- Synthesis of carbon-supported Pd/SnO2 catalyst for highly selective hydrogenation of 2,4-difluoronitrobenzene
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Halogenated anilines have a wide range of applications in the production of pharmaceuticals and agrochemical substances, and thus it is of great importance to develop highly active and selective catalysts for the hydrogenation of halogenated nitrobenzenes. We approach this challenge by probing noble metal/non-noble metal oxide nanoparticles (NPs) catalysts. Carbon-supported Pd/SnO2 catalysts were synthesized by the chemical reduction method, and their catalytic activity was evaluated by the hydrogenation reaction of 2,4-difluoronitrobenzene (DFNB) to the corresponding 2,4-difluoroaniline (DFAN), showing a remarkable synergistic effect of the Pd and SnO2 NPs. The as-prepared Pd/SnO2/C catalysts were characterized using TEM, XRD, H2 TPD and XPS techniques. Modifications to the electronic structure of the Pd atoms through the use of SnO2 led to the suppression of the hydrogenolysis of the CF bond and the acceleration of nitrosobenzene (DFNSB) conversion and consequently, resulted in the inhibition of the formation of reactive by-products and may be responsible for the enhancements observed in selectivity.
- Zhao, Jia,Ma, Lei,Xu, Xiao-Liang,Feng, Feng,Li, Xiao-Nian
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- Efficient and recyclable bimetallic Co–Cu catalysts for selective hydrogenation of halogenated nitroarenes
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Silica supported N-doped carbon layers encapsulating Co–Cu nanoparticles (Co1Cux@CN/SiO2) were prepared by a one-step impregnation of Co(NO3)2·6H2O, Cu(NO3)2·3H2O, urea and glucose, following in situ carbothermal reduction. Effects of Cu contents on the catalytic performance of the Co1Cux@CN/SiO2 catalysts were investigated for selective hydrogenation of p-chloronitrobenzene to p-chloroaniline. The Co1Cu0.30@CN/SiO2 with Cu/Co molar ratio of 0.30:1 presented much higher activity and stability than the monometallic Co@CN/SiO2 catalyst. The addition of Cu into Co1Cux@CN/SiO2 catalysts had favorable effects on the formation of highly active Co–N sites and N-doped carbon layer. The role of the N-doped carbon layer was to protect the Co from oxidation by air, and the Co1Cu0.30@CN/SiO2 could be reused for at least 12 cycles without decrease in catalytic efficiency. Mechanistic and in situ infrared studies revealed that the interaction effect between the Co and Cu atoms made the surface of Co highly electron rich, which decreased adsorption of halogen groups and resulting in the enhanced selectivity during chemoselective hydrogenation of halogenated nitroarenes for a wide scope of substrates.
- Lu, Xionggang,Ren, Jiaan,Sheng, Yao,Wang, Xueguang,Wu, Baoqin,Zou, Xiujing
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- Novel preparation method of 2, 4, 5-trifluorophenylacetic acid
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The invention discloses a novel preparation method of 2, 4, 5-trifluorophenylacetic acid, which belongs to the technical field of preparation of medical intermediates, and comprises the following preparation steps: carrying out nitration reaction on sulfuric acid and m-dichlorobenzene to obtain an intermediate II; adding the intermediate II, a phase transfer catalyst and potassium fluoride into an aprotic solvent to obtain an intermediate III; performing hydrogenation reaction on the intermediate III to obtain an intermediate IV; carrying out diazotization reaction on the intermediate IV, nitrosyl sulfuric acid and sodium fluoborate to obtain an intermediate V; performing cracking reaction on the intermediate V to obtain an intermediate VI; carrying out reduction reaction on the intermediate VI, and then carrying out bromination reaction on the intermediate VI and liquid bromine to obtain an intermediate VII; subjecting the intermediate VII to a substitution reaction with diethyl malonate, and obtaining 2, 4, 5-trifluorophenylacetic acid after hydrolysis and purification. A novel synthesis route is provided, the problem that technological operation is tedious is solved, the requirements for reaction and operation conditions are low, anhydrous and oxygen-free reaction conditions are not needed, the method is suitable for industrial production, and the yield and purity are greatly improved.
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Paragraph 0037; 0075; 0080-0081; 0097-0100; 0102-0103; ...
