Preparation method of clomazone

Abstract

The invention relates to a preparation method of clomazone, wherein an intermediate, 4,4-dimethylisoxazole-3-one, is synthesized by dropwise adding chloro-pivaloyl chloride to a raw material, hydroxylamine hydrochloride, under the effects of a self-made ether catalyst; and then the intermediate is condensed with o-chlorobenzyl chloride under the effects of a caustic soda flake catalyst to synthesize a raw drug of the clomazone. The preparation method uses easy-to-obtained raw materials and mild reactions, is high in yield and is simple in separation and purification, has low cost, is environment-friendly, and has great industrial application prospect.

Description

Technical field

[0001] The invention relates to a new method for preparing the herbicide clomazone, which is a kind of pigment inhibiting pre-emergence herbicide, and relates to the fields of oximation, ring closure, condensation and the like. Background technique

[0002] Clomazone is a high-efficiency, low-toxicity, and isoxazolone selective pre-emergence herbicide. It is mainly used to control broadleaf weeds and gramineous weeds in soybean fields. It can also be used for cassava, corn, rape, sugarcane and Tobacco field weeding. The main mechanism of action of clomazone is to inhibit the biosynthesis of carotene and chlorophyll by inhibiting the synthesis of isoprene compounds. At present, the preparation methods reported in the literature are generally as follows: The o-chlorobenzaldehyde method mainly uses o-chlorobenzaldehyde as the starting material. First, o-chlorobenzaldehyde and salt

[0003] Acid hydroxylamine reacts to generate oxime, and then the oxime is reduced to o...

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