A kind of synthetic method of pyroxazole

A synthesis method and a technology for sulfofenazone, applied in the field of organic synthesis, can solve the problems of increased product cost, unpleasant smell of compounds, toxicity and the like

Active Publication Date: 2021-11-30
HEFEI JIUYI AGRI DEV
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0008] This method uses relatively dangerous isobutylene gas when preparing dihydroisoxazole intermediates, which will cause potential safety hazards in large-scale industrial production; the halogenation step uses relatively expensive reagents NBS or NCS, which will increase product costs. ; This route also uses sodium methyl mercaptide, which has an unpleasant smell and is poisonous; not only that, but the route has undergone multi-step oxidation and reduction reactions, and the steps are cumbersome, so it is not suitable for industrial production

Method used

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  • A kind of synthetic method of pyroxazole
  • A kind of synthetic method of pyroxazole
  • A kind of synthetic method of pyroxazole

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preparation example Construction

[0031] The invention provides a kind of synthetic method of pyrazafen, comprising the following steps:

[0032] Using compound I as the starting material, the intermediate II is synthesized through a cyclization reaction, and the intermediate II is subjected to a chlorination reaction under the action of a chlorinating agent to obtain the intermediate III; the intermediate III is reacted with thiourea to obtain the salt Salt intermediate IV;

[0033] The chlorination reagent is phosphorus pentachloride and / or phosphorus oxychloride;

[0034] The hydrochloride intermediate IV, compound VI react with formaldehyde to obtain intermediate VII, and the intermediate VII undergoes a difluoromethoxylation reaction under the condition of a catalyst to obtain intermediate VIII, and finally use hydrogen peroxide to treat The intermediate VIII is oxidized to obtain pyroxazole IX;

[0035] Described catalyst is sodium tungstate and acid;

[0036] The synthetic route among the present inv...

Embodiment 1

[0079] (1) Synthesis of compound II

[0080] Under the condition of nitrogen protection, 83.6 g (1.1 mol) of hydroxyurea was added into 500 mL methanol solution (2.4 mol / L) of potassium methoxide, and then stirred and dissolved at 25°C. At the same temperature, 128 g (1 mol) of ethyl 3,3-dimethacrylate was added dropwise for half an hour. Then it was stirred at 25°C for 18 hours. After the reaction was completed, the reaction solution was filtered to obtain a white solid, which was then dissolved in water and neutralized by adding 100 mL of hydrochloric acid (35%, 1.2 mol). Finally, it was extracted three times with 200 mL of 1,2-dichloroethane, the organic phases were combined, dried, and the solvent was distilled off under reduced pressure to obtain 91 g of a white solid with a yield of 80%.

[0081] (2) Synthesis of compound III

[0082] At 25°C, under nitrogen protection conditions, 99.5g of phosphorus pentachloride (0.48mol) was dissolved in 100mL of 1,2-dichloroethane...

Embodiment 2

[0095] Step (2) The synthesis of compound III was carried out according to the following steps, and the rest of the steps were carried out according to the method in Example 1.

[0096] (2) Synthesis of compound III

[0097] At 25°C, under nitrogen protection, 50g of phosphorus pentachloride (0.24mol) was dissolved in 100mL of toluene, compound II (25g, 0.22mol) was added to the solution in batches, and stirred at 25°C for 5 Hours. Control the reaction in the liquid phase. After the reaction, the reaction liquid was distilled under reduced pressure to obtain a yellow liquid, and then the liquid was poured into 100 mL of water, extracted 3 times with 150 mL of dichloroethane, the organic phase was collected, and the solvent was removed by distillation under reduced pressure. Obtained 20 g of light yellow liquid, yield: 68%.

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Abstract

The invention provides a synthetic method of metazazone sulfone, comprising the following steps: taking compound I as a starting material, and obtaining intermediate II through cyclization reaction, and the intermediate II is chlorinated under the action of a chlorination reagent. The reaction obtains intermediate III; the intermediate III reacts with thiourea to obtain the hydrochloride intermediate IV; the chlorination reagent is phosphorus pentachloride and / or phosphorus oxychloride; the hydrochloride intermediate IV, Compound VI is reacted with formaldehyde to obtain intermediate VII, and the intermediate VII is subjected to a difluoromethoxylation reaction to obtain intermediate VIII, and finally, under the condition of a catalyst, hydrogen peroxide is used to oxidize the intermediate VIII to obtain sulfone Metazazole IX; the catalyst is sodium tungstate and acid. In the present invention, the total yield is increased to 31-38%, and the raw materials are simple and easy to obtain, the reaction process is simple and safe, and the yield is relatively high, which has certain significance for industrial production.

Description

technical field [0001] The invention belongs to the technical field of organic synthesis, in particular to a synthetic method of pyrazafen. Background technique [0002] The English name of pyroxazole is Pyroxasulfone, and its chemical name is [3-[(5-difluoromethoxy-1-methyl-3-trifluoromethylpyrazol-4-yl)-methylsulfonyl] -4,5-dihydro-5,5-dimethyl-1,2-oxazole], the chemical formula structure is shown below. [0003] [0004] Metrafenazole is a pre-emergent soil treatment agent developed by Japan Combination Chemicals Co., Ltd. that can be used in most crop fields. Its mechanism of action is similar to that of acetochlor and its related herbicides. Absorption, inhibition of early growth of seedlings, destruction of meristems and coleoptiles, is a serious potential inhibitor of VLCFA (very long side chain fatty acid) biosynthesis in plants. However, it can be applied to a wide variety of crops, and its biological activity is much greater than that of acetochlor and metolac...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): C07D413/12
CPCC07D413/12
Inventor 祝玉超
Owner HEFEI JIUYI AGRI DEV
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