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All total 150 Articles be foundMetal Ion-Catalyzed Reduction of Substituted Nitrosobenzenes by 1-Benzyl-3,5-bis(1-pyrrolidinylcarbonyl)-1,4-dihydropyridine in Acetonitrile
Awano, Hiroshi,Takemoto, Kazuo,Ohya, Hirohisa,Tomio, Minaki,Tamagaki, Seizo,Tagaki, Waichiro
, p. 1887 - 1894 (1987)
Metal ion catalyzed reduction of substituted nitrosobenzenes by 1-benzyl-3,5-bis(1-pyrrolidinylcarbonyl)-1,4-dihydropyridine (BPDH) in acetonitrile has been studied for seven bivalent metal ions.The reduction of N-methylacridinium salt (MA) has also been examined.In the former cases, it was found that the metal ions catalyze the reduction by forming a 1 : 1 complex with BPDH according to a Michaelis-Menten type saturation kinetics which allowed to derive the association constants, KM, for the complexation and the second-order rate constants, k2, for the reduction.A linear relationship was found between log k2 and the ionization potentials of metal ions with a positive slope.A linear Hammett relationship was also observed between log k2 and the Hammett ? constants with a positive p value for three metal ions.These results suggest that a bivalent metal ion is sandwiched between the BPDH and the substrate and acts as a Lewis acid to stabilize the incipient N-oxide anion of the substrate which is formed by hydride transfer in the transition state.In the cases of MA, all metal ions inhibited the reduction.Repulsion between the positive charges of the metal ion-BPDH complex and the substrate salt appears to be prevailing.
Rapid and convenient conversion of nitroarenes to anilines under microwave conditions using nonprecious metals in mildly acidic medium
Keenan, Corey S.,Murphree, S. Shaun
, p. 1085 - 1089 (2017)
Nitroarenes are reduced to the corresponding aniline derivatives using iron or zinc under mild conditions under microwave heating conditions. Mild acidity is provided by ammonium chloride in an aqueous methanol medium. The conditions are tolerant to other functional groups, with the exception of bromoalkyl derivatives, which yield complex reaction mixtures; otherwise, yields are generally quite high (80–99%).
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Patrick et al.
, p. 1758 (1974)
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A study on the selective hydrogenation of nitroaromatics to N-arylhydroxylamines using a supported Pt nanoparticle catalyst
Boymans, Evert H.,Witte,Vogt
, p. 176 - 183 (2015)
A supported Pt nanoparticle-based catalyst was used in the chemoselective hydrogenation of nitroarenes to N-arylhydroxylamines (N-AHA). Optimization of NB hydrogenation conditions showed that substantially higher N-PHA yields can be obtained at low temperature. Especially, the influence of an increased hydrogen pressure on selectivity is remarkable. Maximum yields increase from 55% N-PHA at 4 bar H2 to 80% at 23 bar H2 in ethanol. Further optimization led to the use of small amounts of amine additive, TMEDA, with 50 bar H2 raising the maximum yield to 97% N-PHA. The decreased N-PHA hydrogenation rate at high H2 pressure and the presence of TMEDA allow for selective transformation of a range of other nitroarenes containing electron-withdrawing and -donating (reducible) functional groups to their N-AHAs in excellent (more than 90%) yields.
MECHANISM OF CATALYTIC HYDROGENATION OF NITROBENZENE IN AN APROTIC MEDIUM IN THE PRESENCE OF QUINONES
Kushch, S. D.,Izakovich, E. N.,Khidekel', M. L.,Strelets, V. V.
, p. 1201 - 1206 (1981)
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Model molecules with oxygenated groups catalyze the reduction of nitrobenzene: Insight into carbocatalysis
Wu, Shuchang,Wen, Guodong,Liu, Xiumei,Zhong, Bingwei,Su, Dang Sheng
, p. 1558 - 1561 (2014)
The role of different oxygen functional groups on a carbon catalyst was studied in the reduction of nitrobenzene by using a series of model molecules. The carbonyl and hydroxyl groups played important roles, which may be ascribed to their ability to activate hydrazine. In comparison, the ester, ether, and lactone groups seemed to be inactive, whereas the carboxylic group had a negative effect. The reaction occurred most likely through a direct route, during which nitrosobenzene may be converted directly into aniline. Modeling carbon: Thanks to model molecules, the carbon-catalyzed reduction of nitrobenzene is mimicked. The role of different oxygen functional groups on a carbon catalyst is studied, and the carbonyl and hydroxyl groups seem to be the most important moieties, which may be ascribed to their ability to activate hydrazine. The reaction occurs more likely through a direct route, during which nitrosobenzene may also be converted directly into aniline.
