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Preparation method of 2-(3,4)-dichlorophenyl-4-fluoroaniline

A technology of dichlorophenyl and fluoroaniline, which is applied in the field of drug synthesis, can solve the problems of high toxicity, high price, and environmental pollution of Pd reagents, and achieve the effects of high control effect, fast speed, and easy use

Active Publication Date: 2018-08-24
JIANGSU UNIV OF SCI & TECH
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

Xue Liang et al. used p-fluoroaniline as a raw material to obtain 2-bromo-4-fluoroacetanilide through acetylation and bromination, and then used palladium (Pd) reagent as a catalyst to prepare 2-(3,4)- Dichlorophenyl-4-fluoroaniline, but the Pd reagent is more toxic, the price is relatively high, and it will pollute the environment

Method used

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  • Preparation method of 2-(3,4)-dichlorophenyl-4-fluoroaniline

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0023] (1) Add 15mL of dichloroethane and 10.4g (0.06mol) of 2-bromo-4-fluoroaniline into a 125mL three-necked flask, add 6.2g (0.06mol) of acetic anhydride dropwise at 45°C, and complete the dropwise addition in 30 minutes; Reaction at 50°C for 30 minutes after completion of the incubation; sampling and testing showed that the acetylation conversion rate was 98%;

[0024] 1 H NMR (500MHz, CDCl 3 )δ: 8.28-8.24 (m, 1H), 7.53 (s, 1H), 7.31-7.28 (m, 1H), 7.08-7.03 (m, 1H), 2.25 (s, 3H).

[0025] (2) At room temperature, the compound 2-bromo-4-fluoroacetanilide (74mg, 0.32mmol) and 3,4-dichlorobromobenzene (72mg, 0.32mmol) were dissolved in THF (15mL), electromagnetically stirred, and then Add Rieke Zn drop by drop ﹡ (10 mL, 5g / 100mLin THF), reflux at 80°C for 3h; in another three-necked flask, CuBr·SMe 2 (70mg, 0.36mmol) was dissolved in THF (5mL). After stirring for 20min, the above mixture was added to the solution. After continuing the reaction for 20min, the oxidant R (1...

Embodiment 2

[0030] Compared with Example 1, other reaction techniques and reaction conditions are all the same, adjust copper reagent (CuBr SMe 2 ) and the mol ratio and reaction temperature of the oxidant R, obtain the yield of the target compound in the step (2), as shown in table 1, the mol ratio of the copper reagent and the oxidant has the highest yield when 1:2; normal temperature and -40 ℃ The comparison shows that the reaction yield is higher at normal temperature; the reaction needs to be carried out under the protection of anhydrous, oxygen and nitrogen.

[0031] Table 1 Reverse Catalytic System Condition Product Yield

[0032] serial number

Embodiment 3

[0034] Compared with Example 1, other reaction techniques and reaction conditions are all the same, adjust organic solvent kind, as shown in table 2, each organic solvent in the following table can be used as the solvent of step (2) reaction; Under the protection of water, anaerobic and nitrogen.

[0035] The product yield under the different solvents of table 2

[0036] serial number

[0037]The coupling of carbon-carbon bonds mainly includes Kharasch reaction, Negishi reaction, Stille reaction, Suzuki reaction, etc. These reactions are characterized by using rare metals such as Pd and Ti as catalysts to complete the coupling reaction. However, these metal catalysts have obvious disadvantages: such as high toxicity, high price or dependence on unstable and highly toxic organophosphorus ligands. And copper reagent has very strong reactivity, and also has advantages such as low price, little environmental pollution, the present invention uses cheap and easy-to-get Ri...

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Abstract

The invention discloses a preparation method of 2-(3,4)-dichlorophenyl-4-fluoroaniline, comprising the steps of (1) dissolving 2-bromo-4-fluoroaniline in dichloroethane, dropwise adding acetic anhydride to obtain the compound 2-bromo-4-fluoroacetanilide; (2) dissolving the product of step (1) and 3,4-dichlorobromobenzene in an organic solvent, and dropwise adding Rieke Zn; in another reaction vessel, dissolving CuBr Sme2 in the same organic solvent, mixing, adding an oxidant for reaction, filtering the reacted liquid via silica gel, distilling in vacuum, and carrying out column chromatographyto obtain 2-(3,4-dichlorophenyl)-4-fluoroacetanilide; (3) adding the product of step (2) into the reaction vessel, adding methanol to allow full dissolution, and dropwise adding concentrated sulfuricacid slowly; when the materials completely react, pouring the mixed solution into ice water while it is hot for the purpose of quenching. A copper reagent that is low in price and easy to obtain is used to replace toxic heavy metals such as palladium; the domestic blank of studies on bixafen is filled; the foreign monopoly for bixafen is broken; progress of leaf blight and rust disease can be controlled.

Description

technical field [0001] The invention belongs to the technical field of medicine synthesis, and specifically relates to a preparation method of 2-(3,4)-dichlorophenyl-4-fluoroaniline. Background technique [0002] Food is of great significance to the survival and development of human beings, but the infestation of various diseases and insect pests causes the annual loss of crops to be roughly equivalent to one-third of the world's annual harvest. How to recover this huge loss and ensure the safety of various crops Stable and high yield has always been an important issue worldwide. Traditional chemical control has developed rapidly due to its advantages of high control effect, fast speed and easy use, but it has also caused a series of serious ecological and environmental problems, especially for the surrounding environment in rural areas, water ecological safety and farmers' health. had a serious impact. Therefore, the development of new green pesticides with high efficienc...

Claims

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Application Information

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IPC IPC(8): C07C211/52C07C209/62C07C231/02C07C231/12C07C233/15
CPCC07C209/62C07C231/02C07C231/12C07C233/15C07C211/52
Inventor 郑绍军蔡星伟朱瑞
Owner JIANGSU UNIV OF SCI & TECH
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