A kind of preparation method of thiofluxamide key intermediate-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 achieves yield The effect of increasing rate and purity

Active Publication Date: 2019-03-12
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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  • A kind of preparation method of thiofluxamide key intermediate-2,6-dibromo-4-(trifluoromethoxy)aniline

Examples

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Embodiment 1

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

[0031] Put 250g of water into a 1000mL three-necked flask, start stirring to drop 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℃, start dripping 38g of 35% hydrogen peroxide, the temperature rises when dripping, when the temperature rises to 50℃, control the dripping temperature at 50℃ by controlling the coolant Keep the temperature between ~55℃, keep the temperature for 3 hours after dripping, cool to about 30℃, filter and dry the filter cake to obtain white crystals of 2,6-dibromo-4-trifluoromethoxyaniline 55.6 g, purity 99.8% (HPLC), yield 99%.

[0032] The mother liquor is suction filtered and cooled to 0°C, and then filtered to obtain 10g filter cake and 310g mother liquor.

Embodiment 2

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

[0035] Put 310g of the mother liquor from the potassium sulfate crystals in Example 1 into a 1000mL three-necked flask, start stirring to drop 17.5 (0.175mol) sulfuric acid, and then add 43.5g potassium bromide (0.365moL) and 30g (99%, 0.168mol) 4-Trifluoromethoxyaniline, adjust the temperature to above 30℃, start to add 38g (0.391mol) of 35% hydrogen peroxide dropwise, the temperature rises when the temperature rises, when the temperature rises to 50℃, control the dropwise temperature by controlling the coolant Between 50~55℃, keep this temperature for dripping, keep the temperature for 3.5 hours after dripping, cool to about 30℃, 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 is suction filtered and cooled to 0°C, and then filtered to obtain 30.5g of fi...

Embodiment 3

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

[0039] Put 350g of the mother liquor from the potassium sulfate crystals in Example 2 into a 1000mL three-necked flask, start stirring to drop 17.5 (0.175mol) sulfuric acid, and then add 43.5g potassium bromide (0.365moL) and 30g (99%, 0.168mol) 4-Trifluoromethoxyaniline, adjust the temperature to above 30℃, start to add 38g (0.391mol) of 35% hydrogen peroxide dropwise, the temperature rises when the temperature rises, when the temperature rises to 50℃, control the dropwise temperature by controlling the coolant Between 50~55℃, keep this temperature for dripping, keep the temperature for 3.5 hours after dripping, cool to about 30℃, 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 suction filtered and cooled to 0°C, and then filtered to obtain 31 g of fi...

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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 specifically relates to a method for synthesizing the key intermediate 2,6-dibromo-4-(trifluoromethoxy)aniline of thiafluzamide. Background technique [0002] Thiofuramid was first developed by Monsanto in 1992 and sold to Rohm and Haas for development in 1994. In 2001, Rohm and Haas was merged into Dow AgroScience, under the trade name Mansui. Mansui is a new thiazole carboxyl N-benzamide broad-spectrum fungicide, which has specific effects on many Basidiomycetes diseases on rice, wheat, other field crops, lawns and grasslands. [0003] At present, the process route for preparing 2,6-dibromo-4-(trifluoromethoxy)aniline is mainly to choose 4-trifluoromethoxyaniline as the raw material, and obtain it by bromination reaction in different systems. . [0004] US5045554 discloses that 2,6-dibromo-4-(trifluoromethoxy)aniline is a key intermediate for the preparation of thiafluzamide, and discloses the syn...

Claims

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Application Information

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Patent Type & Authority Patents(China)
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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