(2021/06/23)
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- Efficient synthesis method of meta-fluoranisole (by machine translation)
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The method is characterized by comprising the following steps: taking m-chloronitrobenzene as a raw material, carrying out high-temperature chlorination reaction, nitration reaction and fluorination reaction to obtain 2,4 - 2,4 -difluorobenzene and carrying out a methoxylation reaction with m-difluorobenzene as a raw material and carrying out methoxylation reaction to obtain m-fluorobenzyl ether; and the hydrogenation catalyst is a porous alumina loaded NiO-Co222O3-MoOO3 composite catalyst. The method disclosed by the invention is simple in process and high in product yield. (by machine translation)
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Paragraph 0026; 0033; 0036; 0043; 0046; 0053; 0056; 0063
(2020/06/05)
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- Highly selective hydrogenation of halogenated nitroarenes over Ru/CN nanocomposites by: In situ pyrolysis
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A highly chemoselective and recyclable ruthenium catalyst for the hydrogenation of halogenated nitroarenes has been prepared via the simple in situ calcination of a mixture of melamine, glucose and ruthenium trichloride. Superfine Ru particles (2.3 ± 0.3 nm) were obtained and highly dispersed in the nitrogen-doped carbon matrix. The Ru/CN catalyst smoothly transforms a variety of halogenated nitroarenes to the corresponding haloanilines with high intrinsic activity (e.g. TOF = 1333 h-1 for p-chloronitrobenzene) and selectivity of more than 99.6percent. Furthermore, through an analysis of the products in the reaction process, it was concluded that there are two parallel reaction pathways (a direct pathway and an indirect pathway) for the hydrogenation of aromatic nitro compounds over the Ru/CN catalyst, and the direct pathway was proved to be dominant in catalyzing the intermediates. This journal is
- Yue, Shengnan,Wang, Xueguang,Li, Shaoting,Sheng, Yao,Zou, Xiujing,Lu, Xionggang,Zhang, Chunlei
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p. 11861 - 11869
(2020/07/28)
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- Solvent-Controlled CO2 Reduction by a Triphos-Iron Hydride Complex
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The selective reduction of CO2 is of high interest toward future applications as a C1-building block. Therefore, metal complexes that allow for the formation of specific CO2 reduction products under distinct reaction conditions are necessary. A detailed understanding of the CO2 reduction pathways on a molecular level is, however, required to help in designing catalytic platforms for efficient CO2 conversion with specific product formation. Reported herein is a unique example of a solvent-controlled reduction of CO2 using a Triphos-based iron hydride complex. In THF, CO2 reduction selectively leads to CO formation, whereas experiments in acetonitrile exclusively afford formate, HCOO-. In order to explain the experimental findings, theoretical calculations of the reaction pathways were performed and further demonstrate the importance of the applied solvent for a selective reduction of CO2.
- Iffland, Linda,Khedkar, Abhishek,Petuker, Anette,Lieb, Max,Wittkamp, Florian,Van Gastel, Maurice,Roemelt, Michael,Apfel, Ulf-Peter
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supporting information
p. 289 - 299
(2019/02/01)
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- Anion ligand promoted selective C-F bond reductive elimination enables C(sp2)-H fluorination
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A detailed mechanism study on the anion ligand promoted selective C-H bond fluorination is reported. The role of the anion ligand has been clarified by experimental evidence and DFT calculations. Moreover, the nitrate promoted C-F bond reductive elimination enabled a selective C-H bond fluorination of various symmetric and asymmetric azobenzenes to access diverse o-fluoroanilines.
- Mao, Yang-Jie,Luo, Gen,Hao, Hong-Yan,Xu, Zhen-Yuan,Lou, Shao-Jie,Xu, Dan-Qian
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supporting information
p. 14458 - 14461
(2019/12/09)
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- Synthesis of 2 - fluoro aniline compounds of the method
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The invention discloses a method for synthesizing 2 - fluoro aniline compounds of the method, the method is: shown in formula Ia aniline compound of formula Ib α and β shown aniline compound as raw materials, through coupling reaction shown [...] azobenzene compound II, then the type II shown azobenzene compound with a palladium catalyst, fluorination reagent, additive, organic solvent, in the 30 - 150 °C temperature closed agitating the fluorination reaction, [...] compound of formula III, type III compounds are shown in the reaction under the action of a reducing [...] shown IV 2 - fluoro aniline compounds; this invention synthetic 2 - fluoro aniline compounds substrate wide adaptability, mild reaction conditions, the operation is simple, fluorinated and good selectivity, [...] aniline compounds is prepared by many drug molecule is an important intermediate and starting material, wide application prospects.
