- Polystyrene stabilized iridium nanoparticles catalyzed chemo- and regio-selective semi-hydrogenation of nitroarenes to N-arylhydroxylamines
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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.
- Bhattacherjee, Dhananjay,Das, Pralay,Kumar, Ajay,Shaifali,Zyryanov, Grigory V.
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- Disperse dye intermediate preparation method
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The invention provides a disperse dye intermediate preparation method, which is characterized by utilizing m-dinitrobenzene as a raw material and obtaining a target product through amination, amidation and reduction reaction. In addition, the disperse dye intermediate preparation method disclosed by the invention enables waste residues generated in a reaction process to be recycled through a circular metal reduction method. Furthermore, the disperse dye intermediate preparation method disclosed by the invention has environmental friendliness and no pollution.
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Paragraph 0062; 0071; 0072
(2017/08/31)
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- Highly selective and controllable synthesis of arylhydroxylamines by the reduction of nitroarenes with an electron-withdrawing group using a new nitroreductase BaNTR1
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A new bacterial nitroreductase has been identified and used as a biocatalyst for the controllable reduction of a variety of nitroarenes with an electron-withdrawing group to the corresponding N-arylhydroxylamines under mild reaction conditions with excellent selectivity (>99%). This method therefore represents a green and efficient method for the synthesis of arylhydroxylamines.
- Nguyen-Tran, Hieu-Huy,Zheng, Gao-Wei,Qian, Xu-Hong,Xu, Jian-He
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supporting information
p. 2861 - 2864
(2014/03/21)
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- Selective reduction of nitroarenes to N-arylhydroxylamines by use of Zn in a CO2-H2O system, promoted by ultrasound
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The promoting effect of ultrasound on the selective reduction of nitroarenes to N-arylhydroxylamines by use of Zn in an environmentally benign CO2-H2O system has been demonstrated. The yield of N-phenylhydroxylamine reaches 95% when the reaction is carried out with a Zn-to-nitrobenzene molar ratio of 2.2 under ultrasound (40 kHz) at 25 °C and normal pressure of CO2 for 60 min. Application of ultrasound to the reaction has the advantages of higher yield of N-arylhydroxylamines, shorter reaction time, and consumption of less Zn. Springer Science+Business Media B.V. 2012.
- Liu, Shijuan,Wang, Yanhua,Yang, Xun,Jiang, Jingyang
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p. 2471 - 2478
(2013/02/25)
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- Carbon supported Pt colloid as effective catalyst for selective hydrogenation of nitroarenes to arylhydroxylamines
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The Pt colloid supported on carbon is an active and selective catalyst for the partial hydrogenation of nitroaromatics with electron-withdrawing substituents to the corresponding N-arylhydroxylamine, indicating an additive-free green catalytic approach fo
- Rong, Zeming,Du, Wenqiang,Wang, Yue,Lu, Lianhai
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supporting information; experimental part
p. 1559 - 1561
(2010/06/12)
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- Solvent hydrogen bonding and structural influences on the CrVI oxidation of anilines in aqueous acetic acid medium
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The oxidation of meta- and para-substituted anilines by CrVI oxidant, imidazolium fluorochromate (IFC), in aqueous acetic acid mixtures of varying compositions in the presence of p-toluenesulfonic acid (PTS) is first order in IFC and PTS. Michaelis-Menten type kinetics is observed with all of the anilines. The IFC oxidation of 15 meta- and para-substituted anilines at 299-322 K complies with the isokinetic relationship but not to any of the linear free energy relationships. The isokinetic temperature lies within the experimental range. The rate data failed to correlate with macroscopic solvent parameters such as relative permittivity, εr, and ionizing power, Y, correlation of rate data with Kamlet-Taft solvatochromic parameters (hydrogen bond donor acidity, α, hydrogen bond acceptor basicity, β, and dipolarity/polarizability, π*) is linear which suggests that the specific solute-solvent interactions play a dominating role in governing the reactivity.
