- Hydroborative reduction of amides to amines mediated by La(CH2C6H4NMe2-: O)3
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The deoxygenative reduction of amides to amines is a great challenge for resonance-stabilized carboxamide moieties, although this synthetic strategy is an attractive approach to access the corresponding amines. La(CH2C6H4NMe2-o)3, a simple and easily accessible lanthanide complex, was found to be highly efficient not only for secondary and tertiary amide reduction, but also for the most challenging primary reduction with pinacolborane. This protocol exhibited good tolerance for many functional groups and heteroatoms, and could be applied to gram-scale synthesis. The active species in this catalytic cycle was likely a lanthanide hydride.
- Gong, Mingliang,Guo, Chenjun,Luo, Yunjie,Xie, Hongzhen,Zhang, Fangcao
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p. 779 - 791
(2022/01/22)
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- Method for catalyzing hydrodesulfurization of thioamide derivative
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The invention provides a method for catalyzing hydrodesulfurization of a thioamide derivative, which comprises the following steps: sequentially adding a pentacarbonyl manganese bromide catalyst, a reaction substrate thioamide derivative, Lewis acid, a solvent and alkali into a polytetrafluoroethylene lined reaction tube, putting the reaction tube into a high-pressure kettle, introducing hydrogen to carry out catalytic hydrogenation reaction, cooling to room temperature, discharging gas, washing the reaction tube with ethyl acetate, passing through a silica gel small short column, carrying out spin drying, and carrying out column chromatography purification to obtain a target product. The monovalent manganese which is low in toxicity and good in chemical selectivity and biocompatibility is used as the catalyst to catalyze hydrodesulfurization of the thioamide derivative, the substrate range is wide, the yield of amine is high, and the method has high drug synthesis application value.
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Paragraph 0064-0068
(2021/07/09)
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- Benzyne-Mediated Esterification Reaction
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A benzyne-mediated esterification of carboxylic acids and alcohols under mild conditions has been realized, which is made possible via a selective nucleophilic addition of carboxylic acid to benzyne in the presence of alcohol. After a subsequent transesterification with alcohol, the corresponding esters can be produced efficiently. This benzyne-mediated protocol can be used on the modification of Ibuprofen, cholesterol, estradiol, and synthesis of nandrolone phenylpropionate. In addition, benzyne can also be used to promote lactonization and amidation reaction.
- Li, Yang,Shi, Jiarong,Zhao, Jinlong
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supporting information
p. 7274 - 7278
(2021/10/01)
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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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- Transition-Metal-Free and Base-Promoted Carbon-Heteroatom Bond Formation via C-N Cleavage of Benzyl Ammonium Salts
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A facile and general method for constructing carbon-heteroatom (C-P, C-O, C-S, and C-N) bonds via C-N cleavage of benzyl ammonium salts under transition-metal-free conditions was reported. The combination of t-BuOK and 18-crown-6 enabled a wide range of substituted benzyl ammonium salts to couple readily with different kinds of heteroatom nucleophiles, i.e. hydrogen phosphoryl compounds, alcohols, thiols, and amines. Good functional group tolerance was demonstrated. The scale-up reaction and one-pot synthesis were also successfully performed.
- Liu, Long,Tang, Yuanyuan,Wang, Kunyu,Huang, Tianzeng,Chen, Tieqiao
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p. 4159 - 4170
(2021/03/09)
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- BF3·Et2O as a metal-free catalyst for direct reductive amination of aldehydes with amines using formic acid as a reductant
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A versatile metal- and base-free direct reductive amination of aldehydes with amines using formic acid as a reductant under the catalysis of inexpensive BF3·Et2O has been developed. A wide range of primary and secondary amines and diversely substituted aldehydes are compatible with this transformation, allowing facile access to various secondary and tertiary amines in high yields with wide functional group tolerance. Moreover, the method is convenient for the late-stage functionalization of bioactive compounds and preparation of commercialized drug molecules and biologically relevant N-heterocycles. The procedure has the advantages of simple operation and workup and easy scale-up, and does not require dry conditions, an inert atmosphere or a water scavenger. Mechanistic studies reveal the involvement of imine activation by BF3and hydride transfer from formic acid.
- Fan, Qing-Hua,Liu, Xintong,Luo, Zhenli,Pan, Yixiao,Xu, Lijin,Yang, Ji,Yao, Zhen,Zhang, Xin
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supporting information
p. 5205 - 5211
(2021/07/29)
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- Regioselective Synthesis of 2° Amides Using Visible-Light-Induced Photoredox-Catalyzed Nonaqueous Oxidative C-N Cleavage of N, N-Dibenzylanilines
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A visible-light-driven photoredox-catalyzed nonaqueous oxidative C-N cleavage of N,N-dibenzylanilines to 2° amides is reported. Further, we have applied this protocol on 2-(dibenzylamino)benzamide to afford quinazolinones with (NH4)2S2O8 as an additive. Mechanistic studies imply that the reaction might undergo in situ generation of α-amino radical to imine by C-N bond cleavage followed by the addition of superoxide ion to form amides.
- Neerathilingam, Nalladhambi,Bhargava Reddy, Mandapati,Anandhan, Ramasamy
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supporting information
p. 15117 - 15127
(2021/10/25)
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- Direct benzylation of amines with benzylic alcohols catalyzed by palladium/phosphine-borane catalyst system
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Direct catalytic benzylation of amines with benzylic alcohols to give benzylamines has been newly developed by using palladium/phosphine-borane catalyst system. In this catalytic reaction, the linking between both phosphine and borane moieties in the ligand is very important. Hydroxy group of benzylic alcohols is activated by Lewis acidic borane to form a benzylpalladium intermediate which is attacked by amines to give benzylamine products.