SELECTIVE HYDROGENATION OF NITROBENZENE IN APROTIC MEDIA
Kushch, S. D.
, p. 33 - 36 (1991)
The kinetics of hydrogenation of nitrobenzene in aprotic media was studied, and a scheme of the mechanism and a kinetic equation, corresponding to it, for the initial reaction rate are proposed.High selectivity with respect to N-phenylhydroxylamine is apparently due to the aprotic nature and donor properties of the solvent and also to the functioning of the catalyst as a unique "hydrogen electrode."
Synthesis of N-arylhydroxylamines by antimony-catalyzed reduction of nitroarenes
Ren, Pingda,Dong, Tingwei,Wu, Shihui
, p. 1547 - 1552 (1997)
Metallic antimony catalyzes the reduction of aromatic nitro compounds to the corresponding N-arylhydroxylamines in good yields with NaBH4 under mild conditions. The azoxybenzenes from autoxidation of N-arylhydroxylamines were also obtained in basic conditions.
Acid-catalysed Multi-electron Reduction of Nitrobenzene Derivatives by a Dihydronicotinamide Adenine Dinucleotide (NADH) Model Compound, 9,10-Dihydro-10-methylacridine
Fukuzumi, Shunichi,Chiba, Makoto,Tanaka, Toshio
, p. 941 - 943 (1989)
Acid-catalysed multi-electron reduction of nitrobenzene derivatives by a dihydronicotinamide adenine dinucleotide (NADH) model compound proceeds efficiently under mild conditions in the presence of perchloric acid in acetonitrile.
Magnetically Recyclable Catalytic Carbon Nanoreactors
Aygün, Mehtap,Chamberlain, Thomas W.,Gimenez-Lopez, Maria del Carmen,Khlobystov, Andrei N.
, (2018)
Multifunctional nanoreactors are assembled using hollow graphitized carbon nanofibers (GNFs) combined with nanocatalysts (Pd or Pt) and magnetic nanoparticles. The latter are introduced in the form of carbon-coated cobalt nanomagnets (Co@Cn) adsorbed on GNF, or formed directly on GNF from ferrocene yielding carbon-coated iron nanomagnets (Fe@Cn). High-resolution transmission electron microscopy demonstrates that Co@Cn and Fe@Cn are attached effectively to the GNFs, and the loading of nanomagnets required for separation of the nanoreactors from the solution with an external magnetic field is determined using UV–vis spectroscopy. Magnetically functionalized GNFs combined with palladium or platinum nanoparticles result in catalytically active magnetically separable nanoreactors. Applied to the reduction of nitrobenzene the multifunctional nanoreactors demonstrate high activity and excellent durability, while their magnetic recovery enables significant improvement in the reuse of the nanocatalyst over five reaction cycles (catalyst loss 0.5 wt%) as compared to the catalyst recovery by filtration (catalyst loss 10 wt%).
Reduction of nitroarenes to N-arylhydroxylamines with KBH4/BiCl3 system
Ren, Ping-Da,Pan, Xin-Wei,Jin, Qi-Hui,Yao, Zi-Peng
, p. 3497 - 3503 (1997)
Aromatic nitro compounds could be selectively and rapidly reduced to the corresponding N-arylhydroxylamines in good yields with KBH4/BiCl3 system under mild conditions.
Preparation of para -Aminophenol from Nitrobenzene through Bamberger Rearrangement Using a Mixture of Heterogeneous and Homogeneous Acid Catalysts
Joncour, Roxan,Ferreira, Amadéo,Duguet, Nicolas,Lemaire, Marc
, p. 312 - 320 (2018)
The direct preparation of para-aminophenol (PAP) from nitrobenzene (NB) through Bamberger rearrangement was studied in a biphasic medium using a mixture of NbOx/SiO2 and H2SO4 as an acid catalyst. After optimization of the reaction parameters, PAP was obtained with 85-88% selectivity that represents a 10% selectivity improvement compared to sulfuric acid alone. The optimized conditions were implemented in a scale-up reaction, and PAP was isolated in 84% yield (based on the recovered starting material) with 97% HPLC purity. Overall, this process requires less sulfuric acid than the traditional process, leading to a drastic reduction of the saline waste.
