- 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; 0075-0077; 0097-0100; 0102-0103; 0105-0108
(2021/06/23)
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- Nitration of aromatics with dinitrogen pentoxide in a liquefied 1,1,1,2-tetrafluoroethane medium
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Regardless of the sustainable development path, today, there are highly demanded chemical productions still operating that bear environmental and technological risks inherited from the previous century. The fabrication of nitro compounds, and nitroarenes in particular, is traditionally associated with acidic wastes formed in nitration reactions exploiting mixed acids. However, nitroarenes are indispensable for industrial and military applications. We faced the challenge and developed a greener, safer, and yet effective method for the production of nitroaromatics. The proposed approach comprises the application of an eco-friendly nitrating agent, namely dinitrogen pentoxide (DNP), in the medium of liquefied 1,1,1,2-tetrafluoroethane (TFE) - one of the most non-hazardous Freons. Importantly, the used TFE is not emitted into the atmosphere but is effortlessly recondensed and returned into the process. DNP is obtainedviathe oxidation of dinitrogen tetroxide with ozone. The elaborated method is characterized by high yields of the targeted nitro arenes, mild reaction conditions, and minimal amount of easy-to-utilize wastes.
- Fauziev, Ruslan V.,Kharchenko, Alexandr K.,Kuchurov, Ilya V.,Zharkov, Mikhail N.,Zlotin, Sergei G.
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p. 25841 - 25847
(2021/08/09)
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- Method for catalytically synthesizing 2, 4-dichloronitrobenzene by adopting tetraphenylphosphine iodide
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The invention discloses a method for catalytically synthesizing 2, 4-dichloronitrobenzene by adopting tetraphenylphosphine iodide, and relates to the technical field of preparation of 2, 4-dichloronitrobenzene. The method specifically comprises the follow
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Paragraph 0021-0035
(2021/07/10)
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- Dehydroxyalkylative halogenation of C(aryl)-C bonds of aryl alcohols
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We herein report Cu mediated side-directed dehydroxyalkylative halogenation of aryl alcohols. C(aryl)-C bonds of aryl alcohols were effectively cleaved, affording the corresponding aryl chlorides, bromides and iodides in excellent yields. Aryl alcohols could serve as both aromatic electrophilic and radical synthetic equivalents during the reaction.
- Liu, Mingyang,Zhang, Zhanrong,Liu, Huizhen,Wu, Tianbin,Han, Buxing
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p. 7120 - 7123
(2020/07/14)
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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; 0031; 0036; 0041; 0046; 0051; 0056; 0061
(2020/06/05)
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- A convenient room temperature ipso-nitration of arylboronic acid catalysed by molecular iodine using zirconium oxynitrate as nitrating species: An experimental and theoretical investigation
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A simple and convenient protocol has been developed for ipso-nitration of arylboronic acid catalysed by molecular iodine at room temperature, using zirconium oxynitrate as the nitrating species. The protocol is applicable to electronically diverse aryl- and heteroarylboronic acid moieties under mild reaction conditions with good to excellent isolated yields. Furthermore, a theoretical investigation has been performed for the same reaction, and reaction profiles are modelled using modern density functional theory (DFT). DFT-based results support the experimentally observed results.
- Mahanta, Abhijit,Gour, Nanda Kishor,Sarma, Plaban Jyoti,Borah, Raju Kumar,Raul, Prasanta Kumar,Deka, Ramesh Chandra,Thakur, Ashim Jyoti,Bora, Utpal
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- Preparation method for 5-chloro-2-nitroaniline
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The invention discloses a preparation method for 5-chloro-2-nitroaniline. The preparation method comprises the following steps: performing nitration by using m-dichlorobenzene as a starting material to prepare 2,4-dichloronitrobenzene, adding the 2,4-dichlorobenzene and a solvent into an autoclave, adding ammonia, performing high-pressure amination, after the amination is completed, performing cooling, performing pressure filtration, removing the solvent from a filtrate, and performing refining to obtain the target product 5-chloro-2-nitroaniline. The method provided by the invention has the following advantages: (1) nitrogen dioxide is used as a nitrating reagent to replace a traditional nitric acid-sulfuric acid mixed acid nitrating agent, so that no waste acid is produced, cleanliness of an industrial synthesis reaction is improved, and environmental pollution is reduced; and (2) after the amination is completed, by-product ammonium chloride is directly removed by pressure filtration, so that an amount of waste water is small, and an amination yield is high.