- Onodera, Gen,Kumagae, Hidenobu,Nakamura, Daiki,Hayasaki, Takuto,Fukuda, Tsutomu,Kimura, Masanari
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supporting information
(2020/11/04)
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- Ultrasound-assisted construction of a Z-scheme heterojunction with g-C3N4 nanosheets and flower-like Bi2WO6 microspheres and the photocatalytic activity in the coupling reaction between alcohols and amines under visible light irradiation
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Flower-like Bi2WO6 microspheres and bulk g-C3N4 were prepared by the hydrothermal method and high-temperature calcining method, respectively. A new method based on the combination of ultrasonic stripping and mechanical stirring was used to obtain uniform composite x-Bi2WO6/g-C3N4 (x is the Bi2WO6 mass ratio) photocatalysts with a Z-scheme heterojunction. In the reaction of benzyl alcohol and aniline to form imine, the optimal composite, 30percent-Bi2WO6/g-C3N4, showed a conversion rate of 87.6percent, which is much higher than that of pure Bi2WO6 and g-C3N4. Characterization by SEM and TEM showed that the ultrasonically stripped g-C3N4 significantly reduced the radial dimension compared to bulk g-C3N4. A uniformly dispersed photocatalytic material was formed, and it maintained a flower-like microsphere structure. Materials characterized by N2 adsorption–desorption isotherms (BET) showed that the specific surface area of the g-C3N4 nanosheets increased by approximately ten times after ultrasonic stripping. The photostability of the composite was verified by cyclic experiments. Under visible light irradiation, the activation energy of the coupling reaction between benzyl alcohol and aniline was found to be decreased by 29.8 kJ mol?1. A capture experiment was used to verify the active species in the photocatalytic system, with the reaction found to be mainly completed through the synergistic action of h+, e? and ?O2?.
- Hao, Xueli,Li, Enbo,Li, Haiying,Li, Jingyi,Wang, Yan,Wang, Zhibao,Yu, Xiujuan,Zhang, Zhiying
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- ROMP-Boranes as Moisture-Tolerant and Recyclable Lewis Acid Organocatalysts
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Although widely used in catalysis, the multistep syntheses and high loadings typically employed are limiting broader implementation of highly active tailor-made arylborane Lewis acids and Lewis pairs. Attempts at developing recyclable systems have thus far met with limited success, as general and versatile platforms are yet to be developed. We demonstrate a novel approach that is based on the excellent control and functional group tolerance of ring-opening metathesis polymerization (ROMP). The ROMP of highly Lewis acidic borane-functionalized phenylnorbornenes afforded both a soluble linear copolymer and a cross-linked organogel. The polymers proved highly efficient as recyclable catalysts in the reductive N-alkylation of arylamines under mild conditions and at exceptionally low catalyst loadings. The modular design presented herein can be readily adapted to other finely tuned triarylboranes, enabling wide applications of ROMP-borane polymers as well-defined supported organocatalysts.
- Vidal, Fernando,McQuade, James,Lalancette, Roger,J?kle, Frieder
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supporting information
p. 14427 - 14431
(2020/10/13)
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- Double and Single Hydroboration of Nitriles Catalyzed by a Ruthenium-Bis(silyl)xanthene Complex: Application to One-Pot Synthesis of Diarylamines and N-Arylimines
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A ruthenium complex bearing a bis(silyl)xanthene chelate ligand xantsil, i.e. Ru[κ3(Si,O,Si)-xantsil](CO)(PCyp3) (1a, Cyp = cyclopentyl), was found to catalyze both double and single hydroboration reactions of nitriles with pinacolborane (HBpin) and 9-borabicyclo[3.3.1]nonane (9-BBN) to give bis(boryl)amines 2 and N-borylimines 3, respectively, in mostly >99% yields. By combination of these reactions with subsequent palladium-catalyzed deborylative C-N coupling reactions of 2 and 3 with a 1:1 mixture of bromoarenes and KOtBu, one-pot synthetic routes to tertiary N,N-diarylamines 4 and N-arylaldimines 5 from nitriles were developed.
- Kitano, Takeo,Komuro, Takashi,Tobita, Hiromi
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supporting information
p. 1417 - 1420
(2019/03/19)
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- Frustrated Lewis Pair Catalyzed Hydrogenation of Amides: Halides as Active Lewis Base in the Metal-Free Hydrogen Activation
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A method for the metal-free reduction of carboxylic amides using oxalyl chloride as an activating agent and hydrogen as the final reductant is introduced. The reaction proceeds via the hydrogen splitting by B(2,6-F2-C6H3)3 in combination with chloride as the Lewis base. Density functional theory calculations support the unprecedented role of halides as active Lewis base components in the frustrated Lewis pair mediated hydrogen activation. The reaction displays broad substrate scope for tertiary benzoic acid amides and α-branched carboxamides.