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Paragraph 0104; 0105; 0107; 0108; 0109
(2019/05/15)
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- Method for producing 2,4-difluroaniline by virtue of solvent-free catalytic hydrogenation method
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The invention provides a method for producing 2,4-difluroaniline by virtue of a solvent-free catalytic hydrogenation method. According to the method, 2,4-difluroaniline is prepared through catalytic hydrogenation in a high-pressure kettle by adding a catalyst and phosphate under a solvent-free condition. Compared with a solvent hydrogenation method in the past, the solvent-free hydrogenation method has the advantages that the reaction efficiency is greatly improved, the utilization rate of equipment is obviously increased, meanwhile, the energy consumption and equipment cost due to recycling of a solvent can be effectively avoided, the method is a pollution-free environment-friendly process, and the generation of a large number of wastewater and waste residues is effectively avoided. By utilizing a noble metal catalyst, namely Pt/C, the preparation is simple, the catalyst can be circularly used in the reaction, and the metal can be recycled, so that the production cost is further lowered; and by utilizing phosphate as a dehydrogenation inhibitor, the reaction conversion rate can be increased.
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Paragraph 0017-0032
(2019/01/08)
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- Amino pyrimidine compound and preparation method and application thereof
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The invention relates to an amino pyrimidine compound and a preparation method and application thereof. The amino pyrimidine compound has a structure as shown in a formula I. The formula is shown in the description. The compound is an inhibitor of an epidermal growth factor receptor (EGFR) kinase. The invention further relates to a medicine composition comprising the compound, a preparation methodand application thereof in preparation of anti-tumor medicines.
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Paragraph 1043; 1046; 1047; 1048
(2018/11/22)
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- Efficient and selective hydrogenation of amides to alcohols and amines using a well-defined manganese-PNN pincer complex
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Novel well-defined NNP and PNP manganese pincer complexes have been synthetized and fully characterized. The catalyst Mn-2 containing an imidazolyaminolphosphino ligand shows high activity and selectivity in the hydrogenation of a wide range of secondary and tertiary amides to the corresponding alcohols and amines, under relatively mild conditions. For the first time, more challenging substrates like primary aromatic amides including an actual herbicide can also be hydrogenated using this earth-abundant metal-based pincer catalyst.
- Papa, Veronica,Cabrero-Antonino, Jose R.,Alberico, Elisabetta,Spanneberg, Anke,Junge, Kathrin,Junge, Henrik,Beller, Matthias
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p. 3576 - 3585
(2017/07/11)
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- ARYL SULFONAMIDE COMPOUNDS AS CARBONIC ANHYDRASE INHIBITORS AND THEIR THERAPEUTIC USE
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Disclosed herein are compounds having the following structure useful as inhibitors of carbonic anhydrase IX (CAIX) and XII, and particularly useful for reducing or eliminating metastases see Formula (I).
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Page/Page column 67; 68
(2017/01/23)
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- Copper-catalyzed hydrodefluorination of fluoroarenes by copper hydride intermediates
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Breaking bad: Efficient copper-catalyzed C-F bond activation has been achieved by replacing fluorine with hydrogen. A copper hydride is proposed as the active intermediate, which proceeds through a nucleophilic attack on the fluorocarbon, as determined by experimental and theoretical results (see structure; C gray, H white, Cu light red, F light blue; distances in ?).
- Lv, Hongbin,Cai, Yuan-Bo,Zhang, Jun-Long
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supporting information
p. 3203 - 3207
(2013/04/23)
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- Polymeric PEG35k-Pd nanoparticles: Efficient and recyclable catalyst for reduction of nitro compounds
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The small size polymeric PEG35k-Pd nanoparticles are key attractions for catalysis due to their large surface to volume ratio, non-toxicity, inexpensive, thermal stability, and recoverability. Polymeric PEG35k-Pd nanoparticles in the absence of phosphine ligands are insensitive to the air and moisture and act as an active heterogeneous catalyst for the reduction of nitroarenes. Supplementary materials are available for this article. Go to the publisher's online edition of Synthetic Communications to view the free supplemental file. Taylor & Francis Group, LLC.
