- Deoxygenation of primary amides to amines with pinacolborane catalyzed by Ca[N(SiMe3)2]2(THF)2
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Deoxygenative reduction of amides is a challenging but favorable synthetic method of accessing amines. In the presence of a catalytic amount of Ca[N(SiMe3)2]2(THF)2, pinacolborane (HBpin) could efficiently reduce a broad scope of amides, primary amides in particular, into corresponding amines. Functional groups and heteroatoms showed good tolerance in this process of transformation, and a plausible reaction mechanism was proposed.
- Gong, Mingliang,Guo, Chenjun,Jiang, Linhong,Luo, Yunjie,Yu, Chong
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supporting information
p. 1201 - 1206
(2021/05/29)
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- Lithium compound catalyzed deoxygenative hydroboration of primary, secondary and tertiary amides
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A selective and efficient route for the deoxygenative reduction of primary to tertiary amides to corresponding amines has been achieved with pinacolborane (HBpin) using simple and readily accessible 2,6-di-tert-butyl phenolate lithium·THF (1a) as a catalyst. Both experimental and DFT studies provide mechanistic insight. This journal is
- Bisai, Milan Kumar,Gour, Kritika,Das, Tamal,Vanka, Kumar,Sen, Sakya S.
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supporting information
p. 2354 - 2358
(2021/03/03)
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- Reduction of Amides to Amines with Pinacolborane Catalyzed by Heterogeneous Lanthanum Catalyst La(CH2C6H4NMe2- o)3@SBA-15
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Hydroboration of amides is a useful synthetic strategy to access the corresponding amines. In this contribution, it was found that the supported lanthanum benzyl material La(CH2C6H4NMe2-o)3@SBA-15 was highly active for the hydroboration of primary, secondary, and tertiary amides to amines with pinacolborane. These reactions selectively produced target amines and showed good tolerance for functional groups such as -NO2, -halogen, and -CN, as well as heteroatoms such as S and O. This reduction procedure exhibited the recyclable and reusable property of heterogeneous catalysts and was applicable to gram-scale synthesis. The reaction mechanisms were proposed based on some control experiments and the previous literature. This is the first example of hydroborative reduction of amides to amines mediated by heterogeneous catalysts.
- Guo, Chenjun,Zhang, Fangcao,Yu, Chong,Luo, Yunjie
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supporting information
p. 13122 - 13135
(2021/08/31)
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- A Lewis Base Nucleofugality Parameter, NFB, and Its Application in an Analysis of MIDA-Boronate Hydrolysis Kinetics
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The kinetics of quinuclidine displacement of BH3 from a wide range of Lewis base borane adducts have been measured. Parameterization of these rates has enabled the development of a nucleofugality scale (NFB), shown to quantify and predict the leaving group ability of a range of other Lewis bases. Additivity observed across a number of series R′3-nRnX (X = P, N; R′ = aryl, alkyl) has allowed the formulation of related substituent parameters (nfPB, nfAB), providing a means of calculating NFB values for a range of Lewis bases that extends far beyond those experimentally derived. The utility of the nucleofugality parameter is explored by the correlation of the substituent parameter nfPB with the hydrolyses rates of a series of alkyl and aryl MIDA boronates under neutral conditions. This has allowed the identification of MIDA boronates with heteroatoms proximal to the reacting center, showing unusual kinetic lability or stability to hydrolysis.
- García-Domínguez, Andrés,Gonzalez, Jorge A.,Leach, Andrew G.,Lloyd-Jones, Guy C.,Nichol, Gary S.,Taylor, Nicholas P.
