- Zeolite (H-ZSM 5)-catalysed reduction of conjugated nitroalkenes with sodium cyanoborohydride
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Conjugated nitroalkenes are readily reduced to the corresponding nitroalkanes with sodium cyanoborohydride in the presence of the zeolite H-ZSM 5 in methanol.
- Gupta, Anuradha,Haque, Azizul,Vankar, Yashwant D.
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- Direct and Efficient Preparation of gem-Chloronitro Compounds or Nitro Compounds from gem-Bromonitro Compounds
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Sodiumethanethiolate in methanol is an efficient reducing agent for gem-bromonitro compounds; treatment of the resultant nitronates with a protic acid or with N-chlorosuccinimide gives high yields of the corresponding nitro or gem-chloronitro compounds, respectively.
- Amrollah-Madjdabadi, A.,Beugelmans, R.,Lechevallier, A.
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- Fast cleavage reactions following electron transfer. Reduction of 1,1-dinitrocyclohexane
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One-electron reduction of 1,1-dinitrocyclohexane is followed by rapid cleavage of a C-N bond, giving nitrite and 1-nitrocyclohexyl radical. The rate constant has been determined in dimethylformamide by homogeneous redox catalysis (1.6 × 106 s-1) and in aqueous solution by pulse radiolysis (1.1 × 106 s-1). These values are of the order of 106 larger than the rate constant for cleavage of mononitroalkane radical anions. In the case of electrochemical reduction, the electron transfer and bond cleavage are followed by further reduction of the nitroalkyl radical to give the nitronate anion of nitrocyclohexane. For scan rates exceeding about 0.1 V/s in cyclic voltammetry, the 1-nitrocyclohexyl radical is reduced by the anion radical of 1,1-dinitrocyclohexane rather than at the electrode. Controlled potential electrolysis and product analysis showed that about 1.2 electrons were required per molecule of 1,1-dinitrocyclohexane; essentially no nitronate was found, but instead some nitrocyclohexane and substantial amounts of 1,1′-dinitrobicyclohexyl (5) were produced. This latter product arises from the radical chain reaction of nitronate with starting material. A key chain-carrying step in this reaction scheme is the reaction of 1-nitrocyclohexyl radical with the nitronate to give the anion radical of 5. The rate constant for this step was found to be 2.6 × 106 L mol-1 in water by pulse radiolysis. Fitting of fast-scan cyclic voltammograms by digital simulation showed that this rate constant must be about 5 × 108 L mol-11 s-1 in dimethylformamide with a termination reaction (kt = 2 × 104 s-1) of hydrogen atom abstraction by 1-nitrocyclohexyl to produce the nitrocyclohexane found in the electrolyzed solutions.
- Rühl, Janet C.,Evans, Dennis H.,Hapiot, Philippe,Neta, Pedatsur
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- From azides to nitro compounds in a few seconds using HOF·CH3CN
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HOF·CH3CN, a very efficient oxygen-transfer agent, was reacted with various azides to form the corresponding nitro compounds in excellent yields and in very short reaction times. The respective nitroso derivatives were found to be intermediates in this reaction. When the azides were reacted with MCPBA or DMDO, no reaction took place, and the starting materials were fully recovered. Copyright
- Rozen, Shlomo,Carmeli, Mira
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- Highly selective co-production of nitrocyclohexane and adipic acid from vapor phase catalytic nitration-oxidation of cyclohexane with NO2
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A simple and efficient approach for highly selectivity co-production of nitrocyclohexane and adipic acid from vapor phase nitration-oxidation of cyclohexane with NO2 at atmospheric pressure has been successfully developed in this work. This finding provides a novel strategy for co-production of nitroalkanes and dicarboxylic acids from vapor phase nitration-oxidation of low-carbon cycloalkanes. This method may be very significant to establish such a synthesis process for aliphatic nitro-compounds and dicarboxylic acids in organic fields.
- You, Kuiyi,Jian, Jian,Xiao, Haijun,Liu, Pingle,Ai, Qiuhong,Luo, He'An
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- Structure, Synthesis, and Properties of Some Persubstituted 1,2-Dinitroethanes. In Quest of Nitrocyclopropyl-Anion Derivatives
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Attempts to deprotonate nitrocyclopropane led to solutions which showed strong ESR. signals (Fig. 1) and from which 1-nitro-1'-nitroso-bicyclopropyl (3) and 1,1'-dinitro-bicyclopropyl (2) were isolated.The activation energy for rotation about the central C,C-bond of 2 is estimated to be about 12 kcal/mol (1H-NMR. spectra in Fig. 2).In contrast, the open-chain analoque 2,3-dimethyl-2,3-dinitrobutane (1) shows a metyl singlet down to -70 deg C.Low-temperature X-ray analyses of 1, 2, 3, and also of 1,1'-dinitro-bicyclobutyl (4) show that all four molecules have gauche-conformations but reveal striking structural differences between the open-chain and the cyclic derivatives (Fig. 4-6): the central C,C-bond is long in 1 (1.575 Angstroem), short in 2 (1.479 Angstroem); the C,N-bonds are long in 1 (1.549 Angstroem), short in 2 (1.488 Angstroem); the orientation of the nitro groups is bisected in 2 and perpendicular in 1.The crystal structure of the nitro-nitroso compound 3 is isimorphous with that of the dinitro compound 2 and thus disordered (Fig. 15-16).The effect of the nitro group as ?-electron acceptor on the molecular conformations and bond lengths is discussed.From analysis of the anisotropic vibrational parameters of 2 the root-mean-square librational amplitude of the nitro groups about their C,N-bonds is estimated to be about 5.8 deg at 95 K, corresponding to a rotational barrier of about 9 kcal/mol, i. e. the same order of magnitude as the NMR. estimate of about 12 kcal/mol for C,C-rotation.
- Kai, Yasushi,Knochel,Paul,Kwiatkowski, Stefan,Dunitz, Jack D.,Oth, Jean F. M.,et al.
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- SELECTIVE C-C BOND HYDROGENATION IN UNSATURATED NITRO COMPOUNDS IN THE PRESENCE OF THE RhCl3-ALIQUAT 336 CATALYST SYSTEM
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The ion pair formed from aqueous rhodium trichloride and Aliquat 336 catalyzes the selective hydrogenation of olefinic bonds of a variety of unsaturated nitro compounds in a two liquid phase system at 30 deg C.Nitrobenzene gives, under these conditions, a mixture of aniline and nitrocyclohexane.
