- Palladium-Assisted Amination of Olefins. A Mechanistic Study
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The mechanism of the palladium-assisted amination of olefins has been studied by low-temperature NMR and ultraviolat spectroscopy, conductivity measurements, and stoichiometry and exchange studies.The specific sequence of steps followed strongly depends on the temperature of amine.With dimethylamine, the sequence consists of cleavage of the chloride bridge by the amine to give a single olefin-palladium-amine complex (2).This undergoes amination of the olefin and concomitant cyclization to form the β-aminoalkylpalladium complex (3) directly and dimethylammonium hydrochloride.In contrast, with diethylamine, the initially formed olefin-palladium-amine complex undergoes amination to form a discrete zwitterionic complex (6).This reacts slowly with additional added amine to give the chelating β-aminoalkylpalladium complex (7).
- Hegedus, Louis S.,Akermark, Bjorn,Zetterberg, Krister,Olsson, Lars F.
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- Zirconium-hydride-catalyzed site-selective hydroboration of amides for the synthesis of amines: Mechanism, scope, and application
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Developing mild and efficient catalytic methods for the selective synthesis of amines is a longstanding research objective. In this respect, catalytic deoxygenative amide reduction has proven to be promising but challenging, as this approach necessitates selective C–O bond cleavage. Herein, we report the selective hydroboration of primary, secondary, and tertiary amides at room temperature catalyzed by an earth-abundant-metal catalyst, Zr-H, for accessing diverse amines. Various readily reducible functional groups, such as esters, alkynes, and alkenes, were well tolerated. Furthermore, the methodology was extended to the synthesis of bio- and drug-derived amines. Detailed mechanistic studies revealed a reaction pathway entailing aldehyde and amido complex formation via an unusual C–N bond cleavage-reformation process, followed by C–O bond cleavage.
- Han, Bo,Jiao, Haijun,Wu, Lipeng,Zhang, Jiong
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p. 2059 - 2067
(2021/09/02)
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- Intermittent synthesis method N and N -dimethyl n-butylamine
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The invention relates to N. The invention N-dimethyln-butylamine intermittent synthesis method. Some conversion rates of the main synthetic method of the prior art are relatively low, and some byproducts can be generated, the separation difficulty is increased, the method is economical, N - methylbutylamine is not generated, the separation difficulty is increased, and the production difficulty is large. The method is characterized in that n-butylamine and N-formaldehyde are used as raw materials, and the molar ratio of n-butylamine, n-butylamine and formaldehyde is prepared under the conditions N - and 37 - 40% through nickel catalytic hydrogenation. 60 - 90 °C. 2 - 4 mpa 2 - 1 . 2.6 1. To the invention, a new nickel catalyst is selected. The catalyst cost is reduced, the reaction is prepared by taking n-butylamine and formaldehyde as raw materials, the reaction is simple, the selectivity is good, and the yield is higher.
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Paragraph 0031-0034
(2021/09/26)
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- The selective reductive amination of aliphatic aldehydes and cycloaliphatic ketones with tetragonal zirconium dioxide as the heterogeneous catalyst
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A selective reductive amination of aliphatic aldehydes and cycloaliphatic ketones is achieved with tetragonal zirconium dioxide (t-ZrO2) as the catalyst. With N, N-dimethyl formamide (DMF) as the solvent, low-molecular-weight amine source and reductant, a more than 99 percent yield of N, N-dimethylpentan-1-amine or N, N-dimethyl cyclohexanamine was obtained when n-pentanal or cyclohexanone was used as the substrate. Particularly, the crystallographic structures exhibit a significant effect on catalytic performance where the tetragonal crystalline was preferable to monoclinic one during the reductive amination reaction. In addition, the recycling experiments of catalysts indicate that t-ZrO2 still kept a high catalytic activity even after being reused five times. From the result of DFT calculations, it is concluded that the crystalline of zirconium dioxide is closely related to the charge transferring rate between the catalyst and the adsorbed reactant. Finally, based on the experiment phenomena and simulation result, a possible reaction mechanism is proposed for the reductive amination of cyclohexanone.
