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One-step Synthesis of 6-Chloro-3h-oxazolo[4,5-b]pyridin-2-one

A 5-b, synthetic method technology, applied in the direction of organic chemistry, can solve the problems of harsh reaction conditions, high production cost, high reaction temperature, etc., and achieve the effect of easy-to-obtain raw materials, low production cost and mild reaction conditions

Active Publication Date: 2016-06-29
陕西友帮生物医药科技有限公司
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

The main disadvantage of this method is that the raw materials used are more expensive, the reaction conditions are harsh, the operation is cumbersome, the reaction temperature is high, and other chlorination products are generated simultaneously, the processing is troublesome, and the industrial production cost is high.
The synthetic method of 6-chloro-oxazol[4,5-b]pyridin-2(3H)-one disclosed in the patent literature (CN1386741A) is based on oxazol[4,5-b]pyridine-2(3H)- Ketones are obtained by chlorine chlorination as raw materials, but are accompanied by other chlorination products, and the cost of industrial production is high

Method used

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  • One-step Synthesis of 6-Chloro-3h-oxazolo[4,5-b]pyridin-2-one

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0014]

[0015] Add acetonitrile (150mL) and glacial acetic acid (36mL) into a 250mL three-neck round bottom flask. Add a reflux condenser to the three-necked flask, start the magnetic stirrer and add 2,3-dihydropyrido[2,3-d][1,3]oxazol-2-one (4.1g). When the 2,3-dihydropyrido[2,3-d][1,3]oxazol-2-one was completely dissolved, N-chlorosuccinimide (4.7 g) was added in portions. The reaction was stirred at 10°C for 4 hours, then heated to 60°C for an additional 6 hours. TLC and GC confirmed the completion of the reaction. Most of the solvent was removed by rotary evaporation, 100 mL of water was added to the reaction flask, and suction filtration was performed to obtain 4.95 g of crude product. The crude product was recrystallized from dichloromethane and ethyl acetate to obtain the pure product 6-chlorooxazol[4,5-b]pyridin-2(3H)-one (3.44g), with a yield of 67% and a purity of 99.2% (GC ). The melting point is 184~187°C (literature 183~186°C). NMR analysis, 1 HNMR (DMSO...

Embodiment 2

[0017] Add acetonitrile (1000mL) and glacial acetic acid (300mL) into a 2500mL three-neck round bottom flask. Add a reflux condenser to the three-necked flask, start the magnetic stirrer and add 2,3-dihydropyrido[2,3-d][1,3]oxazol-2-one (41g). When 2,3-dihydropyrido[2,3-d][1,3]oxazol-2-one was completely dissolved, N-chlorosuccinimide (47 g) was added in portions. It was then heated to 60° C. and reacted for another 6 hours. TLC and GC confirmed the completion of the reaction. Most of the solvent was removed by rotary evaporation, 500 mL of water was added to the reaction flask, and suction filtration was performed to obtain 49 g of crude product. The crude product was recrystallized from dichloromethane and ethyl acetate to obtain the pure product 6-chlorooxazol[4,5-b]pyridin-2(3H)-one (38g), yield 74%, purity 98.8% (GC) . The melting point is 185~187°C (literature 183~186°C).

Embodiment 3

[0019] Add dichloromethane (200 mL) into a 250 mL three-neck round bottom flask. Add a reflux condenser to the three-necked flask, start the magnetic stirrer and add 2,3-dihydropyrido[2,3-d][1,3]oxazol-2-one (4.1g). When the 2,3-dihydropyrido[2,3-d][1,3]oxazol-2-one was completely dissolved, N-chlorosuccinimide (4.7 g) was added in portions. The reaction was stirred at 10°C for 4 hours, then heated to reflux for 12 hours. TLC and GC confirmed the completion of the reaction. The solvent was removed by rotary evaporation. The crude product was recrystallized from dichloromethane and ethyl acetate to obtain the pure product 6-chlorooxazol[4,5-b]pyridin-2(3H)-one (3.14g), with a yield of 61% and a purity of 97.3% (GC ). The melting point is 182°C~185°C (literature 183°C~186°C).

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Abstract

The invention belongs to the field of organic synthesis, and particularly relates to a one-step synthesis method of 6-chlorine-3H-oxazole [4,5-b] pyridine-2-ketone. The one-step synthesis method of 6-chlorine-3H-oxazole [4,5-b] pyridine-2-ketone comprises the step as follows: oxazole [4,5-b] pyridine-2(3H)-ketone reacts with NCS(N-chlorosuccinimide) in a proper solvent at proper temperature, so as to generate 6-chlorine oxazole [4,5-b] pyridine-2(3H)-ketone. The 6-chlorine-3H-oxazole [4,5-b] pyridine-2-ketone is prepared by adopting a one-step method by reaction disclosed by the invention. The 6-chlorine-3H-oxazole [4,5-b] pyridine-2-ketone is cheap and available in raw materials, the method is simple and convenient to operate, mild in reaction condition, low in production cost, and easy in achieving industrial amplification, and the yield can be up to 89%.

Description

technical field [0001] The invention belongs to the field of organic synthesis, in particular to a one-step synthesis method of 6-chloro-3H-oxazolo[4,5-b]pyridin-2-one. Background technique [0002] Pyridophos is an excellent insecticide. Its corresponding preparations are contact and stomach poisoning agents with a validity period of more than 10 weeks. It has a broad spectrum of insecticide and can be used for public health insecticide, control or kill pastures Mosquitoes and flies in farms, farms, etc., especially have special effects on flies and cockroaches; it contains fast-acting and powerful sex hormone attractant ingredients. In agriculture, it can be used in cotton, fruit trees, vegetables and livestock to prevent and control various mites and moths, aphids, leaf lice, small borers, potato beetles, etc. Safe for mammals, it is a safe agent with high efficiency, low toxicity, low residue, and resistance to drug resistance. It is an organophosphorus insecticide reco...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): C07D498/04
CPCC07D498/04
Inventor 韩猛曹惊涛来新胜
Owner 陕西友帮生物医药科技有限公司