- Synthesis of C 14 labeled pentachlorobenzene
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The preparation of pentachlorobenzene-14C from pentachloronitrobenzene via pentachloroaniline for metabolic studies in animals is described. The overall radiochemical yield, after purification, was 68% at a specific activity of 5 mCi/mmol. The chemical purity of 99% was established.
- Mueller,Attar,Kurth,Bieniek
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- Cyclic (Alkyl)(amino)carbene Ligand-Promoted Nitro Deoxygenative Hydroboration with Chromium Catalysis: Scope, Mechanism, and Applications
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Transition metal catalysis that utilizes N-heterocyclic carbenes as noninnocent ligands in promoting transformations has not been well studied. We report here a cyclic (alkyl)(amino)carbene (CAAC) ligand-promoted nitro deoxygenative hydroboration with cost-effective chromium catalysis. Using 1 mol % of CAAC-Cr precatalyst, the addition of HBpin to nitro scaffolds leads to deoxygenation, allowing for the retention of various reducible functionalities and the compatibility of sensitive groups toward hydroboration, thereby providing a mild, chemoselective, and facile strategy to form anilines, as well as heteroaryl and aliphatic amine derivatives, with broad scope and particularly high turnover numbers (up to 1.8 × 106). Mechanistic studies, based on theoretical calculations, indicate that the CAAC ligand plays an important role in promoting polarity reversal of hydride of HBpin; it serves as an H-shuttle to facilitate deoxygenative hydroboration. The preparation of several commercially available pharmaceuticals by means of this strategy highlights its potential application in medicinal chemistry.
- Zhao, Lixing,Hu, Chenyang,Cong, Xuefeng,Deng, Gongda,Liu, Liu Leo,Luo, Meiming,Zeng, Xiaoming
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supporting information
p. 1618 - 1629
(2021/01/25)
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- Development and Application of Efficient Ag-based Hydrogenation Catalysts Prepared from Rice Husk Waste
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The development of strategies for the sustainable management and valorization of agricultural waste is of outmost importance. With this in mind, we report the use of rice husk (RH) as feedstock for the preparation of heterogeneous catalysts for hydrogenation reactions. The catalysts were prepared by impregnating the milled RH with a silver nitrate solution followed by carbothermal reduction. The composition and morphology of the prepared catalysts were fully assessed by IR, AAS, ICP-MS, XPS, XRD and STEM techniques. This novel bio-genic silver-based catalysts showed excellent activity and remarkable selectivity in the hydrogenation of nitro groups in both aromatic and aliphatic substrates, even in the presence of reactive functionalities like halogens, carbonyls, borate esters or nitriles. Recycling experiments showed that the catalysts can be easily recovered and reused multiple times without significant drop in performance and without requiring re-activation.
- Unglaube, Felix,Kreyenschulte, Carsten Robert,Mejía, Esteban
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p. 2583 - 2591
(2021/04/09)
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- Production process 3,5-dichloroaniline (by machine translation)
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The production process 3,5 - of,dichloroaniline in the non-protonic polar solvent generates,dichloroaniline, under the action of a certain ratio, DEG C, pressure, time to separate,dichloroaniline; from the ammonium chloride, aprotic polar solvent, thereby greatly reducing the raw material cost; and having the advantages 3,5 - of easily available, reaction steps and suitability for industrial production with hexachlorobenzene as main raw materials. 3,5 - The method has the advantages of simple process, and easy reaction . The present invention provides a, method for industrially producing, hexachloroaniline, by, using hexachlorobenzene as a main, raw material. (by machine translation)
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Page/Page column 4-5
(2020/04/22)
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- Chemoselective Hydrogenation of Nitroarenes Catalyzed by Molybdenum Sulphide Clusters
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Herein, we describe an atom efficient and general protocol for the chemoselective hydrogenation of nitroarenes to anilines catalyzed by well-defined diimino and diamino cubane-type Mo3S4 clusters. The novel diimino [Mo3S4Cl3(dnbpy)3]+ ([5]+) (dnbpy=4,4′-dinonyl-2,2′-dipyridyl, L1) trinuclear complex was synthesized in high yields by simple ligand substitution reactions starting from the thiourea (tu) [Mo3S4(tu)8(H2O)]Cl4?4 H2O (3) precursor. This strategy has also been successfully adapted for the isolation of the diamino [Mo3S4Cl3(dmen)3](BF4) ([6](BF4)), (dmen=N,N′-dimethylethylenediamine) salt. Applying these catalysts, high selectivity in the hydrogenation of functionalized nitroarenes has been accomplished. Over thirty anilines bearing synthetically functional groups have been synthesized in 70 to 99 % yield. Notably, the integrity of the cluster core is preserved during catalysis. Based on kinetic studies on the hydrogenation of nitrobenzene and other potential reaction intermediates, the direct reduction to aniline is the preferential route.
