586-96-9Relevant articles and documents
An effective medium of H2O and low-pressure CO2 for the selective hydrogenation of aromatic nitro compounds to anilines
Meng, Xiangchun,Cheng, Haiyang,Fujita, Shin-Ichiro,Yu, Yancun,Zhao, Fengyu,Arai, Masahiko
, p. 570 - 572 (2011)
Chemoselective hydrogenation of water-insoluble aromatic nitro compounds can be achieved over Ni catalysts in a H2O-compressed CO2 system at 35-50 °C without using any environmentally harmful solvent. The effective CO2 pressure is much lower than the critical pressure of CO2. The hydrogenation of nitro group should be the rate-determining step. The Royal Society of Chemistry.
Dimeric assemblies of lanthanide-stabilised dilacunary Keggin tungstogermanates: A new class of catalysts for the selective oxidation of aniline
Trautwein, Guido,El Bakkali, Bouchra,Alca?iz-Monge, Juan,Artetxe, Be?at,Reinoso, Santiago,Gutiérrez-Zorrilla, Juan M.
, p. 110 - 117 (2015)
In this work we demonstrate the efficiency of some dimeric [Ln4(H2O)6(β-GeW10O38)2]12- anions composed of lanthanide-stabilised dilacunary Keggin tungstogermanate fragments (ββ-Ln4, Ln = Dy, Ho, Er, Tm) as heterogeneous catalysts for the organic phase oxidation of aniline with hydrogen peroxide. The results obtained evidence total conversion of aniline at room temperature, as well as full selectivity towards nitrosobenzene, and the catalysts are able to retain both their activity and selectivity after several runs. Peroxopolyoxometalate intermediaries have been identified as the catalytically active species during the aniline-to-nitrosobenzene oxidation process.
Fabrication of hybrid mesoporous TiO2-SiO2(Et) supported Ni nanoparticles: An efficient and air/water stable catalyst
Li, Wei,Cheng, Haiyang,Lin, Weiwei,Liang, Guanfeng,Zhang, Chao,Zhao, Fengyu
, p. 214 - 221 (2016)
We prepared a series of mesostructured Ni/TiO2-SiO2(Et) hybrid catalysts with highly dispersed Ni nanoparticles and incorporated ethane-bridged organosilica moieties. Ni/TiO2-SiO2(Et) showed high activity in the hydrogenation of nitrobenzene in water, and it could be recycled for several times with a constant activity and selectivity. It was confirmed that Ni/TiO2-SiO2(Et) catalyst is of hydrophobicity as the ethane-bridged organosilica fragments were incorporated into the mesoporous framework, and so the Ni active species was protected without contacting with water to form the inactive Ni species. In particularly, the Ni/TiO2-SiO2(Et) catalyst was air-stable, it could remain good activity after being exposed to air for a week. Accordingly, this work developed a kind of hydrophobic Ni catalyst with high stability to water and air, which is expected to have a wide application in the hydrogenation reactions.
Radical Cations of Nitroso Derivatives. A Radiation-chemical and Electron Spin Resonance Study
Chandra, Harish,Keeble, David J.,Symons, Martyn C. R.
, p. 609 - 616 (1988)
Exposure of dilute solutions containing nitrosobenzene in trichlorofluoromethane to 60Co γ-rays at 77 K gave the corresponding radical cation, characterised by e.s.r. spectroscopy.The results confirm the interpretation of liquid-phase data assigned to this cation, which showed that loss is from an in-plane ?-orbital localised on nitrogen and oxygen, rather than from the aromatic ?-system.However, solutions containing the t-butyl derivative in equilibrium with its dimer, (Me3CNO)2, gave primarily the dimer cation, (Me3CNO)2+, with possible traces of the monomer cation.The e.s.r. data for the latter resemble those for the nitrosobenzene cation, whereas results for the dimer cation suggest that loss is from a ?-type orbital with very low spin density on the two equivalent nitrogen atoms.
Continuous proline catalysis via leaching of solid proline
Opalka, Suzanne M.,Longstreet, Ashley R.,Tyler McQuade
, p. 1671 - 1679 (2011)
Herein, we demonstrate that a homogeneous catalyst can be prepared continuously via reaction with a packed-bed of a catalyst precursor. Specifically, we perform continuous proline catalyzed α-aminoxylations using a packed-bed of L-proline. The system relies on a multistep sequence in which an aldehyde and thiourea additive are passed through a column of solid proline, presumably forming a soluble oxazolidinone intermediate. This transports a catalytic amount of proline from the packed-bed into the reactor coil for subsequent combination with a solution of nitrosobenzene, affording the desired optically active α-aminooxy alcohol after reduction. To our knowledge, this is the first example in which a homogeneous catalyst is produced continuously using a packedbed. We predict that the method will not only be useful for other L-proline catalyzed reactions, but we also foresee that it could be used to produce other catalytic species in flow.
