Preparation method of pyrazosulfuron

The esterification and rearrangement reactions in the presence of alkaline substances and solvents were carried out by one pot method, which solved the problems of complex preparation process of the existing sulfonyl pyrazole and low yield, and achieved the preparation effect of high purity and high yield .

CN119490456APending Publication Date: 2025-02-21SHANDONG ACHIEVE TESTING TECHNOLOGY CO LTD
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Patent Information

Application Number
CN202311044368.3
Authority / Receiving Office
CN · China
Patent Type
Applications(China)
Current Assignee / Owner
Filing Date
2023-08-18
Publication Date
2025-02-21

AI Technical Summary

Technical Problem

The existing preparation process of sulfonyl pyrazole is complex and complicated, requiring the separation of intermediates, with low yields and high equipment requirements.

Method used

The one-pot method is used to prepare sulfonyl pyrazole. By esterification and rearrangement reactions in the presence of alkaline substances and solvents, the post-treatment method of thermal delamination or filtration is avoided, which simplifies the process and reduces equipment requirements.

Benefits of technology

The preparation of sulfonyl pyrazole with high purity and high yield is achieved, which simplifies the process flow, reduces equipment demand, and improves product yield.

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Abstract

The invention relates to the field of herbicide preparation, and discloses a preparation method of pyrazosulfuron, and the preparation method comprises the following steps: S1, in the presence of an alkaline substance 1 and a solvent, mixing 1, 3-dimethyl-5-hydroxypyrazole and 2-methylsulfonyl-4-trifluoromethyl benzoyl chloride, and carrying out an esterification reaction; s2, dehydrating the reaction product obtained in the step S1; s3, in the presence of an alkaline substance 2 and a catalyst, carrying out rearrangement reaction on the dewatered product obtained in S2; and S4, desolventizing and purifying the reaction product obtained in S3 to obtain the pyrazosulfuron. The one-pot method is adopted to prepare the pyrazosulfuron, so that the condition that an ester intermediate needs to be obtained from an esterification product in a post-treatment mode of thermal stratification or filtration is avoided, operations such as secondary powder recovery of the ester intermediate are avoided, the process is simplified, post-treatment equipment is reduced, and the yield is increased.
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Citation Information

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