-morpholinomethyl-GVL (7), α-methylene-GVL (8), and 4-hydroxyvaleric acid morpholide (13)) were observed among the main degradation products. At temperatures of 150 °C and at a water content a significant extent. While the biomass component cellulose was largely unreactive, lignin was the main culprit that caused degradation reactions in the system. The formation of NMM (5) from NMMO and the resulting ring opening of GVL to 4-hydroxyvaleric acid (3), which is immediately oxidized by NMMO to levulinic acid (4), were the initial reactions that triggered the subsequent, more complex decomposition pathways. The chemical structures of all degradation products were fully analytically confirmed. Due to the instability of the NMMO/GVL system, the combination of NMMO biomass pre-treatment and GVL biomass digestion is prohibited, unless a careful removal of NMMO is carried out beforehand. Besides these practical conclusions with regard to biomass processing in biorefineries, the present study provides hopefully helpful insights into the chemistry of NMMO and GVL and the underlying reaction mechanisms.
- Bacher, Markus,Hettegger, Hubert,Jusner, Paul,Lê, Huy Quang,Potthast, Antje,Rosenau, Thomas,Sixta, Herbert
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- Radicals derived from N-methylmorpholine-N-oxide (NMMO): Structure, trapping and recombination reactions
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The two carbon-centered radicals 4-morpholinomethyl (4) and 4-methylmorpholin-3-yl (5), generated from the primary cation radical intermediate 3 by β-deprotonation, are the major radical species in reaction mixtures of N-methylmorpholine-N-oxide (1) as de
- Rosenau,Potthast,Sixta,Kosma
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- Chiral phosphorus(III) triflates. On the nature of the phosphorus-oxygen interaction
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Reaction of chiral phosphorodiamidites with trimethylsilyltriflate affords chiral phophorus(III) triflate species, such as 1-trifluoromethylsulfonato-2,9-(dibenzyl)diaza-1-phospha[4.0.3]bicyclononane 4, which has been examined by a combination of solution and solid state analytical techniques. Arguably the most important feature of this molecule is the nature of the interaction between phosphorus and triflate oxygen atoms. Single crystal X-ray diffraction analysis reveals that the phosphorus atom interacts principally with two oxygen atoms from two different triflate groups in the solid state, implying overall four-coordination at phosphorus. At distances of 2.841 and 2.755 A, these interactions are well within the van der Waals distance for a phosphorus-oxygen [P-O] interaction (ca. 3.35 A) but are nevertheless over 1 A longer than expected for a single [P-O] covalent bond. Investigations in solution via a combination of 31P, 19F, 13C, variable concentration, variable temperature NMR spectroscopy and solution conductivity provide support for a phosphorus-oxygen interaction which is intermediate between 'ionic' (two-coordinate phosphorus) and 'covalent' (three-coordinate phosphorus) and which possesses dynamic character in solution. Indeed, it has proved possible to calculate a relative equilibrium constant between 'ionic' and 'covalent' forms of 4 using empirical NMR data (13C and 19F; CH2Cl2 solvent; 300 K). These calculations return an equilibrium constant of ca. 3 (2.8 using 13C-NMR data and 3.3 using 19F-NMR data) in favour of the ionic form, a result commensurate with those suggested from variable temperature 19F-NMR and solution conductivity studies. Indeed, that the triflate group in 4 is capable of being displaced readily has been demonstrated by reaction with two-electron nitrogen, oxygen and phosphorus donor molecules. We have found 13C{1H}-NMR spectroscopy to be an extremely valuable probe of the ionic character of the triflate group in such systems providing a quantitative measure of the relative strength of interaction (relative basicity Br) between donor molecule and phosphorus atom of 4; the stronger the interaction, the more ionic the character of the triflate group and the lower the value of Br. Indeed, Br values for various ligands correlate well with steric and electronic properties of the latter and 31P-NMR resonances of the adducts themselves. As expected, the relative basicity of a given ligand correlates to the equilibrium constants K for adduct formation, which range from 39 M-1 for the weakest binding ligand studied (1,4-dioxane) to 5.4×104 M-1 for the strongest binding ligand (4-Me2N-NC5H4).
- Jones, Victoria A.,Sriprang, Sarin,Thornton-Pett, Mark,Kee, Terence P.
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- Selective synthesis of formamides, 1,2-bis(N-heterocyclic)ethanes and methylamines from cyclic amines and CO2/H2 catalyzed by an ionic liquid-Pd/C system
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The reduction of CO2 with amines and H2 generally produces N-formylated or N-methylated compounds over different catalysts. Herein, we report the selective synthesis of formamides, 1,2-bis(N-heterocyclic)ethanes, and methylamines, which is achieved over an ionic liquid (IL, e.g., 1-butyl-3-methylimidazolium tetrafluoroborate, [BMIm][BF4])-Pd/C catalytic system. By simply varying the reaction temperature, formamides and methylamines can be selectively produced, respectively, in high yields. Interestingly, 1,2-bis(N-heterocyclic)ethanes can also be obtained via the McMurry reaction of the formed formamide coupled with subsequent hydrogenation. It was found that [BMIm][BF4] can react with formamide to form a [BMIm]+-formamide adduct; thus combined with Pd/C it can catalyze McMurry coupling of formamide in the presence of H2 to afford 1,2-bis(N-heterocyclic)ethane. Moreover, Pd/C-[BMIm][BF4] can further catalyze the hydrogenolysis of 1,2-bis(N-heterocyclic)ethane to access methylamine. [BMIm][BF4]-Pd/C was tolerant to a wide substrate scope, giving the corresponding formamides, 1,2-bis(N-heterocyclic)ethanes or methylamines in moderate to high yields. This work develops a new route to produce N-methylamine and opens the way to produce 1,2-bis(N-heterocyclic)ethane from cyclic amine as well.
- Li, Ruipeng,Zhao, Yanfei,Wang, Huan,Xiang, Junfeng,Wu, Yunyan,Yu, Bo,Han, Buxing,Liu, Zhimin
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- An Improved Rapid and Mild Deoxygenation of Amine N-oxides
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An improved mild and selective method for the deoxygenation of a variety of amine N-oxides has been carried out in the presence of silica gel under mild conditions at room temperature to afford corresponding amines in relatively good yields without purification. The reaction is tolerant of a variety of functional groups such as hydroxyl, ester, acid, carbonyl, and cyano groups, as well as halogens. This method would be of great utility to synthesize various pyridines and amines easily.