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supporting information
(2022/01/04)
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- Organic amine mediated cleavage of Caromatic-Cαbonds in lignin and its platform molecules
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The activation and cleavage of C-C bonds remains a critical scientific issue in many organic reactions and is an unmet challenge due to their intrinsic inertness and ubiquity. Meanwhile, it is crucial for the valorization of lignin into high-value chemicals. Here, we proposed a novel strategy to enhance the Caromatic-Cα bond cleavage by pre-functionalization with amine sources, in which an active amine intermediate is first formed through Markovnikov hydroamination to reduce the dissociation energy of the Caromatic-Cα bond which is then cleaved to form target chemicals. More importantly, this strategy provides a method to achieve the maximum utilization of the aromatic nucleus and side chains in lignin or its platform molecules. Phenols and N,N-dimethylethylamine compounds with high yields were produced from herbaceous lignin or the p-coumaric acid monomer in the presence of industrially available dimethylamine (DMA). This journal is
- Cheng, Xiaomeng,Dong, Minghua,Han, Buxing,Liu, Huizhen,Liu, Shulin,Shen, Xiaojun,Wang, Zhenpeng,Xin, Yu,Yang, Junjuan
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p. 15110 - 15115
(2021/12/04)
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- Bench-Stable Cobalt Pre-Catalysts for Mild Hydrosilative Reduction of Tertiary Amides to Amines and Beyond
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The readily synthesized and bench-stable cobalt dichloride complex (dpephos)CoCl2 is employed as a pre-catalyst for a diversity of silane additions to unsaturated organic molecules, including the normally challenging reduction of amides to amines. With regard to hydrosilative reduction of amides even more effective and activator free catalytic systems can be generated from the bench-stable, commercially available Co(acac)2 and Co(OAc)2 with dpephos and PPh3 ligands. These systems operate under mild conditions (100 °C), with many examples of room temperature transformations, presenting a first example of mild cobalt-catalyzed hydrosilylation of amides.
- Nurseiit, Alibek,Janabel, Jaysan,Gudun, Kristina A.,Kassymbek, Aishabibi,Segizbayev, Medet,Seilkhanov, Tulegen M.,Khalimon, Andrey Y.
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p. 790 - 798
(2019/01/09)
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- Hydrogenolysis of Amide Acetals and Iminium Esters
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Amide acetals and iminium esters were hydrogenated into amines under very mild reaction conditions over common hydrogenation catalysts. This finding provides a new strategy for the selective reduction of amides. The synthetic utility of this approach was demonstrated by the selective reduction of amides bearing ester and nitrile groups.
- Kadyrov, Renat
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p. 170 - 172
(2017/12/26)
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- Zinc hydridotriphenylborates supported by a neutral macrocyclic polyamine
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The zinc hydridotriphenylborates [(L)Zn(TMDS)][HBPh3] and [(L)ZnX][HBPh3] (L = Me4TACD, Me4[12]aneN4; TMDS = N(SiHMe2)2; X = Cl, Br, I) were synthesized by BPh3-mediated β-SiH abstraction and salt metathesis with KHBPh3, respectively. CO2 is rapidly inserted into the B-H bonds. [(L)Zn(TMDS)][HBPh3] catalyzes the hydroboration of polar substrates including CO2.
- Mukherjee, Debabrata,Wiegand, Ann-Kristin,Spaniol, Thomas P.,Okuda, Jun
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supporting information
p. 6183 - 6186
(2017/07/11)
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- Chemoselective Reduction of Tertiary Amides to Amines Catalyzed by Triphenylborane
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Triphenylborane (BPh3) was found to catalyze the reduction of tertiary amides with hydrosilanes to give amines under mild condition with high chemoselectivity in the presence of ketones, esters, and imines. N,N-Dimethylacrylamide was reduced to provide the α-silyl amide. Preliminary studies indicate that the hydrosilylation catalyzed by BPh3may be mechanistically different from that catalyzed by the more electrophilic B(C6F5)3.