- Bai, Peng,Li, Jiacong,Tong, Xinli,Wang, Shun,Zhang, Haigang,Zhang, Ming
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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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- 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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- 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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- 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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- 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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- Supramolecular Ga4L612- cage photosensitizes 1,3-rearrangement of encapsulated guest via photoinduced electron transfer
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The K12Ga4L6 supramolecular cage is photoactive and enables an unprecedented photoreaction not observed in bulk solution. Ga4L612- cages photosensitize the 1,3-rearrangement of encapsulated cinnamylammonium cation guests from the linear isomer to the higher energy branched isomer when irradiated with UVA light. The rearrangement requires light and guest encapsulation to occur. The Ga4L612- cage-mediated reaction mechanism was investigated by UV/vis absorption, fluorescence, ultrafast transient absorption, and electrochemical experiments. The results support a photoinduced electron transfer mechanism for the 1,3-rearrangement, in which the Ga4L612- cage absorbs photons and transfers an electron to the encapsulated cinnamylammonium ion, which undergoes C-N bond cleavage, followed by back electron transfer to the cage and recombination of the guest fragments to form the higher energy isomer.
- Dalton, Derek M.,Ellis, Scott R.,Nichols, Eva M.,Mathies, Richard A.,Dean Toste,Bergman, Robert G.,Raymond, Kenneth N.
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supporting information
p. 10128 - 10131
(2015/09/01)
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- Electrochemical degradation of butyltrimethylammonium bis(trifluoromethylsulfonyl)imide for lithium battery applications
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Ionic liquids (ILs) are being considered as electrolytes for lithium ion batteries due to their low volatility, high thermal stability, and wide electrochemical windows which are stable at the strongly reducing potentials present in Li/Li+ batteries. Lithium metal deposition occurs under strongly reducing conditions and the effect that Li metal and any overpotential has on the stability of ILs is important in furthering the application of ILs in lithium based batteries. Here, N-butyl-N-trimethylammonium bis(trifluoromethylsulfonyl)imide was exposed to various potential differences in order to collect and characterize the volatile products. The IL produced more volatile products when exposed to strong reducing potentials which included reactive products such as hydrogen, alkanes, and amines. Water is a known contributor to hydrogen production in reducing environments, but the IL is also a source of hydrogen. If Li+ was present, the preferred pathway of reduction was plating of the lithium onto the working electrode, thus decreasing the reaction rate of degraded ILs.
- Klug, Christopher L.,Bridges, Nicholas J.,Visser, Ann E.,Crump, Stephen L.,Villa-Aleman, Eliel
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p. 3879 - 3884
(2014/08/05)
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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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p. 43195 - 43203
(2015/02/19)
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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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- Reductive methylation of primary and secondary amines and amino acids by aqueous formaldehyde and zinc
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Amines can be methylated when treated with formaldehyde and zinc in aqueous medium. Selective mono- or dimethylation can be achieved by proper choice of pH, stoichiometry and reaction time. This method can also be applied for amino acids.
- da Silva, Renato A.,Estevam, Idália H.S.,Bieber, Lothar W.
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p. 7680 - 7682
(2008/03/30)
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- A novel strategy for oligopeptide synthesis using a polymer-supported ammonium fluoride
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A novel method for the preparation of oligopeptides with a PS-ammonium fluoride in the solution phase is reported. The synthesis of lipid II pentapeptide is efficiently synthesized via a PS-ammonium fluoride without chromatographic purifications. The method reported here is very convenient to synthesize a relatively large amount of oligopeptides with abundantly available Fmoc-protected amino acids in a time efficient manner.
- Kurosu, Michio,Crick, Dean C.
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p. 5325 - 5328
(2007/10/03)
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- Efficient and mild procedure for reductive methylation of amines using N-methylpiperidine zinc borohydride
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A simple and efficient procedure for reductive methylation of primary and secondary amines using N-methylpiperidine zinc borohydride (ZBNMPP), giving tertiary amines, is described. The reaction is carried out in methanol at room temperature under neutral conditions. Copyright Taylor & Francis Group, LLC.