- Rajesh
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- Self-Sufficient Formaldehyde-to-Methanol Conversion by Organometallic Formaldehyde Dismutase Mimic
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The catalytic networks of methylotrophic organisms, featuring redox enzymes for the activation of one-carbon moieties, can serve as great inspiration in the development of novel homogeneously catalyzed pathways for the interconversion of C1molecules at ambient conditions. An imidazolium-tagged arene–ruthenium complex was identified as an effective functional mimic of the bacterial formaldehyde dismutase, which provides a new and highly selective route for the conversion of formaldehyde to methanol in absence of any external reducing agents. Moreover, secondary amines are reductively methylated by the organometallic dismutase mimic in a redox self-sufficient manner with formaldehyde acting both as carbon source and reducing agent.
- van der Waals, Dominic,Heim, Leo E.,Vallazza, Simona,Gedig, Christian,Deska, Jan,Prechtl, Martin H. G.
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- Germyliumylidene: A Versatile Low Valent Group 14 Catalyst
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Bis-NHC stabilized germyliumylidenes [RGe(NHC)2]+ are typically Lewis basic (LB) in nature, owing to their lone pair and coordination of two NHCs to the vacant p-orbitals of the germanium center. However, they can also show Lewis acidity (LA) via Ge?CNHC σ* orbital. Utilizing this unique electronic feature, we report the first example of bis-NHC-stabilized germyliumylidene [MesTerGe(NHC)2]Cl (1), (MesTer=2,6-(2,4,6-Me3C6H2)2C6H3; NHC= IMe4=1,3,4,5-tetramethylimidazol-2-ylidene) catalyzed reduction of CO2 with amines and arylsilane, which proceeds via its Lewis basic nature. In contrast, the Lewis acid nature of 1 is utilized in the catalyzed hydroboration and cyanosilylation of carbonyls, thus highlighting the versatile ambiphilic nature of bis-NHC stabilized germyliumylidenes.
- Sarkar, Debotra,Dutta, Sayan,Weetman, Catherine,Schubert, Emeric,Koley, Debasis,Inoue, Shigeyoshi
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- Chemoselective deoxygenation of nitrones and N-oxides with tetrathiomolybdate
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Reaction of nitrones and N-oxides with benzyltriethylammonium tetrathiomolybdate 1 in acetonitrile (25°C) yielded the corresponding imines and amines in good yields. Sulfoxides and azoxy benzenes are unaffected.
- Ilankumaran, Palanichamy
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- Kinetic evidence for the formation of monocationic N,N′-disubstituted phthalamide in tertiary amine-catalyzed hydrolysis of N-substituted phthalimides
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(Chemical Equation Presented) A kinetic study on the aqueous cleavage of N-(2-methoxyphenyl)phthalimide (1) and N-(2-hydroxyphenyl)-phthalimide (2), under the buffers of N-methylmorpholine, reveals the equilibrium presence of monocationic amide (Ctam) formed due to nucleophilic reactions of N-methylmorpholine with 1 and 2. Pseudo-first-order rate constants for the reactions of water and HO- with Ctam (formed through nucleophilic reaction of N-methylmorpholine with 1) are 4.60 × 10-5 s -1 and 47.9 M-1 s-1, respectively. But the cleavage of Ctam, formed through nucleophilic reaction of N-methylmorpholine with 2, involves intramolecular general base (2′-O- group of Ctam)-assisted water attack at carbonyl carbon of cationic amide group of Ctam in or before the rate-determining step.
- Sim, Yoke-Leng,Ariffin, Aznar,Khan, M. Niyaz
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- Additive-free selective methylation of secondary amines with formic acid over a Pd/In2O3 catalyst
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Formic acid is used as the sole carbon and hydrogen source in the methylation of aromatic and aliphatic amines to methylamines. The reaction proceeds via a formylation/transfer hydrogenation pathway over a solid Pd/In2O3 catalyst without the need for any additive.
- Benaissa, Idir,Cantat, Thibault,Genre, Caroline,Godou, Timothé,Pinault, Mathieu
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- Simple RuCl3-catalyzed N-Methylation of Amines and Transfer Hydrogenation of Nitroarenes using Methanol
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Methanol is a potential hydrogen source and C1 synthon, which finds interesting applications in both chemical synthesis and energy technologies. The effective utilization of this simple alcohol in organic synthesis is of central importance and attracts scientific interest. Herein, we report a clean and cost-competitive method with the use of methanol as both C1 synthon and H2 source for selective N-methylation of amines by employing relatively cheap RuCl3.xH2O as a ligand-free catalyst. This readily available catalyst tolerates various amines comprising electron-deficient and electron-donating groups and allows them to transform into corresponding N-methylated products in moderate to excellent yields. In addition, few marketed pharmaceutical agents (e. g., venlafaxine and imipramine) were also successfully synthesized via late-stage functionalization from readily available feedstock chemicals, highlighting synthetic value of this advanced N-methylation reaction. Using this platform, we also attempted tandem reactions with selected nitroarenes to convert them into corresponding N-methylated amines using MeOH under H2-free conditions including transfer hydrogenation of nitroarenes-to-anilines and prepared drug molecules (e. g., benzocaine and butamben) as well as key pharmaceutical intermediates. We further enable one-shot selective and green syntheses of 1-methylbenzimidazole using ortho-phenylenediamine (OPDA) and methanol as coupling partners.
- Sarki, Naina,Goyal, Vishakha,Tyagi, Nitin Kumar,Puttaswamy,Narani, Anand,Ray, Anjan,Natte, Kishore
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p. 1722 - 1729
(2021/04/19)
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- Electrochemical Activation of Diverse Conventional Photoredox Catalysts Induces Potent Photoreductant Activity**
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Herein, we disclose that electrochemical stimulation induces new photocatalytic activity from a range of structurally diverse conventional photocatalysts. These studies uncover a new electron-primed photoredox catalyst capable of promoting the reductive cleavage of strong C(sp2)?N and C(sp2)?O bonds. We illustrate several examples of the synthetic utility of these deeply reducing but otherwise safe and mild catalytic conditions. Finally, we employ electrochemical current measurements to perform a reaction progress kinetic analysis. This technique reveals that the improved activity of this new system is a consequence of an enhanced catalyst stability profile.