- Sitte, Nikolai A.,Bursch, Markus,Grimme, Stefan,Paradies, Jan
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p. 159 - 162
(2019/01/04)
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- Efficient and Selective Hydrosilylation of Secondary and Tertiary Amides Catalyzed by an Iridium(III) Metallacycle: Development and Mechanistic Investigation
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Readily accessible cationic IrIII metallacycles catalyze efficiently the chemoselective hydrosilylation of tertiary and secondary amides to amines. The catalyst described herein operates at low loadings using inexpensive 1,1,3,3-tetramethyldisiloxane and allows fast reactions with high yields, selectivities, and turnover numbers. A transient iminium intermediate has been observed for the first time by using mass spectrometry, and the activation of the catalyst and the silane reagent have been studied by using DFT calculations. These fundamental insights support the present and future improvements of IrIII metallacycles through proper ligand modifications and enable further broad applications of catalysts based on metallacycles.
- Corre, Yann,Trivelli, Xavier,Capet, Frédéric,Djukic, Jean-Pierre,Agbossou-Niedercorn, Francine,Michon, Christophe
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p. 2009 - 2017
(2017/06/13)
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- Synthesis of amines by reductive amination of aldehydes and ketones using Co3O4/NGr@C catalyst
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Heterogenized non-noble metal-based catalysts allow for costefficient and environmentally benign hydrogenations. Here, we have developed a straightforward reductive amination methodology using molecular hydrogen in the presence of a Co3O4/ NGr@C catalyst system. Various carbonyl compounds were transformed with secondary amines to the corresponding tertiary amines with good to excellent yields and selectivity. The Co3O4/NGr@C catalyst is recycled up to five times without significant loss of activity.
- Pisiewicz, Sabine,Stemmler, Tobias,Surkus, Annette-Enrica,Junge, Kathrin,Beller, Matthias
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- SiO2-Cu2O: An efficient and recyclable heterogeneous catalyst for N-benzylation of primary and secondary amines
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A mild, effective, and selective procedure is reported for the mono N-benzylation and N,N-dibenzylation of primary amines as well as mono N-benzylation of secondary amines using silica-supported copper(I) oxide in water. The silica-supported Cu2O was generated in situ by the reaction of Fehling solution and glucose at 100 C onto activated silica. The catalyst was filtered, washed with water, and oven-dried, and was characterized by Fourier transform infrared spectroscopy, thermogravimetric analysis, scanning electron microscopy, transmission electron microscopy, and atomic absorption spectroscopy. The prepared Cu2O-SiO2 was found to be thermally stable up to 325 C. The copper was uniformly distributed onto the surface of the silica, and the mean particle diameter was 7 nm. The catalyst served as a selective heterogenous catalyst for the N-benzylation of primary and secondary amines. The catalyst is recyclable and was used effectively upto fifth run without a significant loss of catalytic activity. Various reaction solvents including water, acetonitrile, and toluene were screened for N-benzylation of amines, and the success of the aqueous system highlights the low environmental impact of the procedure.
- Gupta, Manjulla,Paul, Satya,Gupta, Rajive
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p. 444 - 450
(2014/04/03)
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- Silica-functionalized CuI: An efficient and selective catalyst for N-benzylation, allylation, and alkylation of primary and secondary amines in water
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Silica-functionalized CuI has been reported as an efficient and selective catalyst for the selective mono-N- and N,N-dibenzylation, allylation, and alkylation of primary amines with benzylic, allylic, and alkyl halides using NaOH as base in aqueous medium. By changing the reaction temperature, mono- or di-benzylation, allylation, or alkylation could be achieved in good yield and selectivity. Secondary amines have also been benzylated, allylated, and alkylated under similar conditions. SiO2-CuI has been characterized by Fourier transform-infrared, atomic absorption spectrometry, thermalgravimetric analysis, X-ray diffraction, scanning electron microscopy, and transmission electron microscopy, and found to be highly selective and recyclable under the reaction conditions. [Supplementary materials are available for this article. Go to the publisher's online edition of Synthetic Communications for the following free supplemental resource(s): Full experimental and spectral details.] Copyright
- Shamim, Tahira,Kumar, Vineet,Paul, Satya
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p. 620 - 632
(2014/01/17)
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- Solvent free acid catalysed direct N-alkylation of amines with alcohols using Al grafted MCM-41
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The catalytic activity of Al grafted MCM-41 (Al-MS) was explored for solvent free acid catalysed direct N-alkylation of amines using alcohols as green alkylating agent to establish a clean method for synthesis of N-alkylated amines. The study revealed that acidity of Al-MS catalyst, reaction conditions and substrate's (amines and alcohols) nature are important factors influencing the N-alkylation reaction. The Al grafted MCM-41 with Si/Al molar ratio of 5 showed excellent activity for N-alkylation of amines with alcohols. The reusability of spent catalyst regenerated by simple washing with acetone was demonstrated for subsequent four reaction cycles.
- Tayade, Kamlesh N.,Mishra, Manish,Munusamy,Somani, Rajesh S.
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- Palladium-catalysed amination of aryl- and heteroaryl halides using tert-butyl tetraisopropylphosphorodiamidite as an easily accessible and air-stable ligand
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The phosphorus compound tert-butyl tetraisopropylphosphorodiamidite, prepared from bis(diisopropylamino)chlorophosphine, is an excellent ligand for palladium-catalysed Buchwald-Hartwig amination of aryl- and heteroaryl chlorides and bromides. Based on its ready accessibility and air-stability, this amination protocol is a practical approach to the synthesis of industrially important aryl- and heteroarylamines. Copyright
- Roiban, Gheorghe-Doru,Mehler, Gerlinde,Reetz, Manfred T.
