Synthetic process of 1-(4-chlorophenyl)-3-hydroxy-1-h-pyrazole

Abstract

The invention relates to a synthetic process of 1-(4-chlorophenyl)-3-hydroxy-1-h-pyrazole, which is characterized by comprising the following steps: firstly, preparing heavy nitrogen liquid by using p-chloroaniline as a raw material; then reducing the heavy nitrogen liquid by sodium sulfite solution; next, reacting with dimethyl ester, carrying out acidification by hydrochloric acid so as to obtain a mixture of 1-(4-chlorophenyl) pyrazolidine-3-ketone; finally, reacting with sodium hydroxide solution, carrying out acid modulation, and filtration and rectification, so as to obtain a final product. According to the synthetic process disclosed by the invention, after the heavy nitrogen liquid mixture is obtained in the step 1, the heavy nitrogen liquid mixture is directly used for the next step of reaction without being treated, the process of acidification of the hydrochloric acid is omitted temporarily through the reaction in the step 2, and the hydrochloric acid is directly adopted to carry out acidification and acid modulation in the step 3, so that one acidification process is omitted, and outputs of waste acid and waste water are reduced; synthesis of each ton of the 1-(4-chlorophenyl)-3-hydroxy-1-h-pyrazole can reduce generation of 10 tons of waste water and reduce consumption of 5 tons of hydrochloric acid.

Description

technical field [0001] The invention relates to a synthesis process, in particular to the synthesis process of 1-(4-chlorophenyl)-3-pyrazolol. Background technique [0002] 1-(4-Chlorophenyl)-3-pyrazolol is a very important intermediate in the synthesis of pyraclostrobin. Pyraclostrobin is a methoxyacrylate fungicide with a pyrazole structure. It was discovered by BASF in 1993, registered and launched in 2001, and has been used on more than 100 crops. In 2009, its sales reached 735 million US dollars, second only to azoxystrobin, becoming the second largest fungicide in the world. Pyraclostrobin has broad spectrum, high efficiency, low toxicity, is safe to non-target organisms, and is safe and friendly to users and the environment. It is an important product with good market prospects among strobilurin fungicides and whose patent is about to expire. [0003] At present, the synthetic route of 1-(4-chlorophenyl)-3-pyrazolol at home and abroad is as follows: [0004] [...

AI Technical Summary

Problems solved by technology

[0005] First synthesize p-chlorophenylhydrazine hydrochloride by chloroaniline, then synthesize 1-(4-chlorophenyl)pyrazolidin-3-one with esters, and finally react with potassium hydroxide solution to generate the final product. In the traditional technology Hydrochloric acid is used many times to adjust the pH of the solution, and the reaction is divided into three steps, the reaction is cumbersome, and it is easy to cause waste of materials and decrease in product yield

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