- Chernowsky, Colleen P.,Chmiel, Alyah F.,Wickens, Zachary K.
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supporting information
p. 21418 - 21425
(2021/08/25)
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- Clean protocol for deoxygenation of epoxides to alkenes: Via catalytic hydrogenation using gold
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The epoxidation of olefin as a strategy to protect carbon-carbon double bonds is a well-known procedure in organic synthesis, however the reverse reaction, deprotection/deoxygenation of epoxides is much less developed, despite its potential utility for the synthesis of substituted olefins. Here, we disclose a clean protocol for the selective deprotection of epoxides, by combining commercially available organophosphorus ligands and gold nanoparticles (Au NP). Besides being successfully applied in the deoxygenation of epoxides, the discovered catalytic system also enables the selective reduction N-oxides and sulfoxides using molecular hydrogen as reductant. The Au NP catalyst combined with triethylphosphite P(OEt)3 is remarkably more reactive than solely Au NPs. The method is not only a complementary Au-catalyzed reductive reaction under mild conditions, but also an effective procedure for selective reductions of a wide range of valuable molecules that would be either synthetically inconvenient or even difficult to access by alternative synthetic protocols or by using classical transition metal catalysts. This journal is
- Fiorio, Jhonatan L.,Rossi, Liane M.
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p. 312 - 318
(2021/01/29)
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- Reactivity of heterocyclic α-aminomethylsilanes with alcohols
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[Figure not available: see fulltext.] Alkoxylation of N-substituted heterocyclic aminomethylsilyl moieties was studied using primary and tertiary alcohols. The reaction of 4-(silylmethyl)morpholine and 1-(silylmethyl)azepane under catalyst- and solvent-free conditions leads to the formation of dialkoxy- and trialkoxyaminomethylsilyl derivatives. The methanolysis of 4-(silylmethyl)morpholine resulted in trimethoxyaminomethylsilane formation as the main product and two byproducts, i.e., tetramethoxysilane and N-methylmorpholine.
- Pypowski, Krzysztof,Mojzych, Mariusz
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p. 320 - 324
(2021/03/31)
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- Degradation of Organic Cations under Alkaline Conditions
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Understanding the degradation mechanisms of organic cations under basic conditions is extremely important for the development of durable alkaline energy conversion devices. Cations are key functional groups in alkaline anion exchange membranes (AAEMs), and AAEMs are critical components to conduct hydroxide anions in alkaline fuel cells. Previously, we have established a standard protocol to evaluate cation alkaline stability within KOH/CD3OH solution at 80 °C. Herein, we are using the protocol to compare 26 model compounds, including benzylammonium, tetraalkylammonium, spirocyclicammonium, imidazolium, benzimidazolium, triazolium, pyridinium, guanidinium, and phosphonium cations. The goal is not only to evaluate their degradation rate, but also to identify their degradation pathways and lead to the advancement of cations with improved alkaline stabilities.
- You, Wei,Hugar, Kristina M.,Selhorst, Ryan C.,Treichel, Megan,Peltier, Cheyenne R.,Noonan, Kevin J. T.,Coates, Geoffrey W.
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supporting information
p. 254 - 263
(2020/12/23)
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- Borane-Trimethylamine Complex as a Reducing Agent for Selective Methylation and Formylation of Amines with CO2
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We report herein that a borane-trimethylamine complex worked as an efficient reducing agent for the selective methylation and formylation of amines with 1 atm CO2 under metal-free conditions. 6-Amino-2-picoline serves as a highly efficient catalyst for the methylation of various secondary amines, whereas in its absence, the formylation of primary and secondary amines was achieved in high yield with high chemoselectivity. Mechanistic studies suggest that the 6-amino-2-picoline-borane catalytic system operates like an intramolecular frustrated Lewis pair to activate CO2.
- Zhang, Yanmeng,Zhang, He,Gao, Ke
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supporting information
p. 8282 - 8286
(2021/10/25)
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- Electrochemical Reductive N-Methylation with CO2Enabled by a Molecular Catalyst
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The development of benign methylation reactions utilizing CO2 as a one-carbon building block would enable a more sustainable chemical industry. Electrochemical CO2 reduction has been extensively studied, but its application for reductive methylation reactions remains out of the scope of current electrocatalysis. Here, we report the first electrochemical reductive N-methylation reaction with CO2 and demonstrate its compatibility with amines, hydroxylamines, and hydrazine. Catalyzed by cobalt phthalocyanine molecules supported on carbon nanotubes, the N-methylation reaction proceeds in aqueous media via the chemical condensation of an electrophilic carbon intermediate, proposed to be adsorbed or near-electrode formaldehyde formed from the four-electron reduction of CO2, with nucleophilic nitrogenous reactants and subsequent reduction. By comparing various amines, we discover that the nucleophilicity of the amine reactant is a descriptor for the C-N coupling efficacy. We extend the scope of the reaction to be compatible with cheap and abundant nitro-compounds by developing a cascade reduction process in which CO2 and nitro-compounds are reduced concurrently to yield N-methylamines with high monomethylation selectivity via the overall transfer of 12 electrons and 12 protons.
- Rooney, Conor L.,Wu, Yueshen,Tao, Zixu,Wang, Hailiang
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supporting information
p. 19983 - 19991
(2021/12/01)
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- Electroactivated alkylation of amines with alcohols: Via both direct and indirect borrowing hydrogen mechanisms
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A green, efficient N-alkylation of amines with simple alcohols has been achieved in aqueous solution via an electrochemical version of the so-called "borrowing hydrogen methodology". Catalyzed by Ru on activated carbon cloth (Ru/ACC), the reaction works well with methanol, and with primary and secondary alcohols. Alkylation can be accomplished by either of two different electrocatalytic processes: (1) in an undivided cell, alcohol (present in excess) is oxidized at the Ru/ACC anode; the aldehyde or ketone product condenses with the amine; and the resulting imine is reduced at an ACC cathode, combining with protons released by the oxidation. This process consumes stoichiometric quantities of current. (2) In a membrane-divided cell, the current-activated Ru/ACC cathode effects direct C-H activation of the alcohol; the resulting carbonyl species, either free or still surface-adsorbed, condenses with amine to form imine and is reduced as in (1). These alcohol activation processes can alkylate primary and secondary aliphatic amines, as well as ammonia itself at 25-70 °C and ambient pressure.