Selective synthesis of N-aryl hydroxylamines by the hydrogenation of nitroaromatics using supported platinum catalysts
Takenaka, Yasumasa,Kiyosu, Takahiro,Choi, Jun-Chul,Sakakura, Toshiyasu,Yasuda, Hiroyuki
, p. 1385 - 1390 (2009)
Various substituted nitroaromatics were successfully hydrogenated to the corresponding N-aryl hydroxylamines in excellent yields (up to 99%) using supported platinum catalysts such as Pt/SiO2 under a hydrogen atmosphere (1 bar) at room temperature. The key to the fast and highly selective formation of hydroxylamines is the addition of small amounts of amines such as triethylamine and dimethyl sulfoxide; amines promote the conversion of nitroaromatics, while dimethyl sulfoxide inhibits further hydrogenation of hydroxylamines to anilines. The promotive effect depends on which type of amine and primary amine was most effective. The hydrogenation efficiently proceeded in common organic solvents, including isopropanol, diethyl ether, and acetone. This methodology should extend the application range of conventional solid catalysts to fine chemicals synthesis. The Royal Society of Chemistry 2009.
Environmentally friendly hydrogenation of nitrobenzene to p-aminophenol using heterogeneous catalysts
Deshpande, Abhay,Figueras,Lakshmi Kantam,Jeeva Ratnam,Sudarshan Reddy,Sekhar
, p. 250 - 256 (2010)
Nitrobenzene was converted to p-aminophenol at 353 K, using water as solvent and a bi-functional catalyst composed of a mechanical mixture of supported Pt catalyst with zirconium sulphate calcined at 773-923 K. The performance of this system is independent of the support used for Pt, and various supports, such as pure or sulphated zirconia and titania, carbon, MgLa mixed oxide, give similar results. At low Pt content, the reaction rate is first order relative to nitrobenzene, and the slow step is the partial hydrogenation of nitrobenzene to phenylhydroxylamine, which requires only minute amounts of Pt. At higher Pt loadings, the rate of hydrogenation of nitrobenzene to phenylhydroxylamine and consequently to aniline takes over that of the acid-catalysed Bamberger rearrangement of phenylhydroxylamine to p-aminophenol. The selectivity of this step depends critically on the solid acid: strong acids such as sulphated zirconia or zeolites give poor selectivities because they tend to decompose the hydroxylamine intermediate. This process does not require sulphuric acid or additives such as DMSO or alkylsulphides, thereby simplifying the downstream processing.
Highly Selective and Solvent-Dependent Reduction of Nitrobenzene to N-Phenylhydroxylamine, Azoxybenzene, and Aniline Catalyzed by Phosphino-Modified Polymer Immobilized Ionic Liquid-Stabilized AuNPs
Doherty, Simon,Knight, Julian G.,Backhouse, Tom,Summers, Ryan J.,Abood, Einas,Simpson, William,Paget, William,Bourne, Richard A.,Chamberlain, Thomas W.,Stones, Rebecca,Lovelock, Kevin R. J.,Seymour, Jake M.,Isaacs, Mark A.,Hardacre, Christopher,Daly, Helen,Rees, Nicholas H.
, p. 4777 - 4791 (2019)
Gold nanoparticles stabilized by phosphine-decorated polymer immobilized ionic liquids (AuNP@PPh2-PIILP) is an extremely efficient multiproduct selective catalyst for the sodium borohydride-mediated reduction of nitrobenzene giving N-phenylhydroxylamine, azoxybenzene, or aniline as the sole product under mild conditions and a very low catalyst loading. The use of a single nanoparticle-based catalyst for the partial and complete reduction of nitroarenes to afford three different products with exceptionally high selectivities is unprecedented. Under optimum conditions, thermodynamically unfavorable N-phenylhydroxylamine can be obtained as the sole product in near quantitative yield in water, whereas a change in reaction solvent to ethanol results in a dramatic switch in selectivity to afford azoxybenzene. The key to obtaining such a high selectivity for N-phenylhydroxylamine is the use of a nitrogen atmosphere at room temperature as reactions conducted under an inert atmosphere occur via the direct pathway and are essentially irreversible, while reactions in air afford significant amounts of azoxy-based products by virtue of competing condensation due to reversible formation of N-phenylhydroxylamine. Ultimately, aniline can also be obtained quantitatively and selectively by adjusting the reaction temperature and time accordingly. Introduction of PEG onto the polyionic liquid resulted in a dramatic improvement in catalyst efficiency such that N-phenylhydroxylamine could be obtained with a turnover number (TON) of 100000 (turnover frequency (TOF) of 73000 h-1, with >99% selectivity), azoxybenzene with a TON of 55000 (TOF of 37000 h-1 with 100% selectivity), and aniline with a TON of 500000 (TOF of 62500 h-1, with 100% selectivity). As the combination of ionic liquid and phosphine is required to achieve high activity and selectivity, further studies are currently underway to explore whether interfacial electronic effects influence adsorption and thereby selectivity and whether channeling of the substrate by the electrostatic potential around the AuNPs is responsible for the high activity. This is the first report of a AuNP-based system that can selectively reduce nitroarenes to either of two synthetically important intermediates as well as aniline and, in this regard, is an exciting discovery that will form the basis to develop a continuous flow process enabling facile scale-up.
