Preparation method of haloxyfop-R-methyl

Abstract

The invention discloses a preparation method of haloxyfop-R-methyl, which comprises the following steps: with hydroquinone as a raw material, reacting hydroquinone with (R)-2-methyl bromopropionate in the presence of an alkaline reagent to generate an intermediate (R)-2-(4-hydroxyphenoxy) methyl propionate; and then the haloxyfop-R-methyl and 3-chloro-2-bromo-5-trifluoromethylpyridine are directly prepared under the action of a catalyst to obtain the haloxyfop-R-methyl. The raw materials and reagents used in the method are cheap and easy to obtain, and the production cost can be effectively controlled; conditions are mild, operation is simple, and post-treatment is convenient; the prepared haloxyfop-R-methyl has high yield and purity, the optical purity of the target configuration (R) can reach 99%, the product quality is effectively guaranteed, and industrial production of the haloxyfop-R-methyl is better facilitated.

Description

technical field [0001] The invention belongs to the field of pesticide synthesis, and in particular relates to a preparation method of high-efficiency haloxyfop-pylene. Background technique [0002] High-efficiency fluroxyfop-pyl, the chemical name is 2-[4-(5-trifluoromethyl-3-chloro-pyridine-2-oxyl-)phenoxy]propionic acid methyl ester, is a new generation of fluorohetero High-efficiency herbicide. This species is a systemic conduction herbicide with good selectivity. It has excellent control effect on perennial stubborn grass weeds such as reed, imperata, and bermudagrass. It is highly safe for broad-leaved crops, and the effect is more stable under low temperature conditions. Compared with gazolone, high-efficiency haloxyfop-pyl replaces the ethoxyethyl group in gazolone with a methyl group in structure, and removes the inactive S configuration, which is a refined product of R configuration. At the same dose, it has higher and more stable activity than Gaygrass, and it i...

AI Technical Summary

Problems solved by technology

The disadvantages of this method are: the use of chlorine is highly toxic and poor in safety and environmental protection; the high temperature and high pressure reaction requires too much equipment; the total yield of the three-step reaction is less than 80%, the route is complicated but the effect is not ideal, and it is not suitable for high-efficiency flupirin Industrialized Production of Methylhexapyl

Although the method achieves one-step preparation of the target product, its starting materials 2-fluoro-3-chloro-5-trifluoromethylpyridine and (R)-(+)-2-(4-hydroxyphenoxy)propane The preparation difficulty of methyl ester is all bigger, has increased production cost greatly

Moreover, the inventor of the present application also restored the process during the route development process, and the yield and purity of the prepared target product were significantly lower than the results recorded in the application text, so it is believed that this preparation method also cannot meet the high-efficiency fenopyrhe Industrial preparation of spirit

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