- SUPPORTED HETEROGENEOUS CATALYST, PREPARATION AND USE THEREOF
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A supported heterogeneous catalyst comprises rhodium and vanadium on a support, wherein the supported heterogeneous catalyst is preparable by depositing vanadium on a supported rhodium catalyst by impregnation. A process for preparing the aforementioned catalyst and a process for converting an amide into an amine in the presence of the aforementioned catalyst are provided.
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Page/Page column 22-23
(2021/06/11)
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- PROCESS FOR CONVERTING AMIDE TO AMINE
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Provided is a process for converting an amide into an amine comprising hydrogenation of the amide at a temperature not higher than 130°C and a hydrogen pressure not higher than 50 bar in the presence of a supported heterogeneous catalyst preparable by a method comprising depositing vanadium on a supported noble metal catalyst by impregnation.
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Page/Page column 23; 24
(2021/06/11)
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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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- Microwave-assisted nucleophilic degradation of organophosphorus pesticides in propylene carbonate
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Propylene carbonate is becoming a suitable green alternative to volatile organic solvents in the study of chemical reactions. In this study, an efficient method for nucleophilic degradation of five organophosphorus pesticides, fenitrothion, malathion, diazinon, parathion, and paraoxon, using propylene carbonate as a solvent is proposed. The effect of changing the nature of the nucleophile and the influence of microwave (MW) heating were investigated. A screening of temperatures (50 °C-120 °C) was performed under microwave heating. The pesticide degradation was followed by 31P NMR, and the extent of conversion (%) was calculated by the integration of phosphorus signals. Keeping in mind that recently it has been reported that some ionic liquids play a nucleophilic role, in this work we report for the first time the degradation of organophosphorus pesticides by using an amino acid-based ionic liquid such as Bmim[Ala] as a nucleophile and a bio-based solvent (propylene carbonate) as a reaction medium in combination with microwave heating. This journal is
- Millán, Daniela,Pavez, Paulina,Rojas, Mabel,Tapia, Ricardo A.
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supporting information
p. 7868 - 7875
(2020/11/02)
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- Method for catalytically synthesizing 1-substituted pyrrolidine/piperidine derivative by using supported metal
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The invention provides a method for catalytically synthesizing a 1-substituted pyrrolidine/piperidine derivative by using a supported metal. The method comprises: carrying out a reaction with ammoniato form a pyrrolidine ring/piperidine ring by using a supported metal as a catalyst, using 1,4-butanediol/1, 5-pentanediol as a cyclization raw material and using alcohol as an N-alkylation raw material, wherein the high-selectivity synthesis of the 1-substituted pyrrolidine/piperidine derivative is achieved through the one-step reaction, the active components of the supported metal catalyst are Cu, Ni and Pd/Ru, the total loading capacity of the active components Cu and Ni is 3-15 wt% of the carrier, and the loading capacity of Pd/Ru is 0-1 wt% of the carrier. According to the invention, themethod is simple, low in cost and environmentally friendly, the conversion rate of 1,4-butanediol/1,5-pentanediol is high, the selectivity of the pyrrolidine/piperidine derivatives is high, and the method is a production route with practical application value.
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Paragraph 0020
(2020/02/20)
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- A BEt3-Base catalyst for amide reduction with silane
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Reported herein is the development of a simple but practical catalytic system for the selective reduction of amides with hydrosilane or hydrosiloxane. Low-cost and readily available triethylborane (1.0 M in THF), in combination with a catalytic amount of an alkali metal base, was found to catalyze the reduction of all three amide classes (tertiary, secondary, and primary amides) to form amines under mild conditions. In addition, the selective transformation of secondary amides to aldimines and primary amides to nitriles can also be achieved by using a proper combination of BEt3 and base. The scope of these BEt3-base-catalyzed amide hydrosilylation reactions has been explored in depth. Preliminary results of mechanistic studies suggest a modified Piers' silane Si-H···B activation mode wherein the hydride abstraction by BEt3 is promoted by the coordination of an alkoxide or hydroxide anion to the Si center.
- Yao, Wubing,Fang, Huaquan,He, Qiaoxing,Peng, Dongjie,Liu, Guixia,Huang, Zheng
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- A BEt3-Base Catalyst for Amide Reduction with Silane
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Reported herein is the development of a simple but practical catalytic system for the selective reduction of amides with hydrosilane or hydrosiloxane. Low-cost and readily available triethylborane (1.0 M in THF), in combination with a catalytic amount of an alkali metal base, was found to catalyze the reduction of all three amide classes (tertiary, secondary, and primary amides) to form amines under mild conditions. In addition, the selective transformation of secondary amides to aldimines and primary amides to nitriles can also be achieved by using a proper combination of BEt3 and base. The scope of these BEt3-base-catalyzed amide hydrosilylation reactions has been explored in depth. Preliminary results of mechanistic studies suggest a modified Piers' silane Si-H···B activation mode wherein the hydride abstraction by BEt3 is promoted by the coordination of an alkoxide or hydroxide anion to the Si center.