- Amer, Ibrahim,Bravdo, Tamar,Blum, Jochanan,Vollhardt, K. Peter C.
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- New Method for the Facile Reduction of α-Nitro Sulfones to Nitroalkanes via an Electron-Transfer-Hydrogen Atom Abstraction Mechanism
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The mechanism for the reduction of several α-nitro sulfones with 1,3-dimethyl-2-phenylbenzimidazoline (DMBI) was investigated.The reduction proceeds by a free-radical chain process where the initiation step and one of the propagation steps involve single electron transfer reactions.The synthetic utility of the reduction was investigated.
- Chen, Jian,Tanner, Dennis D.
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- Structural insights into the ene-reductase synthesis of profens
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Reduction of double bonds of α,β-unsaturated carboxylic acids and esters by ene-reductases remains challenging and it typically requires activation by a second electron-withdrawing moiety, such as a halide or second carboxylate group. We showed that profen precursors, 2-arylpropenoic acids and their esters, were efficiently reduced by Old Yellow Enzymes (OYEs). The XenA and GYE enzymes showed activity towards acids, while a wider range of enzymes were active towards the equivalent methyl esters. Comparative co-crystal structural analysis of profen-bound OYEs highlighted key interactions important in determining substrate binding in a catalytically active conformation. The general utility of ene reductases for the synthesis of (R)-profens was established and this work will now drive future mutagenesis studies to screen for the production of pharmaceutically-active (S)-profens.
- Waller,Toogood,Karuppiah,Rattray,Mansell,Leys,Gardiner,Fryszkowska,Ahmed,Bandichhor,Reddy,Scrutton
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- Preparation method of cyclohexanone oxime
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The invention relates to a preparation method of cyclohexanone oxime. The method comprises the following steps: carrying out partial oxidation reaction on cyclohexylamine and molecular oxygen under the action of a catalyst to obtain an oxidation reaction product consisting of cyclohexanone oxime, a byproduct and possibly unconverted cyclohexylamine; and then treating the oxidation reaction product in one of the following modes: (i) carrying out hydrogenation amination reaction with H2 and NH3 at the same time or carrying out hydrogenation and amination reaction in sequence under the action of a catalyst without separation or after part or all of water in the oxidation reaction product is separated, and then carrying out separation to obtain cyclohexanone oxime; and (ii) carrying out hydrogenation reaction with H2 under the action of a catalyst without separation or after part or all of water is separated out, and then carrying out separation to obtain the cyclohexanone oxime. The method disclosed by the invention has the characteristics of short process flow, small occupied area and investment, low material consumption and energy consumption (low cost), simplicity and convenience in operation, environment friendliness and the like.
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Paragraph 0067-0071
(2021/06/13)
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- Method for co-producing adipic acid and cyclohexanone-oxime from cyclohexane
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The invention relates to a method for co-producing adipic acid and cyclohexanone-oxime from cyclohexane. The method comprises the following steps: (1) carrying out oxidation nitration on cyclohexane and NOx to generate adipic acid, nitrocyclohexane, nitrogen oxides and a byproduct-A, and separating to obtain crude adipic acid and nitrocyclohexane; (2) carrying out catalytic hydrogenation on the obtained nitrocyclohexane and hydrogen to generate cyclohexanone-oxime and a small amount of cyclohexylamine, separating to obtain crude cyclohexanone-oxime and cyclohexylamine, and enabling cyclohexylamine to be directly used as a byproduct or to be continuously converted into cyclohexanone-oxime. and (3) partially oxidizing the cyclohexylamine obtained in the previous step with molecular oxygen to obtain an oxidation reaction product consisting of cyclohexanone-oxime, a byproduct B and possibly unconverted cyclohexylamine, and then separating the oxidation reaction product without separation, or firstly separating part or all of water in the oxidation reaction product, carrying out hydrogenation amination reaction under the action of a catalyst, or carrying out hydrogenation and amination reaction, or only carrying out hydrogenation reaction, and then separating to obtain the cyclohexanone-oxime. The method can realize high-selectivity co-production of adipic acid and cyclohexanone-oxime, and is short in process flow, low in equipment investment and low in material consumption, energy consumption and cost.
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Paragraph 0111-0113
(2021/06/13)
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- Ozone-Mediated Amine Oxidation and Beyond: A Solvent-Free, Flow-Chemistry Approach
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Ozone is a powerful oxidant, most commonly used for oxidation of alkenes to carbonyls. The synthetic utility of other ozone-mediated reactions is hindered by its high reactivity and propensity to overoxidize organic molecules, including most solvents. This challenge can largely be mitigated by adsorbing both substrate and ozone onto silica gel, providing a solvent-free oxidation method. In this manuscript, a flow-based packed bed reactor approach is described that provides exceptional control of reaction temperature and time to achieve improved control and chemoselectivity over this challenging transformation. A powerful method to oxidize primary amines into nitroalkanes is achieved. Examples of pyridine, C-H bond, and arene oxidations are also demonstrated, confirming the system is generalizable to diverse ozone-mediated processes.
- Skrotzki, Eric A.,Vandavasi, Jaya Kishore,Newman, Stephen G.
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supporting information
p. 14169 - 14176
(2021/06/30)
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- Nitroalkene reduction in deep eutectic solvents promoted by BH3NH3
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Deep eutectic solvents (DESs) have gained attention as green and safe as well as economically and environmentally sustainable alternative to the traditional organic solvents. Here, we report the combination of an atom-economic, very convenient and inexpensive reagent, such as BH3NH3, with bio-based eutectic mixtures as biorenewable solvents in the synthesis of nitroalkanes, valuable precursors of amines. A variety of nitrostyrenes and alkyl-substituted nitroalkenes, including α- and β-substituted nitroolefins, were chemoselectively reduced to the nitroalkanes, with an atom economy-oriented, simple and convenient experimental procedure. A reliable and easily reproducible protocol to isolate the product without the use of any organic solvent was established, and the recyclability of the DES mixture was successfully investigated.