- Appiagyei, Benjamin,Bhatia, Souful,Keeney, Gabriela L.,Dolmetsch, Troy,Jackson, James E.
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supporting information
p. 860 - 869
(2020/02/21)
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- A Mild Method for Electrochemical Reduction of Heterocyclic N-Oxides
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Deoxygenation of heteroaromatic N-oxides is commonly accomplished using chemical or enzymatic methods. In this work, we report on an expedient protocol for electrochemical reduction of pyridine N-oxide derivatives under mild conditions. A diverse range of mono- and bis N-oxides were converted into the corresponding nitrogen bases in good yields. Importantly, the method is highly selective towards N-oxides and tolerates challenging halo and nitro substituents in the heteroaromatic ring.
- Fukazawa, Yasuaki,Rubtsov, Aleksandr E.,Malkov, Andrei V.
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supporting information
p. 3317 - 3319
(2020/05/25)
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- Reductive Alkylation of Amines with Carboxylic Ortho Esters
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We have demonstrated for the first time that carboxylic ortho esters could be used as an alkylating agent in the reductive alkylation of amines. A variety of amines, including amino acid esters, were alkylated affording mono-alkylated products with high selectivity in practical to high yields using standard heterogeneous catalysts. By applying acyclic ortho esters alkylation was completed at room temperature. (Figure presented.).
- Kadyrov, Renat,Moebus, Konrad
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supporting information
p. 3352 - 3357
(2020/07/04)
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- Triazinetriamine-derived porous organic polymer-supported copper nanoparticles (Cu-NPs@TzTa-POP): an efficient catalyst for the synthesis of: N -methylated products via CO2fixation and primary carbamates from alcohols and urea
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In recent times, carbon dioxide fixation has received much attention for its potential application as an abundant C1 source and a range of important fine chemicals can be manufactured via this fixation. Here, a copper nanoparticle-decorated porous organic polymer-based (Cu-NPs@TzTa-POP) material was prepared by a simple in situ process. The catalyst was characterized by various techniques such as UV-vis spectra, FTIR spectra, HR-TEM, PXRD, N2 adsorption-desorption, TG-DTA, XPS, and AAS analysis. The synthesized heterogeneous catalyst showed excellent activity in an atmospheric carbon dioxide fixation reaction to produce N-methylated products from aromatic/heterocyclic amines in the presence of polymethyl-hydrosiloxane (PMHS) as the reducing agent at 80 °C within 12 h of the reaction. Through this catalytic N-methylation reaction, we obtained 98% yield of the product with turnover frequency ranging from 18 to 42 h-1. The catalyst is also very stable for the formation of primary carbamates from alcohols using the eco-friendly carbonylating agent, urea. Diverse alcohols (such as benzylic alcohols, phenols, heterocyclic alcohols, as well as aliphatic alcohols) showed much acceptance to this catalytic reaction and produced moderate to excellent yields of the respective carbamate products under ambient reaction conditions. Moreover, Cu-NPs@TzTa-POP is effortlessly recyclable and reusable without the extensive loss of active copper metal centres for many catalytic rounds (up to six catalytic rounds were examined).
- Haque, Najirul,Biswas, Surajit,Basu, Priyanka,Haque Biswas, Imdadul,Khatun, Resmin,Khan, Aslam,Islam, Sk Manirul
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supporting information
p. 15446 - 15458
(2020/10/22)
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- Fast continuous alcohol amination employing a hydrogen borrowing protocol
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A continuous flow method for the direct conversion of alcohols to amines via a hydrogen borrowing approach is reported. The method utilises a low loading (0.5%) of a commercial catalyst system ([Ru(p-cymene)Cl2]2 and DPEPhos), reagent grade solvent and is selective for primary alcohols. Successful methylation of amines using methanol and the direct dimethylamination of alcohols using commercial dimethylamine solution are reported. The synthesis of two pharmaceutical agents Piribedil (5) and Buspirone (25) were accomplished in good yields employing these new methods.
- Labes, Ricardo,Mateos, Carlos,Battilocchio, Claudio,Chen, Yiding,Dingwall, Paul,Cumming, Graham R.,Rincón, Juan A.,Nieves-Remacha, Maria José,Ley, Steven V.
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supporting information
p. 59 - 63
(2019/01/11)
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- Commercial Pd/C-Catalyzed N-Methylation of Nitroarenes and Amines Using Methanol as Both C1 and H2 Source
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Herein, we report commercially available carbon-supported-palladium (Pd/C)-catalyzed N-methylation of nitroarenes and amines using MeOH as both a C1 and a H2 source. This transformation proceeds with high atom-economy and in an environmentally friendly way via borrowing hydrogen mechanism. A total of >30 structurally diverse N-methylamines, including bioactive compounds, were selectively synthesized with isolated yields of up to 95%. Furthermore, selective N-methylation and deuteration of nimesulide, a nonsteroidal anti-inflammatory drug, were realized through the late-stage functionalization.
- Goyal, Vishakha,Gahtori, Jyoti,Narani, Anand,Gupta, Piyush,Bordoloi, Ankur,Natte, Kishore
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p. 15389 - 15398
(2019/12/04)
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- Selective formylation or methylation of amines using carbon dioxide catalysed by a rhodium perimidine-based NHC complex
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Carbon dioxide can play a vital role as a sustainable feedstock for chemical synthesis. To be viable, the employed protocol should be as mild as possible. Herein we report a methodology to incorporate CO2 into primary, secondary, aromatic or alkyl amines catalysed by a Rh(i) complex bearing a perimidine-based NHC/phosphine pincer ligand. The periminide-based ligand belongs to a class of 6-membered NHC ligand accessed through chelate-assisted double C-H activation. N-Formylation and -methylation of amines were performed using a balloon of CO2, and phenylsilane as the reducing agent. Product selectivity between formylated and methylated products was tuned by changing the solvent, reaction temperature and the quantity of phenylsilane used. Medium to excellent conversions, as well as tolerance to a range of functional groups, were achieved. Stoichiometric reactions with reactants employed in catalysis and time course studies suggested that formylation and methylation reactions of interest begin with hydrosilylation of CO2 followed by reaction with amine substrates.