- Yao, Wubing,Fang, Huaquan,He, Qiaoxing,Peng, Dongjie,Liu, Guixia,Huang, Zheng
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p. 6084 - 6093
(2019/05/24)
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- Catalytic Homogeneous Hydrogenation of CO to Methanol via Formamide
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A novel amine-assisted route for low temperature homogeneous hydrogenation of CO to methanol is described. The reaction proceeds through the formation of formamide intermediates. The first amine carbonylation part is catalyzed by K3PO4. Subsequently, the formamides are hydrogenated in situ to methanol in the presence of a commercially available ruthenium pincer complex as a catalyst. Under optimized reaction conditions, CO (up to 10 bar) was directly converted to methanol in high yield and selectivity in the presence of H2 (70 bar) and diethylenetriamine. A maximum TON of 539 was achieved using the catalyst Ru-Macho-BH. The high yield, selectivity, and TONs obtained for methanol production at low reaction temperature (145 °C) could make this process an attractive alternative over the traditional high temperature heterogeneous catalysis.
- Kar, Sayan,Goeppert, Alain,Prakash, G. K. Surya
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supporting information
p. 12518 - 12521
(2019/08/26)
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- Mild Hydrogenation of Amides to Amines over a Platinum-Vanadium Bimetallic Catalyst
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Hydrogenation of amides to amines is an important reaction, but the need for high temperatures and H2 pressures is a problem. Catalysts that are effective under mild reaction conditions, that is, lower than 30 bar H2 and 70 °C, have not yet been reported. Here, the mild hydrogenation of amides was achieved for the first time by using a Pt-V bimetallic catalyst. Amide hydrogenation, at either 1 bar H2 at 70 °C or 5 bar H2 at room temperature was achieved using the bimetallic catalyst. The mild reaction conditions enable highly selective hydrogenation of various amides to the corresponding amines, while inhibiting arene hydrogenation. Catalyst characterization showed that the origin of the catalytic activity for the bimetallic catalyst is the oxophilic V-decorated Pt nanoparticles, which are 2 nm in diameter.
- Mitsudome, Takato,Miyagawa, Kazuya,Maeno, Zen,Mizugaki, Tomoo,Jitsukawa, Koichiro,Yamasaki, Jun,Kitagawa, Yasutaka,Kaneda, Kiyotomi
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supporting information
p. 9381 - 9385
(2017/08/01)
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- Rhenium-Loaded TiO2: A Highly Versatile and Chemoselective Catalyst for the Hydrogenation of Carboxylic Acid Derivatives and the N-Methylation of Amines Using H2 and CO2
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Herein, we report a heterogeneous TiO2-supported Re catalyst (Re/TiO2) that promotes various selective hydrogenation reactions, which includes the hydrogenation of esters to alcohols, the hydrogenation of amides to amines, and the N-methylation of amines, by using H2 and CO2. Initially, Re/TiO2 was evaluated in the context of the selective hydrogenation of 3-phenylpropionic acid methyl ester to afford 3-phenylpropanol (pH2 =5 MPa, =5 MPa, T=180 °C), which revealed a superior performance over other catalysts that we tested in this study. In contrast to other typical heterogeneous catalysts, hydrogenation reactions with Re/TiO2 did not produce dearomatized byproducts. DFT studies suggested that the high selectivity for the formation of alcohols in favor of the hydrogenation of aromatic rings is ascribed to the higher affinity of Re towards the COOCH3 group than to the benzene ring. Moreover, Re/TiO2 showed a wide substrate scope for the hydrogenation reaction (19 examples). Subsequently, this Re/TiO2 catalyst was applied to the hydrogenation of amides, the N-methylation of amines, and the N-alkylation of amines with carboxylic acids or esters.
- Toyao, Takashi,Siddiki,Morita, Yoshitsugu,Kamachi, Takashi,Touchy, Abeda S.,Onodera, Wataru,Kon, Kenichi,Furukawa, Shinya,Ariga, Hiroko,Asakura, Kiyotaka,Yoshizawa, Kazunari,Shimizu, Ken-Ichi
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supporting information
p. 14848 - 14859
(2017/10/27)
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- Continuous N-alkylation reactions of amino alcohols using γ-Al2O3 and supercritical CO2: Unexpected formation of cyclic ureas and urethanes by reaction with CO2
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The use of γ-Al2O3 as a heterogeneous catalyst in scCO2 has been successfully applied to the amination of alcohols for the synthesis of N-alkylated heterocycles. The optimal reaction conditions (temperature and substrate flow rate) were determined using an automated self-optimising reactor, resulting in moderate to high yields of the target products. Carrying out the reaction in scCO2 was shown to be beneficial, as higher yields were obtained in the presence of CO2 than in its absence. A surprising discovery is that, in addition to cyclic amines, cyclic ureas and urethanes could be synthesised by incorporation of CO2 from the supercritical solvent into the product.
- Streng, Emilia S.,Lee, Darren S.,George, Michael W.,Poliakoff, Martyn
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p. 329 - 337
(2017/03/15)
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- Production method of single nitrogenous heterocyclic ring-containing compound
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The invention discloses a production method of a single nitrogenous heterocyclic ring-containing compound. Lactone and fatty amine which are cheap and easy to obtain are used as raw materials for producing the single nitrogenous heterocyclic ring-containing compound; lactone and fatty amine are used for synthesis of amide, and hydrodeoxygenation is carried out in order to obtain the corresponding nitrogenous heterocyclic compound. The process has only two reaction steps, and has the advantages of low investment, high yield, simple separation for intermediate products, few by-products, and easy processing.