- Benaglia, Maurizio,Boselli, Monica Fiorenza,Faverio, Chiara,Gonzalez, Patricia Camarero,Puglisi, Alessandra
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supporting information
p. 1041 - 1047
(2021/05/17)
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- Preparation method of cyclohexanone-oxime
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The invention relates to a preparation method of cyclohexanone-oxime, which mainly comprises the following steps: (1) oxidizing cyclohexane and molecular oxygen under the action of a solid catalyst, carrying out one-step reaction to generate KA oil, and performing separation to obtain the KA oil; (2) directly aminating the KA oil with ammonia and hydrogen under the action of a solid catalyst to generate cyclohexylamine and a small amount of byproduct-A, and performing separation to obtain cyclohexylamine; (3) carrying out partial oxidation on cyclohexylamine and molecular oxygen under the action of a solid catalyst to obtain an oxidation product mainly composed of cyclohexanone-oxime, a small amount of byproduct-B and cyclohexylamine which may not be completely converted; and (4) aminatingthe oxidation product, namely, directly carrying out amination reaction on the oxidation product obtained in the step (3), ammonia and hydrogen under the action of a solid catalyst without separation, converting the byproduct-B into cyclohexylamine, and performing separation to obtain cyclohexanone-oxime. The method is short in technological process, small in occupied area and investment, low incost and environmentally friendly.
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Paragraph 0037
(2020/06/05)
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- Facile access to nitroalkanes: Nitration of alkanes by selective C[sbnd]H nitration using metal nitrate, catalyzed by in-situ generated metal oxide
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Direct C ? H functionalization of inactive alkanes is an important strategy to streamline the preparation of functional molecules. Herein, we describe an operationally simple and effective alkane C ? H nitration reaction to access versatile nitroalkanes without cleavage of the C ? C skeleton. Nontoxic and inexpensive metal nitrate (Fe(NO3)3·9H2O) plays a dual role as catalyst precursors as well as nitro sources for the transformation. Experimental evidence and theoretical modeling have shown the formation of iron oxide as a key catalytic species for the alkane C ? H and NO2 activation, which favors a stepwise radical mechanism with initial alkyl radical formation.
- Li, Na,Mao, Liqiu,Peng, Haoyu,Peng, Ling,Yin, Dulin,You, Kuiyi,Zhong, Wenzhou
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- Site-specific catalytic activities to facilitate solvent-free aerobic oxidation of cyclohexylamine to cyclohexanone oxime over highly efficient Nb-modified SBA-15 catalysts
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The development of highly active and selective heterogeneous catalysts for efficient oxidation of cyclohexylamine to cyclohexanone oxime is a challenge associated with the highly sensitive nitrogen center of cyclohexylamine. In this work, dispersed Nb oxide supported on SBA-15 catalysts are disclosed to efficiently catalyze the selective oxidation of cyclohexylamine with high conversion (>75%) and selectivity (>84%) to cyclohexanone oxime by O2without any addition of solvent (TOF = 469.8 h?1, based on the molar amount of Nb sites). The role of the active-site structure identity in dictating the site-specific catalytic activities is probed with the help of different reaction and control conditions and multiple spectroscopy methods. Complementary to the experimental results, further poisoning tests (with KSCN or dehydroxylation reagents) and DFT computational studies clearly unveil that the surface exposed active centers toward activation of the reactants are quite different: the surface -OH groups can catch the NH2group from cyclohexylamine by forming a hydrogen bond and lead to a more facile cyclohexylamine oxidation to desired products, while the monomeric or oligomeric Nb sites with a highly distorted structure play a key role in the dissociation of O2molecules beneficial for insertion of active oxygen species into cyclohexylamine. These catalysts exhibit not only satisfactory recyclability for cyclohexylamine oxidation but also efficiently catalyze the aerobic oxidation of a wide range of amines under solvent-free conditions.
- Ding, Wei,Mao, Liqiu,Peng, Haoyu,Yin, Dulin,Zhong, Wenzhou
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p. 3409 - 3422
(2020/06/09)
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- Green synthesis method for preparing nitroalkanes by oxime oxidation
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The invention belongs to the field of organic chemical industries, and provides a green synthesis method for preparing nitroalkanes by oxime oxidation. At the temperature of 55 to 120 DEG C and under the pressure of 0 to 1.0 MPa, oxime, a solvent and hydrogen peroxide are reacted for 20 to 200min in the presence of certain amounts of nanoporous skeleton metal hybrid catalysts and cocatalysts, a reaction liquid is subjected to membrane separation, the catalysts can be repeatedly used for more than 7 times, and distilled to obtain nitroalkane products, the purity of the products is not less than 99%, and the yield of the products is not less than 95%. Furthermore, the green synthesis method for preparing nitroalkanes by the oxime oxidation disclosed by the invention is a green synthesis method of nitroalkanes, and suitable for large-scale industrialized production.
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Paragraph 0041; 0042
(2017/08/29)
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- Boosting one-step conversion of cyclohexane to adipic acid by NO2 and VPO composite catalysts
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We demonstrate VPO composites as efficient catalysts for highly selective oxidation of cyclohexane to adipic acid with NO2. In particular, the Ni-Al-VPO composite catalyst exhibits the striking conversion of cyclohexane (60.6%) and exceptionally high selectivity towards adipic acid (85.0%). Moreover, N2O is an environmentally harmful gas, and its yield in the present process is only 0.03 t/t adipic acid, which is far below that obtained using the industrial method (0.3 t/t adipic acid). This work provides a new strategy for the one-step synthesis of dicarboxylic acids from cycloalkanes.
