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Preparation method of thifluzamide key intermediate, namely 2,6-dibromo-4-(trifluoromethoxy)aniline

A technology of trifluoromethoxyaniline and trifluoromethoxy, which is applied in the synthesis field of thifuramide key intermediate-2,6-dibromo-4-aniline, can solve the problems of incomplete reaction and the like, and achieve the reaction The effect of rapid thoroughness, yield and purity improvement

Active Publication Date: 2017-05-10
YANCHENG LIMIN CHEM
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0009] The technical problem mainly solved by the present invention is to provide a kind of preparation method of 2,6-dibromo-4-(trifluoromethoxy)aniline, the method adopts metal bromide (sodium bromide or potassium bromide) , Sulfuric acid and hydrogen peroxide are used as brominating agents, water is used as the reaction medium, and tetrabutylammonium bromide is used as the phase transfer catalyst, which avoids the use of bromine and organic solvents, and solves the problem of incomplete reaction

Method used

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  • Preparation method of thifluzamide key intermediate, namely 2,6-dibromo-4-(trifluoromethoxy)aniline

Examples

Experimental program
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Effect test

Embodiment 1

[0030] A preparation method of 2,6-dibromo-4-(trifluoromethoxy)aniline, comprising the following steps:

[0031] Put 250g of water into a 1000mL three-necked bottle, start stirring and drop in 17.5 (0.175mol) sulfuric acid, then add 45g of potassium bromide (0.378moL) and 0.3g of tetrabutylammonium bromide, and then add 30g (99%, 0.168 mol) 4-trifluoromethoxyaniline, adjust the temperature to above 30°C, start to add 38g of 35% hydrogen peroxide dropwise, the temperature rises during the dropwise addition, when the temperature rises to 50°C, control the dropwise temperature at 50°C by controlling the cooling liquid Between ~55°C, keep the temperature until the drop is completed, keep the temperature for 3 hours after dropping, cool down to about 30°C, filter, and dry the filter cake to obtain white crystal 2,6-dibromo-4-trifluoromethoxyaniline 55.6 g, purity 99.8% (HPLC), yield 99%.

[0032] Suction filter the mother liquor and cool it down to 0°C, then filter again to obtain...

Embodiment 2

[0034] A preparation method of 2,6-dibromo-4-(trifluoromethoxy)aniline, comprising the following steps:

[0035] Put 310g of the mother liquor in which potassium sulfate crystals were filtered out in Example 1 into a 1000mL three-necked flask, start stirring and drop in 17.5 (0.175mol) sulfuric acid, then add 43.5g of potassium bromide (0.365mol) and 30g (99%, 0.168mol) 4-Trifluoromethoxyaniline, adjust the temperature above 30°C, start to add 38g (0.391mol) of 35% hydrogen peroxide dropwise, the temperature rises during the dropwise addition, when the temperature rises to 50°C, control the dropwise temperature by controlling the cooling liquid Keep the temperature between 50 and 55°C, keep the temperature for dripping, keep warm for 3.5 hours after dripping, cool down to about 30°C, filter, and dry the filter cake to obtain white crystal 2,6-dibromo-4-trifluoromethoxy Aniline 55.3g, purity 99.7% (HPLC), yield 98.4%.

[0036] The mother liquor was cooled to 0 degree by suctio...

Embodiment 3

[0038] A preparation method of 2,6-dibromo-4-(trifluoromethoxy)aniline, comprising the following steps:

[0039] Put 350g of the mother liquor in which potassium sulfate crystals were filtered out in Example 2 into a 1000mL three-necked flask, start stirring and drop in 17.5 (0.175mol) sulfuric acid, then add 43.5g of potassium bromide (0.365mol) and 30g (99%, 0.168mol) 4-Trifluoromethoxyaniline, adjust the temperature above 30°C, start to add 38g (0.391mol) of 35% hydrogen peroxide dropwise, the temperature rises during the dropwise addition, when the temperature rises to 50°C, control the dropwise temperature by controlling the cooling liquid Keep the temperature between 50 and 55°C, keep the temperature for dripping, keep warm for 3.5 hours after dripping, cool down to about 30°C, filter, and dry the filter cake to obtain white crystal 2,6-dibromo-4-trifluoromethoxy Aniline 55.4g, purity 99.2% (HPLC), yield 98.1%.

[0040] The mother liquor was cooled to 0 degrees by sucti...

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Abstract

The invention discloses a preparation method of a thifluzamide key intermediate, namely 2,6-dibromo-4-(trifluoromethoxy)aniline. The method comprises the following operating steps: (1) adding water into a reaction bottle, dropwise adding concentrated sulfuric acid under the stirring condition, putting metal bromide and a catalyst, adding 4-trifluoromethoxyaniline and stirring for 30 minutes; (2) dropwise adding hydrogen peroxide at 30 DEG C, controlling the dropwise adding speed to enable the reaction temperature to be slowly increased to 50 DEG C, controlling the temperature of the reaction bottle by cooling liquid at 50 to 55 DEG C, continuously adding the hydrogen peroxide dropwise, and performing heat-preserving reaction at 50 to 55 DEG C for 2 to 3.0 hours after addition; (3) after the reaction, adding water and stirring, and filtering to obtain white-like 2,6-dibromo-4-trifluoromethoxyaniline. The synthesis method provided by the invention has the characteristics of environmental friendliness, safety, no three wastes, high synthesis yield and high product quality.

Description

technical field [0001] The invention belongs to the field of organic synthesis, and in particular relates to a method for synthesizing 2,6-dibromo-4-(trifluoromethoxy)aniline, a key intermediate of thiofluxamide. Background technique [0002] Thiofuramide was first developed by Monsanto in 1992, and sold to Rohm and Haas in 1994 for development. In 2001, Rohm and Haas was merged into Dow AgroSciences, and the trade name was Mansui. Mansui is a new thiazole carboxyl N-benzamide broad-spectrum fungicide, which has special effects on many basidiomycete diseases in rice, wheat, other field crops, lawns and pastures. [0003] At present, the process route for preparing 2,6-dibromo-4-(trifluoromethoxy)aniline is mainly to select 4-trifluoromethoxyaniline as raw material and obtain it by bromination reaction in different systems. . [0004] US5045554 discloses that 2,6-dibromo-4-(trifluoromethoxy)aniline is the key intermediate for the preparation of thifluxamide, and discloses t...

Claims

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Application Information

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IPC IPC(8): C07C217/84C07C213/08
CPCC01B7/093C07C213/02C07C213/08C07C217/84
Inventor 黄海军朱明亮
Owner YANCHENG LIMIN CHEM
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