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Paragraph 0046; 0047
(2016/12/01)
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- Amino-alcohol cyclization: Selective synthesis of lactams and cyclic amines from amino-alcohols
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By employing an amination catalyst, previously used in the direct synthesis of amines from alcohol with ammonia, n-amino-alcohols could be selectively cyclized to either the amide or the amine. By the addition of water, the amine could be produced as the major product whereas adding a sacrificial ketone as a hydrogen acceptor resulted in the amide as the major product. Without an additive a mixture of both the amine and the amide was observed. N-substituted amino-alcohols solely gave cyclic amines under these conditions. From 2-(n-alkanol) anilines the cyclic amines were produced, where the n-propanol derivative selectively formed quinoline as the major product.
- Pingen, Dennis,Vogt, Dieter
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- Design of a bifunctional Ir-Zr based metal-organic framework heterogeneous catalyst for the N-alkylation of amines with alcohols
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The direct N-alkylation of amines with alcohols was performed with an Ir-Zr-based metal-organic framework multifunctional heterogeneous catalyst. This system is efficient and environmentally benign for the synthesis of various organic amines in air in the absence of a base. The catalyst was recovered and reused without significant loss of activity, and only water was produced as a byproduct. Better be direct than elusive: The direct N-alkylation of amines with alcohols is performed with an Ir-Zr-based metal-organic framework multifunctional heterogeneous catalyst. This system is efficient and environmentally benign for the synthesis of various organic amines in air in the absence of a base. The catalyst is recovered and reused without significant loss of activity, and only water is produced as a byproduct.
- Rasero-Almansa,Corma,Iglesias,Sanchez
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p. 1794 - 1800
(2014/06/24)
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- Palladium-catalyzed one-pot three- or four-component coupling of aryl iodides, alkynes, and amines through C-N bond cleavage: Efficient synthesis of indole derivatives
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An efficient synthesis of N-substituted indole derivatives was realized by combining the Pd-catalyzed one-pot multicomponent coupling approach with cleavage of the C(sp3)-N bonds. Three or four components of aryl iodides, alkynes, and amines were involved in this coupling process. The cyclopentadiene-phosphine ligand showed high efficiency. A variety of aryl iodides, including cyclic and acyclic tertiary amino aryl iodides, and substituted 1-bromo-2-iodobenzene derivatives could be used. Both symmetric and unsymmetric alkynes substituted with alkyl, aryl, or trimethylsilyl groups could be applied. Cyclic secondary amines such as piperidine, morpholine, 4-methylpiperidine, 1-methylpiperazine, 2-methylpiperidine, and acyclic amines including secondary and primary amines all showed good reactivity. Further application of the resulting indole derivatives was demonstrated by the synthesis of benzosilolo[2,3-b]indole. All in one: Efficient synthesis of N-substituted indole derivatives was realized by combining a Pd-catalyzed one-pot multicomponent coupling approach with the cleavage of C(sp 3)-N bonds (see scheme). Three or four components of aryl iodides, alkynes, and amines were involved in this coupling process. The cyclopentadiene-phosphine ligand (1) showed high efficiency. Copyright
- Hao, Wei,Geng, Weizhi,Zhang, Wen-Xiong,Xi, Zhenfeng
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p. 2605 - 2612
(2014/03/21)
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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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- Mechanisms of degradation of paraoxon in different ionic liquids
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Herein, the reactivity and selectivity of the reaction of O,O-diethyl 4-nitrophenyl phosphate triester (Paraxon, 1) with piperidine in ionic liquids (ILs), three conventional organic solvents (COS), and water is studied by 31P NMR, UV-vis, and GC/MS. Three phosphorylated products are identified as follows: O,O-diethyl piperidinophosphate diester (2), O,O-diethyl phosphate (3), and O-ethyl 4-nitrophenyl phosphate diester (4). Compound 4 also reacts with piperidine to yield O-ethyl piperidinophosphate monoester (5). The results show that both the rate and products distribution of this reaction depend on peculiar features of ILs as reaction media and the polarity of COS.
- Pavez, Paulina,Millan, Daniela,Morales, Javiera I.,Castro, Enrique A.,Lopez A., Claudio,Santos, Jose G.
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p. 9670 - 9676
(2013/10/22)
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- Intermolecular rhodium-catalysed hydroamination of non-activated olefins: Effect of olefin, amine, phosphine and phosphonium salt
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The catalytic system RhCl3·3H2O/2P(p-CH3C6H4)3/65nBu4PI/2I2, which was discovered recently in our research group, allows the highest catalytic activity ever reported for the intermolecular hydroamination of ethylene, 1-butene, and 1-hexene with aniline-type amines (0.3 mol% catalytic precursor) to give the expected N-alkyl- (N-ethyl-, 1) and N,N-dialkyl-anilines (N,N-diethyl-, 2) along with 2-methyl quinolines (3; in the case of ethylene). The effects of time and temperature, as well as the nature of the phosphonium salt, phosphine, and amine on the catalytic activity of this reaction have been studied. This system is particularly efficient for the hydroamination of ethylene with aniline in the presence of 2,2′-bis(diphenylphosphino)- 1,1′-binaphthyl (CE=460) and tri(p-tolyl)phosphine (CE= 520). Good to excellent activities were also found by combining Wilkinson′s catalysts (RhI complexes) with nBu4PI and I2. The simple association of PPh3 and I2 has been shown to be a very efficient "in-situ generated" source of I- promoters. CE (catalytic efficiency)=TON1+2TON2+2TON3.