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supporting information
p. 2070 - 2076
(2014/04/17)
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- N-heterocyclic carbene-palladium(II)-4,5-dihydrooxazole complexes: Synthesis and catalytic activity toward amination of aryl chlorides
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A series of novel N-heterocyclic carbene-palladium(II)-4,5-dihydrooxazole (NHC-PdII-Ox) complexes 3 were successfully synthesized from commercially available imidazolium salts 1, PdCl2, and 4,5-dihydrooxazoles 2 in a one-step process, and these complexes showed efficient catalytic activity toward the amination of aryl chlorides. Both secondary and primary amines were tolerated under the same reaction conditions. Under the optimal reaction conditions, the expected coupling products were obtained in moderate to high yields.
- Huang, Pei,Wang, Yi-Xiang,Yu, Hong-Fei,Lu, Jian-Mei
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supporting information
p. 1587 - 1593
(2014/05/06)
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- Direct reductive amination using triethylsilane and catalytic bismuth(III) chloride
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Direct reductive amination (DRA) using triethylsilane (TESH) and catalytic bismuth(III) chloride (BiCl3) is described for the first time. The use of TESH and BiCl3 provides easy handling, low cost, non-toxicity, and a mild Lewis acid activity, thereby meeting the demand for green and sustainable chemistry. The developed DRA is highly chemoselective and applicable to less-basic amines. The experimental results of this study revealed that the developed DRA could be catalyzed by BiCl3, which was gradually reduced to Bi(0) or bismuth with a low valency by TESH, but TESCl, Bi(0), and Bi(0) with TESCl catalyzed the DRA to some extent.
- Matsumura, Takehiko,Nakada, Masahisa
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p. 1829 - 1834
(2014/03/21)
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- A simple and convenient method for the synthesis of N, N-diaryl tertiary amines
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Direct preparation of tertiary amines in which two substituents are aromatic is described. In the presence of either the inorganic base sodium tert-butoxide or the sterically hindered organic base diisopropylethylamine, the alkylation of secondary diarylamines is achieved smoothly. In contrast to methods previously reported in the literature, this procedure is high-yielding and does not require the use of transition-metal catalysts or functional-group-intolerant hydride reductants. Georg Thieme Verlag Stuttgart ? New York.
- Wekesa, Francis S.,Phadke, Neha,Jahier, Claire,Cordes, David B.,Findlater, Michael
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p. 1046 - 1051
(2014/05/06)
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- Homogeneous catalytic hydrogenation of amides to amines
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Hydrogenation of amides in the presence of [Ru(acac)3] (acacH=2,4-pentanedione), triphos [1,1,1-tris- (diphenylphosphinomethyl)ethane] and methanesulfonic acid (MSA) produces secondary and tertiary amines with selectivities as high as 93 % provided that there is at least one aromatic ring on N. The system is also active for the synthesis of primary amines. In an attempt to probe the role of MSA and the mechanism of the reaction, a range of methanesulfonato complexes has been prepared from prepared from [Ru(acac) 3], triphos and MSA, or from reactions of [RuX-(OAc)(triphos)] (X=H or OAc) or [RuH2(CO)(triphos)] with MSA. Crys-tallographically characterised complexes include: [Ru(OAc-κ1O) 2(H2O)-(triphos)], [Ru(OAc-κ2O,O') (CH3SO3-κ1O)(triphos)], [Ru(CH 3SO3-κ1O)2-(H 2O)(triphos)] and [Ru2(μ-CH3SO 3)3-(triphos)2][CH3SO3], whereas other complexes, such as [Ru(OAc-κ1O)(OAc- κ2O,O')(triphos)],[Ru(CH3SO3- κ1O)(CH3SO3-κ2O,O')- (triphos)], H[Ru(CH3SO3-κ1O) 3-(triphos)], [RuH(CH3SO3-κ1O) (CO)-(triphos)] and [RuH(CH3SO3-k2O,O')- (triphos)] have been characterised spectroscopically. The interactions between these various complexes and their relevance to the catalytic reactions are discussed.
- Coetzee, Jacorien,Dodds, Deborah L.,Klankermayer, Jürgen,Brosinski, Sandra,Leitner, Walter,Slawin, Alexandra M. Z.,Cole-Hamilton, David J.
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supporting information
p. 11039 - 11050
(2013/09/02)
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- A convenient and general reduction of amides to amines with low-valent titanium
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Low-valent titanium readily prepared in situ from TiCl4 and Mg powder in THF is found to be an active agent for the reduction of amides which were previously considered to be inert towards low-valent titanium. The reaction proceeds under very mild conditions, and is applicable to all types of amides, primary, secondary and tertiary, to produce the corresponding amines in good to excellent yields. This new finding provides a practical, convenient and general method for the important transformation of amides to amines. A plausible reaction mechanism is proposed.
- Zhang, Tongxin,Zhang, Yan,Zhang, Weixi,Luo, Meiming
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supporting information
p. 2775 - 2780
(2014/03/21)
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- Direct intermolecular aniline ortho- arylation via benzyne intermediates
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A method for direct, transition-metal-free ortho-arylation of anilines by aryl chlorides, bromides, fluorides, and triflates has been developed. This methodology provides the most direct approach to 2-arylanilines since no protecting or directing groups on nitrogen are required. The arylation is functional-group tolerant, with alkene, ether, trifluoromethyl, dimethylamino, carbonyl, chloro, and cyano functionalities tolerated. Phenylation of enantiopure binaphthyldiamine affords a product with >99% ee.
