Synthetic process of herbicide tembotrione

Abstract

The invention discloses a synthetic process of herbicide tembotrione. The synthetic process comprises the following steps: step 1) adding methyl 2-chloro-3-methyl-4-methylsulfonylbenzoate, a solvent,a catalyst and hydrobromic acid at the first, then dropwise adding hydrogen peroxide, washing with water, concentrating and recrystallizing after reaction to obtain bromine methyl 2-chloro-3-bromomethyl-4-methylsulfonylbenzoate; step 2) enabling the bromide, an alkali 1, the catalyst, the solvent and 2,2,2-trifluoroethanol to react, filtering, washing with water and concentrating after reaction; adding an alkali 2 and water to react, acidifying, filtering, washing and drying to obtain an etherate 2-chloro-3-(2,2,2-trifluoroethoxy)methyl-4-methanesulfonylbenzoic acid; and step 3) removing the solvent after reacting the etherate, the catalyst, thionyl chloride and the solvent; adding 1,3-cyclohexanedione and the solvent, dropwise adding triethylamine; adding acetone cyanohydrin after reaction, washing with water, layering, removing the solvent from an oil layer, adding the solvent for recrystallization, filtering and drying to obtain a beige solid, namely tembotrione. The synthetic process provided by the invention increases the yield of an intermediate, is more environmentally-friendly and safer, and reduces production costs.

Description

Technical field: [0001] The invention belongs to the field of preparation of pesticide technical materials, and in particular relates to a synthesis process of herbicide tembotrione. Background technique: [0002] Herbicide Tembotrione, chemical name: 2-{2-chloro-4-methylsulfonyl-3-[(2,2,2-trifluoroethoxy)methyl]benzoyl}cyclohexyl Alkane-1,3-dione is a triketone cornfield herbicide developed by Bayer in 2007. Its activity is higher than that of mesotrione (mesotrione, mesotrione), and it is safe for crops. Ebisulfone is mainly used in cornfields. It is a post-emergence HPPD (p-hydroxyphenylpyruvate dioxygenase) inhibitor herbicide, which can block the biosynthesis of prenyl quinone in plants, causing chlorosis and discoloration , tissue necrosis, and eventually died within 2 weeks. Teratrione has a wide herbicidal spectrum and a long suitable period for weeding. It mainly targets various broad-leaved weeds and gramineous weeds in the middle and late stages of cornfields af...

AI Technical Summary

Problems solved by technology

[0006] The patent No. CN105601548A of Heilongjiang University has reported that the technique of synthesizing tembotrione with 3-chloro-2-methylaniline is in the preparation of 2-chloro-3-bromomethyl-4-methylsulfonylbenzoic acid methyl ester At that time, expensive NBS was also used as bromination agent, a large amount of solid waste would be generated, and the yield was low, only 75.2%.

[0007] The patent No. CN104292137A of Wuhan Engineering University has reported the technique that takes 2-chlorotoluene as starting material synthetic tembotrione, when preparing 2-chloro-3-bromomethyl-4-methylsulfonylbenzoic acid methyl ester, with The more dangerous bromine is a brominating agent, and the yield is low, only 70%; In the case of benzoic acid, the sodium 2,2,2-trifluoroethoxide used cannot be mass-produced at present, and the raw materials cannot be bought; when preparing tembotrione, the price of cyanoacetone is too expensive, the production cost is high, and the intermediate state 2-Chloro-3-(2,2,2-trifluoroethoxy)methyl-4-methanesulfonylbenzoic acid-3-oxo-1-cyclohexenyl ester is separately separated and treated, resulting in complicated process and low yield The rate is low, only 69%

[0008] The patent No. CN106008290A of Anhui Jiuyi Agricultural Co., Ltd. has reported the synthetic technique of tembotrione, in the preparation of 2-chloro-3-(2,2,2-trifluoroethoxy)methyl-4-methylsulfonylbenzene For formic acid, the sodium 2,2,2-trifluoroethoxide used cannot be mass-produced at present, and the raw materials cannot be bought; when preparing tembotrione, an expensive condensing agent is used, and the amount is large, and the synthesis cost is high

[0009] "Pesticides" volume 56, No. 5, reported the synthesis process of the cornfield herbicide tembotrione. When synthesizing 2-chloro-3-bromomethyl-4-methylsulfonylbenzoic acid methyl ester, the risk is relatively high. Large bromine is a brominating agent; when synthesizing 2-chloro-3-(2,2,2-trifluoroethoxy)methyl-4-methanesulfonylbenzoic acid, sodium methylate was used as a raw material, Sodium methoxide is flammable, explosive, sensitive to air and moisture, and quickly decomposes into methanol and sodium hydroxide when it encounters water. The conditions of use in the industrial process are harsh. Acetonitrile is used in the synthesis of tembotrione, which belongs to the control category. Toxic chemicals, because they are extremely volatile, may easily cause chronic poisoning accidents during the reproduction process

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