- Rodriguez-Zubiri, Mireia,Baudequin, Christine,Bethegnies, Aurelien,Brunet, Jean-Jacques
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p. 445 - 454
(2014/01/17)
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- Selective N-alkylation of amines using nitriles under hydrogenation conditions: Facile synthesis of secondary and tertiary amines
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Nitriles were found to be highly effective alkylating reagents for the selective N-alkylation of amines under catalytic hydrogenation conditions. For the aromatic primary amines, the corresponding secondary amines were selectively obtained under Pd/C-catalyzed hydrogenation conditions. Although the use of electron poor aromatic amines or bulky nitriles showed a lower reactivity toward the reductive alkylation, the addition of NH4OAc enhanced the reactivity to give secondary aromatic amines in good to excellent yields. Under the same reaction conditions, aromatic nitro compounds instead of the aromatic primary amines could be directly transformed into secondary amines via a domino reaction involving the one-pot hydrogenation of the nitro group and the reductive alkylation of the amines. While aliphatic amines were effectively converted to the corresponding tertiary amines under Pd/C-catalyzed conditions, Rh/C was a highly effective catalyst for the N-monoalkylation of aliphatic primary amines without over-alkylation to the tertiary amines. Furthermore, the combination of the Rh/C-catalyzed N-monoalkylation of the aliphatic primary amines and additional Pd/C-catalyzed alkylation of the resulting secondary aliphatic amines could selectively prepare aliphatic tertiary amines possessing three different alkyl groups. According to the mechanistic studies, it seems reasonable to conclude that nitriles were reduced to aldimines before the nucleophilic attack of the amine during the first step of the reaction.
- Ikawa, Takashi,Fujita, Yuki,Mizusaki, Tomoteru,Betsuin, Sae,Takamatsu, Haruki,Maegawa, Tomohiro,Monguchi, Yasunari,Sajiki, Hironao
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supporting information; experimental part
p. 293 - 304
(2012/02/01)
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- Selective hydrogenation of amides using bimetallic Ru/Re and Rh/Re catalysts
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Heterogeneous Ru/Re and Rh/Re catalysts, formed in situ from Ru 3(CO)12/Re2(CO)10 and Rh 6(CO)16/Re2(CO)10 respectively, are effective for the liquid phase hydrogenation of cyclohexanecarboxamide (CyCONH2) to CyCH2NH2 in up to 95% selectivity without the requirement for ammonia to inhibit secondary and tertiary amine formation. Good amide conversions are noted within the reaction condition regimes 50-100 bar H2 and ≥150 (Rh) - 160 °C (Ru). Variations in Ru:Re and Rh:Re composition result in only minor changes in product selectivity with no evidence of catalyst deactivation at higher levels of Re. In situ HP-FTIR spectroscopy has shown that catalyst genesis occurs via decomposition of the metal carbonyl precursors. Ex situ characterization, using XRD, XPS and EDX-STEM, has provided evidence for the active components of these catalysts containing bimetallic Ru/Re and Rh/Re nanoclusters, the surfaces of which become significantly oxidized after use in amide reduction. Potential mechanistic pathways for amide hydrogenation are discussed, including initial dehydration to nitrile, a pathway potentially specifically accessible to primary amides, and evidence for often postulated imine intermediates.
- Beamson, Graham,Papworth, Adam J.,Philipps, Charles,Smith, Andrew M.,Whyman, Robin
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body text
p. 228 - 238
(2011/04/21)
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- Selective hydrogenation of amides using Rh/Mo catalysts
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Rh/Mo catalysts formed in situ from Rh6(CO)16 and Mo(CO)6 are effective for the liquid phase hydrogenation of CyCONH2 to CyCH2NH2 in up to 87% selectivity, without the requirement for ammonia to inhibit secondary amine formation. Use of in situ HP-FTIR spectroscopy has shown that decomposition of metal carbonyl precursors occurs during an extended induction period, with the generation of recyclable, heterogeneous, bimetallic catalysts. Variations in Mo:Rh content have revealed significant synergistic effects on catalysis, with optimum performance at values of ca. 0.6, and substantially reduced selectivities at ≥1. Good amide conversions are noted within the reaction condition regimes 50-100 bar H2 and 130-160 °C. Ex situ characterization of the catalysts, using XRD, XPS and EDX-STEM, has provided evidence for intimately mixed (ca. 2-4 nm) particles that contain metallic Rh and reduced Mo oxides, together with MoO3. Silica-supported Rh/Mo analogues, although active, perform poorly at 150 °C and deactivate during recycle.