- Truong, Thanh,Daugulis, Olafs
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supporting information
p. 5964 - 5967
(2013/02/22)
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- Development and mechanistic investigation of a highly efficient iridium(V) silyl complex for the reduction of tertiary amides to amines
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The cationic Ir(III) acetone complex (POCOP)Ir(H)2(acetone) + (POCOP = 2,6-bis(di-tert-butylphosphinito)phenyl) was shown to catalyze the reduction of a variety of tertiary amides to amines using diethylsilane as reductant. Mechanistic studies established that a minor species generated in the reaction, the neutral silyl trihydride Ir(V) complex (POCOP)IrH3(SiEt2H), was the catalytically active species. High concentrations of this species could be conveniently generated by treatment of readily available (POCOP)IrHCl with tert-butoxide in the presence of Et2SiH2 under H2. Thus, using this mixture in the presence of a trialkylammonium salt, a wide array of tertiary amides, including extremely bulky substrates, are rapidly and quantitatively reduced to tertiary amines under mild conditions with low catalyst loading. A detailed mechanistic study has been carried out and intermediates identified. In brief, (POCOP)IrH3(SiEt2H) reduces the amide to the hemiaminal silyl ether that, in the presence of a trialkylammonium salt, is ionized to the iminium ion, which is then reduced to the tertiary amine by Et 2SiH2. Good functional group compatibility is demonstrated, and a high catalyst stability has provided turnover numbers as high as 10 000.
- Park, Sehoon,Brookhart, Maurice
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experimental part
p. 640 - 653
(2012/03/13)
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- Pyridine-catalyzed double C-N coupling reaction of an isocyanate with two benzynes
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A pyridine-catalyzed double C-N bond cross-coupling reaction involving two benzynes with an isocyanate was carried out. The coupling reaction proceeded through a unique pathway involving the formation of an unstable carbamic acid intermediate and facile decarboxylation. Subsequent nucleophilic addition/protonation of in situ prepared amines with benzynes afforded variously substituted diaryl- and triarylamines in moderate to good yields with tolerance of a variety of functional groups. Copyright
- Lee, Yi-Hsien,Chen, Yen-Chung,Hsieh, Jen-Chieh
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supporting information; experimental part
p. 247 - 250
(2012/02/04)
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- Enantioselective oxidative cross-dehydrogenative coupling of tertiary amines to aldehydes
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Cooperative catalysts: An enantioselective and direct oxidative coupling of aldehydes to tertiary amines to give β-amino alcohols is described. Catalyzed by copper(II), the reaction proceeds to give a racemic mixture of products; however, by using a combination of copper(II) and a chiral amine catalyst, the reaction gives the desired products with high enantioselectivity (see scheme).
- Zhang, Junmin,Tiwari, Bhoopendra,Xing, Chong,Chen, Xingkuan,Chi, Yonggui Robin
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supporting information; experimental part
p. 3649 - 3652
(2012/06/01)
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- Palladium catalyzed N-alkylation of amines with alcohols
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An iron oxide immobilized palladium catalyst was prepared for the N-alkylation of amines with alcohols under base and organic ligand free conditions. Applying the optimized reaction conditions, the coupling reactions of amines and alcohols with various structures could be realized with up to 99% isolated yields. The catalysts were studied by XRD, BET, and XPS and the mechanism was studied by DFT calculations.
- Zhang, Yan,Qi, Xiujuan,Cui, Xinjiang,Shi, Feng,Deng, Youquan
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supporting information; experimental part
p. 1334 - 1338
(2011/03/22)
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- C(sp3)-N bond-forming reductive elimination of amines: Reactions of bisphosphine-ligated benzylpalladium(II) diarylamido complexes
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(Chemical Equation Presented) A rare event: The benzylpalladium amido complex 1 (Ar= napthyl) was used to study the mechanism of an unusual reductive elimination of amines (see scheme). The observed inversion of configuration is proposed to result from dissociation of the amido ligand, followed by nucleophilic attack on the benzylic carbon atom. binap = 2,2′- bis(diphenylphosphanyl)-1,1′-binaphthyl, dppf=1,1′- bis(diphenylphosphanyl)ferrocene.
- Marquard, Seth L.,Rosenfeld, Devon C.,Hartwig, John F.
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p. 793 - 796
(2010/04/24)
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- Efficient palladium-catalyzed amination of aryl chlorides using dicyclo-hexylamino[(2,6-dimethyl)morpholino]phenylphosphine as a PN2 ligand
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The palladium-catalyzed amination of aryl chlorides with various amines is accomplished using dicyclohexyl- amino[(2,6-dimethyl)morpholino]phenylphosphine as a bulky electron-rich monoaryl phosphine ligand. The optimized reaction conditions required the use of 1 mol% each of catalyst and ligand. Georg Thieme Verlag Stuttgart.
- Park, Song-Eun,Kang, Seung Beom,Jung, Kwang-Ju,Won, Ju-Eun,Lee, Sang-Gyeong,Yoon, Yong-Jin
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experimental part
p. 815 - 823
(2009/07/11)
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- A convenient and general iron-catalyzed reduction of amides to amines
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While the iron is hot: The first general and efficient iron-catalyzed reduction of secondary and tertiary amides into amines using polymethylhydrosiloxane (PMHS) has been developed (see scheme).