- Yadav, Veena,Gupta, Shweta,Kumar, Rupesh,Singh, Gajendra,Lagarkha, Rekha
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experimental part
p. 213 - 222
(2011/10/31)
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- Highly selective hydrogenation of halonitroaromatics to aromatic haloamines by ligand modified Ni-based catalysts
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Ligand modification of Ni-based catalysts by coordination of dicyandiamide to Ni metal leads to enhanced selectivity for the selective hydrogenation of halonitroaromatics. The selectivity of above 99.9% to aromatic haloamines can be achieved at the conversion of 100%. The results of H2-TPD and FT-IR experiments show that Ni-H+ species possessing the properties of Lewis acid site on the surface of Raney Ni could be responsible for the hydrodehalogenation. When Raney Ni was treated by dicyandiamide, Ni -H+ species interacted with N atom from the dicyandiamide. This interaction was stable even at reaction temperature, which reduced the possibility to form the intermediate state of ArCl?H+Ni -. And then CCl bond could not be polarized and activated. The hydrodechlorination process was suppressed effectively.
- Lu, Chun Shan,Lv, Jing Hui,Ma, Lei,Zhang, Qun Feng,Feng, Feng,Li, Xiao Nian
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experimental part
p. 545 - 548
(2012/06/16)
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- Catalytic reduction of nitroarenes with polymeric palladium nanoparticles
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An efficient synthesis of Pd nanoparticles in water has been developed using PEG10k as the capping agent. The PEG10k-Pd NPs (2 mol%) efficiently catalyzes reduction of nitro compounds performed in air. The stability of the catalyst allows an extensive recycle in the reduction of nitro compounds. Copyright Taylor & Francis Group, LLC.
- Kumar, Rupesh,Yadav, Veena,Gupta, Shweta,Lagarkha, Rekha,Chandra, Harish
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experimental part
p. 114 - 119
(2011/03/22)
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- A new class of heterogeneous platinum catalysts for the chemoselective hydrogenation of nitroarenes
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A new series of nanostructured platinum catalysts able to catalyze the selective reduction of nitroarenes has been developed. The materials, made of organosilica physically doped with nanostructured platinum(0), are stable and efficient. Reactions in general proceed with high yield and often go to completion, while the catalysts can be reused in further reaction runs. This establishes a new class of relevant solid catalysts for synthetic organic chemistry named SiliaCat Platinum-Hydrogel.
- Pandarus, Valerica,Ciriminna, Rosaria,Beland, Francois,Pagliaro, Mario
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scheme or table
p. 1306 - 1316
(2011/06/25)
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- Electrophilic aromatic fluorination with fluorine: meta-Directed fluorination of anilines
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Anilines are mainly or selectively fluorinated in the meta-position with F2 when dissolved in triflic acid, sometimes in the presence of small quantities of antimony pentafluoride. The regioselectivity is increased when an electron-donating substituent is present at the para-position.
- Alric,Marquet,Billard,Langlois
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p. 661 - 667
(2007/10/03)
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- SUBSTITUTED QUINAZOLINE DERIVATIVES AND THEIR USE AS INHIBITORS
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The use of a compound of formula (I) 1 or a salt, ester or amide thereof; where X is O, or S, S(O) or S(O)2, or NR6 where R6 is hydrogen or C1-6 alkyl,; R5 is an optionally substituted 5-membered heteroaromatic ring, R1, R2 ,R3, R4 are independently selected from various specified moieties, in the preparation of a medicament for use in the inhibition of aurora 2 kinase. Certain compounds are novel and these, together with pharmaceutical compositions containing them are also described and claimed
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- Process for the preparation of fluoroanilines from fluorinated nitrated benzene compounds
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The instant invention relates to a process for the preparation of fluoroanilines of formula (I) wherein a fluorinated nitrated benzene compound of formula (II) is subjected to a catalytic hydrogenation in a liquid medium containing a catalyst, under hydrogen pressure, carrying out a catalytic reduction reaction and, optionally, a hydrogenolysis reaction, wherein the compound of formula (II) is introduced gradually into the said medium so that the content of compound of formula (II) in the liquid remains less than or equal to 1000 ppm by mass, in order selectively to form the compound of formula (I).