- Beamson, Graham,Papworth, Adam J.,Philipps, Charles,Smith, Andrew M.,Whyman, Robin
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scheme or table
p. 93 - 102
(2010/09/16)
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- Selective hydrogenation of amides using ruthenium/ molybdenum catalysts
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Recyclable, heterogeneous bimetallic ruthenium/molybdenum catalysts, formed in situ from triruthenium dodecacarbonyl [Ru3(CO)12] and molybdenum hexacarbonyl [Mo(CO)6], are effective for the selective liquid phase hydrogenation of cyclohexylcarboxamide (CyCONH2) to cyclohexanemethylamine (CyCH2NH2), with no secondary or tertiary amine by-product formation. Variation of Mo:Ru composition reveals both synergistic and poisoning effects, with the optimum combination of conversion and selectivity at ca. 0.5, and total inhibition of catalysis evident at ≥1. Good amide conversions are noted within the reaction condition regimes 20100 bar hydrogen and 145-160°C. The order of reactivity of these catalysts towards reduction of different amide functional groups is primary > tertiary ? secondary. In situ HP-FT-IR spectroscopy confirms that catalyst genesis occurs during an induction period associated with decomposition of the organometallic precursors. Ex situ characterisation, using XRD, XPS and EDX-STEM, for active Mo:Ru compositions, has provided evidence for intimately mixed ca. 2.5-4 nm particles that contain metallic ruthenium, and molybdenum (in several oxidation states, including zero).
- Beamson, Graham,Papworth, Adam J.,Philipps, Charles,Smith, Andrew M.,Whyman, Robin
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experimental part
p. 869 - 883
(2010/07/05)
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- The elimination kinetics and mechanisms of ethyl piperidine-3-carboxylate, ethyl 1-methylpiperidine-3-carboxylate, and ethyl 3-(piperidin-1-yl)propionate in the gas phase
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The gas-phase elimination kinetics of the above-mentioned compounds were determined in a static reaction system over the temperature range of 369-450.3°C and pressure range of 29-103.5 Torr, The reactions are homogeneous, unimolecular, and obey a first-order rate law. The rate coefficients are given by the following Arrhenius expressions: ethyl 3-(piperidin-1-yl) propionate, log κ1(s-1) = (12.79 ± 0.16) - (199.7±2.0) kJ mol-1 (2.303 RT)-1; ethyl 1-methylpiperidine-3-carboxylate, log κ1(s-1) = (13.07 ± 0.12)-(212.8 ± 1.6) kJmol-1 (2,303 RT) -1; ethyl piperidine-3-carboxylate, log κ1(s -1) = (13.12 ± 0.13) - (210.4 ± 1.7) kJ mol -1 (2.303 RT)-1 and 3-piperidine carboxylic acid, log κ1(s-1) = (14.24 ± 0.17) - (234.4 ± 2.2) kJ mol-1 (2.303 RT)-1. The first step of decomposition of these esters is the formation of the corresponding carboxylic acids and ethylene through a concerted six-membered cyclic transition state type of mechanism. The intermediate β-amino acids decarboxylate as the α-amino acids but in terms of a semipolar six-membered cyclic transition state mechanism.
- Monsalve, Angiebelk,Rosas, Felix,Tosta, Maria,Herize, Armando,Dominguez, Rosa M.,Brusco, Doris,Chuchani, Gabriel
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p. 106 - 114
(2008/02/03)
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- METHOD FOR THE CATALYTIC REDUCTION OF AMIDES
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Described is a method for the catalytic reduction of an amide for the preparation of an amine at a temperature of below 200° C and a pressure of below 50 bar, the catalyst being chosen from bimetallic and trimetallic catalysts of the group consisting of ABC, AB, AC and BC, wherein: A is a metal, chosen from the group, consisting of Co, Fe, Ir, Pt, Rh and Ru, B is a metal, chosen from the group, consisting of Cr, Mo, Re and V, and, C is a metal, chosen from the group, consisting of Cu, In and Zn. Further, novel catalysts and a selection method for such catalysts is disclosed.
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Page/Page column 8
(2008/06/13)
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- Aminomethylation of organic halides promoted by zinc in protic medium
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Organic halides undergo smooth aminomethylation by secondary amines and aqueous formaldehyde promoted by metallic zinc under copper(I) catalysis. Good to excellent yields are obtained with primary, secondary, and tertiary iodides, allylic, propargylic, and benzylic bromides and with α-bromoesters. In most cases, DMSO is the best solvent, but dioxane is preferable for some more reactive halides. Additional experiments with radical quenchers and promoters and the use of 'radical clocks' indicate a stepwise reaction mechanism initiated by the attack of an alkyl radical to iminium ion.
- Estevam, Idália H. S.,Da Silva, Margarete F.,Bieber, Lothar W.
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p. 7601 - 7604
(2007/10/03)
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- Aromatic sulfone hydroxamates and their use as protease inhibitors
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This invention is directed to aromatic sulfone hydroxamates (also known as “aromatic sulfone hydroxamic acids”) and salts thereof that, inter alia, inhibit matrix metalloproteinase (also known as “matrix metalloprotease” or “MMP”) activity and/or aggrecanase activity. This invention also is directed to a prevention or treatment method that comprises administering such a compound or salt in an MMP-inhibiting and/or aggrecanase-inhibiting effective amount to an animal, particularly a mammal having (or disposed to having) a pathological condition associated with MMP and/or aggrecanase activity.
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- Soluble polymer-supported synthesis of tertiary amines
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The synthesis of tertiary amines on a modified soluble polymer, poly(ethylene glycol) (PEG), is described. The PEG-bound quaternary intermediates were assembled via Michael addition reaction, followed by alkylation. Cleavage from the soluble polymer support was induced by insoluble weak basic resin, to afford the target tertiary amines in excellent purity.
