- RAPID REDUCTIVE-CARBOXYLATION OF SECONDARY AMINES. ONE POT SYNTHESIS OF TERTIARY N-METHYLATED AMINES
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Various tertiary N-methylated amines were synthesized by using a new reductive-carboxylation approach.Secondary amines, on carboxylation with carbon dioxide under moderate reaction conditions, afforded their corresponding carbamate esters, which, on in situ lithium aluminum hydride reduction, gave desired tertiary N-methylated amines in high yield.
- Ram, Siya,Ehrenkaufer, Richard E.
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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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- 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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- RANEY nickel-catalyzed reductive N-methylation of amines with paraformaldehyde: Theoretical and experimental study
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RANEY Ni-catalyzed reductive N-methylation of amines with paraformaldehyde has been investigated. This reaction proceeds in high yield with water as a byproduct. RANEY Ni can be easily recovered and reused with a slight decrease of the yield. Using density functional theory (DFT), the mechanism of RANEY Ni-catalyzed reductive N-methylation is discussed in detail. The reaction pathway involves the addition of amine with formaldehyde, dehydration to form the imine and hydrogenation. In the transition state of hemiaminal dehydration, the C-O bond cleavage of the aromatic amine is more difficult than that of the aliphatic amine. For the aromatic amine, a higher energy barrier must be overcome, which results in a relatively low yield. After addition of amine with formaldehyde and dehydration, imine is obtained and preferred to adsorb on the bridge site of the Ni(111) surface. The preferential pathways of imine hydrogenation involve the pre-adsorbed hydrogen atom attacking the nitrogen atom of the imine. The energy barrier of hydrogenation is much lower than that of addition and dehydration. Thus, the hydrogenation of imine is a relatively rapid reaction step. In the reductive N-methylation of secondary amine, the possible dehydration pathway is different from the one of the primary amine. In the dehydration of the secondary amine, the intermediate hemiaminal is initially adsorbed on the bridge site of the Ni(111) surface, then undergoes C-O bond cleavage, and eventually the hydroxyl is located in the bridge site. With the final hydrogenation, the product is obtained by adsorption on the top site of the Ni(111) surface.
- Ge, Xin,Luo, Chenxi,Qian, Chao,Yu, Zhiping,Chen, Xinzhi
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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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- Towards the Development of Frustrated Lewis Pair (FLP) Catalyzed Hydrogenations of Tertiary and Secondary Carboxylic Amides
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The development of the frustrated Lewis pair catalyzed hydrogenation of tertiary and secondary amides is reviewed. Detailed insight into our strategies in order to overcome challenges during the reaction development process is provided. Furthermore, the d
- K?ring, Laura,Paradies, Jan,Sitte, Nikolai A.
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supporting information
p. 1287 - 1300
(2022/01/20)
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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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- Selective reduction of formamides to O-silylated hemiaminals or methylamines with HSiMe2Ph catalyzed by iridium complexes
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The reaction of (4-methyl-pyridin-2-iloxy)ditertbutylsilane (NSitBu-H, 1) with [IrCl(coe)2]2 affords the iridium(iii) complex [Ir(H)(Cl)(κ2-NSitBu)(coe)] (2), which has been fully characterized including X-ray diffraction studies. The reaction of 2 with AgCF3SO3 leads to the formation of species [Ir(H)(CF3SO3)(κ2-NSitBu)(coe)] (3). The iridium complexes 2 and 3 are effective catalysts for the reduction of formamides with HSiMe2Ph. The selectivity of the reduction process depends on the catalyst. Thus, by using complex 2, with a chloride ancillary ligand, it has been possible to selectively obtain the corresponding O-silylated hemiaminal by reaction of formamides with one equivalent of HSiMe2Ph, while complex 3, with a triflate ligand instead of chloride, catalyzed the selective reduction of formamides to the corresponding methylamine.
- Guzmán, Jefferson,Bernal, Ana M.,García-Ordu?a, Pilar,Lahoz, Fernando J.,Oro, Luis A.,Fernández-Alvarez, Francisco J.
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p. 4255 - 4262
(2019/04/01)
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- Mild Hydrogenation of Amides to Amines over a Platinum-Vanadium Bimetallic Catalyst
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Hydrogenation of amides to amines is an important reaction, but the need for high temperatures and H2 pressures is a problem. Catalysts that are effective under mild reaction conditions, that is, lower than 30 bar H2 and 70 °C, have not yet been reported. Here, the mild hydrogenation of amides was achieved for the first time by using a Pt-V bimetallic catalyst. Amide hydrogenation, at either 1 bar H2 at 70 °C or 5 bar H2 at room temperature was achieved using the bimetallic catalyst. The mild reaction conditions enable highly selective hydrogenation of various amides to the corresponding amines, while inhibiting arene hydrogenation. Catalyst characterization showed that the origin of the catalytic activity for the bimetallic catalyst is the oxophilic V-decorated Pt nanoparticles, which are 2 nm in diameter.