Dual catalysis with an IrIII-AuI heterodimetallic complex: Reduction of nitroarenes by transfer hydrogenation using primary alcohols
Sabater, Sara,Mata, Jose A.,Peris, Eduardo
, p. 6380 - 6385 (2012)
A triazolyl-di-ylidene ligand has been used for the preparation of a homodimetallic complex of gold, and a heterodimetallic compound of gold and iridium. Both complexes have been fully characterized and their molecular structures have been determined by means of X-ray diffraction. The catalytic properties of these two complexes have been evaluated in the reduction of nitroarenes by transfer hydrogenation using primary alcohols. The two complexes afford different reaction products; whereas the AuI-AuI catalyst yields a hydroxylamine, the IrIII-AuI complex facilitates the formation of an imine. Copyright
Polystyrene stabilized iridium nanoparticles catalyzed chemo- and regio-selective semi-hydrogenation of nitroarenes to N-arylhydroxylamines
Bhattacherjee, Dhananjay,Das, Pralay,Kumar, Ajay,Shaifali,Zyryanov, Grigory V.
, (2021)
Polystyrene stabilized Iridium (Ir@PS) nanoparticles (NPs) as a heterogeneous catalyst have been developed and characterized by IR, UV–Vis, SEM, TEM, EDX and XRD studies. The prepared Ir@PS catalyst showed excellent reactivity for chemo- and regio-selective controlled-hydrogenation of functionalized nitroarenes to corresponding N-arylhydroxylamine using hydrazine hydrate as reducing source and environmentally benign polyethylene glycol (PEG-400) as green solvent. The present methodology was applied for vast substrate scope and found to be compatible with wide range of reducible functional groups. The reaction performed at 85 °C or ambient temperature and completed within 5–80 minutes. The catalyst can easily be filtered out from reaction mixture and reusable.
Water Exclusion Reaction in Aqueous Media: Nitrone Formation and Cycloaddition in a Single Pot
Chatterjee, Amrita,Maiti, Dilip Kumar,Bhattacharya, Pranab Kumar
, p. 3967 - 3969 (2003)
(Equation Presented) The formation of nitrone (a water exclusion reaction) in aqueous media using surfactant and subsequent cycloaddition in the same pot, a new example of green chemistry, is reported. The control of regioselectivity favors the formation
Synthesis of N-Arylhydroxylamines by Tellurium-Catalyzed Reduction of Aromatic Nitro Compounds
Uchida, Shuji,Yanada, Kazuo,Yamaguchi, Hiromi,Meguri, Haruo
, p. 1069 - 1070 (1986)
p-Substituted nitrobenzenes were readily reduced with sodium borohydride and a catalytic amount of tellurium to give the corresponding hydroxylamines in good yields.
Pulse Radiolysis of Nitrobenzene in Aqueous Solutions Containing Colloidal Platinum
Nahor, Gad S.,Rabani, Joseph
, p. 4541 - 4546 (1985)
The pulse radiolysis of nitrobenzene (NB) in aqueous solutions containing 2-propanol in the presence of colloidal Pt has been studied.The NB- anion decays away by a single first-order process.The rate of decay is also first order in colloidal platinum (Ptc).The rate depends on the pH of the solutions.At relatively high pHs, hydrogen reduces NB and this reaction is mediated by the Ptc.Irreversible redox processes which produce nitrosobenzene and phenylhydroxylamine also take place, competing effectively with hydrogen formation.
Exploring Opportunities for Platinum Nanoparticles Encapsulated in Porous Liquids as Hydrogenation Catalysts
Hemming, Ellen B.,Masters, Anthony F.,Maschmeyer, Thomas
, p. 7059 - 7064 (2020)
The unusual combination of characteristics observed for porous liquids, which are typically associated with either porous solids or liquids, has led to considerable interest in this new class of materials. However, these porous liquids have so far only been investigated for their ability to separate and store gases. Herein, the catalytic capability of Pt nanoparticles encapsulated within a Type I porous liquid (Pt@HS-SiO2 PL) is explored for the hydrogenation of several alkenes and nitroarenes under mild conditions (T=40 °C, PH2=1 atm). The different intermediates in the porous liquid synthesis (i.e., the initial Pt@HS-SiO2, the organosilane-functionalized intermediate, and the final porous liquid) are employed as catalysts in order to understand the effect of each component of the porous liquid on the catalysis. For the hydrogenation of 1-decene, the Pt@HS-SiO2 PL catalyst in ethanol has the fastest reaction rate if normalized with respect to the concentration of Pt. The reaction rate slows if the reaction is completed in a “neat” porous liquid system, probably because of the high viscosity of the system. These systems may find application in cascade reactions, in particular, for those with mutually incompatible catalysts.