- Jian, Jian,You, Kuiyi,Duan, Xuezhi,Gao, Hongxu,Luo, Qing,Deng, Renjie,Liu, Pingle,Ai, Qiuhong,Luo, He'an
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supporting information
p. 3320 - 3323
(2016/02/27)
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- MANUFACTURING METHOD OF AMIDE COMPOUND, ALLOY PARTICLE AND CATALYST CONTAINING THE SAME
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PROBLEM TO BE SOLVED: To provide an alloy particle for a catalyst capable of manufacturing an amide compound with high efficiency and capable of manufacturing the amide compound at low cost easily on an industrial scale. SOLUTION: There is provided an alloy particle for catalyst used in manufacturing an amide compound having a B2 type or L12 type crystal structure constituted by Cu and Pd or a L10 type crystal structure constituted by Cu and Au and having average particle diameter of the alloy particle of 1 to 200 nm. SELECTED DRAWING: Figure 1 COPYRIGHT: (C)2016,JPO&INPIT
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Paragraph 0150-0151
(2017/03/23)
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- Mesoporous silica gel as an effective and eco-friendly catalyst for highly selective preparation of cyclohexanone oxime by vapor phase oxidation of cyclohexylamine with air
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A simple and environmentally benign approach to highly selective preparation of cyclohexanone oxime by vapor phase catalytic oxidation of cyclohexylamine with air over mesoporous silica gel under atmospheric pressure has been successfully developed in this work. The results demonstrate that the nonmetallic mesoporous silica gel is an effective and eco-friendly catalyst for the vapor phase selective oxidation of cyclohexylamine to cyclohexanone oxime and the surface silicon hydroxyl groups as active sites are responsible for the excellent catalytic performance of silica gel. The present silica gel catalyst has advantages of low cost, long-time stable reactivity, easy regeneration, and reusability. This method employing inexpensive mesoporous silica gel as catalyst and air as green terminal oxidant under facile conditions is a promising process and has the potential to enable sustainable production of cyclohexanone oxime from the selective oxidation of cyclohexylamine with air in industrial applications.
- Liu, Shuilin,You, Kuiyi,Jian, Jian,Zhao, Fangfang,Zhong, Wenzhou,Yin, Dulin,Liu, Pingle,Ai, Qiuhong,Luo, He'an
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p. 239 - 249
(2016/04/06)
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- A simple and efficient approach for highly selective preparation of nitrocyclohexane from cyclohexane with tert-butyl nitrite catalyzed by N-hydroxyphthalimide
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A simple and effective approach for highly selective preparation of nitrocyclohexane from cyclohexane using tert-butyl nitrite as a nitrating agent under atmospheric pressure has been successfully developed in this work. The results indicate that the N-hydroxyphthalimide catalyst gave the best results with 27.3 % of cyclohexane conversion and 88.0 % of selectivity to nitrocyclohexane under optimal reaction conditions. The present reaction provides a novel strategy for the synthesis of nitroalkanes from the nitration of low-carbon alkanes because of the mild reaction condition, simple experimental procedure and high selectivity towards the desired product. This method may be very significant to establish such a synthesis method for aliphatic nitro-compounds from the low-carbon alkanes in organic fields.
- Liu, Shuilin,You, Kuiyi,Jian, Jian,Luo, Qing,Liu, Pingle,Ai, Qiuhong,Luo, He'An
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p. 2211 - 2220
(2016/03/16)
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- Silver(I)-Promoted ipso-Nitration of Carboxylic Acids by Nitronium Tetrafluoroborate
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A novel and efficient method for the regioselective nitration of a series of aliphatic and aromatic carboxylic acids to their corresponding nitro compounds using nitronium tetrafluoroborate and silver carbonate in dimethylacetamide has been described. This transformation is believed to proceed via the alkyl-silver or aryl-silver intermediate, which subsequently reacts with the nitronium ion to form nitro substances. Mild reaction conditions, tolerant of a broad range of functional groups, and formation of only the ipso-nitrated products are the key features of this methodology when compared to known methods for syntheses of nitroalkyls and nitroarenes.
- Natarajan, Palani,Chaudhary, Renu,Venugopalan, Paloth
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p. 10498 - 10504
(2015/11/18)
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- Alkane oxidation with peroxides catalyzed by cage-like copper(II) silsesquioxanes
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Isomeric cage-like tetracopper(II) silsesquioxane complexes [(PhSiO1.5)12(CuO)4(NaO0.5)4] (1a), [(PhSiO1.5)6(CuO)4(NaO0.5)4(PhSiO1.5)6] (1b) and binuclear complex [(PhSiO1.5)10(CuO)2(NaO0.5)2] (2) have been studied by various methods. These compounds can be considered as models of some multinuclear copper-containing enzymes. Compounds 1a and 2 are good pre-catalysts for the alkane oxygenation with hydrogen peroxide in air in an acetonitrile solution. Thus, the 1a-catalyzed reaction with cyclohexane at 60°C gave mainly cyclohexyl hydroperoxide in 17% yield (turnover number, TON, was 190 after 230 min and initial turnover frequency, TOF, was 100 h-1). The alkyl hydroperoxide partly decomposes in the course of the reaction to afford the corresponding ketone and alcohol. The effective activation energy for the cyclohexane oxygenation catalyzed by compounds 1a and 2 is 16 ± 2 and 17 ± 2 kcal mol-1, respectively. Selectivity parameters measured in the oxidation of linear and branched alkanes and the kinetic analysis revealed that the oxidizing species in the reaction is the hydroxyl radical. The analysis of the dependence of the initial reaction rate on the initial concentration of cyclohexane led to a conclusion that hydroxyl radicals attack the cyclohexane molecules in proximity to the copper reaction centers. The oxidations of saturated hydrocarbons with tert-butylhydroperoxide (TBHP) catalyzed by complexes 1a and 2 exhibit unusual selectivity parameters which are due to the steric hindrance created by bulky silsesquioxane ligands surrounding copper reactive centers. Thus, the methylene groups in n-octane have different reactivities: the regioselectivity parameter for the oxidation with TBHP catalyzed by 1a is 1:10.5:8:7. Furthermore, in the oxidation of methylcyclohexane the position 2 relative to the methyl group of this substrate is noticeably less reactive than the corresponding positions 3 and 4. Finally, the oxidation of trans-1,2-dimethylcyclohexane with TBHP catalyzed by complexes 1a and 2 proceeds stereoselectively with the inversion of configuration. The 1a-catalyzed reaction of cyclohexane with H216O2 in an atmosphere of 18O2 gives cyclohexyl hydroperoxide containing up to 50% of 18O. The small amount of cyclohexanone, produced along with cyclohexyl hydroperoxide, is 18O-free and is generated apparently via a mechanism which does not include hydroxyl radicals and incorporation of molecular oxygen from the atmosphere.
- Vinogradov, Mikhail M.,Kozlov, Yuriy N.,Bilyachenko, Alexey N.,Nesterov, Dmytro S.,Shul'pina, Lidia S.,Zubavichus, Yan V.,Pombeiro, Armando J. L.,Levitsky, Mikhail M.,Yalymov, Alexey I.,Shul'pin, Georgiy B.
