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A kind of 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 the problems of complicated operation, difficult to meet safety production, low safety factor, etc., and achieve the effect of simple process

Active Publication Date: 2022-04-12
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

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

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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 specific 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 material solution dropwise, add dropwise for 2 hours, keep warm for 3-4 hours, after the reaction is completed, 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, ra...

Embodiment 2

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

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Abstract

The invention belongs to the field of chemical synthesis, and relates to a preparation method of 3-[3-bromo-2-methyl-6-(methylsulfonyl)phenyl]-4,5 dihydroisoxazole, which uses 2 ,3-dimethylaniline is obtained by reacting 2,3-dimethylaniline as the starting material. The oximation product is obtained by diazotizing, brominating and then oximating the 2,3-dimethylaniline. The main feature is that the oximation product is passed through a pot Oxidation and ring formation of isoxazole to obtain the target product. The advantage of the invention is that the last two-step route breaks the monopoly of the traditional route, is safe and environmentally friendly, easy to industrialize, and has a 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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Patent Type & Authority Patents(China)
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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