A Modified System for the Synthesis of Enantioenriched N-Arylamines through Copper-Catalyzed Hydroamination
Ichikawa, Saki,Zhu, Shaolin,Buchwald, Stephen L.
, p. 8714 - 8718 (2018)
Despite significant recent progress in copper-catalyzed enantioselective hydroamination chemistry, the synthesis of chiral N-arylamines, which are frequently found in natural products and pharmaceuticals, has not been realized. Initial experiments with N-arylhydroxylamine ester electrophiles were unsuccessful and, instead, their reduction in the presence of copper hydride (CuH) catalysts was observed. Herein, we report key modifications to our previously reported hydroamination methods that lead to broadly applicable conditions for the enantioselective net addition of secondary anilines across the double bond of styrenes, 1,1-disubstituted olefins, and terminal alkenes. NMR studies suggest that suppression of the undesired reduction pathway is the basis for the dramatic improvements in yield under the reported method.
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Lapworth,Pearson
, p. 765 (1921)
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Application of Al2O3/AlNbO4 in the oxidation of aniline to azoxybenzene
Batalha, Daniel C.,Luz, Sulusmon C.,Taylor, Jason G.,Fajardo, Humberto V.,Noremberg, Bruno S.,Cherubin, Igor J. S.,Silva, Ricardo M.,Gon?alves, Margarete R. F.,Bergmann, Carlos P.,Valentini, Antoninho,Carre?o, Neftalí L. V.
, p. 543 - 553 (2020)
Al2O3/AlNbO4 powder was fabricated by a facile high-energy milling process. The precursor materials, Al2O3 and Nb2O5, are readily available and have very attractive properties. Moreover, the catalytic activity of the sample in the liquid phase oxidation of aniline (OA) in the presence of hydrogen peroxide as oxidant was evaluated. The catalyst was found to be highly efficient and selective in the oxidation of aniline to azoxybenzene under mild conditions. When mixed with 28% AlNbO4 the alumina-based catalyst achieved high conversion and selectivity and very similar to the pure Nb2O5.
Selective conversion of nitroarenes using a carbon nanotube-ruthenium nanohybrid
Jawale, Dhanaji V.,Gravel, Edmond,Boudet, Caroline,Shah, Nimesh,Geertsen, Valérie,Li, Haiyan,Namboothiri, Irishi N. N.,Doris, Eric
, p. 1739 - 1742 (2015)
Ruthenium nanoparticles were assembled on carbon nanotubes and the resulting nanohybrid was used in the hydrazine-mediated catalytic hydrogenation of various nitroarenes, at room temperature. Depending on the solvent, a selective transformation occurred, giving either access to the corresponding aniline or hydroxylamine derivative.
Solvent-free synthesis of nitrone-containing template as a chemosensor for selective detection of Cu(II) in water
Angolini, Célio F. F.,Bartoloni, Fernando H.,Carneiro, Leonardo M.,Keppler, Artur F.
supporting information, (2021/10/30)
A state-of-the-art method was developed for repurposing nitrone-containing compounds in the chemosensory field, the ability of the designed molecules to chelate metal cations was evaluated, and their unprecedented solubility in water was confirmed. A faci
Selective Photoinduced Reduction of Nitroarenes to N-Arylhydroxylamines
Kallitsakis, Michael G.,Ioannou, Dimitris I.,Terzidis, Michael A.,Kostakis, George E.,Lykakis, Ioannis N.
supporting information, p. 4339 - 4343 (2020/06/08)
We report the selective photoinduced reduction of nitroarenes to N-arylhydroxylamines. The present methodology facilitates this transformation in the absence of catalyst or additives and uses only light and methylhydrazine. This noncatalytic photoinduced transformation proceeds with a broad scope, excellent functional-group tolerance, and high yields. The potential of this protocol reflects on the selective and straightforward conversion of two general antibiotics, azomycin and chloramphenicol, to the bioactive hydroxylamine species.