- Lam, Raphael H.,McQueen, Caitlin M. A.,Pernik, Indrek,McBurney, Roy T.,Hill, Anthony F.,Messerle, Barbara A.
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supporting information
p. 538 - 549
(2019/02/14)
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- Mn-Catalyzed Selective Double and Mono-N-Formylation and N-Methylation of Amines by using CO2
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Functionalization of amines by using CO2 is of fundamental importance considering the abundance of amines and CO2. In this context, the catalytic formylation and methylation of amines represent convenient and successful protocols for selective CO2 utilization as a C1 building block. This study represents the first example of selective catalytic double N-formylation of aryl amines by using a dinuclear Mn complex in the presence of phenylsilane. This robust system also allows for selective formylation and methylation of amines under a range of conditions.
- Huang, Zijun,Jiang, Xiaolin,Zhou, Shaofang,Yang, Peiju,Du, Chen-Xia,Li, Yuehui
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p. 3054 - 3059
(2019/04/10)
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- Ethanol-mediated N-formylation of amines with CO2/H2 over cobalt catalysts
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The CO2-involved synthesis of chemicals is of great significance from a green and sustainable point of view. Herein, we present an efficient Co-based catalytic system composed of a commercially available Co salt, the tetradentate phosphine ligand P-(CH2CH2PPh2)3, and a base, denoted as [Co]/PP3/base, for the synthesis of formamides via the formylation of amines with CO2/H2. It was indicated that the selectivity of products (i.e., formamide or methylamine) could be tuned to some extent via changing the solvent and the base. Using ethanol as the solvent, the Co(ClO4)2·6H2O/PP3/K2CO3 system showed high activity for the production of formamides, affording product yields of 82-95%, together with its broad substrate scope. Exploration of the reaction mechanism indicated that formamide was formed with HCOOH as the intermediate, while the methylamine byproduct was produced with HCHO as the intermediate via the hydrogenolysis of dialkylaminomethane.
- Liu, Zhenghui,Yang, Zhenzhen,Ke, Zhengang,Yu, Xiaoxiao,Zhang, Hongye,Yu, Bo,Zhao, Yanfei,Liu, Zhimin
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p. 13933 - 13937
(2018/08/21)
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- Tungstate catalysis: Pressure-switched 2- and 6-electron reductive functionalization of CO2 with amines and phenylsilane
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An efficient and environmentally benign tungstate catalyst for reductive functionalization of CO2 with amines and phenylsilane was developed. By simply varying the pressure, 2-electron or 6-electron reduction of CO2 was successfully achieved with simultaneous C-N bond formation, thus leading to the formation of formamides and methylamines, respectively. That is, secondary and primary amines furnished the corresponding methylamines or dimethylamines in excellent yields under atmospheric pressure of CO2, while various formamides were formed in yields ranging from 52% to 98% when increasing the CO2 pressure to 2 MPa. 1H NMR studies and control experiments demonstrate that N-formylation proceeds through the formation of silyl formate, while N-methylation proceeds through an aminal intermediate generated by 4-electron reduction of CO2.
- Wang, Mei-Yan,Wang, Ning,Liu, Xiao-Fang,Qiao, Chang,He, Liang-Nian
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supporting information
p. 1564 - 1570
(2018/04/12)
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- Diverse catalytic reactivity of a dearomatized PN3P?-nickel hydride pincer complex towards CO2 reduction
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A dearomatized PN3P?-nickel hydride complex has been prepared using an oxidative addition process. The first nickel-catalyzed hydrosilylation of CO2 to methanol has been achieved, with unprecedented turnover numbers. Selective methylation and formylation of amines with CO2 were demonstrated by such a PN3P?-nickel hydride complex, highlighting its versatile functions in CO2 reduction.
- Li, Huaifeng,Gon?alves, Théo P.,Zhao, Qianyi,Gong, Dirong,Lai, Zhiping,Wang, Zhixiang,Zheng, Junrong,Huang, Kuo-Wei
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supporting information
p. 11395 - 11398
(2018/10/20)
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- Copper catalysis: Ligand-controlled selective: N -methylation or N -formylation of amines with CO2 and phenylsilane
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Cupric subcarbonate (Cu2(OH)2CO3) was found to be effective for the reductive functionalization of CO2 to produce formamides and methylamines with phenylsilane as reductant. Interestingly, N-formylation and N-methylation were switched on/off by subtly choosing the ligand: DPPB (1,4-bis(diphenylphosphino)butane) promoted N-methylation whereas Ph2CyP (diphenylcyclohexylphosphine) favored for N-formylation.
- Li, Xue-Dong,Xia, Shu-Mei,Chen, Kai-Hong,Liu, Xiao-Fang,Li, Hong-Ru,He, Liang-Nian
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supporting information
p. 4853 - 4858
(2018/11/21)
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- Method for preparing formamide and N-methylamines by carrying out selective reduction on carbon dioxide and amines regulated by ligand
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The invention relates to a method for preparing formamide and N-methylamines by carrying out selective reduction on carbon dioxide and amines regulated by a ligand. According to the method, copper salt is used as a catalyst, organic amine or organic phosphorus is used as the ligand, CO2 and a hydrosilane are respectively used as a C1 resource and a reducing agent, and amines are used as a nucleophilic reagent; a reaction is carried out in an organic solvent, the consumption of the catalyst is 1-5mol%, and the consumption of the ligand is 1-20 mol%, the reaction temperature is 20-80 DEG C, theCO2 pressure is 0.1-8.0 MPa, the reaction time is 10-48h, the highest yield of the formamide is up to 98%, and the highest yield of the N-methylamine is up to 95%. The method provided by the inventionhas the advantages that the ligand is used for a regulation method for selective reduction preparation of the formamide and the N-methylamines for the first time; the catalyst is low in price, easy to obtain and simple in composition; the renewable CO2 is used as a raw material, so that the use of the traditional toxic formylation and methylation reagents is avoided; the substrate is wide in application scope and is suitable for a variety of secondary amines.
