- Industrial preparation method of 2,4,5-trifluorophenylacetic acid
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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.
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Paragraph 0030-0031; 0053
(2021/03/11)
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- Method for synthesizing 2 and 4 - dichlorobenzoyl chloride
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The invention discloses a synthesis 2. The method comprises the following steps: heating to 4 - adding a catalyst benzoyl peroxide and phosphorus trichloride, adding the catalyst peroxide benzoyl chloride and phosphorus trichloride to obtain 2, 4 -dichlorobenzoyl chloride solution, adding a metal catalyst, dropping water to generate 80 - 100 °C-120 - 140 °C dichlorobenzoyl chloride crude product, and carrying out vacuum distillation. 2 2. The 4 - 4 -dichlorobenzoyl chloride solution is obtained 4 - by distillation under reduced pressure 2. ≤ 0.1%. 2 The 4 - process is carried out under reduced pressure by adding a metal catalyst and dropping water. To 2, 4 -dichlorotoluene is under the action of benzoyl peroxide and phosphorus trichloride. The chlorination is 2, 4 -dichlorobenzyl is high in conversion rate and low in byproduct content, 2, 4 -dichlorobenzoyl chloride can be directly hydrolyzed to 2 and 4 -dichlorobenzoyl chloride under the catalysis action, 2-4 -dichlorobenzoyl chloride is obtained.
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Paragraph 0014-0018
(2021/11/03)
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- N -Hydroxyphthalimide/benzoquinone-catalyzed chlorination of hydrocarbon C-H bond using N -chlorosuccinimide
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The direct chlorination of C-H bonds has received considerable attention in recent years. In this work, a metal-free protocol for hydrocarbon C-H bond chlorination with commercially available N-chlorosuccinimide (NCS) catalyzed by N-hydroxyphthalimide (NHPI) with 2,3-dicyano-5,6-dichlorobenzoquinone (DDQ) functioning as an external radical initiator is presented. Aliphatic and benzylic substituents and also heteroaromatic ones were found to be well tolerated. Both the experiments and theoretical analysis indicate that the reaction goes through a process wherein NHPI functions as a catalyst rather than as an initiator. On the other hand, the hydrogen abstraction of the C-H bond conducted by a PINO species rather than the highly reactive N-centered radicals rationalizes the high chemoselectivity of the monochlorination obtained by this protocol as the latter is reactive towards the C(sp3)-H bonds of the monochlorides. The present results could hold promise for further development of a nitroxy-radical system for the highly selective functionalization of the aliphatic and benzylic hydrocarbon C-H.
- Li, Zi-Hao,Fiser, Béla,Jiang, Biao-Lin,Li, Jian-Wei,Xu, Bao-Hua,Zhang, Suo-Jiang
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supporting information
p. 3403 - 3408
(2019/04/01)
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- Technological method for preparing halogenated-3,4-dihydro-1H-2-naphthalenone
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The invention relates to a technological preparation method of halogenated-3,4-dihydro-1H-2-naphthalenone as shown in a formula (I). (As shown in the description). According to the method disclosed by the invention, through a cheap raw material namely 2,4-dihalogeno-benzene carbonitrile, and an intermediate namely 2,4-dihalogeno-benzene acetic acid is synthesized, and through a reusable trifluoroacetic anhydride/acid system catalyst, a target product namely the halogenated-3,4-dihydro-1H-2-naphthalenone is synthesized. According to the method disclosed by the invention, a large quantity of catalysts such as aluminumtrichloride, and costly catalysts such as Rh, are not needed, and the reaction route can be shortened, so that a large quantity of reagents and time can be saved, and the industrial economic benefits can be greatly increased.
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Paragraph 0053; 0054; 0055; 0056
(2017/07/20)
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- 6-HYDROXY-2-NAPHTHYLCARBINOL AND PROCESS FOR THE PREPARATION THEREOF
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6-Hydroxy-2-naphthylcarbinol useful as a synthetic intermediate for preparation of 6-hydroxy-2-naphthaldehyde represented by the following formula (I), and a method for preparing 6-hydroxy-2-naphthylcarbinol comprising the step of reducing 6-hydroxy-2-naphthalenecarboxylic acid.
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- Side-chain chlorination of alkylated nitrogen heteroaromatics
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In the chlorination of the side chain of an alkylated nitrogen heteroaromatic such as pyridine or pyrimidine by reaction with elemental chlorine, the reaction is effected in acetronitrile as solvent.
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