- Bhuvaneshwari,Elango
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experimental part
p. 242 - 249
(2010/04/26)
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- The selective reduction of nitroarenes to N-arylhydroxylamines using Zn in a CO2/H2O system
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Nitroarenes are reduced to the corresponding N-arylhydroxylamines with high selectivity using Zn dust in a CO2/H2O system under mild conditions. The yield of N-phenylhydroxylamine from nitrobenzene is 88% when the reaction is carried out at 25 °C for 1.5 hours with a Zn to nitrobenzene molar ratio equal to 3 under 0.1 MPa CO2. Other nitroarenes, which contain reducible functionality other than a nitro group, are also reduced to the corresponding N-arylhydroxylamines with yield from 88% to 99%. The process fully removes the need to use NH4Cl and is environmentally benign. The Royal Society of Chemistry 2009.
- Liu, Shijuan,Wang, Yanhua,Jiang, Jingyang,Jin, Zilin
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experimental part
p. 1397 - 1400
(2010/05/17)
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- Effect of solvent on the rate of oxidation of substituted anilines with nicotinium dichromate in aqueous-acetic acid media
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Mechanistic studies on the oxidation of 15 para- and meta-substituted anilines by nicotinium dichromate in water-acetic acid medium of varying mole fractions have been performed. The reaction can be characterized by the experimental rate equation, -d[oxidizing agent]/dt = Kk [substrate] [HCrO 4-]/(1 + K [substrate]) The addition of p-toluenesulfonic acid enhances the reaction. The oxidation substituted anilines at 299-322 K complies with the isokinetic relationship but not to any of the linear free energy relationships, the isokinetic temperature lies within the experimental range. Correlation of rate data with Kamlet-Taft solvatochromic parameters (α, β, π*) suggests that the specific solute-solvent interactions play a major role in governing the reactivity.
- Bhuvaneshwari,Elango
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p. 999 - 1005
(2007/10/03)
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- Effect of substituents on the rate of oxidation of anilines with peroxomonosulfate monoanion (HOOSO3-) in aqueous acetonitrile: A mechanistic study
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Mechanistic studies on the oxidation of 18 meta-, para-, and ortho-substituted anilines (Ans) by HOOSO3- in aqueous acetonitrile medium have been performed. The reaction can be characterized by the experimental rate equation, -d[HSO5-]/dt = k[An][HSO5-] The addition of p-toluenesulfonic acid (TsOH) retards the reaction. The increase in the reactivity of anilines as the medium is made more aqueous is interpreted. The reaction is enhanced by electron-donating groups on the amine in the series consistent with the rate-limiting nucleophilic attack of the amine on the persulfate oxygen. The proposed mechanism involves the conversion of phenylhydroxylamine to nitrosobenzene in a fast step. The ESR study reveals the absence of free radicals in the reaction. Various attempts have been made to analyze the experimental rate constants in terms of LFER plots. Improved correlations are obtained with σ- values and the σ- form of the Yukawa-Tsuno equation.
- Meenakshisundaram, Subbiah,Selvaraju,Made Gowda,Rangappa, Kanchugarakoppal S.
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p. 649 - 657
(2007/10/03)
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- Ultrasonically activated reduction of substituted nitrobenzenes to corresponding N-arylhydroxylamines
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Arylhydroxylamines can be obtained by reduction of the corresponding nitroaromatic compounds. We report here an efficient preparation of arylhydroxylamines by a controlled reduction of nitro compounds using zinc metal and ammonium chloride under ultrasonic activation in very short reaction times.
- Ung, Stéphane,Falguières, Annie,Guy, Alain,Ferroud, Clotilde
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p. 5913 - 5917
(2007/10/03)
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- Mechanism and reactivity in perborate oxidation of anilines in acetic acid
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Perborate but not percarbonate in acetic acid generates peracetic acid on standing and the peracetic acid oxidation of anilines is fast. The oxidation with a fresh solution of perborate in acetic acid is smooth and second order but the specific oxidation rate increases with increasing [perborate]0 or [boric acid]. Perborate on dissolution affords hydrogen peroxide and a borate; the latter assists the former in the oxidation. The oxidation rates of anilines under identical conditions do not conform to any of the linear free energy relationships but the reaction rates of molecular anilines do. Perborate oxidation proceeds via two reaction paths but the overall oxidation rates of molecular anilines conform to structure reactivity relationships; the transition states do not differ significantly. Analysis of the oxidation rates of perborate and percarbonate reveals that while perborate oxidation is faster than percarbonate it is at least as selective as the latter.