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p. 187 - 199
(2015/02/19)
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- Chemoselective Hydrogenation and Transfer Hydrogenation of Olefins and Carbonyls with the Cluster-Derived Ruthenium Nanocatalyst in Water
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Ion pairing of [H3Ru4(CO)12]- with the quaternary ammonium groups of water-soluble poly(diallyldimethylammonium chloride) gives the precursor of a nanocatalyst for hydrogenation and transfer hydrogenation reactions in water. In hydrogenation reactions, "on water" effect is seen for substrates such as cyclohexanones, methyl pyruvate, acetophenone, and safflower oil. With these substrates, higher turnover numbers are obtained in water than in methanol. The cluster-derived catalyst shows unique chemoselectivity, which is not seen either in a catalyst prepared through ion pairing of [RuCl4]- with the quaternary ammonium groups of the same polymer or in commercial (5%) Ru/Al2O3. In contrast to Ru/Al2O3, the [RuCl4]--derived catalyst, or many other ruthenium-based catalytic systems, the cluster-derived catalyst is totally inert toward the hydrogenation of -NO2, -CN, and aromatic ring functionalities. In water, typical ketones and aldehydes could be reduced by using the cluster-derived catalyst and formate as the hydrogen donor. Industrially important cyano- and nitrobenzyl alcohols could thus be made from the corresponding aldehydes. High-resolution TEM data suggest that unique chemoselectivity is a result of highly crystalline ruthenium nanoparticles that consist mainly of Ru(111) crystal planes.
- Indra, Arindam,Maity, Prasenjit,Bhaduri, Sumit,Lahiri, Goutam Kumar
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p. 322 - 330
(2013/03/13)
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- Biocatalytic asymmetric alkene reduction: Crystal structure and characterization of a double bond reductase from Nicotiana tabacum
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The application of biocatalysis for the asymmetric reduction of activated C=C is a powerful tool for the manufacture of high-value chemical commodities. The biocatalytic potential of "-ene" reductases from the Old Yellow Enzyme (OYE) family of oxidoreductases is well-known; however, the specificity of these enzymes toward mainly small molecule substrates has highlighted the need to discover "-ene" reductases from different enzymatic classes to broaden industrial applicability. Here, we describe the characterization of a flavin-free double bond reductase from Nicotiana tabacum (NtDBR), which belongs to the leukotriene B4 dehydrogenase (LTD) subfamily of the zinc-independent, medium chain dehydrogenase/reductase superfamily of enzymes. Using steady-state kinetics and biotransformation reactions, we have demonstrated the regio- and stereospecificity of NtDBR against a variety of α,β-unsaturated activated alkenes. In addition to catalyzing the reduction of typical LTD substrates and several classical OYE-like substrates, NtDBR also exhibited complementary activity by reducing non-OYE substrates (i.e., reducing the exocyclic C=C double bond of (R)-pulegone) and in some cases showing an opposite stereopreference in comparison with the OYE family member pentaerythritol tetranitrate (PETN) reductase. This serves to augment classical OYE "-ene" reductase activity and, coupled with its aerobic stability, emphasizes the potential industrial value of NtDBR. Furthermore, we also report the X-ray crystal structures of the holo-, binary NADP(H)-bound, and ternary [NADP+ and 4-hydroxy-3-methoxycinnamaldehyde (9a)-bound] NtDBR complexes. These will underpin structure-driven site-saturated mutagenesis studies aimed at enhancing the reactivity, stereochemistry, and specificity of this enzyme.
- Mansell, David J.,Toogood, Helen S.,Waller, John,Hughes, John M.X.,Levy, Colin W.,Gardiner, John M.,Scrutton, Nigel S.
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p. 370 - 379
(2013/08/25)
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- Hydrogenolysis-hydrogenation of aryl ethers: Selectivity pattern
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The selectivity pattern of nickel-catalyzed hydrogenolysis-hydrogenation of aryl ethers has been studied in the micellar media. The micellar conditions selectively formed arenes and alcohols with enhanced yields.
- Samant, Bhupesh S.,Kabalka, George W.
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supporting information; experimental part
p. 8658 - 8660
(2012/10/08)
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- Sequential continuous flow processes for the oxidation of amines and azides by using HOF·MeCN
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The generation and use of the highly potent oxidising agent HOF·MeCN in a controlled single continuous flow process is described. Oxidations of amines and azides to corresponding nitrated systems by using fluorine gas, water and acetonitrile by sequential gas-liquid/liquid-liquid continuous flow procedures are reported. Oxidation in flow: The oxidation of amines and azides to the corresponding nitrated systems by using fluorine gas, water and acetonitrile by sequential gas-liquid/liquid-liquid continuous flow procedures are reported. Copyright
- McPake, Christopher B.,Murray, Christopher B.,Sandford, Graham
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scheme or table
p. 312 - 319
(2012/06/15)
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- Nicotinamide-dependent Ene reductases as alternative biocatalysts for the reduction of activated alkenes
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Four NAD(P)H-dependent non-flavin ene reductases have been investigated for their ability to reduce activated C=C bonds in an asymmetric fashion by using 20 structurally diverse substrates. In comparison with flavin-dependent Old Yellow Enzyme homologues, a higher degree of electronic activation was required, because the best activities were obtained with enals and nitroalkenes rather than enones and carboxylic esters. Although FaEO from Fragaria x ananassa (strawberry) and its homologue SlEO from Solanum lycopersicum (tomato) exhibited a narrow substrate spectrum, progesterone 5β-reductase (At5β-StR) from Arabidopsis thaliana (thale cress) and leukotriene B4 12-hydroxydehydrogenase (LTB4DH/PGR) from Rattus norvegicus (rat) appear to be promising candidates, in particular for the asymmetric bioreduction of open-chain enals, nitroalkenes and α,β-unsaturated γ-butyrolactones. Competing nitro reduction and non-enzymatic Weitz-Scheffer epoxidation were largely suppressed. Electronically activated alkenes have been stereoselectively reduced by using a single-enzyme-cofactor system employing nicotinamide-dependent non-flavin ene reductases. Copyright
- Durchschein, Katharina,Wallner, Silvia,MacHeroux, Peter,Schwab, Wilfried,Winkler, Thorsten,Kreis, Wolfgang,Faber, Kurt
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p. 4963 - 4968
(2013/01/14)
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- Reductive biotransformation of nitroalkenes via nitroso-intermediates to oxazetes catalyzed by xenobiotic reductase A (XenA)
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A novel reductive biotransformation pathway for β,β-disubstituted nitroalkenes catalyzed by flavoproteins from the Old Yellow Enzyme (OYE) family was elucidated. It was shown to proceed via enzymatic reduction of the nitro-moiety to furnish the corresponding nitroso-alkene, which underwent spontaneous (non-enzymatic) electrocyclization to form highly strained 1,2-oxazete derivatives. At elevated temperatures the latter lost HCN via a retro-[2 + 2]-cycloaddition to form the corresponding ketones. This pathway was particularly dominant using xenobiotic reductase A, while pentaerythritol tetranitrate-reductase predominantly catalyzed the biodegradation via the Nef-pathway.
