Method for synthesizing isoxaflutole

Abstract

The invention discloses a method for synthesizing isoxaflutole. The method includes the steps of S1, performing etherification reaction, to be more specific, adding dichloroethane, sodium methyl mercaptide, cyclopropyl-4-(2-chloro-4-trifluoromethyl) benzoyl isoxazole and a phase transfer catalyst into a reaction kettle, performing sufficient reaction under certain temperature, and performing heat preservation on the reaction kettle during the reaction; after the reaction, taking out reaction liquid for detection, standing the qualified reaction liquid, and removing wastewater containing the sodium methyl mercaptide to obtain C15H12F3NO2S mixed liquid; S2, performing oxidation reaction, to be more specific, dropwise adding hydrogen peroxide into the obtained C15H12F3NO2S mixed liquid while stirring, performing heat preservation after the adding of the hydrogen peroxide, and standing for a certain period of time. The method has the advantages that the dichloroethane which is cheap and easy to obtain is used as the solvent, the dichloroethane can be directly recycled after simple desolvation, simple operation is achieved, and cost is lowered; conversion rate in each step is high, high yield is achieved, the purity of obtained intermediate is high, and the method is easy to popularize and industrialize.

Description

technical field [0001] The invention relates to the synthesis of isoxaflutole, in particular to a method for synthesizing isoxaflutole. Background technique [0002] Isoxaflutole is an organic heterocyclic herbicide with high efficiency and low toxicity. It has broad-spectrum herbicidal activity and can be used both pre-emergence and post-emergence. Among the various synthetic techniques that have been published so far, isoxafenazole is obtained by using 2-bromo-5-trifluoromethylaniline and dimethyl disulfide as raw materials through reactions such as methylthiolation, carboxyl substitution and hydrolysis. ketone intermediates; there are also 3,4-dichlorotrifluoromethylbenzene as raw materials, through carboxyl substitution, esterification and methylthiolation to obtain isoxaflutole intermediates; but the raw materials used in the above routes are all relatively expensive High, difficult to obtain, and the synthetic route needs to undergo methylthiolation first, and then un...

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Problems solved by technology

[0004] Patent EP524018 discloses a preparation process of isoxaflutole: 2-bromo-5-trifluoromethylaniline is used as raw material, and the intermediate 2-methylthio is obtained through reactions such as methylthiolation, carboxyl substitution and hydrolysis. -Methyl 4-trifluoromethylbenzoate, then undergoes condensation reaction with cyclopropylmethyl ketone, and then undergoes oxidation reaction to obtain isoxaflutole; therefore, the published prior art, regardless of the substance The starting material, which synthetic route to use, all need to undergo methylthiolation first, and then undergo condensation reaction, and the presence of methylthio on the benzene ring has a large steric hindrance, which makes the condensation reaction more difficult and the yield is low.

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