209995-38-0Relevant articles and documents
Industrial preparation method of 2,4,5-trifluorophenylacetic acid
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, (2021/03/11)
The invention relates to the technical field of preparation of chemical drug intermediates, and particularly discloses an industrial preparation method of 2,4,5-trifluorophenylacetic acid. The preparation method comprises the following steps: carrying out a nitration reaction, a fluorination reaction, a hydrogenation reduction reaction, a diazotization reaction, a halogenation reaction, a cyaniding reaction, a thermal decomposition reaction and a hydrolysis reaction on 2,4-dichlorotoluene to prepare the 2,4,5-trifluorophenylacetic acid. The method has the advantages of low preparation cost andhigh product yield.
Novel preparation method of 2, 4, 5-trifluorophenylacetic acid
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, (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.
Preparation method of 2,4,5-trifluorophenylacetic acid
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Paragraph 0025; 0027-0028, (2020/07/21)
The invention provides a preparation method of 2,4,5-trifluorophenylacetic acid. 1,2,4-trifluorobenzene as a raw material and glycolide are catalyzed by a Lewis acid to obtain a final product that issitagliptin intermediate 2,4,5-trifluorophenylacetic acid. The method is mild in reaction condition, and convenient to operate, raw materials are cheap and easily available, steps are simple, and operability is high. High-pressure reaction equipment is not used in the production process, harmful and toxic reagents are not involved, the method has the advantages of being high in safety and environmentally friendly, the obtained 2,4,5-trifluorophenylacetic acid is high in purity, a more valuable synthetic route is provided for preparation of sitagliptin, good social benefits and economic benefits can be brought, and the economic value potential is large.