- Zhou, Shaolin,Junge, Kathrin,Addis, Daniele,Das, Shoubhik,Beller, Matthias
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supporting information; experimental part
p. 9507 - 9510
(2010/03/24)
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- Highly chemoselective metal-free reduction of tertiary amides
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This communication describes the chemoselective metal-free reduction of tertiary amides to the corresponding amines. Hantzsch ester is used as a mild reducing agent for the reduction of trifluoromethanesulfonic anhydride activated amides providing the tertiary amines with high functional group tolerance. Copyright
- Barbe, Guillaume,Charette, Andre B.
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- One-pot reductive amination of aldehydes catalyzed by a hydrio-iridium(III) complex in aqueous medium
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A combination of sodium tetrakis[3,5-di(trifluoromethyl)phenyl]borate [NaBArF4] and hydrio-iridium(III) complex efficiently catalyzed the one-pot reductive amination of aldehydes with various amines and ammonia in water under mild conditions in good to excellent yields.
- Lai, Rung-Yi,Lee, Chun-I.,Liu, Shiuh-Tzung
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p. 1213 - 1217
(2008/09/17)
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- N-Arylation of aliphatic, aromatic and heteroaromatic amines catalyzed by copper bis(2,2,6,6-tetramethyl-3,5-heptanedionate)
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Copper bis(2,2,6,6-tetramethyl-3,5-heptanedionate) was found to be an efficient catalyst for N-arylation of aliphatic, aromatic and heteroaromatic amines with aryl iodides/bromides under mild conditions. The system tolerated a variety of hindered and functionalized amines/aryl halides and the desired N-aryl amines were obtained in good to excellent yields.
- Nandurkar, Nitin S.,Bhanushali, Mayur J.,Bhor, Malhari D.,Bhanage, Bhalchandra M.
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p. 6573 - 6576
(2008/02/12)
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- Correlation analysis in the reactions of benzyl bromide with N-substituted anilines
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The nucleophilic substitution reaction between benzyl bromide and N-substituted anilines in methanol medium suggests that the reactivity of the nucleophiles increases with their pkb values. A linear relationship exists between the rate and the Computed values of the dipole moment and electronegativity of the nucleophiles. The frontier orbital interactions and correlation of rate with HOMO-LUMO gap of the two reactants suggest that the reaction is not orbital controlled but is controlled by the electrostatic interactions between the reactants.
- Reddy, S. Ranga,Rao, B. Rajeswara,Manikyamba
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p. 436 - 439
(2008/02/12)
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- Regioselectively N-methylated azacalix[8]arene octamethyl ether prepared by catalytic aryl amination reaction using a temporal N-silylation protocol
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(Chemical Equation Presented) A temporal N-silylation protocol in the catalytic aryl amination reaction has been devised to prepare nitrogen-bridged calixarene analogues. The protocol involves a smooth in situ N-silylation before aryl amination reaction, followed by spontaneous cleavage of the N-Si bond in the usual workup process, to furnish secondary aromatic amines as the cross-coupled product with no silyl group on the nitrogen atom. A successful application to the preparation of regioselectively N-methylated azacalix[8]arene is described, together with the crystallographic analysis.
- Ishibashi, Koichi,Tsue, Hirohito,Tokita, Satoshi,Matsui, Kazuhiro,Takahashi, Hiroki,Tamura, Rui
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p. 5991 - 5994
(2007/10/03)
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- Facile N-arylation of amines and sulfonamides and O-arylation of phenols and arenecarboxylic acids
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An efficient, transition-metal-free procedure for the N-arylation of amines, sulfonamides, and carbamates and O-arylation of phenols and carboxylic acids has been achieved by allowing these substrates to react with a variety of o-silylaryl inflates in the presence of CsF. Good to excellent yields of arylated products are obtained under very mild reaction conditions. This chemistry readily tolerates a variety of functional groups.
- Liu, Zhijian,Larock, Richard C.
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p. 3198 - 3209
(2007/10/03)
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- Solvation models in the reaction between benzyl bromide and diphenyl amine
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The effect of different protic and dipolar aprotic solvents on the rate of the reaction between benzyl bromide and diphenyl amine has been studied. Correlation of the rate constants with different solvent parameters indicates that the polarity, nucleophilicity and hydrogen bond donor ability of the solvent simultaneously influence the rate and the solvation of the reactants and the transition state is due to these properties of the solvent.
- Reddy, S. Ranga,Manikyamba
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p. 1092 - 1094
(2007/10/03)
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- N-Alkylation of anilines, carboxamides and several nitrogen heterocycles using CsF-Celite/alkyl halides/CH3CN combination
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It has been found that the N-alkylation of aniline, carboxamides and heterocyclic compounds bearing an acidic hydrogen atom attached to nitrogen can be accomplished with alkyl halides in acetonitrile and cesium fluoride-celite employed as a solid base. In this manner, pyrrole, indole, pyrazole, imidazole, benzimidazole, carbazole, phthalimide, indazole, indoline, 2-pyrrolidinone, piperidine and 1,2,4-triazole can be successfully alkylated. The procedure is convenient, efficient and generally gives rise to the N-alkylated product exclusively.
- Hayat, Safdar,Atta-Ur-Rahman,Iqbal Choudhary,Khan, Khalid Mohammed,Schumann, Wilhelm,Bayer, Ernst
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p. 9951 - 9957
(2007/10/03)
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- A general synthesis of amines and hydrazines by oxidation of amidocuprates and zinc-amidocuprates
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A wide range of amines and hydrazines were synthesized according to an electrophilic amination protocol by oxidative decomposition of readily generated lithium- and zinc-amidocyanocuprates. Optimization of the yields was achieved by the appropriate combination of the organometallic cluster and the nature of the oxidizing agent.
