Method for preparing herbicide topramezone

A technology based on phenyl and isoxazolyl, which is applied in the field of preparing the herbicide fenflumezone, which can solve the problems of difficult recovery, expensive catalyst, and low total yield

Inactive Publication Date: 2014-05-14
CHINA PHARM UNIV
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0006] Through a large number of literature surveys, it was found that because fenfentrazone is still in the patent protection period, the current domestic research on fenfentrazone mainly focuses on its mechanism of action, field application, safety research, and the separation and quantitative analysis of the original drug. There are few literatures about the synthesis, and the German BASF company and the Japanese Soda Co., Ltd. have made patent reports on the synthesis of fenfentrazone respectively.
Among them, the initial raw material 3-dimethyl-4-methylsulfonylbenzoic acid methyl ester in the patent route reported by Soda Company is difficult to obtain, there is no ready-made product on the market, and there are many steps in the experiment that cannot be completely reacted , needs to be purified and separated by column chromatography; in addition, this route also uses highly toxic reagents such as acetone cyanohydrin, and the total yield is only about 5%; the route is long, the total yield is low, the cost is high, and the operation is troublesome, which is not conducive to industrial production
BASF has reported two complete synthetic routes and several possible synthetic routes. The total yield of the two reported complete routes can reach more than 20%, but multiple steps require the use of high pressure and heating equipment, which requires high equipment; In addition, precious metal compound catalysts such as metal palladium and metal platinum need to be used. These catalysts are expensive and difficult to recycle, which makes the total cost relatively high.

Method used

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  • Method for preparing herbicide topramezone
  • Method for preparing herbicide topramezone
  • Method for preparing herbicide topramezone

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0059] Synthesis of compound (VIII)

[0060]

[0061] Add 120ml of N,N-dimethylformamide into a 500ml reaction flask, cool to -40°C, slowly add 33.6g of potassium methoxide in batches, and stir evenly. Then, under strong stirring, 30g (0.2mol) of 3-nitro-o-xylene and 27.4g of n-butyl nitrite mixed solution was slowly added dropwise to the reaction solution, and the temperature was controlled at -45~-35°C for about 4.5h. After the dropwise addition, the reaction was continued at this temperature for 3.5h. After the reaction is completed, slowly add 40mL of water dropwise, then add 40mL of glacial acetic acid to adjust the pH of the reaction solution to 5-6, control the temperature below -5°C, then pour the reaction solution into 600ml of ice water, stir for 30min, filter with suction, and wash the filter cake with water , and dried to obtain 30.9 g of off-white solid. The crude product was added to 100ml of toluene, stirred at room temperature for 1.5h, filtered, and the f...

Embodiment 2

[0064] Synthesis of compound (VII)

[0065]

[0066] Add 10.8g (0.06mol) of 2-methyl-6-nitrobenzaldehyde oxime to a 250ml reaction bottle, dissolve it in 100ml of acetonitrile, heat to 60°C, add a small amount of N-chlorosuccinimide, wait until the reaction starts, Cool the reaction solution, dissolve 8.2g of N-chlorosuccinimide in 60ml of acetonitrile and slowly add it dropwise into the reaction solution at 40-50°C, continue stirring for 30min after the addition, evaporate the acetonitrile under reduced pressure, and wash the residue with 150ml of toluene After dissolving, stir for 1 hour, filter with suction, transfer the filtrate to a 250ml autoclave, slowly add 6.0g of triethylamine dropwise, and then feed ethylene to react for 8 hours under a pressure of 6bar. After the reaction, the reaction liquid was washed with saturated sodium bicarbonate solution and water respectively, dried over anhydrous sodium sulfate, and the solvent was evaporated under reduced pressure to ...

Embodiment 3

[0069] Synthesis of compound (VI)

[0070]

[0071] Add 10.0g (0.05mol) 3-(2-methyl-6-nitrophenyl)-4,5-dihydroisoxazole in 250ml reaction bottle, 35g stannous chloride dihydrate, dissolve with 150ml ethanol, Heat to reflux for 5 hours, spin to dry ethanol, adjust the pH of the residue to 10-11 with 20% sodium hydroxide, add ethyl acetate, stir well, filter with suction, wash the filter cake with ethyl acetate, and wash the filtrate three times with water, without After drying with sodium sulfate, the solvent was distilled off under reduced pressure to obtain 7.8 g of brown-gray crystalline product with a yield of 91.3%.

[0072] 1 H NMR (CDCl 3 , 300Hz) δ: 2.27(s, 3H, CH 3 ), 3.26(t, 2H, CH 2 ), 4.10 (s, 2H, NH 2 ), 4.46(t, 2H, CH 2 ), 6.61(t, 2H, Ar-H), 7.06(t, 1H, Ar-H); ESI-MS: 199.1[M+Na] + .

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Abstract

The invention aims to provide a method for synthesis and preparation of [2-methyl-3- (4,5-dihydro-3-isoxazole)-4-(methyl sulfonyl) phenyl]-(5-hydroxy-1-methyl-1H-parazole-4-based) ketone (topramezone). According to the method, raw materials are simple and easy to obtain, post-processing is simple, the total recovery is high, the defects existing in the prior art and the defects concerning cost are overcome, and an important reference can be provided for industrial production.

Description

technical field [0001] The invention relates to a method for preparing the herbicide fenflumezone by using 3-nitro-o-xylene as a raw material. technical background [0002] [2-Methyl-3-(4,5-dihydro-3-isoxazolyl)-4-(methylsulfonyl)phenyl]-(5-hydroxy-1-methyl-1H-pyrazole -4-yl) ketone (Topramezone) fenflumezone (CAS210631-68-8, ISO common name is Topramezone), its chemical structure is as follows: [0003] [0004] Fenfentrazone is a p-hydroxyphenylpyruvate dioxygenase (4-HPPD) inhibitor discovered and developed by BASF in Germany, which contains both pyrazole and isoxazole structures. The 4-HPPD inhibitor is A new herbicide target identified in the 1990s. It indirectly affects the synthesis of carotenoids by inhibiting 4-hydroxyphenylpyruvate dioxygenase (HPPD) in plastoquinone biosynthesis and interferes with the synthesis of chloroplasts under light. And features that eventually lead to weed death. Since HPPD inhibitors have different mechanisms of action in animals a...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C07D413/10
CPCC07D413/10
Inventor 张大永陈志银余双双吴晓明
Owner CHINA PHARM UNIV
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