- Pedrajas, Elena,Sorribes, Iván,Gushchin, Artem L.,Laricheva, Yuliya A.,Junge, Kathrin,Beller, Matthias,Llusar, Rosa
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p. 1128 - 1134
(2017/03/27)
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- Highly selective transfer hydrogenation of functionalised nitroarenes using cobalt-based nanocatalysts
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Anilines are important feedstock for the synthesis of a variety of chemicals such as dyes, pigments, pharmaceuticals and agrochemicals. The chemoselective catalytic reduction of nitro compounds represents the most important and prevalent process for the manufacture of functionalized anilines. Consequently, the development of selective catalysts for the reduction of nitro compounds in the presence of other reducible groups is a major challenge and is crucial. In this regard, herein we show that the cobalt oxide (Co3O4-NGr@C) based nano-materials, prepared by the pyrolysis of cobalt-phenanthroline complexes on carbon constitute highly selective catalysts for the transfer hydrogenation of nitroarenes to anilines using formic acid as a hydrogen source. Applying these catalysts, a series of structurally diverse and functionalized nitroarenes have been reduced to anilines with unprecedented chemo-selectivity tolerating halides, olefins, aldehyde, ketone, ester, amide and nitrile functionalities.
- Jagadeesh, Rajenahally V.,Banerjee, Debasis,Arockiam, Percia Beatrice,Junge, Henrik,Junge, Kathrin,Pohl, Marga-Martina,Radnik, J?rg,Brückner, Angelika,Beller, Matthias
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supporting information
p. 898 - 902
(2015/03/04)
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- Nitrogen-doped graphene-activated iron-oxide-based nanocatalysts for selective transfer hydrogenation of nitroarenes
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Nanoscaled iron oxides on carbon were modified with nitrogen-doped graphene (NGr) and found to be excellent catalysts for the chemoselective transfer hydrogenation of nitroarenes to anilines. Under standard reaction conditions, a variety of functionalized and structurally diverse anilines, which serve as key building blocks and central intermediates for fine and bulk chemicals, were synthesized in good to excellent yields.
- Jagadeesh, Rajenahally V.,Natte, Kishore,Junge, Henrik,Beller, Matthias
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p. 1526 - 1529
(2015/03/14)
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- Nanoscale Fe2O3-based catalysts for selective hydrogenation of nitroarenes to anilines
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Production of anilines - key intermediates for the fine chemical, agrochemical, and pharmaceutical industries - relies on precious metal catalysts that selectively hydrogenate aryl nitro groups in the presence of other easily reducible functionalities. Herein, we report convenient and stable iron oxide (Fe2O3) - based catalysts as a more earth-abundant alternative for this transformation. Pyrolysis of iron-phenanthroline complexes on carbon furnishes a unique structure in which the active Fe2O 3 particles are surrounded by a nitrogen-doped carbon layer. Highly selective hydrogenation of numerous structurally diverse nitroarenes (more than 80 examples) proceeded in good to excellent yield under industrially viable conditions.