- Durchschein, Katharina,Fabian, Walter M. F.,MacHeroux, Peter,Zangger, Klaus,Trimmel, Gregor,Faber, Kurt
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experimental part
p. 3364 - 3369
(2011/06/25)
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- PROCESS FOR MAKING AND USING HOF.RCN
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The invention relates to a process for making HOF.RCN and using it to oxidise organic substrates in a quick and safe way. The process comprises passing diluted fluorine through a conduit and RCN in water through another conduit into a microreactor to form HOF.RCN and reacting this with an organic substrates.
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Page/Page column 7
(2011/04/14)
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- HYDROCARBON FEED FLEXIBLE HIGH PRESSURE NITRATION PLANT DESIGN
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Disclosed is an apparatus for synthesizing nitroalkanes by reaction of a hydrocarbon feedstock with aqueous nitric acid. The apparatus may be designed such that it can synthesize more than one nitroalkane using the same equipment.
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Page/Page column 16-20
(2011/07/09)
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- Nitroreductase from Salmonella typhimurium: Characterization and catalytic activity
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The biocatalytic activity of nitroreductase from Salmonella typhimurium (NRSal) was investigated for the reduction of α,β-unsaturated carbonyl compounds, nitroalkenes, and nitroaromatics. The synthesized gene was subcloned into a pET28 overexpression system in E.coli BL21 strain, and the corresponding expressed protein was purified to homogeneity with 15% protein mass yield and 41% of total activity recovery. NRSal showed broad substrate acceptance for various nitro compounds such as 1-nitrocyclohexene and aliphatic nitroalkenes (alkene reductase activity), as well as nitrobenzene (nitroreductase activity), with substrate conversion efficiency of > 95%. However, the reduction of enones was generally low, proceeding albeit with high stereoselectivity. The efficient biocatalytic reduction of substituted nitroalkenes provides a route for the preparation of the corresponding nitroalkanes. NRSal also demonstrated the first single isolated enzyme-catalyzed reduction of nitrobenzene to aniline through the formation of nitrosobenzene and phenylhydroxylamine as intermediates. However, chemical condensation of the two intermediates to produce azoxybenzene currently limits the yield of aniline.
- Yanto, Yanto,Hall, Melanie,Bommarius, Andreas S.
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experimental part
p. 1826 - 1832
(2010/08/06)
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- Characterization of xenobiotic reductase A (XenA): Study of active site residues, substrate spectrum and stability
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Xenobiotic reductase A (XenA) has broad catalytic activity and reduces various α,β-unsaturated and nitro compounds with moderate to excellent stereoselectivity. Single mutants C25G and C25V are able to reduce nitrobenzene, a non-active substrate for the wild type, to produce aniline. Total turnover is dominated by chemical rather than thermal instability. The Royal Society of Chemistry 2010.
- Yanto, Yanto,Yu, Hua-Hsiang,Hall, Melanie,Bommarius, Andreas S.
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supporting information; scheme or table
p. 8809 - 8811
(2011/02/28)
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- Structure-based insight into the asymmetric bioreduction of the C=C double bond of α,β-unsaturated nitroalkenes by pentaerythritol tetranitrate reductase
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Biocatalytic reduction of α- or β-alkyl-barylnitroalkenes provides a convenient and efficient method to prepare chiral substituted nitroalkanes. Pentaerythritol tetranitrate reductase (PETN reductase) from Enterobacter cloacae st. PB2 catalyses the reduction of nitroolefins such as 1-nitrocyclohexene (1) with steady state and rapid reaction kinetics comparable to other old yellow enzyme homologues. Furthermore, it reduces 2-aryl-1-nitropropenes (4a-d) to their equivalent (S)-nitropropanes 9a-d. The enzyme shows a preference for the (Z)-isomer of substrates 4a-d, providing almost pure enantiomeric products 9a-d (ees up to > 99%) in quantitative yield, whereas the respective (E)-isomers are reduced with lower enantioselectivity (63-89% ee) and lower product yields. 1-Aryl-2-nitropropenes (5a, b) are also reduced efficiently, but the products (R)-10 have lower optical purities. The structure of the enzyme complex with 1-nitrocyclohexene (1) was determined by X-ray crystallography, revealing two substrate-binding modes, with only one compatible with hydride transfer. Models of nitropropenes 4 and 5 in the active site of PETN reductase predicted that the enantioselectivity of the reaction was dependent on the orientation of binding of the (E)- and (Z)- substrates. This work provides a structural basis for understanding the mechanism of asymmetric bioreduction of nitroalkenes by PETN reductase.
- Toogood, Helen S.,Fryszkowska, Anna,Hare, Victoria,Fisher, Karl,Roujeinikova, Anna,Leys, David,Gardiner, John M.,Stephens, Gill M.,Scrutton, Nigel S.
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supporting information; experimental part
p. 2789 - 2803
(2009/10/20)
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- Aerobic oxidation of primary amines to oximes catalyzed by DPPH and WO 3/Al2O3
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(Chemical Equation Presented) Catalytic teamwork: Aerobic oxidation of primary amines to the corresponding oximes proceeds highly efficiently in the presence of the catalysts 1,1-diphenyl-2-picrylhydrazyl (DPPH) and WO 3/Al2O3 under mild conditions (see scheme). This new method is both selective and environmentally benign.
