Production method of aryl pyrazole nitrile

Abstract

The invention discloses a production method of aryl pyrazole nitrile, which comprises the following steps: dissolving 2, 6-dichloro-4-trifluoromethylaniline and ethyl 2, 3-dicyanopropionate in an acidic solvent to form a solution, adding the solution and sodium nitrite or a suspension composed of sodium nitrite and an alcohol into a reactor at the same time, and reacting to obtain a synthetic solution 1; adding a reducing agent into the synthetic liquid 1 to terminate the reaction to obtain a synthetic liquid 2; adding an alkaline material into the synthetic liquid 2 to carry out alcoholysis and cyclization under an alkaline condition to obtain a synthetic liquid 3; and adding the synthetic liquid 3 into an acidic solvent for neutralization, desolventizing and refining to obtain a target product.

Description

technical field [0001] The present invention proposes a continuous process for synthesizing arylpyrazole nitriles. Background technique [0002] The arylpyrazole nitrile chemical name of the present invention is 5-amino-3-cyano-1-(2,6-dichloro-4-trifluoromethylphenyl) pyrazole, also known as pyrazole ring, which The structural formula is as follows: [0003] [0004] 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 the death of insects. Due to this unique mechanism of action, this type of pesticide has significant characteristics different from conventional insecticides: this series of insecticides are effective against pests including Hemiptera...

AI Technical Summary

Problems solved by technology

The patent reaction produces a large amount of waste acid, the "three wastes" are difficult to deal with, and the yield is low; patent CN1137090C discloses a 5-amino-3-cyano-1-(2,6-dichloro-4-trifluoroform The preparation method of phenyl) pyrazole, sodium cyanide, ethyl cyanoacetate, paraformaldehyde react in ethanol hydrochloride to obtain ethyl 2,3-dicyanopropionate, then add ethanol hydrochloride, 2,6- Dichloro-4-trifluoromethylaniline, sodium nitrite, to obtain 2,3-dicyano-2-[2,6-dichloro-4-trifluoromethylphenyl)azo]propionic acid ethyl ester, and then cyclized with ammonia gas at 0°C, after extraction and crystallization, 5-amino-3-cyano-1-(2,6-dichloro-4-trifluoromethylphenyl)pyrazole was obtained , yield 78%

The patent uses highly toxic sodium cyanide, which poses a great safety hazard in production

Patent literature CN103396366B discloses a production method of 5-amino-3-cyano-1-(2,6-dichloro-4-trifluoromethylphenyl)pyrazole, 2,6-dichloro-4- Mix trifluoromethylaniline with acid, add ethyl 2,3-dicyanopropionate, add sodium nitrite or potassium nitrite at 5-15°C, add water phase after the reaction, and adjust the oil phase with concentrated ammonia water pH ≥ 11, after washing, suction filtration and drying, the target product is obtained with a yield of 83%. Although the process shows that sulfuric acid is not used, a large amount of hydrochloric acid or acetic acid solution is still used, and a large amount of waste water is generated after the synthesis

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