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A kind of preparation method of 5-amino-3-cyano-1-(2,6-dichloro-4-trifluoromethylphenyl)pyrazole

A technology of trifluoromethylphenyl and trifluoromethylaniline is applied in the field of preparation of 5-amino-3-cyano-1-pyrazole, which can solve the problem that the product content can only reach 98%, and the production risk coefficient can be quantified. Large, poor chlorination reaction selectivity, etc., to achieve the effect of high product yield, low equipment requirements, and good selectivity

Active Publication Date: 2021-02-26
SUZHOU KAIYUAN MINSHENG SCI & TECH CORP
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  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

However, the product content of the process can only reach 98%, and the yield can only reach about 90%;
[0007] In CN201911238649.6, the synthesis method using 2,6-dichloro-4-trifluoromethylaniline as a raw material, the main disadvantage of this process is that the reaction mechanism is complicated, there are many side reactions, and the content of the obtained product can only reach 95%, and The yield is low, such as considering the yield of 2,6-dichloro-4-trifluoromethylaniline, the yield of the whole reaction will be lower
[0008] In CN201911238649.6, 2,6-dichloro-4-trifluoromethylaniline is used as raw material to form a salt with 2,6-dichloro-4-trifluoromethylaniline in an acid solution, and then quickly add 2 , Ethyl 3-dicyanopropionate, adding sodium nitrite at room temperature, then stirring and adding water to separate layers, and finally ring-closing reaction in ammonia water medium to obtain the finished product, but the reaction time of this process is long, and the product content reaches 96%. The yield is more than 83%, and if the yield of 2,6-dichloro-4-trifluoromethylaniline is also considered, the yield of the whole reaction will be even lower
[0009] In CN101289401B, it is proposed to use 3,4,5-trifluorotoluene as a raw material to prepare 2,6-dichloro-4-trifluoromethylaniline directly through ammonia, but the ammonia conditions of this technical scheme are harsh, and the reaction pressure is between Above 10MPa, the quantitative production risk factor is large, and the selectivity of the chlorination reaction is poor, there are many side reactions, and the product is difficult to purify
[0010] In CN1137090C, the highly toxic sodium cyanide is used, and there is a great potential safety hazard in production

Method used

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  • A kind of preparation method of 5-amino-3-cyano-1-(2,6-dichloro-4-trifluoromethylphenyl)pyrazole
  • A kind of preparation method of 5-amino-3-cyano-1-(2,6-dichloro-4-trifluoromethylphenyl)pyrazole
  • A kind of preparation method of 5-amino-3-cyano-1-(2,6-dichloro-4-trifluoromethylphenyl)pyrazole

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0039] Synthesis of intermediate ring compounds

[0040] Add 167.2g (1.1mol) of ethyl 2,3-dicyanopropionate, 500g ethanol, and 200g 30% hydrochloric acid into a 2000mL four-necked reaction flask, start stirring, cool down to 0°C, and start to drop trifluoro Mixed solution of 161g (1.0mol) of methylaniline and 160g of ethanol and 195g of sodium nitrite solution (sodium nitrite: 79g, water: 116g), control the rate of addition, and finish dropping at the same time for about 6 hours. For 4 hours, the sample was controlled in the middle, and the purity of trifluoromethylaniline was 0.3% by HPLC. Add 50g of sodium bisulfite solution (sodium bisulfite: 20g, water: 30g) to quench the reaction. After the reaction, dilute with 15% 120g of ammonia water was used to adjust the pH=5, the dropping time was 4h, the temperature was 12°C, and then the temperature was kept at 15°C for 2h. The central control, the HPLC detection purity of the ring compound was 99.2%, and the solvent ethanol was ...