- Suzuki, Ken,Watanabe, Tomonari,Murahashi, Shun-Ichi
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supporting information; experimental part
p. 2079 - 2081
(2009/02/06)
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- Organocatalytic biomimetic reduction of conjugated nitroalkenes
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A thiourea-catalyzed biomimetic reduction of conjugated nitroalkenes has been developed. Various aromatic and aliphatic conjugated nitroalkenes can be reduced to give the respective nitroalkanes with good yields under mild conditions. This protocol is not only practical, but may also provide insight into the mechanisms of redox transformations in biological systems. Georg Thieme Verlag Stuttgart.
- Zhang, Zhiguo,Schreiner, Peter R.
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p. 2559 - 2564
(2008/03/13)
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- Oxidation of azides by the HOF·CH3CN: A novel synthesis of nitro compounds
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The HOF·CH3CN complex, readily prepared by passing F 2 through aqueous acetonitrile, is an exceptionally efficient oxygen transfer agent. It is unique in its capacity to oxidize various azides into the corresponding nitro derivatives. This method requires short reactions times and room temperature or below, and the desired nitro compounds were usually isolated in very good yields. The respective nitroso derivatives are believed to be the intermediates in this reaction. Functional groups such as aromatic rings, ketones, nitriles, halides, alcohols, and esters are tolerated. Sulfides react with HOF·CH3CN usually at the same rate as azides. Amines and olefins, however, react faster, so they have to be protected first. Nitro derivatives with various oxygen isotopes can be made using the labeled H 18OF·CH3CN. In the case of chiral azides the stereochemistry around the nitrogen-bonded carbons is retained.
- Carmeli, Mira,Rozen, Shlomo
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p. 4585 - 4589
(2007/10/03)
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- Synthetic utilities of ionic liquid-supported NHPI complex
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Ionic liquid (IL)-supported NHPI complex for the oxidation and/or nitration was prepared. Synthetic utilities of the complex as recoverable and recyclable system in ionic liquid were described.
- Koguchi, Shinichi,Kitazume, Tomoya
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p. 2797 - 2801
(2007/10/03)
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- Synthesis of nitroalkanes from alkylhalides under mild and nonaqueous conditions by using polymer supported nitrites
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Alkyl halides are efficiently converted to their corresponding nitroalkanes under mild and nonaqueous conditions by using polymer supported nitrites. The polymeric reagent is regenerable.
- Zarchi, Mohammad Ali Karimi,Zarei, Amin
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p. 309 - 311
(2007/10/03)
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- CATALYSTS COMPRISING CYCLIC ACYLUREA COMPOUNDS AND PROCESSES FOR PRODUCTION OF ORGANIC COMPOUNDS WITH THE SAME
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A catalyst of the invention includes a cyclic acylurea compound having a cyclic acylurea skeleton represented by following Formula (I): wherein R is a hydrogen atom or a hydroxyl-protecting group; n is 1 or 2; G is a carbon atom or a nitrogen atom, where two Gs are the same or different when n is 2. The catalyst may include the cyclic acylurea compound and a metallic compound in combination. In the presence of the catalyst, (A) a compound capable of forming a radical is allowed to react with (B) a radical scavenging compound and thereby yields an addition or substitution reaction product of the compound (A) and the compound (B) or a derivative thereof. This catalyst can produce an organic compound with a high selectivity in a high yield as a result of, for example, an addition or substitution reaction under mild conditions.
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- Process for preparation of cyclohexanone oxime
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A method for producing cyclohexanone oxime, which comprises the steps of (1) subjecting to an amination reaction a starting material selected from the group consisting of cyclohexanol, cyclohexanone and a mixture thereof, thereby obtaining cyclohexylamine, and (2) subjecting the obtained cyclohexylamine to a partial oxidation reaction, thereby obtaining cyclohexanone oxime, wherein a by-product (α) formed in the step (1) and/or a by-product (β) formed in the step (2) are/is recycled to a reaction system of the amination reaction in the step (1).
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- [VO(H2O)5]H[PMo12O40]- catalyzed nitration of alkanes with nitric acid
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[VO(H2O)5]H[PMo12O40], which contains vanadyl counter cations and PMo12O40 3-, can act as a catalyst for the nitration of various alkanes including alkylbenzenes using nitric acid as a nitrating agent in acetic acid at 356 K.
- Yamaguchi, Kazuya,Shinachi, Satoshi,Mizuno, Noritaka
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p. 424 - 425
(2007/10/03)
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- A new route to lactam precursors from cycloalkanes: Direct production of nitrosocycloalkanes or cycloalkanone oximes by using tert-Butyl nitrite and N-hydroxyphthalimide
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Clean and selective: Nitrosation and oximation of cycloalkanes was achieved by treating them with tBuONO under Ar in the presente presence of a catalytic amount of N-hydroxyphthalimide (see scheme). The novel, clean nitrosation procedure uses halogen-free, relatively mild reaction conditions and results in good product selectivity (almost no organic byproducts) and high recovery of the catalyst.
- Hirabayashi, Tomotaka,Sakaguchi, Satoshi,Ishii, Yasutaka
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p. 1120 - 1123
(2007/10/03)
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- Nitration of alkanes with nitric acid by vanadium-substituted polyoxometalates
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The nitration of alkanes by using nitric acid as a nitrating agent in acetic acid was efficiently promoted by vanadium-substituted Keggin-type phosphomolybdates such as [H4PVMo11O40], [H5PV2Mo10O40], and [H 6PV3Mo9O40] as catalyst precursors. A variety of alkanes including alkylbenzenes were nitrated to the corresponding nitroalkanes as major products in moderate yields with formation of oxygenated products under mild reaction conditions. The carbon-carbon bond cleavage reactions hardly proceeded. ESR, NMR, and IR spectroscopic data show that the vanadium-substituted polyoxometalate, for example, [H4PVMo 11O40], decomposes to form free vanadium species and [PMo12O40]3- Keggin anion. The reaction mechanism involving a radical-chain path is proposed. The polyoxometalates initially abstract the hydrogen of the alkane to form the alkyl radical and the reduced polyoxometalates. The reduced polyoxometalates subsequently react with nitric acid to produce the oxidized form and nitrogen dioxide. This step would be promoted mainly by the phosphomolybdates, [PMo12O 40]n-, and the vanadium cations efficiently enhance the activity. The nitrogen dioxide promotes the further formation of nitrogen dioxide and an alkyl radical. The alkyl radical is trapped by nitrogen dioxide to form the corresponding nitroalkane.
