Preparation method of azamethiphos intermediate 3H-oxazolo[4,5-b]pyridin-2-one

A technology of picoline phosphorus and intermediates, which is applied in the field of preparation of picoline phosphorus intermediate oxazo[4,5-b]pyridine-2 ketone, can solve the problem of short reaction steps, long reaction steps, difficult operation, etc. The problem is to achieve the effect of warm reaction conditions, short reaction steps and easy operation.

Inactive Publication Date: 2016-09-07
HANDAN ZHAODU FINE CHEM CO LTD
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  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

The preparation of pyridophos is to take oxazol[4,5-b]pyridin-2(3H) ketone as raw material, and obtain through reactions such as chlorination, hydroxymethylation, chlorination and condensation; The preparation method of azole [4,5-b] pyridin-2 (3H) ketone has: BU11.Chen.Jpn.1987,60 (5): 1793-1799 reports under the action of catalyst, the high-pressure reaction of CO; CN1393448A document The disclosed method uses 2-amino-3,5-hydroxypyridine as raw material to prepare oxazol[4,5-b]pyridine-2(3H)thione through cyclization and oxidation reaction to generate oxazol[4,5- B] the method of pyridin-2 (3H) ketone; above-mentioned method reaction step is long, is difficult to operate, and reaction condition is high, therefore, researches a kind of reaction step short, is easy to operate, the intermediate oxazole of picoline phosphorus that reaction condition is gentle[ The preparation method of 4,5-b]pyridin-2(3H)one is of industrial significance

Method used

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Effect test

Embodiment 1

[0014] Add 480g of 30% sodium hydroxide aqueous solution and 66g of 2-amino-3-hydroxypyridine into a 2L three-necked flask, stir to dissolve, and dissolve 192g of triphosgene in 400mL of toluene to make a solution; after the three-necked flask is slowly heated to 80°C, add Sanguang dropwise Gas toluene solution, the reaction temperature is controlled between 75-90 °C, and the reaction is kept for 6 hours after the dropwise addition; the temperature is lowered to 20-30 °C, and the pH value of the reaction solution is adjusted to be neutral with hydrochloric acid or sodium hydroxide, and the temperature is continued to drop to Below 10°C, filter, wash the filter cake once with water, and dry to obtain 54.6 g of white solid oxazol[4,5-b]pyridin-2(3H)one, with a yield of 85.8%. After the filtrate is separated, dry and recover toluene.

Embodiment 2

[0016] Add 810g of 30% sodium hydroxide aqueous solution and 110g of 2-amino-3-hydroxypyridine into a 2L three-necked flask, stir to dissolve, and dissolve 340g of triphosgene in 600mL of toluene and 300mL of chloroform to make a solution; after the three-necked flask is slowly heated to 80°C, Add the toluene and chloroform solution of triphosgene dropwise, control the reaction temperature between 74-88°C, keep the reaction for 8 hours after the dropwise addition; cool down to 20-30°C, adjust the pH value of the reaction solution with hydrochloric acid or sodium hydroxide to be neutral properties, continue to cool down to below 10°C, filter, wash the filter cake once with water, and dry to obtain 91.4g of white solid oxazol[4,5-b]pyridin-2(3H)one with a yield of 86.2%. After the filtrate is separated, dry Toluene and chloroform were recovered.

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Abstract

A preparation method of an azamethiphos intermediate 3H-oxazolo[4,5-b]pyridin-2-one includes the technological steps that 1, 2-amino-3-pyridinol is dissolved in a solvent; 2, alkali is added; 3, a triphosgene organic solution is dripped at -5-30 DEG C; 4, a reaction is carried out for 2-20 h at 40-90 DEG C; 5, solid-liquid separation is carried out after the temperature is cooled to 0-20 DEG C; 6, drying is carried out, and the azamethiphos intermediate 6-chloro-3H-oxazolo[4,5-b]pyridin-2-one is obtained. Compared with the prior art, according to the method, reaction steps are short, operation is easy, and reaction conditions are mild; besides, as triphosgene with low toxicity is used for replacing high-toxicity phosgene, the reaction yield reaches up to 85%, the organic solvent can be recycled and reused, and the method is suitable for industrial production.

Description

technical field [0001] The invention relates to a method for producing picoline, in particular to a method for preparing picoline intermediate oxazol[4,5-b]pyridin-2(3H)one. Background technique [0002] Pyridinium methyl, chemical name S-6-chloro-2,3-dihydro-2-oxo-1,3-oxazol[4,5-b]pyridin-3-yl-methyl-0,0 -Dimethylphosphorothioate; English name Azamethiphos, CAS No.: [35575-96-3], pyridophos is a kind of acaricide, which has both insecticidal activity and is a contact and stomach poisoning agent. Good efficacy, wide insecticidal spectrum, can be used for cotton, fruit trees, vegetables and livestock, public health and household control of various mites and moths, aphids, leaf lice, small borers, potato beetles and flies, cockroaches, etc. Low toxicity, it is a safe agent with high efficiency, low toxicity and low residue. The preparation of pyridophos is to take oxazol[4,5-b]pyridin-2(3H) ketone as raw material, and obtain through reactions such as chlorination, hydroxymet...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C07D498/04
CPCC07D498/04
Inventor 王运红高海珺李秋菊王柏军丁金囤时建刚张昊郑雪赵云赵彤彤
Owner HANDAN ZHAODU FINE CHEM CO LTD
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