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- The Bamberger reaction in hydrogen fluoride: the use of mild reductive metals for the preparation of fluoroaromatic amines
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The reduction of nitroaromatic compounds by various metals (tin, lead, bismuth) in liquid hydrogen fluoride under an inert atmosphere leads to fluoroaromatic amines, in accord with the Bamberger reaction.Generally, a co-solvent such as pentane or methylene chloride is used.Some non-fluorinated arylamines are also formed by a competitive direct reduction of the N-arylhydroxylamine intermediate.Of the mild reductive metals studied, bismuth was the most selective. - Keywords: Bamberger reaction; Hydrogen fluoride; Mild reductive metals; Fluoroaromatic amines; NMR spectroscopy
- Tordeux, Marc,Wakselman, Claude
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p. 251 - 254
(2007/10/03)
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- Synthesis of 2,4-difluoroaniline and 1,3-difluorobenzene from 1,2,4- trichlorbenzene
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Nitration of inexpensive 1,2,4-trichlorobenzene gave 2,4,5- trichloronitrobenzene (90%) which was treated with KF to form 2,4-difluoro- 5-chloronitrobenzene (70%). This was selectively hydrogenated over Pd / C to give 2,4-difluoroaniline (80%). Deamination afforded 1,3-difluorobenzene. The sequence avoids the need for costly 1,3-dichlorobenzene.
- Mason,Milner
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p. 529 - 532
(2007/10/02)
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- N-substituted alpha-arylazacycloalkylmethanamines and their use as cardiovascular agents
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Novel compounds of the formula below wherein W is azetidine, pyrrolidine or piperidine, Q is a straight chain hydrocarbon radical of 1-4 carbons and may contain a double bond, and STR1 Ar is phenyl, pyridinyl or pyrimidinyl, a process for their preparation, and novel intermediates are disclosed. The novel compounds and the pharmaceutical compositions of this invention are useful in the treatment of hypertension, arrhythmias and angina.
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- AROMATIC FLUORINE CHEMISTRY. PART 4. PREPARATION OF 2,6-DIFLUOROANILINE
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The preparation of 2,6-difluoroaniline from 1,3,5-trichlorobenzene is described. 1-Chloro-3,5-difluorobenzene prepared via KF exchange on 1,3,5-trichlorobenzene is dichlorinated and nitrated in a single reactor to a mixture of trichlorodifluoronitrobenzenes.The latter are reduced to ca. 4:1 mixture of 2,6-difluoroaniline and 2,4-difluoroaniline.
- Pews, R. G.,Gall, J. A.
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p. 307 - 316
(2007/10/02)
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- SELECTIVE CLEAVAGE OF THE ETHER AND AMIDE BONDS IN N-(2,4-DIFLUOROPHENYL)-2--3-PYRIDINECARBOXAMIDE (DIFLUFENICAN)
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Heated to reflux in water containing 8 gpercent KOH, the herbicide diflufenican -3-pyridinecarboxamide, 1> was selectively transformed into 2--3-pyridinecarboxylic acid (2) plus 2,4-difluoroaniline (5); after 60 hr of heating, 27percent of the initial diflufenican was transformed, yielding 21percent (molepercent relative to initial diflufenican) of compound 2.Heated to reflux in a mixture of acetic acid + concentrate hydrochloric acid, diflufenican was transformed into a mixture of N-(2,4-difluorophenyl)-2-hydroxy-3-pyridinecarboxamide (3) and 2-hydroxy-3-carboxypyridine (4) plus 2,4-difluoroaniline (5) and 3-trifluoromethylphenol (6); after 48 hr of heating, diflufenican was completely transformed, yielding 28percent (molepercent relative to initial diflufenican) of compound 3, and 57percent of compound 4.The base catalyzed hydrolysis thus selectively yielded compound 2; the acid catalyzed one yielded compounds 3 + 4: diflufenican first was transformed into compound 3, which thereafter was transformed into compound 4.
- Rouchaud, Jean,Gustin, Fabrice,Moulart, Claude,Herin, Marc
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p. 339 - 344
(2007/10/02)
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- Hydrogenation of halogen-substituted aromatic nitro compounds
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This invention relates to the hydrogenation of halogen-substituted aromatic nitro compounds and in particular provides a novel catalyst for use in such processes. In more detail a catalyst suitable for use in the hydrogenation of halogen-substituted aromatic nitro compounds substantially without simultaneous dehalogenation comprises one or more metals from the group consisting of platinum, palladium, rhodium, iridium, ruthenium and osmium supported on or impregnated into a carrier material comprising carbon activated with phosphoric acid or a salt thereof.
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- Preparation of fluorinated anilines
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Fluorinated anilines, especially p-fluoroaniline and 2,4-difluoroaniline, are prepared by treating aromatic azides with anhydrous hydrogen fluoride. The aromatic azides, in turn, are prepared from the corresponding anilines by treatment with nitrous acid or salt thereof and an alkali metal azide in the presence of a mineral acid, and in an aqueous-nonaqueous, two-phase environment.
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