- Alinezhad, Heshmatollah,Tajbakhsh, Mahmood,Zamani, Reza
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p. 3609 - 3615
(2007/10/03)
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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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- Enhanced product selectivity in continuous N-methylation of amino alcohols over solid acid-base catalysts with supercritical methanol
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The unique properties of supercritical fluids can be exploited for fine-tuning product selectivity. Under the conditions listed for the N-methylation of amino alcohols (see scheme) over solid acid-base bifunctional catalysts, the total yield and product selectivity could be improved. Enhanced product selectivity might be attributed to the milder reaction conditions possible with supercritical methanol, as well as the increased concentration of methanol on the catalyst.
- Oku, Tomoharu,Ikariya, Takao
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p. 3476 - 3479
(2007/10/03)
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- ALKYLATING PROPERTIES OF DIALKYL PHOSPHITES
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When the mixture of amines and dialkyl phosphites is used in the reaction, as for example in the Kabachnik-Fields reaction, all possible N-alkylated products are formed.N-ethylation by diethyl phosphite is much slower than N-methylation by dimethyl phosphite and the latter can be easily formed via transesterification when the methanol is present in the mixture.Key words: Amine alkylation, dialkyl phosphites, Kabachnik-Fields synthesis.
- Gancarz, Roman
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p. 193 - 200
(2007/10/02)
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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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- Base-promoted elimination reactions of acetaldehyde N-alkyl-N,N-dimethylhydrazonium salts. A convenient synthesis of N,N-dimethylalkylamines
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The title reaction was utilized for efficient conversion of S(N)2-reactive alkyl halides to the corresponding N,N-dimethylalkylamines.
- Smith,Marcucci,Tingue
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p. 381 - 389
(2007/10/02)
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- Ion-Dipole Complexes in the Unimolecular Reactions of Isolated Organic Ions. Effect of N-Methylation on Olefin and Amine Loss from Protonated Aliphatic Amines
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The slow unimolecular fragmentation reactions os 18 gaseous protonated aliphatic amines of general formula R1NH(1+)R2R3 (R1=Prn, Pri, Bun, Bui, Bus, or But; R2,R3=H,CH3) are reported and discussed.Two decomposition routes are observed for a metastable ions R1NH(1+)R2R3.The first involves elimination of a neutral amine, R2R3NH, and formation of a carbocation, R1(1+), via a mechanism involving an incipient cation bound to the developing amine by an ion-dipole attraction.Rearrangement of the cation, to give thermodynamically more stable isomers, is feasible in these ion-dipole complexes.Further reorganization of the complexes leads to a species in which an incipient olefin 1-H> and an amine 2R3NH> are co-ordinated to a common proton.Dissociation of these proton-bound complexes, with retention of the proton by the developing amine, results in olefin loss, which is the secondreaction undergone by metastable ions R1NH(1+)R2R3.The relative abundance of amine expulsion is greater for protonated amines containing a primary alkyl group, R1, than is the case for isomeric ions containing secondary or tertiary alkyl groups.Progressive methylation of the nitrogen atom decreases the relative abundance of amine loss from R1NH(1+)R2R3, regardless of the nature of the principal alkyl group.These two trends are explained in terms of the energetics of the intermediates and products involved in the decomposition of the protonated amines.
- Bowen, Richard D.,Harrison, Alex G.,Reiner, Eric J.
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p. 1009 - 1014
(2007/10/02)
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- Catalyst system for amine transalkylation
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In the transalkylation of tertiary amines, unexpected higher yields are achieved requiring substantially less catalyst and much shorter reaction times at lower reaction temperatures using a homogeneous catalyst in the presence of an alcohol solvent and carbon monoxide. The process may be exemplified by reacting triethylamine and tripropylamine in the presence of a homogeneous triosmiumdodecacarbonyl catalyst, ethanol, and carbon monoxide to prepare diethylpropylamine and ethyldipropylamine.