- Cane,Brancaleoni,Dembech,Ricci,Seconi
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p. 545 - 548
(2007/10/03)
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- The Nucleophilic Ring-opening of N-Benzylquinuclidinium Bromide
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N-Benzylquinuclidinium bromide was ring opened by a series of heteronucleophiles, in the presence of cesium carbonate, to yield the corresponding N-benzyl-4-(2-hetero-ethyl)piperidines. The best yields were found with thiophenol (56%), phenol (55%), and benzimidazole (38%) as nucleophiles.
- Axelsson, Oskar,Peters, Dan
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p. 461 - 463
(2007/10/03)
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- Synthesis of Amines via Carbon-Sulfur Bond Cleavages of Substituted Aminomethyl Sulfides with Organolithium Reagents: Aminocarbene Route to Enamines and Sterically Hindered Amines
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N-Substituted and N,N-disubstituted aminomethyl sulfides can be converted into secondary and tertiary amines, respectively, by organolithium reagents in high yields, regardless of whether the N-substituent is alkyl or aryl; for the former case, imines, and for the latter case, aminocarbenes, are the most likely intermediates.
- Eisch, John J.,McNulty, John F.,Shi, Xian
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- Dynamics of α-CH deprotonation and α-desilylation reactions of tertiary amine cation radicals
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Time-resolved laser spectroscopy has been used to generate and characterize a series of tertiary amine cation radicals and to determine the rates of their α-CH deprotonation and α-desilylation reactions with bases and silophiles. Laser excitation (308 nm) of a 60:40 MeOH:MeCN solution of PhNMe2 (DMA) and 1,4-dicyanobenzene (DCB) promotes SET-induced formation of the DMA cation radical (460 nm) and DCB anion radical (340 nm), which undergo decay by back electron transfer at nearly equal rates and with respective second-order rate constants of 1.1 × 1010 and 1.3 × 1010 M-1 s-1 (25°C). The decay rate is lowered (ca. 4-fold) by the inclusion of salts (ca. 0.1 M) such as nBu4NClO4, LiClO4, HBu4NCl, nBu4NBF4, and nBu4NO3SCF3 in MeOH-MeCN and by changing the solvent from MeCN to MeOH and to EtOH. The cation radical of PhNMeCH2(TMS) (480 nm) and the simultaneously generated DCB anion radical undergo second order decay in MeCN with respective rate constants of 1.2 × 1010 and 9.9 × 109 M-1 s-1 (25°C). The silylamine cation radical decay rate was found to be governed by the concentration of silophiles (MeOH, H2O and nBu4NF) in MeCN solutions. The observations are consistent with a silophile-induced desilylation process with second-order rate constants of 8.9 × 105 (MeOH), 1.27 × 106 (H2O), and 3.1 × 109 M-1 s-1 (nBu4NF). The rate of DMA cation radical decay is a function of base concentration. Both nBu4NOAc and nBu4NO2CCF3 react with the DMA cation radical (in 60:40 MeOH:MeCN containing 0.1 M nBu4NClO4) with second-order rate constants for α-CH deprotonation of 3.1 × 105 and 8 × 104 M-1 s-1 (25°C), respectively. Measurements with PhN(CD3)2 and nBu4NOAc gave a kH/kD for α-CH deprotonation of 3.6 (60:40 MeOH:MeCN, 25°C). Para-substituents have a pronounced effect on the rate of α-CH deprotonation by nBu4NOAc; second-order rate constants of 2.3 × 104, 1.1 × 105, and 2.5 × 106 M-1 s-1 were determined for the P-OMeC6H4NMe2, p-MeC6H4NMe2 and p-CF3C6H4NMe2 cation radicals. Studies with Ph2NMe demonstrated that its cation radical (645 nm) can be generated by SET to DCB and that its decay through α-CH deprotonation by nBu4NOAc has a second-order rate constant of 9.5 × 105 M-1 s-1 and a kH/kD value of 2.8 (25:75 MeOH:MeCN, 25°C). Finally, the effects of α-substituents on the rates of nBu4-NOAc-induced α-CH deprotonation of tertiary amine cation radicals were evaluated by use of the amines Ph2NCHR1R2. The second-order rate constants (25°C, 25:75 MeOH:MeCN) are 2.3 × 105 (R1 = Me, R2 = H), 1.7 × 105 (R1 = R2 = Me), 3.2 × 106 (R1 = Ph, R2 = H), 2.6 × 106 (R1 = CH=CH2, R2 = H), and 7.0 × 107 M-1 s-1 (R1 = C≡CH, R2 = H).
- Zhang, Xiaoming,Yeh, Syun-Ru,Hong, Seok,Freccero, Mauro,Albini, Angelo,Falvey, Daniel E.,Mariano, Patrick S.
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p. 4211 - 4220
(2007/10/02)
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- Facile preparation of deoxybenzoins via a novel synthesis of enamines
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N-Aryl(or alkyl)-N-benzylanilines and benzylideneaniline condense in N,N-dimethylformamide in the presence of potassium t-butoxide to give enamines in good yields. Hydrolysis of the latter give deoxybenzoin with 100% conversion.