- Mitsudome, Takato,Miyagawa, Kazuya,Maeno, Zen,Mizugaki, Tomoo,Jitsukawa, Koichiro,Yamasaki, Jun,Kitagawa, Yasutaka,Kaneda, Kiyotomi
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supporting information
p. 9381 - 9385
(2017/08/01)
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- Method For Preparing Methylated Amines
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The present invention relates to a method for preparing methylated amines using carbon dioxide and to the use of the method for manufacturing vitamins, pharmaceutical products, glues, acrylic fibres and synthetic leathers, pesticides and fertilizers. The invention also relates to a method for manufacturing vitamins, pharmaceutical products, glues, acrylic fibres, synthetic leathers, pesticides and fertilizers, including a step of preparing methylated amines by the method according to the invention. The present invention also relates to a method for preparing marked methylated amines and to the uses thereof.
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Paragraph 0161-0172
(2015/06/10)
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- Hydrophosphination of CO2 and Subsequent Formate Transfer in the 1,3,2-Diazaphospholene-Catalyzed N-Formylation of Amines
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Hydrophosphination of CO2 with 1,3,2-Diazaphospholene (NHP-H; 1) afforded phosphorus formate (NHP-OCOH; 2) through the formation of a bond between the electrophilic phosphorus atom in 1 and the oxygen atom from CO2, along with hydride transfer to the carbon atom of CO2. Transfer of the formate from 2 to Ph2SiH2 produced Ph2Si(OCHO)2 (3) in a reaction that could be carried out in a catalytic manner by using 5 mol % of 1. These elementary reactions were applied to the metal-free catalytic N-formylation of amine derivatives with CO2 in one pot under ambient conditions.
- Chong, Che Chang,Kinjo, Rei
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supporting information
p. 12116 - 12120
(2015/10/12)
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- Carbon Dioxide Reduction to Methylamines under Metal-Free Conditions
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The first metal-free catalysts are reported for the methylation of amines with carbon dioxide. Proazaphosphatrane superbases prove to be highly active catalysts in the reductive functionalization of CO2, in the presence of hydroboranes. The new methodology enables the methylation of N-H bonds in a wide variety of amines, including secondary amines, with increased chemoselectivity. Organocatalysis: Proazaphosphatrane superbases prove to be highly active catalysts in the reductive functionalization of CO2, in the presence of hydroboranes. The new method makes possible the methylation of N-H bonds in a wide variety of amines, including secondary amines (see picture), with increased chemoselectivity.
- Blondiaux, Enguerrand,Pouessel, Jacky,Cantat, Thibault
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p. 12186 - 12190
(2016/02/23)
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- CO2 as a C1-building block for the catalytic methylation of amines
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A novel catalytic reaction has been designed to utilize, for the first time, CO2 as a C1 feedstock in the synthesis of N-methylamines. Simple zinc catalysts, based on commercially available zinc salts and ligands, prove highly efficient in promoting both a 6 electron reduction of carbon dioxide and the formation of a C-N bond, using hydrosilanes and amines.
- Jacquet, Olivier,Frogneux, Xavier,Das Neves Gomes, Christophe,Cantat, Thibault
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p. 2127 - 2131
(2013/05/21)
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- Catalytic hydrogenation of amides to amines under mild conditions
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Under (not so much) pressure: A general method for the hydrogenation of tertiary and secondary amides to amines with excellent selectivity using a bimetallic Pd-Re catalyst has been developed. The reaction proceeds under low pressure and comparatively low temperature. This method provides organic chemists with a simple and reliable tool for the synthesis of amines. Copyright
- Stein, Mario,Breit, Bernhard
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supporting information
p. 2231 - 2234
(2013/03/28)
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- Amination of aliphatic alcohols catalyzed by CuO-NiO/γ-Al 2O3
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The amination of aliphatic alcohols in the gas-solid phase was investigated in a fixed-bed reactor in the presence of CuO-NiO/γ-Al2O 3 as the catalyst. This catalytic system was successfully applied for both the N-methylation of aliphatic amines and N-alkylation of piperidine with primary or secondary alcohols. N-Alkylation of piperidine with low-carbon alcohols resulted in high conversions and selectivities, and the conversion of piperidine and the selectivities toward the desired products declined gradually with the increase of the carbon number of aliphatic alcohols. The influence of varied conditions on the N-cyclohexylation of piperidine was also evaluated, including liquid hourly space velocity (LHSV), temperature and the catalyst; especially the catalyst had the greatest impact. Finally, the test of the catalyst's stability was performed.
- Huang, Jia-Min,Qian, Chao,Feng, Lie,Chen, Yun-Bin,Chen, Xin-Zhi
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p. 1187 - 1190
(2013/08/23)
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- Electrochemically stable onium salts and electrolytes containing such for electrochemical capacitors
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Based on the discovery that the melting point and solubility of onium salts are affected by the asymmetry of the substitution on cation, and that the branched substituents effectively shield onium cations from electrochemical reduction, new onium salts are synthesized and high performance electrolytes based on these salts for electrochemical capacitor are provided. The composition of the new electrolyte comprises an onium salt or mixture of such onium salts dissolved in aprotic, non-aqueous solvents or mixture of such solvents. The electrolyte is able to perform at high rate of charge/discharge, at low ambient temperatures, and within wide operating voltage, due to the high solubility, low melting temperature, and the improved reduction stability of the new onium cations, respectively.