Embodiment 2

[0042] Synthesis of intermediate ring compounds

[0043] Add 197.6g (1.3mol) of ethyl 2,3-dicyanopropionate, 500g of ethanol, and 250g of 30% hydrochloric acid into a 2000mL four-necked reaction flask, start stirring, cool down to -5°C, and start to dropwise add three Mixed solution of 161g (1.0mol) of fluoromethylaniline and 160g of ethanol and 250g of sodium nitrite solution (sodium nitrite: 100g, water: 150g), control the rate of addition, and drop it at the same time for about 8 hours, and drop it at 5°C Insulated reaction for 4 hours, sampling control, the purity of trifluoromethylaniline HPLC detection is 0.2%, adding 50g of sodium bisulfite solution (sodium bisulfite: 20g, water: 30g) to quench the reaction, after the reaction is completed, use 15 % diluted ammonia water 110g to adjust the pH=4, the dropping time is 3h, the temperature is 18°C, and then continue to keep warm at 15°C for 2h, sampling and testing, the purity of the ring compound is 99.46% by HPLC, the sol...

Embodiment 3

[0046] Synthesis of 5-amino-3-cyano-1-(2,6-dichloro-4-trifluoromethylphenyl)pyrazole

[0047] Add 330g (content: 96.95%) of the intermediate cyclic compound of Example 1 into a 2000mL four-necked reaction flask, 1350g dichloroethane, 8g (0.04878mol) of azobisisobutyronitrile, stir, and start to pass through at 15°C. Chlorine gas 281g (3.96mol), after about 4 hours, the temperature did not exceed 45°C during the chlorine pass, then began to heat up to 80°C and continued to keep warm for 4 hours, sampling and testing, the purity of the intermediate cyclic compound was 0.2% by HPLC, stop the reaction , add 200g of water to stir, let stand to separate and separate, adjust the pH=10 with 150g of 15% dilute ammonia water in the oil phase, add the time for 2h, the temperature is 25°C, continue the reaction at 25°C for 4h, take a sample for detection, and the purity of the product by HPLC is 98.49 %, start to recover dichloroethane under reduced pressure; after the recovery, add 650g ...

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Abstract

The invention provides a preparation method of 5-amino-3-cyano-1-(2,6-dichloro-4-trifluoromethylphenyl)pyrazole. The preparation method takes p-trifluoromethylaniline as a raw material, carries out diazotization reaction and forms a ring with ethyl 2,3-dicyanopropionate under weakly acidic conditions; feeds an appropriate amount of chlorine gas into the ring compound for chlorination , by adjusting the pH decarboxylation to obtain the product 5-amino-3-cyano-1-(2,6-dichloro-4-trifluoromethylphenyl) pyrazole. The preparation method of 5-amino-3-cyano-1-(2,6-dichloro-4-trifluoromethylphenyl)pyrazole of the present invention has simple operation, good chlorination selectivity and few side reactions 1. The product yield is high, and the reaction conditions are mild, which is conducive to realizing industrialization; the average yield of the method is not less than 95%, and the product purity is more than 99.50%.

Description

technical field [0001] The invention relates to a preparation method of 5-amino-3-cyano-1-(2,6-dichloro-4-trifluoromethylphenyl)pyrazole, belonging to the technical field of compound synthesis. Background technique [0002] Arylpyrazoles are important intermediates of N-phenylpyrazole pesticides such as fipronil, ethiprole, butene-fipronil. The action principle of N-phenylpyrazole pesticides such as fipronil and ethiprole is to interfere with the chloride ion channel through the chloride channel regulated by γ-aminobutyric acid, destroy the activity of the normal central nervous system, and cause insect death. Since its entry into the pesticide market, fipronil has been well received by the market due to its excellent insecticidal effect. For many years, the global annual sales volume has ranked among the top ten insecticides and pesticides, becoming one of the best-selling pesticides. Others such as ethiprole (Ethpronil) and butylene fipronil are also excellent insecticide...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): C07D231/38
CPCC07D231/38
Inventor 孙思余志强赵飞沈洁卫海浩
Owner SUZHOU KAIYUAN MINSHENG SCI & TECH CORP
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