- Jagadeesh, Rajenahally V.,Surkus, Annette-Enrica,Junge, Henrik,Pohl, Marga-Martina,Radnik, Joerg,Rabeah, Jabor,Huan, Heming,Schunemann, Volker,Brueckner, Angelika,Beller, Matthias
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p. 1073 - 1076
(2014/01/06)
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- Pinacol as a new green reducing agent: Molybdenum-catalyzed chemoselective reduction of sulfoxides and nitroaromatics
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Pinacol is disclosed as a new chemoselective and environmentally benign reducing agent for sulfoxides and nitroaromatics assisted by readily available dichlorodioxomolybdenum(VI) complexes as catalysts. A wide range of substrates including those bearing challenging functional groups has been efficiently and selectively reduced with acetone and water being the only by-products of these reactions. Copyright
- Garcia, Nuria,Garcia-Garcia, Patricia,Fernandez-Rodriguez, Manuel A.,Rubio, Ruben,Pedrosa, Maria R.,Arnaiz, Francisco J.,Sanz, Roberto
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supporting information; experimental part
p. 321 - 327
(2012/04/11)
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- Pyrazine derivative, and light emitting element, display device, electronic device using the pyrazine derivative
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It is an object to provide a novel material having a bipolar property, a light emitting element provided with the novel material, and a display device that includes the light emitting element. It is an object to provide a pyrazine derivative represented by the following general formula (g-1).
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- Non-metallocene compounds, method for the production thereof and use of the same for the polymerisation of olefins
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The invention relates to a method for producing special transition metal compounds, to novel transition metal compounds and to the use of the same for the polymerisation of olefins.
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- Reductively activated polar" nucleophilic aromatic substitution. IV [1]. Thermal and photochemical behavior of polychloro and polyfluoro-nitrobenzenes in front of soft nucleophiles
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The nucleophilic aromatic substitution of pentachloronitrobenzene (PCNB) with benzenethiolate and benzeneselenide anions in aqueous solution give rise to fast nitro group substitution in both cases. In the same conditions, pentafluoronitrobenzene (PFNB) and 3,4,5-trichloronitrobenzene (TCNB) undergo substitution of the halogen atom placed in para position with respect to the nitro group. Mechanistic studies suggest that the reactions of PCNB and PFNB (substitution of very electronegative leaving groups) follow a mechanism that includes a "polar" attack of the nucleophile on the aromatic substrate in the first step and a fast "radical" evolution of the o-complex intermediate. On the other hand, the chloride substitution in the TCNB reactions follows the classical SNAr mechanism. The photochemical reactions of PCNB, PFNB and TCNB in the presence of nucleophiles (electron donors) lead in all cases to photoreduction products (anilines) probably through the aromatic radical anion. Springer-Verlag 1996.
- Jiang, Ziqi,Marquet, Jordi,Cervera, Maria,Gallardo, Iluminada
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- Epoxy-epimination of cyclic conjugated dienes - VII. Cycloaddition of nitroso-halogenobenzenes to cyclopentadiene followed by rearrangement to epoxy-epimino- and γ-δ-epiminopentadienal derivatives via N-O and C-C bond breaking
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[4 + 2] Cycloaddition of halogenated nitroso benzenes to cyclopentadiene followed by isomerisation of the intermediated adduct occurs already at room temperature to furnish the epoxy-epimine 1 and the epiminopentadienal 2. The structure proof of 1 is based on X-ray analysis.
- Rouselle,Francotte,Feneau-Dupont,Tinant,Declercq,Viehe
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p. 8323 - 8330
(2007/10/02)
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- Replacement of Nitro Group of Pentachloronitrobenzene by Nucleophiles
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Pentachloronitrobenzene (I) reacts with sodium hydroxide, sodium hydrogen sulphide, sodium methoxide and ammonia with replacement of the nitro group by -OH, -SH, -OCH3 and -NH2 groups respectively.Attempted replacement of the nitro group by -CN group has been unsuccessful.
- Hashem, A. I.
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p. 1086 - 1087
(2007/10/02)
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