- Mukherjee, Debabrata,Shirase, Satoru,Mashima, Kazushi,Okuda, Jun
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supporting information
p. 13326 - 13329
(2016/10/30)
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- Reactivity of a Molecular Magnesium Hydride Featuring a Terminal Magnesium-Hydrogen Bond
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The reactivity of the molecular magnesium hydride [Mg(Me3TACD·AliBu3)H] (1) featuring a terminal magnesium-hydrogen bond and an NNNN-type macrocyclic ligand, Me3TACD ((Me3TACD)H = Me3[12]aneN4 = 1,4,7-trimethyl-1,4,7,10-tetraazacyclododecane), can be grouped into protonolysis, oxidation, hydrometalation, (insertion), and hydride abstraction. Protonolysis of 1 with weak Br?nsted acids HX such as terminal acetylenes, amines, silanols, and silanes gave the corresponding derivatives [Mg(Me3TACD·AliBu3)X] (X = C=CPh, 3; HN(3,5-Me2-C6H3), 4; OSiMe3, 5; OSiPh3, 6; Cl, 7; Br, 8). Single-crystal X-ray diffraction of anilide 4 showed a square-pyramidal coordination geometry for magnesium. No correlation with the pKa values of the acids was detected. Oxidation of 1 with elemental iodine gave the iodide [Mg(Me3TACD·AliBu3)I] (9), and oxidation with nitrous oxide afforded the μ-oxo-bridged compound [{Mg(Me3TACD·AliBu3)}2(μ-O)] (10) with a linear Mg-O-Mg core, as characterized by single-crystal X-ray diffraction. The Mg-H bond reacted with benzaldehyde, benzophenone, fluorenone, and CO2 under insertion but not with the olefins 1,1,2-triphenylethylene, tert-butylethylene, and cyclopentene. The unstable formate, prepared also by salt metathesis of iodide 9 with potassium formate, revealed ?°O,?°O′ coordination in the solid state. Hydride abstraction with triphenylborane gave the ion pair [Mg(Me3TACD·AliBu3)(thf)][HBPh3] (16), which catalyzed the hydroboration of polar substrates by pinacolborane.
- Schnitzler, Silvia,Spaniol, Thomas P.,Okuda, Jun
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p. 12997 - 13006
(2016/12/26)
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- Magnesium hydridotriphenylborate [Mg(thf)6][HBPh3]2: A versatile hydroboration catalyst
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Magnesium bis(hydridotriphenylborate), isolated as a solvent-separated ion pair [Mg(thf)6][HBPh3]2, effectively catalyzed the hydroboration of several unsaturated substrates including CO2.
- Mukherjee, Debabrata,Shirase, Satoru,Spaniol, Thomas P.,Mashima, Kazushi,Okuda, Jun
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supporting information
p. 13155 - 13158
(2016/11/09)
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- Facile and efficient KOH-catalysed reduction of esters and tertiary amides
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Esters and tertiary amides were efficiently reduced to their corresponding alcohols and amines in high yields under mild and environmentally friendly conditions. The presented KOH-catalysed system involves a simple hydrosilylation procedure that is carried out under solvent-free conditions and does not require the use of inert conditions.
- Fernandez-Salas, Jose A.,Manzini, Simone,Nolan, Steven P.
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supporting information
p. 9758 - 9760
(2013/10/21)
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- Cesium carbonate-catalyzed reduction of amides with hydrosilanes
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Cesium carbonate has been found to be an effective catalyst for the reduction of tertiary carboxamides with the simple, commercially available PhSiH3 under solvent-free conditions. The catalytic system can effectively reduce a range of amides under relatively mild conditions (from room temperature to 80 C) to yield the corresponding amines in good to excellent yields (71-100%) and thus has the potential for practical applications.
- Xie, Weilong,Zhao, Mengdi,Cui, Chunming
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p. 7440 - 7444
(2014/04/03)
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- Lewis base complexes of AlH3: Prediction of preferred structure and stoichiometry
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The structures adopted by a range of complexes AlH3·nL, (n = 1 or 2), have been explored in detail to identify the factors that determine the value of n, and whether a monomeric or dimeric arrangement is preferred for the 1 : 1 complexes. Single-crystal X-ray diffraction, vibrational and NMR spectroscopies, and thermal analysis data have been collected, DFT calculations have been performed for AlH3·nL species, and pKa values have been collated for a series of amine and phosphine ligands L. The pKa of the ligand L exerts an important influence on the type of complex formed: as the basicity of L increases, a monomeric structure is favoured over a dimeric arrangement. Dimeric amine complexes form if pKa a > 9.99. The steric requirements of L also influence the structural preference: bulky ligands with large cone angles (>163°) tend to favour formation of monomers, while smaller cone angles (3·NMe 2Et, AlH3·NMe3 and AlH 3·nEt2O. The Royal Society of Chemistry 2013.