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Page column 8-9
(2008/06/13)
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- Cyclopentadienyl RuII Complexes as Highly Efficient Catalysts for the N-Methylation of Alkylamines by Methanol
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The ruthenium(II) half-sandwich complex [RuCl(η5-C5H5)(PPh3)2] (1) catalyses the reaction between methanol and alkylamines RNH2 or R1R2NH to afford RN(CH3)2 and R1R2NCH3 products, respectively. The reaction is quantitative and generally fast, at the methanol reflux temperature, for a wide spectrum of substrates. Starting form primary amines, the stepwise formation of RN=CH2, RNHCH3, and RN(CH3)2 has been observed. Both PPh3 and Cl- dissociation from 1 are key-steps in forming the effective catalytic species. The catalytic activity of several half-sandwich neutral or cationic complexes (2-15) related to 1 is also discussed.
- Zotto, Alessandro Del,Baratta, Walter,Sandri, Mauro,Verardo, Giancarlo,Rigo, Pierluigi
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p. 524 - 529
(2007/10/03)
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- Hydrogenation of amides by the use of bimetallic catalysts consisting of group 8 to 10, and group 6 or 7 metals
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Hydrogenation of amides can be catalyzed by bimetallic systems, which consist of Group 8 to 10 late transition-metals and Group 6 or 7 early transition-metals, under the mild conditions to afford the corresponding amines selectively in good to excellent yields.
- Hirosawa, Chitaru,Wakasa, Noriko,Fuchikami, Takamasa
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p. 6749 - 6752
(2007/10/03)
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- Borohydride reductions in dichloromethane: A convenient, environmentally compatible procedure for the methylation of amines
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The combination of zinc chloride and sodium borohydride in dichloromethane is used to effect reductive aminations of formaldehyde with a variety of primary and secondary amines containing potentially acid-sensitive functional groups in good to excellent yields.
- Bhattacharyya
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p. 2061 - 2069
(2007/10/02)
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- Electronic Structure and Gas-Phase Thermolysis of 2-Tetrazenes with Acyclic or Cyclic Amino Groups Studied by Photoelectron Spectroscopy
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The electronic structures and the gas-phase thermolysis of the 2-tetrazenes 2-13 have been studied by He(I) photoelectron spectroscopy.The compounds are characterized by at least three ionization potentials with energies less than 10 eV which are assigned to the molecular orbitals ?3 (HOMO), n(+), ?2, and n(-).In the thermolyses either the formal disproportionation products (amine and imine) of the respective aminyl radical are found, or the latter is stabilized by loss of an alkyl radical affording also an imine.Further products which can be explained by radical reactions are detected in flash vacuum pyrolyses.The tricyclic cis-2-tetrazene 13 is cleaved by cycloreversion.The methoxymethylsubstituted compound 8 exhibit a more complex cleavage pattern. - Key Words: Electronic structure / PE spectroscopy / Thermolysis, gas-phase / Imines / Radicals
- Rademacher, Paul,Heymanns, Peter,Muenzenberg, Ralf,Woell, Heike,Kowski, Klaus,Poppek, Rainer
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p. 2073 - 2080
(2007/10/02)
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- Use of Zinc Borohydride in Reductive Amination: An Efficient and Mild Method for N-Methylation of Amines
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An efficient method for the reductive methylation of amines using paraformaldehyde, zinc chloride and zinc borohydride is described.
- Bhattacharyya, Sukanta,Chatterjee, Arindam,Duttachowdhury, Shiti, Kantha
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- Titanium(IV) Isopropoxide and Sodium Borohydride: A Reagent of Choice for Reductive Amination
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The preliminary results on the novel use of titanium(IV) isopropoxide and sodium borohydride in reductive amination reactions are reported.A highly efficient and mild procedure for reductive aminations of formaldehyde with a variety of primary and secondary amines is described.
- Bhattacharyya, Sukanta
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p. 2401 - 2404
(2007/10/02)
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- Enamines from Iodine Oxidation of Trialkylamines. 1. Electrophilic Capture by Cationic Heterocyclic Rings
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Simple enamines derived from acetaldehyde, acetone, and propionaldehyde were generated in situ by iodine oxidation of triethylamine, N,N-diisopropylmethylamine, and tri-n-propylamine, respectively.The enamines were captured by a variety of cationic substrates including trityl, indolizinium, dithiolium, pyrylium, thiapyrylium, selenapyrylium, and tellapyrylium cations.The use of a second equivalent of iodine (or excess) oxidized the initial products of enamine capture to various iminium dyes.These dyes were easily hydrolyzed to heterocyclylidene aldehydes and ketones.Cyclic amines such as N-methylpyrrolidine gave enamines derived from ring oxidation. 2-Cyano-N,N-dimethylethylamine generated a cyano-substituted enamine under the reaction conditions.
- Wadsworth, Donald H.,Detty, Michael R.,Murray, Bruce J.,Weidner, Charles H.,Haley, Neil F.
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p. 2676 - 2681
(2007/10/02)
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