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Paragraph 0135-0143
(2019/01/14)
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- Efficient Cobalt-Catalyzed Methylation of Amines Using Methanol
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The methylation of amines using methanol is a promising route to synthesize N-methylamines, and the development of cheap and efficient catalytic system for this reaction is of great significance. Herein, we reported a cobalt (Co)-based catalytic system, which was in situ formed from commercially available Co precursor and a tetradentate phosphine ligand P(CH2CH2PPh2)3 combined with K3PO4. This catalystic system was very effective for the selective production of dimethylated products from aliphatic amines and monomethylated ones from aromatic amines. The reaction mechanism was further investigated by control and isotope labelling experiments. (Figure presented.).
- Liu, Zhenghui,Yang, Zhenzhen,Yu, Xiaoxiao,Zhang, Hongye,Yu, Bo,Zhao, Yanfei,Liu, Zhimin
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supporting information
p. 4278 - 4283
(2017/10/23)
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- Deoxygenation of tertiary amine N-oxides under metal free condition using phenylboronic acid
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A simple and efficient method for the deoxygenation of amine N-oxides to corresponding amines is reported using the green and economical reagent phenylboronic acid. Deoxygenation of N,N-dialkylaniline N-oxides, trialkylamine N-oxides and pyridine N-oxides were achieved in good to excellent yields. The reduction susceptible functional groups such as ketone, amide, ester and nitro groups are well tolerated with phenylboronic acid during the deoxygenation process even at high temperature. In addition, an indirect method for identification and quantification of tert-amine N-oxide is demonstrated using UV–Vis spectrometry which may be useful for drug metabolism studies.
- Gupta, Surabhi,Sureshbabu, Popuri,Singh, Adesh Kumar,Sabiah, Shahulhameed,Kandasamy, Jeyakumar
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supporting information
p. 909 - 913
(2017/02/15)
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- Metal-Free Reduction of Phosphine Oxides, Sulfoxides, and N-Oxides with Hydrosilanes using a Borinic Acid Precatalyst
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The general reduction of phosphine oxides, sulfoxides, and amine N-oxides was achieved by combining bis(2-chlorophenyl)borinic acid with phenylsilane. The reaction was shown to tolerate a wide range of substrates and could be performed under mild conditions, with only 2.5 mol % of the easily synthesized catalyst. Mechanistic investigations pointed to a key borohydride as the real catalyst and at bis(2-chlorophenyl)borinic acid as a precatalyst.
- Chardon, Aurélien,Maubert, Orianne,Rouden, Jacques,Blanchet, Jér?me
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p. 4460 - 4464
(2017/11/22)
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- B(C6F5)3-Catalyzed Deoxygenation of Sulfoxides and Amine N-Oxides with Hydrosilanes
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An efficient strategy for the deoxygenation of sulfoxides and amine N-oxides by using B(C6F5)3 and hydrosilanes was developed. This method provided the corresponding aromatic and aliphatic products in good to high yields and showed good functional-group tolerance under mild conditions.
- Ding, Fangwei,Jiang, Yanqiu,Gan, Shaoyan,Bao, Robert Li-Yuan,Lin, Kaifeng,Shi, Lei
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p. 3427 - 3430
(2017/07/04)
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- Method for cyclically preparing N-methyl morpholine
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The invention discloses a method for cyclically preparing N-methyl morpholine. The method comprises the following steps: (1) synthesizing, namely reacting N-methyldiethanolamine and sulfuric acid, cooling to room temperature so as to obtain a synthetic reaction solution; (2) performing ammonium salt transfer, namely adding N-methyldiethanolamine into the synthetic reaction solution obtained in the step (1), adding ammonium salt transfer agent for carrying out an ammonium salt transfer exchange reaction; (3) distilling, namely performing reduced pressure distillation on the ammonium salt transfer reaction solution obtained in the step (2) so as to respectively obtain the fraction and residues, wherein the fraction is N-methyl morpholine; and (4) carrying out circular reaction, namely carrying out synthetic reaction on the residue obtained in the step (3), cooling to room temperature so as to obtain the residue for the circular reaction, replacing the synthetic reaction solution and the ammonium salt transfer agent in the step (2) by using the residue for the circular reaction, and sequentially performing the ammonium salt transfer in the step (2) and distillation in the step (3).
- -
-
Paragraph 0043; 0044; 0045; 0046; 0047; 0048; 0049-0092
(2017/08/28)
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- A catalytic preparation N - methyl morpholine (by machine translation)
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The invention discloses a catalytic preparation N - methyl morpholine method, comprises the following the preparation step: step S1, the rare earth-based solid catalyst is filled in a tubular reactor; step S2, the liquid raw material N - methyl diethanolamine is arranged in the raw material tank, the use of the sampling uniform sampling, the raw material through the tubular reactor of the rare earth-based solid catalyst in the intramolecular dehydration reaction, of the raw material liquid volume hourly space velocity is 0.1 - 0.5h- 1 , Reactor temperature is 200 - 300 °C; step S3, condensed by the condenser collecting the step S2 the resulting reaction solution, to join the sheet alkali reaction fluid lamination, apply supernatant liquid by atmospheric distillation, collecting 115 - 116 °C fraction, to obtain the target product N - methyl morpholine. The method of the invention a simple and feasible, high conversion rate, the catalyst can be used repeatedly, and can be repeatedly used after the first time that non-obviously reduce the catalytic efficiency. (by machine translation)
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Paragraph 0019-0059
(2017/02/24)
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- REDUCTIVE ALKYLATION OF AMINES WITH ORTHOCARBOXYLIC ACID ESTERS
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The present invention relates to a process for the N-alkylation of amines by reacting an amine with an orthocarboxylic acid ester and with hydrogen in the presence of a hydrogenation catalyst.
- -
-
Page/Page column 9; 10
(2017/12/27)
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- Photochemical Activation of Tertiary Amines for Applications in Studying Cell Physiology
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Representative tertiary amines were linked to the 8-cyano-7-hydroxyquinolinyl (CyHQ) photoremovable protecting group (PPG) to create photoactivatable forms suitable for use in studying cell physiology. The photoactivation of tamoxifen and 4-hydroxytamoxifen, which can be used to activate Cre recombinase and CRISPR-Cas9 gene editing, demonstrated that highly efficient release of bioactive molecules could be achieved through one- and two-photon excitation (1PE and 2PE). CyHQ-protected anilines underwent a photoaza-Claisen rearrangement instead of releasing amines. Time-resolved spectroscopic studies revealed that photorelease of the tertiary amines was extremely fast, occurring from a singlet excited state of CyHQ on the 70 ps time scale.