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Paragraph 0016; 0017
(2018/08/28)
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- Inexpensive NaX (X = I, Br, Cl) as a halogen donor in the practical Ag/Cu-mediated decarboxylative halogenation of aryl carboxylic acids under aerobic conditions
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Versatile and practical Ag/Cu-mediated decarboxylative halogenation between readily available aryl carboxylic acids and abundant NaX (X = I, Br, Cl) has been achieved under aerobic conditions in moderate to good yields. The halodecarboxylation is shown to be an effective strategy for S-containing heteroaromatic carboxylic acid and benzoic acids with nitro, chloro and methoxyl substituents at the ortho position. A gram-scale reaction and a three-step procedure to synthesize iniparib have been performed to evaluate the practicality of this protocol. A preliminary mechanistic investigation indicates that Cu plays a vital role and a radical pathway is involved in the transformation.
- Fu, Zhengjiang,Jiang, Ligao,Zuo, Qianming,Li, Zhaojie,Liu, Yanzhu,Wei, Zhenhong,Cai, Hu
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supporting information
p. 5416 - 5421
(2018/08/12)
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- Synthetic method of aryl halide taking aryl carboxylic acid as raw material
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A synthetic method of an aryl halide taking aryl carboxylic acid as a raw material is characterized in that a corresponding aryl halide is formed by carrying out substitution reaction on an aryl carboxylic acid compound and haloid salt MX in an organic solvent under the condition that oxygen, a silver catalyst, a copper additive and a bidentate nitrogen ligand exist, wherein M in MX represents alkali metal or alkaline earth metal, and X represents F, Cl, Br or I. Compared with a conventional aryl halide synthetic method, the synthetic method disclosed by the invention has the obvious advantages that reaction raw materials (comprising aryl carboxylic acid and MX) are cheap and easy to obtain, the using amount of a metal catalyst is small, pollution to the environment when the oxygen is used as an oxidant is the smallest, good tolerance to various functional groups on an aromatic ring is obtained, the yield is high, and the like. The synthetic method disclosed by the invention can be widely applied to synthesis in the fields of medicine, materials, natural products and the like in industry and academia.
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Paragraph 0067
(2018/01/03)
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- A preparation method of curing melanotumor
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The invention discloses a preparation method of fenbendazole and provides a brand-new synthesis route of the fenbendazole. The fenbendazole is prepared from m-dichlorobenzene as a starting material through the steps of nitrification, condensation, amination, reduction and cyclization. The preparation method is characterized in that the starting material m-chloroaniline in the existing industrial route is changed to the cheap m-dichlorobenzene; the existing reduction technology with sodium sulfide dihydrate is changed to the clean and high-efficiency reduction technology; and the new synthesis technology is concise and simple, high in efficiency, slight in pollution, high in quality, and suitable to industrial production.
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Paragraph 0033;0034
(2016/10/27)
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- Production method of 3-ethoxy-4-nitrophenol
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The invention discloses a production method of 3-ethoxy-4-nitrophenol. The low-price m-dichlorobenzene is used instead of the high-price resorcinol as the raw material, and the methoxy is converted into the hydroxy; and a simple alkaline process is used instead of the conventional hydrogen bromide/acetic acid system to prepare the 3-ethoxy-4-nitrophenol. By using low-price m-dichlorobenzene instead of the high-price resorcinol as the raw material to prepare the 3-ethoxy-4-nitrophenol, the method has the advantages of simple synthesis steps, low pollution, environment friendliness, high product quality, high yield, low production cost and normal-pressure operation, and can implement industrial production.
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Paragraph 0032-0034
(2017/05/26)
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- Decarboxylative Halogenation and Cyanation of Electron-Deficient Aryl Carboxylic Acids via Cu Mediator as Well as Electron-Rich Ones through Pd Catalyst under Aerobic Conditions
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Simple strategies for decarboxylative functionalizations of electron-deficient benzoic acids via using Cu(I) as promoter and electron-rich ones by employing Pd(II) as catalyst under aerobic conditions have been established, which lead to smooth synthesis of aryl halides (-I, Br, and Cl) through the decarboxylative functionalization of benzoic acids with readily available halogen sources CuX (X = I, Br, Cl), and easy preparation of benzonitriles from decarboxylative cyanation of aryl carboxylic acids with nontoxic and low-cost K4Fe(CN)6 under an oxygen atmosphere for the first time.