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- Organomagnesium Inner Complexes, Part I. Bis(dialkylaminoalkyl)- and Bis(alkoxybutyl)magnesium Compounds
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A series of magnesium inner complexes has been prepared by reacting MgH2 (prepared by homogeneous catalysis) with dialkylallyl- and -3-butenylamines and -3-butenylethers in the presence of catalytic amounts of ZrCl4.The monomeric nature of bis(4-methoxybutyl)magnesium has been confirmed by X-ray diffraction.The analogous syntheses of bis(3-alkoxypropyl)magnesium compounds failed: cleavage of the allyl ether with elimination of propene occurred.This cleavage reaction is accelerated by catalytic amounts of NiCl2 or ZrCl4. - Keywords: Magnesium, Inner Complexes, Crystal Structure, X-Ray
- Angermund, Klaus,Bogdanovic, Borislav,Koppetsch, Gudrun,Krueger, Carl,Mynott, Richard,et al.
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p. 455 - 466
(2007/10/02)
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- CATALYTIC ALKYL GROUP EXCHANGE REACTION OF PRIMARY AND SECONDARY AMINES.
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It has been shown that primary and secondary amines undergo alkyl group exchange reactions upon treatment with palladium catalyst as depicted in an operationally simple and efficient reaction which provides a convenient method for synthesis of unsymmetrical amines. The application of the reaction for the preparation of various substituted amines and heterocyclic compounds such as hexahydropyrimidine tetrahydropyrimidine, imidazolidine, and imidazoles is described. The preparation of polyamines such as H//2N(CH//2)//mNH(CH//2)//nNH//2 (10) and H//2N(CH//2)//lNH(CH//2)//mNH(CH//2)//nNH//2 (l-n, equals 2,3; 11) is readily performed by the appadium-catalyzed reactions of azetidine (6) and aziridine (7) via azetine (9) and azirine intermediates. The mechanism the palladium-catalyzed reaction has been extensively studied on the carbonylation, racemization, and deuteurium-exchange reaction of (S)-( minus )- alpha -phenylethylamine (17).
- Murahashi,Yoshimura,Tsumiyama,Kojima
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p. 5002 - 5011
(2007/10/02)
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- SELECTIVE CONVERSION OF PRIMARY AMINES INRO N,N-DIMETHYLALKYL- OR N,N-DIALKYLMETHYL-AMINES WITH METHANOL AND RuCl2(Ph3P)3
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N,N-dimethylalkyl- or N,N-dialkylmethyl-amines are selectively obtained from the reaction between aliphatic amines and methanol at 180 deg C for 7 h in the presence of RuCl2(Ph3P)3 catalyst.
- Arcelli, Antonio,Khai, Bui-The,Porzi, Gianni
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- THE HOMOGENEOUSLY CATALYSED SYNTHESIS OF N-METHYLDIALKYLAMINES FROM N-METHYL AND N,N-DIMETHYLALKYLAMIMES
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N-Methyl and N,N-dimethylalkylamines are converted into N-methyldialkylamines in good yields when heated at 180 deg C in the presence of a catalytic amount of RuCl2(Ph3P)3.
- Arcelli, Antonio,Bui-The-Khai,Porzi, Gianni
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p. C31 - C34
(2007/10/02)
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- Transition Metal-catalysed N-Alkylation of Amines by Alcohols
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Primary and secondary alcohols effect alkylation of primary and secondary amines in the presence of rhodium, iridium, and ruthenium compounds at = 100 deg C, whereby selective monoalkylation of primary amines can be achieved, and heterocyclic rings can be constructed by both inter- and intra-molecular processes.
- Grigg, R.,Mitchell, T. R. B.,Sutthivaiyakit, S.,Tongpenyai, N.
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p. 611 - 612
(2007/10/02)
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- Preparation of esters of phosphorus acids
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Esters of phosphorus acids are prepared by an improved process whereby aromatic alcohols and phosphorus halides are reacted at specified temperatures in the presence of amine catalysts thereby providing high yields of substantially pure esters and allowing preparation of selected halogen-containing mono- and di-esters of phosphorus acids wherein halogen is directly bonded to phosphorus having substantially no side reactant contamination. The phosphorus esters are useful as intermediates in the preparation of plasticizers, oil additives and functional fluids.
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