- Asad, Naeem,Deodato, Davide,Lan, Xin,Widegren, Magnus B.,Phillips, David Lee,Du, Lili,Dore, Timothy M.
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supporting information
p. 12591 - 12600
(2017/09/23)
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- Ionic liquid/H2O-mediated synthesis of mesoporous organic polymers and their application in methylation of amines
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Mesoporous Tr?ger's base-functionalized polymers (Meso-TBPs) were prepared using a sulfonic acid group functionalized ionic liquid/H2O system, with surface areas up to 431 m2 g-1 and pore sizes of 3-15 nm. Ir(ii) coordinated Meso-TBPs exhibited extraordinary catalytic performance in the N-methylation of amines using methanol.
- Yu, Xiaoxiao,Yang, Zhenzhen,Zhang, Hongye,Yu, Bo,Zhao, Yanfei,Liiu, Zhenghui,Ji, Guipeng,Liu, Zhimin
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supporting information
p. 5962 - 5965
(2017/07/10)
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- Continuous N-alkylation reactions of amino alcohols using γ-Al2O3 and supercritical CO2: Unexpected formation of cyclic ureas and urethanes by reaction with CO2
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The use of γ-Al2O3 as a heterogeneous catalyst in scCO2 has been successfully applied to the amination of alcohols for the synthesis of N-alkylated heterocycles. The optimal reaction conditions (temperature and substrate flow rate) were determined using an automated self-optimising reactor, resulting in moderate to high yields of the target products. Carrying out the reaction in scCO2 was shown to be beneficial, as higher yields were obtained in the presence of CO2 than in its absence. A surprising discovery is that, in addition to cyclic amines, cyclic ureas and urethanes could be synthesised by incorporation of CO2 from the supercritical solvent into the product.
- Streng, Emilia S.,Lee, Darren S.,George, Michael W.,Poliakoff, Martyn
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supporting information
p. 329 - 337
(2017/03/15)
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- Carboxylate-promoted reductive functionalization of CO2 with amines and hydrosilanes under mild conditions
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Various oxygen-nucleophiles especially carboxylates, e.g. cesium/tetrabutylammonium carboxylate, were proved to be efficient and selective catalysts for reductive functionalization of CO2 with amines and hydrosilanes to methylamines. Various amines including aromatic and aliphatic, primary and secondary ones were methylated successfully in the presence of diphenylsilane as the reductant under 50 °C and an atmospheric pressure of CO2. Furthermore, a reaction pathway involving CO2 reduction to the C0 species i.e. aminal rather than the formamide as the intermediate was proposed. This protocol represents a transition metal-free and environmentally friendly option for CO2 conversion to useful chemicals via the formation of C-N bonds coupled with six-electron reduction of CO2 to the methanol level under mild conditions.
- Liu, Xiao-Fang,Qiao, Chang,Li, Xiao-Ya,He, Liang-Nian
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supporting information
p. 1726 - 1731
(2017/06/07)
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- Betaine Catalysis for Hierarchical Reduction of CO2 with Amines and Hydrosilane To Form Formamides, Aminals, and Methylamines
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An efficient, sustainable organocatalyst, glycine betaine, was developed for the reductive functionalization of CO2 with amines and diphenylsilane. Methylamines and formamides were obtained in high yield by tuning the CO2 pressure and reaction temperature. Based on identification of the key intermediate, that is, the aminal, an alternative mechanism for methylation involving the C0 silyl acetal and aminal is proposed. Furthermore, reducing the CO2 amount afforded aminals with high yield and selectivity. Therefore, betaine catalysis affords products with a diversified energy content that is, formamides, aminals and methylamines, by hierarchical two-, four- and six-electron reduction, respectively, of CO2 coupled with C?N bond formation.
- Liu, Xiao-Fang,Li, Xiao-Ya,Qiao, Chang,Fu, Hong-Chen,He, Liang-Nian
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supporting information
p. 7425 - 7429
(2017/06/13)
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- Copper(II)-Catalyzed Selective Reductive Methylation of Amines with Formic Acid: An Option for Indirect Utilization of CO2
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A copper-catalyzed protocol for reductive methylation of amines and imine with formic acid as a C1 source and phenylsilane as a reductant is reported for the first time, affording the corresponding methylamines in good to excellent yields under mild conditions. This protocol offers an alternative method for indirect utilization of CO2, as formic acid can be readily obtained from hydrogenation of CO2.
- Qiao, Chang,Liu, Xiao-Fang,Liu, Xi,He, Liang-Nian
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supporting information
p. 1490 - 1493
(2017/03/23)
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- Method for selectively preparing N-monomethylamine compound
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The invention discloses a method for selectively preparing an N-monomethylamine compound. The method takes an amine compound, formaldehyde and H2 as reaction raw materials; the raw materials react in a reaction medium in the presence of a compound catalyst at 30 DEG C-180 DEG C for 2h-48h, so as to obtain the N-monomethylamine compound; and the compound catalyst is composed of oxides of at least two of the following metal or oxides of least one of the following metal and at least one metal simple substance: aluminum, copper, nickel, cobalt and iron. According to the method for preparing the N-monomethylamine compound, the conversion ratio and the selectivity of N-monomethylamine are relatively high; the H2 is used as a reducing agent and is clean, cheap and environment-friendly; the catalyst utilized by the method is cheap, simple to prepare and high in catalysis efficiency; and the method has mild preparation and reaction conditions and the catalyst has no corrosiveness, is easy to separate and can be repeatedly used.
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-
Paragraph 0034-0035
(2017/08/29)
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- Ruthenium-Catalyzed Methylation of Amines with Paraformaldehyde in Water under Mild Conditions
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Methylated amines are highly important for a variety of pharmaceutical and agrochemical applications. Existing routes for their formation result in the production of large amounts of waste or require high reaction temperatures, both of which impact the ecological and economical footprint of the methodologies. Herein, we report the ruthenium-catalyzed reductive methylation of a range of aliphatic amines, using paraformaldehyde as both substrate and hydrogen source, in combination with water. This reaction proceeds under mild aqueous reaction conditions. Additionally the use of a secondary phase for catalyst retention and recycling has been investigated with promising results.