The Active Sites of Manganese- and Cobalt-Containing Catalysts in the Selective Gas Phase Reduction of Nitrobenzene
Maltha, A.,Kist, H. F.,Brunet, B.,Ziolkowski, J.,Onishi, H.,et al.
, p. 356 - 363 (1994)
The active sites of the spinels Mn3O4 and Co3O4 in the selective reduction of nitrobenzene to nitrosobenzene have been investigated, by total and partial substitution of Mnn+ (Con+) ions in tetrahedral position and/or Mnn+ (Con+) ions in octahedral position by redox-inactive ions.Investigation of the catalytic activities of the totally substituted manganese spinel ZnMn2O4 and that of the totally substituted cobalt spinels CoAl2O4 and ZnCo2O4 showed that the manganese and cobalt ions in octahedral position were responsible for the activity of the reaction.MnAl2O4, however, also showed some activity for the selective reduction of nitrobenzene, which should be due to surface enrichment and/or oxidative transfer of manganese from tetrahedral sites to octahedral sites.XRD results of the partially substituted spinels MnxZn1-xAl2O4 showed that was a linear correlation between the manganese concentration expressed by x and the lattice constant.Morever, each sample showed segregation of Al2O3; again there was a linear correlation between x in certain series of MnxZn1-xAl2O4 and the amount of free Al2O3.This points to an oxidative transfer of manganese from tetrahedral sites to octahedral sites.XPS showed that the concentration of manganese in the surface layers corresponded roughly to the value x, but the concentration of zinc in the surface layers was much smaller than expected.The catalytic activities of the MnxZn1-xAl2O4 series of catalysts are larger than would be expected from the result on ZnMnO4 and ZnCo2O4.
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Derovane et al.
, p. 196,200 (1974)
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Continuous Flow Synthesis of Azoxybenzenes by Reductive Dimerization of Nitrosobenzenes with Gel-Bound Catalysts
Schmiegel, Carsten J.,Berg, Patrik,Obst, Franziska,Schoch, Roland,Appelhans, Dietmar,Kuckling, Dirk
, p. 1628 - 1636 (2021/03/15)
In the search for a new synthetic pathway for azoxybenzenes with different substitution patterns, an approach using a microfluidic reactor with gel-bound proline organocatalysts under continuous flow is presented. Herein the formation of differently substituted azoxybezenes by reductive dimerization of nitrosobenzenes within minutes at mild conditions in good to almost quantitative yields is described. The conversion within the microfluidic reactor is analyzed and used for optimizing and validating different parameters. The effects of the different functionalities on conversion, yield, and reaction times are analyzed in detail by NMR. The applicability of this reductive dimerization is demonstrated for a wide range of differently substituted nitrosobenzenes. The effects of these different functionalities on the structure of the obtained azoxyarenes are analyzed in detail by NMR and single-crystal X-ray diffraction. Based on these results, the turnover number and the turnover frequency were determined.
"Photo-Rimonabant": Synthesis and Biological Evaluation of Novel Photoswitchable Molecules Derived from Rimonabant Lead to a Highly Selective and Nanomolar " Cis-On" CB1R Antagonist
Rodríguez-Soacha, Diego A.,Fender, Julia,Ramírez, Yesid A.,Collado, Juan Antonio,Mu?oz, Eduardo,Maitra, Rangan,Sotriffer, Christoph,Lorenz, Kristina,Decker, Michael
, p. 1632 - 1647 (2021/05/10)
Human cannabinoid receptor type 1 (hCB1R) plays important roles in the regulation of appetite and development of addictive behaviors. Herein, we describe the design, synthesis, photocharacterization, molecular docking, and in vitro characterization of "photo-rimonabant", i.e., azo-derivatives of the selective hCB1R antagonist SR1411716A (rimonabant). By applying azo-extension strategies, we yielded compound 16a, which shows marked affinity for CB1R (Ki (cis form) = 29 nM), whose potency increases by illumination with ultraviolet light (CB1R Kitrans/cis ratio = 15.3). Through radioligand binding, calcium mobilization, and cell luminescence assays, we established that 16a is highly selective for hCB1R over hCB2R. These selective antagonists can be valuable molecular tools for optical modulation of CBRs and better understanding of disorders associated with the endocannabinoid system.