- Chen, Zuxing,Yang, Guichun,Zhang, Zhaojun
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p. 729 - 734
(2007/10/03)
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- Transition-metal complex-catalyzed reduction of amides with hydrosilanes: A facile transformation of amides to amines
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The reaction of amides with hydrosilanes is catalyzed by a variety of transition-metal complexes in the presence or absence of halides and amines as co-catalysts to afford the corresponding amines in good yields.
- Igarashi, Mamoru,Fuchikami, Takamasa
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p. 1945 - 1947
(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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- Reductive amination of carboxylic acids and [11C]magnesium halide carboxylates
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The reductive amination of carboxylic acids was shown to be promoted by 2-chloropyridine hydrochloride (3 eq). It allowed the one-pot preparation of N-alkylamines in yields up to 93% from carboxylic acid (1 eq), amine (1 eq) and sodium borohydride (5 molar eq). The reaction, carried out with [11C]magnesium halide carboxylates (11C, β+, t1/2:20 min), led to N-[11C]alkylamines in 20-25% radiochemical yields (decay corrected to the end of bombardment, 30 min preparation time from [11C]CO2). In this case, the addition of pyridinium salts led only to the corresponding [11C]carboxylic acids.
- Perrio-Huard, Cecile,Aubert, Catherine,Lasne, Marie-Claire
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p. 311 - 316
(2007/10/03)
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- Synthesis of bridgehead nitrogen heterocycles via cyclization of α- ammonio 5-hexenyl radicals
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Ring-closure of the 2,2-dimethyl-2-azonia-5-hexenyl radical (4) proceeds smoothly and efficiently to give the 5-exo isomer essentially quantitatively, in accordance with predictions based on MP4SDTQ/6-31G* ab initio calculations on the thermodynamic stability of α-ammonio radicals. The corresponding 5-hexynyl radical species 15 and its 6-phenyl derivative 19 display similar behavior affording the analogous 5-exo-3- methylenepyrrolidinium salts in high yield. In none of these cases were the products of reduction were detected. All of the radical intermediates were generated conveniently by treatment of the iodomethyl and/or phenylselenomethyl salts with tributyltin hydride. Application of this procedure to monocyclic precursors such as 1-methyl-1-iodomethyl-4-methylene- 1-azoniacyclohexyl iodide (31) provided an attractive entry into quaternary derivatives of the 1-azabicyclo[2.2.1]heptyl system in good yield via a three-step sequence from 1-methylpiperidone. Dequaternization of the bicyclic salts so obtained unexpectedly leads to rupture of one of the rings rather than loss of the N-methyl group. The 1-azabicyclo[2.2.1]heptane could be accessed readily via tin hydride-induced cyclization of the corresponding N- phenylethylammonium salt 54, followed by Hofmann elimination with potassium tert-butoxide.
- Della, Ernest W.,Smith, Paul A.
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p. 1798 - 1806
(2007/10/03)
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- Eclipsed Conformation of the Exocyclic N-CH2 Bond in N-Neopentylpiperidines and the Stereodynamic Consequences As Studied by Dynamic NMR Spectroscopy and Molecular Mechanics Calculations
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The dynamic stereochemistry of a range of N-neopentylpiperidines 1 with an eclipsed N-CH2-t-Bu bond is compared with that of the corresponding range of N-ethylpiperidines 2 with a gauche N-CH2Me bond. By using dynamic NMR spectroscopy, the relative importance of ring inversion, exocyclic bond rotation, and nitrogen inversion are elucidated and barriers are reported and discussed. Minor populations of the neopentyl-axial-eclipsed conformation are detected directly and identified with the help of molecular mechanics calculations. The corresponding N-alkylpyrrolidines are also reported.
- Anderson, J. Edgar,Ijeh, Anthony I.,Storch, Christine,Casarini, Daniele,Lunazzi, Lodovico
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p. 3310 - 3317
(2007/10/03)
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- Effect of Topologically Controlled Coulombic Interactions on the Dynamic Behavior of Photoexcited Nitrophenyl Alkyl Ethers in the Presence of Tertiary Amines with Limited Motion Freedom
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Time-resolved electronic absorption spectroscopy has been successfully applied to clarify the mechanism of the "abnormal" photochemical cleavage of 4-nitrophenyl piperidinoaikyl ethers induced by controlled Coulombic disturbance of the "normal" electronic distribution of the radical anion intermediate. Thus, photolysis of 1-piperidino-2-(2-methoxy-4-nitrophenoxy)ethane (a system with an amine with limited freedom of motion) in acetonitrile leads to C-O bond photocleavage in a relatively slow process (k ≈ 4 × 105 s-1) from intermediate species that show radical-ion pair behavior. Systems with higher freedom of motion of the amine moiety, such as 1-piperidino-5-(2-methoxy-4-nitrophenoxy)pentane or 4-nitroveratrole 4- triethylamine, show the intermediate radicalion pairs mainly evolving to reduction products, probably a result of intermediates with geometries not allowed for the system with limited freedom of motion of the amine.
- Gonzalez-Blanco, Roberto,Bourdelande, Jose L.,Marquet, Jordi
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p. 6903 - 6910
(2007/10/03)
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- Hydrogenation of amides by the use of bimetallic catalysts consisting of group 8 to 10, and group 6 or 7 metals
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Hydrogenation of amides can be catalyzed by bimetallic systems, which consist of Group 8 to 10 late transition-metals and Group 6 or 7 early transition-metals, under the mild conditions to afford the corresponding amines selectively in good to excellent yields.