- Humphries, Terry D.,Munroe, Keelie T.,Decken, Andreas,McGrady, G. Sean
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p. 6965 - 6978
(2013/08/25)
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- Zinc-catalyzed reduction of amides: Unprecedented selectivity and functional group tolerance
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(Chemical Equation Presented) A novel zinc-catalyzed reduction of tertiary amides was developed. This system shows remarkable chemoselectivity and substrate scope tolerating ester, ether, nitro, cyano, azo, and keto substituents. Copyright
- Das, Shoubhik,Addis, Daniele,Zhou, Shaolin,Junge, Kathrin,Beller, Matthias
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supporting information; experimental part
p. 1770 - 1771
(2010/04/25)
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- Process for obtaining amines by reduction of amides
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Disclosed is a process for the preparation of primary, secondary and tertiary amines via a catalytic hydrogenation of unsubstituted, N-substituted, and N,N- disubstituted amides. The amide is led, together with an auxiliary amine, in vaporised form in a hydrogen containing gas flow over the catalyst. The process can be carried out at relatively low pressures, between 2 and 50 bars, using typical hydrogenation catalysts like CuCr-type catalysts. The amine is obtained with high yield and high selectivity. The process can be carried out in a continuous fixed bed reactor.
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Page/Page column 7
(2008/06/13)
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- Process for obtaining amines by reduction of amides
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Disclosed is a process for the preparation of primary, secondary and tertiary amines via a catalytic hydrogenation of unsubstituted, N-substituted, and N,N-disubstituted amides. The amide is led, together with an auxiliary amine, in vaporised form in a hydrogen containing gas flow over the catalyst. The process can be carried out at relatively low pressures, between 2 and 50 bars, using typical hydrogenation catalysts like CuCr-type catalysts. The amine is obtained with high yield and high selectivity. The process can be carried out in a continuous fixed bed reactor.
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Page/Page column 5
(2008/06/13)
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- PROCESS FOR OBTAINING AMINES BY REDUCTION OF AMIDES
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Disclosed is a process for the preparation of primary, secondary and tertiary amines via a catalytic hydrogenation of unsubstituted, N- substituted, and N,N- disubstituted amides. The amide is led, together with an auxiliary amine, in vaporised form in a hydrogen containing gas flow over the catalyst. The process can be carried out at relatively low pressures, between 2 and 50 bars, using typical hydrogenation catalysts like CuCr-type catalysts. The amine is obtained with high yield and high selectivity. The process can be carried out in a continuous fixed bed reactor.
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Page/Page column 13
(2008/06/13)
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- METHOD FOR THE CONTINUOUS PRODUCTION OF AN AMINE
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The invention relates to a method for the continuous production of an amine by reacting a primary or secondary alcohol, aldehyde and/or ketone with hydrogen and a nitrogen compound, selected from the group containing ammonia and primary and secondary amines, at a temperature that ranges between 60 and 300 °C in the presence of a catalyst containing copper. According to the invention, the catalytically active mass of the catalyst contains the following prior to its reduction with hydrogen: 20 to 85 wt. % aluminium oxide (Al2O3), zirconium dioxide (ZrO2), titanium dioxide (TiO2) and/or silicon dioxide (SiO2); 1 to 70 wt. % copper compounds containing oxygen, calculated as CuO; 0 to 50 wt. % magnesium compounds containing oxygen, calculated as MgO; chromium compounds containing oxygen, calculated as Cr2O3; zinc compounds containing oxygen, calculated as ZnO; barium compounds containing oxygen, calculated as BaO; and/or calcium compounds containing oxygen, calculated as CaO; and less than 30 wt. % nickel compounds containing oxygen, calculated as NiO, in relation to the copper compounds containing oxygen, calculated as CuO. The reaction in the gas phase takes place isothermally in a tubular reactor.
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Page/Page column 24
(2008/06/13)
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- Preparation of amines
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Amines are prepared by reacting primary or secondary alcohols, aldehydes or ketones with nitrogen compounds selected from the group consisting of ammonia and primary and secondary amines at elevated temperatures and superatmospheric pressures in the presence of hydrogen and of a catalyst containing copper and oxygen-containing compounds of titanium by a process in which the catalyst is used in the form of moldings which have been prepared with the addition of metallic copper powder.
