Preparation method of sulfonyl carfentrazone-ethyl

Abstract

The invention relates to a preparation method of sulfonyl carfentrazone-ethyl, which takes 2, 4-dichloroaniline as an initial raw material, and comprises the following steps of: 1, carrying out nitration reaction on a benzene ring of the 2, 4-dichloroaniline; as the N-difluoromethyl substituted triazolinone ring is formed, nitration and reduction reactions on the benzene ring can be carried out before the N-difluoromethyl substituted triazolinone ring is formed, and the N-difluoromethyl substituted triazolinone ring does not need to be placed in reaction environments such as mixed acid nitration and nitro reduction in the presence of concentrated sulfuric acid and concentrated nitric acid, so that the generation of byproducts is reduced, and the synthesis yield of the compound is improved; the production cost of the compound is reduced; and moreover, the problem that an N-difluoromethyl substituted triazolinone ring is unstable under certain nitrification conditions is also avoided, so that the nitrification and reduction methods have more choices, and a more advanced sulfonyl carfentrazone-ethyl production process is favorably developed.

Description

technical field [0001] The invention relates to the technical field of triazolinone herbicides, in particular to a preparation method of sulfentrazone. Background technique [0002] The triazolinone herbicide sulfentrazone is also known as sulfentrazone, and its chemical name is N-(2,4-dichloro-5-(4-difluoromethyl-4,5-dihydro-3 -Methyl-5-oxo-1H-1,2,4-triazol-1-yl)phenyl)methanesulfonamide. This herbicide was first developed by FMC Corporation of the United States. It has a good control effect on annual broad-leaved weeds, grass weeds and sedges. Its specific chemical structure is as follows: [0003] [0004] There are many reports on the preparation method of sulfentrazone, for example, US4743291 and US4818275 disclose the synthesis method of sulfentrazone starting from 2,4-dichloroaniline. In addition, Liang Kai (Liang Kai, Xu Gang, Yang Lirong, Wu Jianping, Chemical Reaction Engineering and Technology, 2012, 28(5), 412-417.) and Zhang Yuanyuan (Zhang Yuanyuan, Sun Yo...

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Problems solved by technology

The common point of all the above-mentioned methods is to synthesize the intermediate IV first, the right side of the intermediate structure is the N-difluoromethyl substituted triazolinone ring structure, and then the N-difluoromethyl substituted triazolinone ring structure Under the premise of the existence of the ketone ring, the reaction of mixed acid nitration and nitro reduction under the conditions of concentrated sulfuric acid and concentrated nitric acid is carried out on the 5-position of the left benzene ring; however, a certain proportion of nitration isomers and By-products such as dinitration products lead to low yields of the target product, and the N-difluoromethyl-substituted triazolinone ring has a risk of instability under conditions such as mixed acid and nitro reduction conditions, making the use of existing The cost of sulfentrazone synthesized by these technical schemes is high, the yield is low, and under the limitation of the presence of N-difluoromethyl-substituted triazolinone ring, the nitration on the 5-position of the left benzene ring is carried out The range of methods that can be adopted for reactions such as reduction and reduction is narrow, which is not conducive to the continuous improvement of the production process of sulfentrazone, a high-efficiency herbicide.

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