- van der Waals, Dominic,Heim, Leo. E.,Gedig, Christian,Herbrik, Fabian,Vallazza, Simona,Prechtl, Martin H. G.
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p. 2343 - 2347
(2016/10/24)
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- N-Methylation of amines with methanol in a hydrogen free system on a combined Al2O3-mordenite catalyst
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N-Methyl amines play a major role in the production of medicines, pesticides, surfactants and dyes. N-Methylation of primary or second amines with methanol is considered to be a green path for the synthesis of N-methyl amines and the catalyst is key. In this article, the combined Al2O3-mordenite catalyst (mass fraction of alumina is 40%) with good activity, selectivity, lifetime and stability was prepared for N-methylation of various amines with methanol in a hydrogen free system in a fixed bed reactor, and characterized by XRD, N2 adsorption and NH3-TPD. Furthermore, the methanol adsorption was investigated by in situ FTIR, and the result indicated that methoxyl species may be the active species for the N-methylation of amines.
- Su, Jiahui,Li, Xungang,Chen, Yunbin,Cui, Yuancun,Xu, Jingwei,Qian, Chao,Chen, Xinzhi
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p. 55643 - 55649
(2016/07/06)
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- Method for synthesizing bis(dimethylaminoethyl)ether under catalysis of metal catalyst
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The invention discloses a method for synthesizing bis(dimethylaminoethyl)ether (BDMAEE) under the catalysis of a metal catalyst. The method comprises the following steps: preparing a metal oxide; then preparing the metal catalyst from the metal oxide; and with dimethylamine and dimethylaminoethoxyethanol as raw materials, preparing BDMAEE under the catalysis of the metal catalyst, wherein a main inorganic by-product is water, and produced organic by-products can be recycled through distillation and purification. The method provided by the invention has good economic benefits and overcomes the problem of environmental pollution of conventional BDMAEE production processes.
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Paragraph 0037; 0038; 0039; 0040
(2018/02/04)
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- Supported nano-gold-catalyzed N-formylation of amines with paraformaldehyde in water under ambient conditions
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A simple and efficient Au/Al2O3 catalyst was prepared by the co-precipitation method for the oxidative N-formylation of amines with paraformaldehyde. Under the optimized reaction conditions, excellent amine conversion and N-formamide selectivity can be obtained with up to 97% yield with water as the solvent under ambient conditions. This catalyst tolerated a wide range of primary amines and second amines, and it can be reused for at least five runs without obvious deactivation.
- Ke, Zhengang,Zhang, Yan,Cui, Xinjiang,Shi, Feng
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p. 808 - 816
(2016/02/12)
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- Fluoride-Catalyzed Methylation of Amines by Reductive Functionalization of CO2with Hydrosilanes
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An effective and inexpensive organocatalyst tetrabutylammonium fluoride (TBAF) was developed for the reductive functionalization of CO2with amines to selectively afford formamides or methylamines by employing hydrosilanes. Hydrosilanes with different substituents show discriminatory reducing activity. Thus, the formation of formamides and further reduction products, that is, methylamines could be controlled by elegantly tuning hydrosilane types. Formamides were obtained exclusively under an atmospheric pressure of CO2with triethoxysilane. Using phenylsilane as a reductant, methylamines were attained with up to 99 % yield at 50 °C coupled to a complete deoxygenation of CO2. The crucial intermediate silyl formate in the formylation step was identified and thereby a tentative mechanism involving the fluoride-promoted hydride transfer from the hydrosilane to CO2/formamide was proposed. Striking features of this metal-free protocol are formylation and methylation of amines by reductive functionalization of CO2with hydrosilanes and mild reaction conditions.
- Liu, Xiao-Fang,Ma, Ran,Qiao, Chang,Cao, Han,He, Liang-Nian
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p. 16489 - 16493
(2016/11/09)
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- Room temperature N-alkylation of amines with alcohols under UV irradiation catalyzed by Cu-Mo/TiO2
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It is highly desirable to develop efficient heterogeneous photocatalysts for organic reactions. Here, we show the preparation and catalytic performance of a novel TiO2 (P25) supported Cu and Mo photocatalyst (Cu-Mo/TiO2) for N-alkylation of amines with alcohols under UV irradiation at room temperature. A variety of aromatic and aliphatic amines were selectively converted into the corresponding secondary amines or tertiary amines in moderate to excellent yields without the addition of any co-catalysts such as bases and organic ligands. Noteworthy, this catalytic system is feasible in the alkylation of anilines containing halogen substituents with alcohols and the yields of the desired products are up to 95%.
- Zhang, Lina,Zhang, Yan,Deng, Youquan,Shi, Feng
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p. 3226 - 3234
(2015/06/08)
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- Light-promoted N,N-dimethylation of amine and nitro compound with methanol catalyzed by Pd/TiO2 at room temperature
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A series of TiO2 supported nano-Pd catalysts (Pd/TiO2) were prepared and used for the N,N-dimethylation of different amines and nitro compounds with methanol under UV irradiation at room temperature. A wide range of N,N-dimethyl amines were one-pot synthesized with up to 98% by applying aliphatic secondary amines, aromatic primary amines, aliphatic primary amines and aromatic nitro compounds as starting materials. It is noteworthy that up to 90% yield of 4-chloro-N,N-dimethylaniline was obtained by adjusting the Pd loadings on the TiO2 and the dehalogenation reaction was inhibited. Finally, a reaction mechanism is discussed, involving PhN = CH2 and PhNHCH3 as reaction intermediates.
- Zhang, Lina,Zhang, Yan,Deng, Youquan,Shi, Feng
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p. 14514 - 14521
(2015/03/05)
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- Deoxygenation of amine N-oxides using gold nanoparticles supported on carbon nanotubes
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Deoxygenation of a variety of aromatic and aliphatic amine N-oxides has been carried out in excellent yield using dimethylphenylsilane as the reducing agent under the catalytic influence of a carbon nanotube-gold nanohybrid at room temperature. Low catalyst loading, good TON and TOF values, and recyclability of the catalyst are some of the salient features of our methodology.
- Donck, Simon,Gravel, Edmond,Shah, Nimesh,Jawale, Dhanaji V.,Doris, Eric,Namboothiri, Irishi N. N.
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p. 50865 - 50868
(2015/06/25)
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