- Shinachi, Satoshi,Yahiro, Hidenori,Yamaguchi, Kazuya,Mizuno, Noritaka
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p. 6489 - 6496
(2007/10/03)
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- SRN1 reactions in the nitrobenzo[1,3]dioxole series
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5-Chloromethyl-6-nitrobenzo[1,3]dioxole has been shown to react with 2-nitropropane anion to give C-alkylation by an SRN1 mechanism. The reaction was extended to various aliphatic, cyclic, and heterocyclic nitronate anions, leading to a new series of nitrobenzo[1,3]dioxole derivatives.
- Meuche-Albeny,Rathelot,Crozet,Vanelle
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p. 989 - 997
(2007/10/03)
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- Catalyst comprising a cyclic imide compound and process for producing organic compounds using the catalyst
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A catalyst includes a cyclic imide compound having an N-substituted cyclic imide skeleton represented by following Formula (I): wherein X is an oxygen atom or a hydroxyl group, and having a solubility parameter of less than or equal to 26 [(MPa)?] as determined by Fedors method. The catalyst may further comprise a metallic compound. By allowing (A) a compound capable of forming a radical to react with (B) a radical scavenging compound in the presence of the catalyst, an addition or substitution reaction product between the compound (A) and the compound (B) or a derivative thereof can be obtained.
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- PROCESS FOR THE PREPARATION OF NITRO COMPOUNDS AND METHOD FOR THE REMOVAL OF NITROGEN DIOXIDE
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In the invented process for producing a nitro compound, an organic substrate and nitrogen dioxide are reacted in the presence of oxygen or are reacted in a molar ratio of nitrogen dioxide to the organic substrate of less than 1 to yield a corresponding nitro compound. The reaction may be performed in the presence of N-hydroxyphthalimide or other imide compounds. Such organic substrates include (a) aliphatic hydrocarbons, (b) alicyclic hydrocarbons, (c) non-aromatic heterocyclic compounds each having a carbon atom on a ring, which carbon atom is bonded to a hydrogen atom, (d) compounds each having a carbon-hydrogen bond at the adjacent position to an aromatic ring, and (e) compounds each having a carbon-hydrogen bond at the adjacent position to a carbonyl group. This process can efficiently nitrate an organic substrate even under relatively mild conditions.
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- Does peroxynitrite partition between aqueous and gas phases? Implication for lipid peroxidation
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Relative reactivity of alkane and alkylbenzene oxidation by peroxynitrite has been determined in acidic aqueous solutions. The observed data are explained assuming that the reaction simultaneously proceeds in both the gas and the liquid phases. The select
- Rudakov,Lobachev,Geletii
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p. 1232 - 1238
(2007/10/03)
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- Nitration of alkanes with nitric acid catalyzed by N-hydroxyphthalimide
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Catalytic nitration of alkanes with nitric acid was first successfully achieved by the use of N-hydroxyphthalimide (NHPI) under mild conditions; the key to the present nitration was found to be the in situ generation of NO2 and phthalimide N-ox
- Isozaki,Nishiwaki,Sakaguchi,Ishii
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p. 1352 - 1353
(2007/10/03)
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- Raney nickel: An efficient reagent to achieve the chemoselective hydrogenation of α,β-unsaturated carbonyl compounds
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Raney Nickel is an effective reagent to achieve the chemoselective reduction of conjugated olefins in σ,β-unsaturated carbonyl compounds that also contain isolated double bonds. Its use is also compatible with a variety of other functional groups.
- Barrero, Alejandro F.,Alvarez-Manzaneda,Chahboun, Rachid,Meneses
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p. 1663 - 1666
(2007/10/03)
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- Zirconium-Catalyzed Oxidation of Primary Aliphatic Amines to Nitro Compounds with tert-Butyl Hydroperoxide
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Primary aliphatic amines are oxidized with tert-butyl hydroperoxide to the corresponding nitro compounds in 50-98% yield using Zr(Ot-Bu)4 as the catalyst. The CH-acidic nitro compounds are not epimerized under these reaction conditions.
- Krohn, Karsten,Kuepke, Jochen
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p. 679 - 682
(2007/10/03)
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- Synthesis of new 2-highly branched 5-nitro-imidazoles by BIS-SRN l methodology
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A versatile bis-SRN l methodology allows straightforward access to 2-highly branched 5-nitroimidazoles by reacting 3-chloro-2-chloromethyl-1-(1-methyl-5-nitroimidazol-2-yl)prop-1-ene with various nitronate anions.
- Vanelle, Patrice,Benakli, Kamel,Maldonado, Jose,Crozet, Michel P.
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p. 181 - 185
(2007/10/03)
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- Unusual kinetics of the reactions of alkanes and arenes with peroxynitrous acid: Synchronous reactions in the aqueous and gas phases under conditions of the kinetic distribution method
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Peroxynitrous acid HOONO oxidizes alkanes to give as major products alcohols and ketones, which are formed concurrently. The reaction selectivity depends on the volume ratio of the liquid (L) and gas (G) in the reactor, due to simultaneous proceeding of the reactions in the two phases. The substrate selectivity and the kinetic isotope effects are determined for reactions of a series of alkanes and arenes in the solution and in the gas phase. In both cases, the reactive species is the same and uncharged: presumably, it is the acid HOONO or its decomposition product, OONO radical. 1996 MAEe Cyrillic signΚ Hayκa/Interperiodica Publishing.
- Rudakov,Lobachev,Geletii,Balavoine
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p. 500 - 507
(2007/10/03)
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- Chromium Silicalite-2 (CrS-2): an Efficient Catalyst for the Direct Oxidation of Primary Amines to Nitro Compounds with TBHP
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A chromium-containing medium-pore molecular sieve (Si:Cr > 140:1) having MEL (CrS-2) topology efficiently catalyses the direct oxidation of various primary amines to the corresponding nitro compounds using 70percent tert-butyl hydroperoxide (TBHP) as the oxidant.
- Jayachandran, B.,Sasidharan, M.,Sudalai, A.,Ravindranathan, T.
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p. 1523 - 1524
(2007/10/02)
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