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Preparation method of 3-[3-bromo-2-methyl-6-(methylsulfonyl) phenyl]-4, 5-dihydroisoxazole

A technology of methylsulfonyl and dihydroisoxazole, applied in the direction of organic chemistry, can solve problems such as difficult to meet safety production, low safety factor, complicated operation, etc., and achieve the goals of reducing raw material types, improving safety index, and simplifying process Effect

Active Publication Date: 2020-10-30
山东京博生物科技有限公司
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

[0008] The above-mentioned two routes for synthesizing the intermediate (E) have many steps, and the reaction uses hydrogen, ethylene, chlorine, flammable, explosive and poisonous gases, which has a low safety factor and complicated operation, and is difficult to meet the needs of safe production. Therefore, a safer method is urgently needed. Environmentally friendly, easy-to-industrial production methods to fill the gaps in this field

Method used

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  • Preparation method of 3-[3-bromo-2-methyl-6-(methylsulfonyl) phenyl]-4, 5-dihydroisoxazole
  • Preparation method of 3-[3-bromo-2-methyl-6-(methylsulfonyl) phenyl]-4, 5-dihydroisoxazole
  • Preparation method of 3-[3-bromo-2-methyl-6-(methylsulfonyl) phenyl]-4, 5-dihydroisoxazole

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0048] A kind of preparation method of 3-[3-bromo-2-methyl-6-(methylsulfonyl) phenyl]-4,5-dihydroisoxazole, its concrete steps are:

[0049] (1) Synthesis of Compound C

[0050] 33.33 g of DMSO, 153.35 g of THF, and 53.19 g of potassium tert-butoxide were added to the reaction flask, and the temperature was lowered to -15°C. Slowly add compound B 31.67g (0.133mol), n-butyl nitrite 20.96g, DMSO 30.0g, THF100g mixed feed solution, add dropwise for 2h, keep warm for 3-4h, after the reaction is complete, add hydrochloric acid dropwise, and control the temperature at Below -5°C, the solvent was recovered by distillation of the feed liquid, washed with water for extraction, and the solvent was recovered by distillation of the organic phase to obtain 27.37 g of compound C with a yield of 75.2%.

[0051] (2) Synthesis of Compound D

[0052] Add 30.11g of ethanol, 27.37g (0.1mol) of compound C, and 0.33g (0.001mol) of sodium tungstate to the reaction flask, raise the temperature to 8...

Embodiment 2

[0056] A kind of preparation method of 3-[3-bromo-2-methyl-6-(methylsulfonyl) phenyl]-4,5-dihydroisoxazole, its concrete steps are:

[0057] (1) Synthesis of Compound C

[0058] 32.83 g of DMSO, 151.34 g of THF, and 52.77 g of potassium tert-butoxide were added to the reaction flask, and the temperature was lowered to -15°C. Slowly add compound B 31.41g (0.1313mol), n-butyl nitrite 20.80g, DMSO 30.0g, THF100g mixed feed solution, dropwise for 2h, heat preservation reaction for 3-4h, after the reaction is completed, add hydrochloric acid dropwise, and control the temperature at Below -5°C, the solvent was recovered by distilling the feed liquid, washed with water and extracted, and the solvent was recovered by distillation of the organic phase to obtain 27.37 g of compound C with a yield of 75.8%.

[0059] (2) Synthesis of Compound D

[0060] Add DMSO 41.05g, compound C 27.37g (0.1mol), sodium tungstate 0.495g (0.0015mol) to the reaction flask, raise the temperature to 90°C, ...

Embodiment 3

[0064] A kind of preparation method of 3-[3-bromo-2-methyl-6-(methylsulfonyl) phenyl]-4,5-dihydroisoxazole, its specific steps are:

[0065] (1) Synthesis of Compound C

[0066] 33.25 g of DMSO, 153.0 g of THF, and 53.12 g of potassium tert-butoxide were added to the reaction flask, and the temperature was lowered to -15°C. Slowly add compound B 31.62g (0.1328mol), n-butyl nitrite 20.94g, DMSO 30.0g, THF100g mixed feed solution, add dropwise for 2h, keep warm for 3-4h, after the reaction is complete, add hydrochloric acid dropwise, and control the temperature at Below -5°C, the solvent was recovered by distillation of the feed liquid, washed with water for extraction, and the solvent was recovered by distillation of the organic phase to obtain 27.37 g of compound C with a yield of 75.3%.

[0067] (2) Synthesis of Compound D

[0068] Add 35.58g of DMF, 27.37g (0.1mol) of compound C, and 0.413g (0.00125mol) of sodium tungstate to the reaction flask, raise the temperature to 85...

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Abstract

The invention belongs to the field of chemical synthesis, the invention relates to a preparation method of 3-[3-bromo-2-methyl-6-(methylsulfonyl) phenyl]-4, 5 -dihydroisoxazole. The 3-[3-bromo-2-methyl-6-(methylsulfonyl) phenyl]-4, 5 -dihydroisoxazole is prepared by taking 2, 3-dimethylaniline as an initial raw material for reaction. The method comprises the following steps: diazotizing, brominating and oximating the 2, 3-dimethylaniline to obtain an oximated product, and is mainly characterized in that the oximated product is oxidized by a one-pot method, and then subjected to isoxazole cyclization to obtain the target product. The method has the advantages that monopoly of a traditional route is broken through in the last two steps, and the method is safe, environmentally friendly, easyto industrialize and promising in market prospect.

Description

technical field [0001] The invention relates to the field of chemical synthesis, and specifically provides a preparation method of 3-[3-bromo-2-methyl-6-(methylsulfonyl)phenyl]-4,5-dihydroisoxazole. Background technique [0002] Fenpyrazone is a new type of herbicide developed by BASF in Germany. This herbicide has significant effects on weeds resistant to glyphosate, triazines, acetolactate synthase inhibitors and acetyl-CoA carboxylase inhibitors. It is a broad-spectrum post-emergence herbicide and can effectively control annual grasses and broad-leaved weeds in corn fields. [0003] 3-[3-Bromo-2-methyl-6-(methylsulfonyl)phenyl]-4,5-dihydroisoxazole is the most important intermediate in the synthesis of fenpyrazone, and its synthetic route There are mainly the following two types (refer to patent US 2003 / 0216580 A1): [0004] (1) Using 2,3-dimethylaniline as the starting material to react to obtain the intermediate 3-[3-bromo-2-methyl-6-(methylsulfonyl)phenyl]-4,5-di Hy...

Claims

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Application Information

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IPC IPC(8): C07D261/04
CPCC07D261/04
Inventor 韩仁萍刘英贤郭龙龙王祥传樊其艳于连友宫薇薇黄文昌冯其龙赵先亮成晓彤
Owner 山东京博生物科技有限公司
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