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- Contrast media synthesized from polyaldehydes
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Microparticles comprising biodegradable polymers, characterized in that they are synthesized from polymerizable aldehydes, which optionally contain additives and/or crosslinkers capable of copolymerization, optionally surfactants or surfactant mixtures, gases and/or highly volatile liquids in free or bound form, coupling agents, optionally biomolecules or macromolecules bound by these coupling agents as well as optionally diagnostically or therapeutically effective components, are suitable as ultrasonic contrast media.
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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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- Novel Borane-Selenium Complex: Highly Selective Reduction of Tertiary Amides and Nitriles to the Corresponding Amines with Sodium Borohydride-Dialkylselenium Dibromide
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The reaction of sodium borohydride with bis(2-bromoethyl)selenium dibromide and/or diethylselenium dibromide in tetrahydrofuran (THF) gave borane.Treatment of tertiary amides with mixtures of sodium borohydride and either of the dibromides in THF gave the corresponding amines.Similar reactions with secondary and primary amides did not proceed.Furthermore, under similar reduction conditions, the reaction of nitriles with the above reagents also gave the corresponding primary amines.
- Akabori, Sadatoshi,Takanohashi, Yoshinori
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p. 479 - 482
(2007/10/02)
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- A Novel Highly Selective Reduction of Tertiary Amides to Amines with Sodium Borohydride-Bis(2-bromoethyl)selenium Dibromide
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Treatment of tertiary amides with sodium borohydride-bis(2-bromoethyl)selenium dibromide in THF gave the corresponding amines, although the similar reactions of secondary and primary amides could not proceeded.
- Akabori, Sadatoshi,Takanohashi, Yoshinori
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p. 251 - 252
(2007/10/02)
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- Process for preparing amines from olefins with ammonium halide catalysts
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The process for preparing aliphatic and aromatic amines by reacting an olefin with either ammonia, a primary amine, or a secondary amine at elevated temperature in the presence of an ammonium halide catalyst, preferably a catalyst-promoter combination, is disclosed herein.
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- Preparation of amines from olefins using certain transition metal catalysts
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Aliphatic and aromatic amines are produced by reacting an olefin with either ammonia or a primary or secondary amine in the presence of a catalytic amount of ruthenium or iron compound catalyst. The reaction is carried out in the liquid phase using an inert liquid, a product amine, or one of the reactants as a solvent. The temperatures used are 100° to 250° C. and the pressures are at least autogenous and up to 12,000 psig.
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- Mechanism of Elimination Reactions. 38. Why Is the Effect of Successive β-Alkyl Substitution on the Rates of Elimination from Quaternary Ammonium Salts Nonadditive?
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Possible reasons are examined for the nonadditivity of the effect of successive β-methyl substitution on the rates of elimination reactions of quaternary ammonium salts.The temperature dependences of the deuterium isotope effects in E2 reactions of R1R2NMe2+ show that tunneling is not a significant source of nonadditivity.Neither is a change of gross mechanism or stereochemistry, for studies with C4H9CHDCHDNMe3+ and C4H9(CH3)CHCHDNMe3+ show the reactions to be very predominantly (>88percent) anti-E2 in both cases.Secondary tritium isotope effects with R1R2CHCHTNMe3+ increase, however in the order ethyl (1.108 +/- 0.002), propyl (1.150 +/- 0.015), isobutyl (1.216 +/- 0.012).This result suggests increasing rehybridization at the α-carbon in the transition state and therefore a shift toward less E1cB and more central-E2 character.Since methyl substitution is expected to favor a developing double bond, the much smaller rate-depressing effect of the second β-methyl is accounted for by such a shift in transition-state character.
- Wu, Shune-Long,Tao, Yu-Tai,Saunders, William H.
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p. 7583 - 7588
(2007/10/02)
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- Oxidation of thiols employing cobalt molybdate/triethylamine catalyst
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A thiol is oxidized to a corresponding disulfide employing a supported cobalt molybdate catalyst in combination with a liquid tertiary amine. 2-propanethiol is converted to diisopropyl disulfide with conversions of the order of 94% and selectivities of the order of 98%.
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