- Fu, Zhengjiang,Li, Zhaojie,Song, Yuanyuan,Yang, Ruchun,Liu, Yanzhu,Cai, Hu
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p. 2794 - 2803
(2016/04/26)
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- Regioselective nitration of aromatics with nanomagnetic solid superacid SO42-/ZrO2-MxOy-Fe 3O4 and its theoretical studies
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A series of micro- and nanosulfated zirconia loaded on Fe3O 4 or other metal oxides (SO42-/ZrO 2-MxOy-Fe3O4 (M=Ti 4+, V5+, and Zn2+)) was prepared, characterized, and used in nitration. The nitration conditions with these solid superacids were then optimized to achieve the best regioselectivity and improve the performances of the catalysts as well. In the experimental results, SZTF (SO42-/ZrO2-TiO2-Fe 3O4) showed excellent catalytic activity and it increased the surface area of SO42-/ZrO2 by up to 15 %. The increase not only facilitated the generation of NO2+, but also provided more opportunities for metal ions to interact with aromatic compounds. With chlorobenzene as substrate, theoretical research on its geometric parameters, electron clouds, and electron spin density was used to investigate the interaction between transition metals and chlorobenzene.
- Wang, Peng Cheng,Zhu, Jie,Liu, Xiang,Lu, Ting Ting,Lu, Ming
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p. 310 - 317
(2013/08/23)
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- Regioselective nitration of aromatics under phase-transfer catalysis conditions
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Mononitration of aromatics was performed in a two-phase system using phase-transfer catalyst. The most advantageous conditions for the nitration were determined (temperature, reaction time, the type and amount of phase transfer catalyst, nitrification strength of the nitro-sulfuric acid). From the results, a significant improvement in the selectivity and conversion of the nitration of xylene was observed: the ratio of 4-nitro-m-xylene to 2-nitro-m-xylene was unprecedented increased up to 91.3%:7.7%, the ratio of 4-nitro-o-xylene to 3-nitro-o-xylene was also increased to 71.1%:27.2%; both the conversions were over 96%.
- Wang, Peng-Cheng,Lu, Ming,Zhu, Jie,Song, Yan-Ming,Xiong, Xian-Feng
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experimental part
p. 42 - 47
(2012/01/15)
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- Silver-catalyzed decarboxylative halogenation of carboxylic acids
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Decarboxylative halogenation of carboxylic acids catalyzed by silver carbonate is reported. ortho-Nitrobenzoic acids react with copper(II) chloride or bromide in DMF/DMSO at 130-140 °C leading to the corresponding aryl halides in moderate to good yields.
- Luo, Yong,Pan, Xiaolin,Wu, Jie
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supporting information; experimental part
p. 6646 - 6648
(2011/02/21)
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- Selective oxidation of aromatic amines to nitro derivatives using potassium iodide-tert-butyl hydroperoxide catalytic system
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The direct oxidation of aromatic primary amines to the corresponding nitro compounds selectively in 47-98% yields has been achieved by using potassium iodide as catalyst and tert-butyl hydroperoxide as the external oxidant. The present catalytic system works well for both electron-rich and electron-poor substrates.
- Reddy, K. Rajender,Maheswari, C. Uma,Venkateshwar,Kantam, M. Lakshmi
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supporting information; experimental part
p. 93 - 96
(2009/08/07)
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- A convenient method for the oxidation of aromatic amines to nitro compounds using tetra-n-alkylammonium bromates
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Tetra-n-propyl and tetra-n-butylammonium bromates were used for the oxidation of a variety of aromatic amines to nitro compounds. Reaction condition and recovery simple and yield of products high.
- Das, Satya Sandhya,Nath, Utpal,Deb, Dibakar,Das, Pranab J.
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p. 2359 - 2363
(2007/10/03)
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- Reaction of dimethyldioxirane with aniline hydrohalides
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Oxidation of aromatic amine hydrohalides (aniline hydrochloride, hydrobromide, and hydrofluoride; 4-methylaniline hydrochloride and hydrobromide; 3-methylaniline and N,N-diethylaniline hydrochlorides) with dimethyldioxirane was studied. The product composition was analyzed in relation to the reactant ratio.
- Ivanova,Grabovskii,Kabal'nova,Shereshovets
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p. 2101 - 2105
(2007/10/03)
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- Ozone-mediated reaction of polychlorobenzenes and some related halogeno compounds with nitrogen dioxide: A novel non-acid methodology for the selective mononitration of moderately deactivated aromatic systems
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In the presence of ozone and preferably methanesulfonic acid as catalyst, polychlorobenzenes undergo selective mononitration with nitrogen dioxide at low temperatures, giving the corresponding polychloronitrobenzenes, in most cases in nearly quantitative yields.
- Suzuki,Mori,Maeda
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p. 841 - 845
(2007/10/02)
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