Synthesizing method of sulfentrazone

Abstract

The invention discloses a synthesizing method of sulfentrazone. The synthesizing method comprises the following steps of using a compound (II) as the raw material, and performing difluoro methylation,chlorination and bromination; then, performing methylsulfonylation, so as to obtain the final product of the sulfentrazone. The synthesizing method has the advantages that the obtained intermediate after chlorination is firstly brominated, and then the obtained intermediate after bromination and the methanesulfonamide are catalyzed by a catalyst to obtain the sulfentrazone; the chemical selectivity is high, and the dangerous technologies of nitrification, hydrogenation and the like in the traditional technology route are avoided; the production of a large amount of waste acid and waste waterin the nitrification process is avoided, the green effect is better, the efficiency is higher, and the safety and reliability are higher; the whole technology is simple and convenient, and the reaction conditions are mild; by adjusting the reaction conditions, the yield rate of the obtained product is high, the quality of the product is high, and the synthesizing method is suitable for industrialized production.

Description

technical field [0001] The invention relates to a method for synthesizing sulfentrazone, in particular to a method for synthesizing sulfentrazone with a brominated intermediate and methylsulfonamide under the catalysis of a catalyst. Background technique [0002] Sulfentrazone is a herbicide of difluoromethyltriazolinone class, the 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, its chemical structural formula is as follows: [0003] . [0004] The traditional synthesis method of sulfentrazone is: use 2,4-dichloroaniline as raw material, undergo diazotization, condensation, N-alkylation, nitration, reduction, and amidation to obtain sulfentrazone, the reaction formula is as follows : [0005] . [0006] U.S. Patent No. 4,818,275 adopts the above-mentioned route to synthesize sulfentrazone. In this synthetic method, concentrated sulfuric acid is used as a solvent for nitration, and iron ...

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Problems solved by technology

2. Excessive triethylamine or pyridine produces a large amount of waste water, consumes 2 equivalents of methanesulfonyl chloride, the atom economy is poor, and the yield of sulfentrazone is low, the yield is only about 66%

U.S. Patent No. 5,990,315 discloses a method for catalyzing sulfonylation reactions using soluble salts such as quaternary ammonium salts and quaternary phosphonium salts. The method uses triazolinone aniline and methanesulfonyl chloride as raw materials to directly obtain sulfentrazone in one step. , this method solves the problem of direct sulfonylation, but there is still the problem of strong corrosion of methanesulfonyl chloride, and the catalyst used is more expensive, and the product yield is about 83%, which is still very low

US7169952 discloses a method for directly sulfonylation of triazolone aniline and methanesulfonyl chloride with high-boiling amides such as DMF and tertiary amines as catalysts. This method uses cheap catalysts to solve the problem of direct sulfonylation, but it will Formamide impurities are produced, which affects product quality and yield, and there are still problems of strong corrosion of methanesulfonyl chloride and generation of saline wastewater

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