- Karunakaran, Chockalingam,Kamalam, Ramasamy
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p. 2011 - 2018
(2007/10/03)
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- Electrophilic intermediate in the reaction of glutathione and nitrosoarenes
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A kinetic study is reported of the reaction of glutathione (γ-L-glutamyl-L-cysteinylglycine, GSH) with nine substituted nitrosobenzenes (3,4-Me2 4-Me, 3,5-Me2, 3-Me, parent, 3-MeO, 4-Cl, 3-Cl, 3-NO2). Previous workers have shown that this reaction proceeds in parallel pathways, producing the appropriate N-arylhydroxylamine and GSSG or a sulfinanilide adduct ArNHS(O)G; a rapid equilibrium addition to form a common intermediate, a semimercaptal ArN(OH)SG, has also been observed. In the present study, equilibrium constants for the formation of this intermediate from ArNO and GSH have been measured by a kinetic method, and the kinetic behavior of the slower additional reactions of the semimercaptal have been examined in detail. For experiments carried out at constant pH and buffer concentration, the decay of ArN(OH)SG follows the rate law k2GSH[GSH] + k2(rearr). A comparison with product ratios previously reported shows that the bimolecular term with GSH represents the process forming ArNHOH and GSSG, while the unimolecular term represents the rearrangement to the sulfmanilide. The former process is found to be proportional to [OH-] for solutions near neutrality, is not buffer catalyzed, and has a ρ value of +1.4. This suggests a mechanism in which glutathione anion GS- reacts at the sulfur of the adduct displacing ArN-(OH) as a leaving group. The rearrangement reaction follows σ+ with a ρ+ value of -3.5 and has a rate law containing a pH-independent term and terms for catalysis by H+ and the acid component of the buffer. An 18O tracer study shows that the S=O oxygen in the sulfmanilide is derived from solvent, not the original N=O group. A mechanism is proposed with rate-limiting N-O cleavage, either uncatalyzed involving direct heterolysis with OH- as a leaving group or catalyzed by acids with H2O as the leaving group. The species produced is a cationic intermediate ArN+SG, a nitrenium ion stabilized by both the aryl ring and the directly attached sulfur atom. Aryl-stabilized nitrenium ions are commonly encountered in Bamberger-like rearrangements of hydroxylamine derivatives. The sulfur atom of PhN(OH)SG is shown to provide an approximately 106 rate acceleration for N-O cleavage in a comparison with the Bamberger rearrangement of PhNHOH.
- Kazanis, Sophia,McClelland, Robert A.
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p. 3052 - 3059
(2007/10/02)
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- A facile synthesis of N-aryl-N-hydroxyformamides from N-arylhydroxylamines
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Several N-arylhydroxylamines (2) have been formylated for the first time with acetic formic anhydride to yield N-hydroxyformanilides (3) in better yields than hitherto reported.
- Ayyangar, N. R.,Brahme, K. C.,Shingare, M. S.,Srinivasan, K. V.
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p. 961 - 963
(2007/10/02)
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- RUBREDOXIN MODEL COMPLEX (Et4N) AS A CATALYST IN THE REDUCTION OF AROMATIC NITRO COMPOUNDS TO HYDROXYLAMINES
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(Et4N), the analogue of oxidized rubredoxin active sites, can catalyze the reduction of aromatic nitro compounds to N-aryl hydroxylamines by o-xylene-α,α'-dithiol.
- Yanada, Kazuo,Nagano, Tetsuo,Hirobe, Masaaki
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p. 5113 - 5116
(2007/10/02)
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