- Hirosawa, Chitaru,Wakasa, Noriko,Fuchikami, Takamasa
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p. 6749 - 6752
(2007/10/03)
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- Aqueous high-temperature chemistry of carbo- and heterocycles: Part 24 [1]. First demonstration of specific C-C bond scission of the pyridine ring. Reactions of piperidine, pyridine and some of their methyl derivatives in aqueous formic acid
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In its reactions with the title compounds, formic acid variously acts as a formylating, methylating, and reducing agent. Both pyridine and piperidine are converted in significant amounts into 1-methyl-, 1-ethyl-, 1-propyl- and 1-pentyl-piperidines. Of the N-alkyl groups, isotopic labeling shows that only N-methyl derives from the formic acid, while the N-ethyl and N-propyl arise from heterocyclic ring C-C bond scission by retro-vinylogous-bis-aza-Aldol reactions. Detailed analysis of the products for pyridine, piperidine, and their 4-methyl derivatives, reacted separately and mixed, supports mechanisms in which a piperidine adds 1,2 to a pyridinium cation, or to a di- or tetra-hydropyridine, to initiate reaction sequences leading to the product slates found.
- Katritzky, Alan R.,Parris, Roslyn L.,Ignatchenko, Elena S.,Balasubramanian, Marudai,Barcock, Richard A.,Siskin, Michael
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p. 220 - 230
(2007/10/03)
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- Nucleophilicity towards a Vinylic Carbon Atom: Rate Constants for the Addition of Amines to the 1-Methyl-4-vinylpyridinium Cation in Aqueous Solution
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Second-order rate constants (kNu) have been measured for the addition of 44 primary amines (including five α-effect amines), 28 secondary amines, 19 tertiary amines, ammonia and hydroxide ion to the vinyl group of the 1-methyl-4-vinylpyridinium cation (1) in aqueous solution at 25 deg C (ionic strength 0.1 mol dm-3).Nucleophilic attack is shown to be rate-determining for primary and secondary amines being generally more reactive than primary amines, with secondary amines of the same basicity.After classification of these species in terms of structure, they describe a number of Broensted-type correlations having βnuc in the range 0.35-0.54 for six structural classes of primary amine, βnuc = 0.48 for α-effect amines, and βnuc in the range 0.23-0.34 for four structural classes of secondary amine.Substitution upon the α-carbon atom reduces amine nucleophilicity of both primary and secondary amines.The presence of an unsaturated carbon atom (either sp2- or sp-hybridized) as the β-carbon atom leads to an enhanced reactivity relative to the corresponding β-sp3 species in all cases.Tertiary amines are in general less reactive than other amines of the same basicity.Broensted-type plots for tertiary amines present the appearance of random scatter which is not readily decipherable in terms of structure. β-Hydroxy and β-amino tertiary amines are unusually reactive relative to their basicity.All of these phenomena suggest that protonation of the carbanionic intermediate by a molecule of water is the rate-determining step for the addition of tertiary amines to 1.Rate constants for the attack of primary and secondary amines on 1 are shown to correlate with literature data for a variety of other reactions involving rate-determining nucleophilic attack of amines upon electrophilic carbon.These kNu for primary and secondary amines reacting with 1 are also shown to correlate with Ritchie's N+ parameters for nucleophilic attack at electrophilic sp2-carbon.N+ parameters for amine nucleophiles have not been widely available previously; the parameters that have been available for selected amines are known to be sensitive to the nature of the defining electrophile.The minimal steric hindrance at the electrophilic centre in nucleophilic attack upon 1 suggests that this species is an appropriate electrophile for the definition of N+ parameters for amine nucleophiles; these parameters are evaluated for 70 primary and secondary amines and ammonia and are suggested to provide an appropriate data base for future investigations of the reactivity and selectivity of amine attack upon sp2-carbon electrophiles in aqueous solution.
- Heo, Christina K. M.,Bunting, John W.
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p. 2279 - 2290
(2007/10/02)
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- Unprecedented Pyridine Ring C-C Bond Cleavages by Formic Acid.
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Formic acid at 350 deg C converts pyridine and 4-methylpyridine into products deriving from both αβ and βγ C-C bond cleavages of the pyridine ring.
- Siskin, Michael,Katritzky, Alan R.,Balasubramanian, Marudai,Ferrughelli, David T.,Brons, Glen,Singhal, Gopal H.
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p. 4739 - 4742
(2007/10/02)
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- Lewis Acid Complexed Heteroatom Carbanions; A New Concept for α-Metallation of Tertiary Amines
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BF3 complexes of typical benzylic, allylic and saturated N-methyl tertiary amines were α-lithiated, with lithium tetramethylpiperidide (LTMP) or sec-butyllithium, and were treated with electrophiles.
- Kessar, Satinder V.,Singh, Paramjit,Vohra, Rahul,Kaur, Nachhattar Pal,Singh, Kamal Nain
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p. 568 - 570
(2007/10/02)
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- PIPERIDINE-MODIFIED FISCHER-TROPSCH SYNTHESIS
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N-Alkylpiperidines with alkyl fragment length from C1 to C15 were synthesized by the reaction of CO + H2 + piperidine.The molecular mass distribution of the N-alkylpiperidines has two different distribution parameters α.Thus, α = 0.45 +/- 0.03 for C1-C5 alkyl fragments, while α = 0.65 +/- 0.02 for C6-C15.Piperidine was found to act as modifier reagent and chemical trap for the intermediates in the synthesis reaction.