- Paventi,Hay
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p. 1617 - 1620
(2007/10/02)
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- Aromatic tertiary amines, enamines, deoxybenzoins and benzils
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A novel synthesis of aromatic tertiary amines involves reacting an aromatic anil and an aromatic ether in a molar ratio of 1:1; adjusting the ratio to 2:1 produces novel enamines and by employing a two step process for enamine production, various unsymmetrically substituted enamines can be obtained which are readily hydrolyzed to corresponding deoxybenzoins which in turn are readily oxidized to benzils, the aromatic tertiary amines may be used to produce charge transport layers in xerography, while the benzils may be used to produce a variety of desired polymers.
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- Novel Synthesis of N,N-Diarylarylmethanamines from N-(Arylmethylene)arenamines and (Arylmethoxy)arenes
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Various N,N-diarylarylmethanamines were synthesized by the reaction of N-(arylmethylene)arenamines with (arylmethoxy)arenes in dimethylformamide solution in the presence of a strong base as a catalyst which is obtained in situ by reacting metallic sodium with this solvent.In general, the reaction may be depicted as the reduction of the imine and addition, on the original imino nitrogen atom, of the aryl group (of the aryloxy moiety) of the ether and presumably oxidation of the arylmethoxy group of the ether to its corresponding aldehyde.Side reactions and a proposed reaction mechanism are discussed.
- Paventi, Martino,Hay, Allan S.
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p. 5875 - 5882
(2007/10/02)
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- Carbon-Skeletal Anionic Rearrangements of Tertiary Benzylic Amines: Geometric and Electronic Requirements for Generating the Spiroazacyclopropane Intermediate
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In order to determine the scope and mechanism for the base-promoted rearrangement of tertiary amines, a wide variety of benzylic amines were treated with n-BuLi in THF or TMEDA, n-BuLi-KO-t-Bu mixtures, or KH.The following amines were examined: benzyldimethylamine, benzylmethylphenylamine, benzyldiphenylamine, N-benzylcarbazole, N-benzyl-1,2,3,4-tetrahydrocarbazole, N-benzyl-1,1a,2,3,4,4a-cis-hexahydrocarbazole, N-(2-phenylethyl)carbazole, N-(3-phenylpropyl)carbazole, N-(2-chloroethyl)carbazole, N-benzyl-9,9-dimethyl-9,10-dihydroacridine, N-benzyl-o,o'-iminodibenzyl, 9-(diphenylamino)fluorene, 9-anilino-9-phenylfluorene, 9-(methylphenylamino)fluorene, and diphenyl(diphenylmethyl)amine.In certain cases, ethylation products were obtained from the interaction of intermediate carbanions with ethylene generated by the decomposition of THF.The results are interpreted in terms of intramolecular shifts of aryl groups from nitrogen to benzylic carbon proceeding by way of a bridging aryl transition state or intermediate.
- Eisch, John J.,Dua, Suresh K.,Kovacs, Csaba A.
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p. 4437 - 4444
(2007/10/02)
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- SN2 Reactions of Nitranions with Benzyl Chlorides
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The rates of SN2 reactions of 19 nitranions with PhCH2Cl and 9 nitranions with m-CF3C6H4CH2Cl were measured in Me2SO at 25 deg C.Bronsted plots of log k vs. pKHA for reactions of anion families derived from carbazoles, phenothiazines, and diphenylamines with PhCH2Cl are linear with slopes of 0.32-0.33.Extension of the carbazole and phenothiazine family lines, which are collinear, provided a reference line by which nucleophilicities of other nitranions could be assessed at constant basicity.Nitranions of varied structural types were found to have remarkably similar nucleophilicities when compared at the same basicities.Steric effects caused rates of reactions of ArAr'N(1-) ions and acetanilide ion to be retarded slightly and that of benzanilide ion to be retarded appreciably.Evidence is presented to show that nitranions, like carbanions, utilize the electron pair in a p orbital for bonding to an electrophile whereas pyridines utilize a nonbonded electron pair.Comparisons with literature data for neutral nitrigen nucleophiles, such as n-BuNH2 and PhNH2, indicate that they are 10-100 times more reactive than nitranion nucleophiles of comparable basicity.The order of nucleophilicities toward PhCH2Cl of anion families with different donor atoms when compared at the same basicity was found to be the following: 9-methylfluoredine ion family (25) > 2-naphthoxide ion family (3) > carbazole ion family (1.0).The results show that basicity is the primary factor in controlling nucleophilicities of nitranions, carbanions, and oxanions of diverse structural types in SN2 reactions.Donor atom, solvation, and steric effects generally play a secondary role.
- Bordwell, Frederick G.,Hughes, David L.
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p. 3234 - 3240
(2007/10/02)
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- Method of manufacturing ketones
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The invention relates to a method for the manufacture of ketones which comprises oxidizing an n-olefin in the presence of a catalyst containing palladium, copper, a halogen, and at least one of specific tertiary amines.
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- THE APPLICATION OF ULTRASOUND TO THE N-ALKYLATION OF AMINES USING PHASE TRANSFER CATALYSIS
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The application of ultrasound to the N-alkylation of a variety of amines by alkyl halides under phase transfer conditions (polyethylene glycol methyl ether and alkylammonium compounds as catalysts) leads to a decrease in the time required to effect reaction.
- Davidson, R. Stephen,Patel, Ali M.,Safdar, Ali,Thornthwaite, David
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p. 5907 - 5910
(2007/10/02)
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