611-06-3Relevant articles and documents
Novel preparation method of 2, 4, 5-trifluorophenylacetic acid
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Paragraph 0037; 0075-0077; 0097-0100; 0102-0103; 0105-0108, (2021/06/23)
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.
Nitration of aromatics with dinitrogen pentoxide in a liquefied 1,1,1,2-tetrafluoroethane medium
Fauziev, Ruslan V.,Kharchenko, Alexandr K.,Kuchurov, Ilya V.,Zharkov, Mikhail N.,Zlotin, Sergei G.
, p. 25841 - 25847 (2021/08/09)
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.
Method for catalytically synthesizing 2, 4-dichloronitrobenzene by adopting tetraphenylphosphine iodide
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Paragraph 0021-0035, (2021/07/10)
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
Dehydroxyalkylative halogenation of C(aryl)-C bonds of aryl alcohols
Liu, Mingyang,Zhang, Zhanrong,Liu, Huizhen,Wu, Tianbin,Han, Buxing
, p. 7120 - 7123 (2020/07/14)
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.
Efficient synthesis method of meta-fluoranisole (by machine translation)
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Paragraph 0026; 0031; 0036; 0041; 0046; 0051; 0056; 0061, (2020/06/05)
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)
A convenient room temperature ipso-nitration of arylboronic acid catalysed by molecular iodine using zirconium oxynitrate as nitrating species: An experimental and theoretical investigation
Mahanta, Abhijit,Gour, Nanda Kishor,Sarma, Plaban Jyoti,Borah, Raju Kumar,Raul, Prasanta Kumar,Deka, Ramesh Chandra,Thakur, Ashim Jyoti,Bora, Utpal
, (2019/05/15)
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.
Preparation method for 5-chloro-2-nitroaniline
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Paragraph 0016; 0017, (2018/08/28)
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.
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
Fu, Zhengjiang,Jiang, Ligao,Zuo, Qianming,Li, Zhaojie,Liu, Yanzhu,Wei, Zhenhong,Cai, Hu
supporting information, p. 5416 - 5421 (2018/08/12)
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.
Synthetic method of aryl halide taking aryl carboxylic acid as raw material
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Paragraph 0067, (2018/01/03)
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.
A preparation method of curing melanotumor
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Paragraph 0033;0034, (2016/10/27)
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.