- Kliger, G. A.,Lesik, O. A.,Mikaya, A. I.,Marchevskaya, E. V.,Zaikin, V. G.,et al.
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p. 435 - 438
(2007/10/02)
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- N-Alkylation d'amines en catalyse homogene. Synthese de mono- et de diamines cycliques
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Ruthenium compounds are appropriate catalysts in the N-alkylation of amines.The synthesis of N-alkylated cyclic amines from a cyclic amine and an alcohol or via the condensation between a diol and a primary amine are described.The reaction with cyclic amines is highly selective, especially in the presence of a phosphine, making it a high yielding preparative procedure.The catalytic condensation between cyclic amines and diols yields either an aminoalcohol (A) or a bicyclic diamine (B).The temperature, the presence of phosphine, and the ratio of amine to diol are decisive in directing the reaction toward A or B.The proposed mechanism involves the dehydrogenation of the alcohol followed by attack of the amine on the aldehyde intermediate.
- Bitsi, G.,Schleiffer, E.,Antoni, F.,Jenner, G.
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p. 343 - 352
(2007/10/02)
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- Catalytic Hydroamination of Furfuryl and Tetrahydrofurfuryl Alcohols with Nitriles
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Reaction of furfuryl and tetrahydrofurfuryl alcohols with nitriles over copper oxide catalysts under a hydrogen pressure of 15 atm at a temperature of 230 deg C gives N-alkylfurfuryl- (yield 46-50percent) and N-alkyltetrahydrofurfurylamines (49-53percent), and N-alkylpiperidines (28-41percent).A reaction mechanism is proposed.
- Kozintsev, S. I.,Basalaeva, L. I.,Gladkikh, L. V.,Kozlov, N. S.
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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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- PHOTOELECTROCHEMICAL SYNTHESIS WITH PT-COATED TiO2 POWDER: ALKYLATION OF 1-ALKYLPYRIDINIUM ION
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A photoelectrochemical approach to the alkylation of 1-alkylpyridinium ion is described.Photolysis of a suspension of Pt-coated TiO2 (anatase) powder in an aqueous medium containing isobutyric acid and 1-ethylpyridinium perchlorate (pH 3-4) yielded 4-isopropyl-1-ethylpyridinium ion.Sevently percent of the isopropyl radicals generated at the TiO2 anode sites by the photo-Kolbe process were found to have alkylated 1-ethylpyridinium ion, in the 4-position, with the remaining 30percent being reduced to propane.
- Ellison, Dean K.,Trulove, Paul C.,Iwamoto, Reynold T.
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p. 6405 - 6410
(2007/10/02)
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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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- THE EFFECT OF SULPHUR COMPOUNDS ON HYDRODENITROGENATION OF NITROGEN COMPOUNDS ON A NICKEL-TUNGSTEN CATALYST
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Hydrodenitrogenation of pyridine on a sulphided NiO-WO3/Al2O3 catalyst has been studied in the presence of ethanethiol, propanethiol, thiophene and hydrogen sulphide and the amount of pentane, 1-methylpiperidine, 1-ethylpiperidine and piperidine has been determined.It was found that in the presence of all the sulphur compounds but hydrogen sulphide, the conversion of pyridine was lower than in their absence.The presence of hydrogen sulphide increased pyridine conversion.
- Cerny, Mirko
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p. 1465 - 1469
(2007/10/02)
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- STUDIES ON HETEROCYCLIC QUATERNARY NITROGEN BASES: KINETICS OF TRANSALKYLATION OF PRIMARY AMINES BY N-SUBSTITUTED 5,6-DIHYDRO-2,4-DIPHENYLNAPHTHOPYRIDINIUM CATIONS
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N-substituents in 5,6-dihydro-2,4-diphenylnaphthopyridiniums are transferred to piperidine by unimolecular and / or bimolecular processes in chlorobenzene solution.The kinetics of this reaction at variable temperatures were studied.It has been shown that the reaction follows either SN1 or SN2 mechanisms dependant on the nature of N-substituent.
- Elshafie, Sayed Mahmoud M.
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p. 525 - 528
(2007/10/02)
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- HYDROGENOLYTIC CLEAVAGE OF PYRIDINE ON DIFFERENT COBALT-MOLYBDENUM AND NICKEL-TUNGSTEN CATALYSTS
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Composition of the reaction products formed by hydrogenation of pyridine at 300 deg C and 15 MPa in the presence of 15 sulphided and unsulphided molybdenum and tungsten catalysts promoted by cobalt and by nickel, respectively, using alumina as the support in most cases, has been examined.It has been proved that the catalyst composition affects both its hydrogenation activity and the ratio of transalkylation to cracking (or hydrocracking) reactions.Relations between the catalysts composition and its activity and selectivity found for the reaction of pyridine differ from those reported for hydrogenolytic cleavage of thiophene, hydrogenation and isomerisation of cyclohexene.
- Cerny, Mirko,Kraus, Milos
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p. 1348 - 1354
(2007/10/02)
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