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A kind of preparation method of 2-fluoro-5-formyl chloride pyridine

A technology of formyl chloride pyridine and picoline, which is applied in the field of preparation of 2-fluoro-5-formyl chloride pyridine, can solve the problems that there is no very mature process technology report, and achieve the effect of low production cost and high conversion rate

Active Publication Date: 2022-03-04
内蒙古佳瑞米精细化工有限公司
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0003] At present, only reagent companies in the domestic market provide a small amount of samples, and the purity is usually only 98%, and there is no very mature process technology report for obtaining high-purity products

Method used

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  • A kind of preparation method of 2-fluoro-5-formyl chloride pyridine

Examples

Experimental program
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Effect test

Embodiment 1

[0025] In a 500mL three-necked flask, add 11.1g (0.1mol) of 2-fluoro-5-picoline, add 250mL of water, start mechanical stirring, and add 31.6g (0.2mol) of KMnO 4 and 5.6g (0.1mol) KOH, heated to 95°C in an oil bath, reacted for 5h, filtered while hot, and collected the filtrate. After the filtrate drops to normal temperature, adjust the pH value to 2-4 with concentrated hydrochloric acid, and filter if solids are precipitated; the filtrate is extracted twice with dichloroethane. The filtered solid and the extracted oil were mixed, and evaporated by rotary evaporation to obtain 11.8 g of off-white solid, which was 2-fluoro-5-carboxylic acid pyridine (melting point 275-278° C.).

[0026] Put the 2-fluoro-5-carboxylic acid pyridine obtained in the first step into a 500mL three-necked flask, add 200mL of dichloromethane, start stirring, add 16.0g of thionyl chloride dropwise, and react under reflux for 6h, distill off the solvent and excess dichloromethane Thionyl chloride. After...

Embodiment 2

[0028] In a 500mL three-necked flask, add 11.1g (0.1mol) of 2-fluoro-5-picoline, add 250mL of water, start mechanical stirring, and add 28.4g (0.2mol) of NaMnO 4 and 4.0g (0.1mol) NaOH, heated to 95°C in an oil bath, reacted for 5h, filtered while hot, and collected the filtrate. After the filtrate drops to normal temperature, adjust the pH value to 2-4 with concentrated hydrochloric acid, and filter if solids are precipitated; the filtrate is extracted twice with dichloroethane. The filtered solid and the extracted oil phase were mixed, and evaporated by rotary evaporation to obtain 11.5 g of off-white solid, which was pyridine 2-fluoro-5-carboxylate (melting point 275-278° C.).

[0029] The other steps were the same as in Example 1 to obtain 12.55 g of the colorless liquid product 2-fluoro-5-formyl chloride pyridine, which became an off-white solid after freezing, with a purity of 99.0% and a total yield of 78.7%.

Embodiment 3

[0031] In a 500mL three-necked flask, add 11.1g (0.1mol) of 2-fluoro-5-picoline, add 250mL of water, start mechanical stirring, and add 47.4g (0.3mol) of KMnO 4 and 5.6g (0.1mol) KOH, heated to 95°C in an oil bath, reacted for 5h, filtered while hot, and collected the filtrate. After the filtrate drops to normal temperature, adjust the pH value to 2-4 with concentrated hydrochloric acid, and filter if solids are precipitated; the filtrate is extracted twice with dichloroethane. The filtered solid and the extracted oil were mixed, and rotovapped to obtain 12.1 g of off-white solid, which was pyridine 2-fluoro-5-carboxylate (melting point: 275-278° C.).

[0032] Put the 2-fluoro-5-carboxylic acid pyridine obtained in the first step into a 500mL three-necked flask, add 200mL of dichloromethane, start stirring, add 16.0g of thionyl chloride dropwise, and react under reflux for 6h, distill off the solvent and excess dichloromethane Thionyl chloride. Add 85mL of n-heptane, cool an...

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Abstract

The invention relates to a preparation method of 2-fluoro-5-formyl chloride pyridine, which belongs to the technical field of organic chemistry. The method steps are: 1) using 2-fluoro-5-picoline as a raw material, reacting in the presence of potassium permanganate or sodium permanganate to obtain 2-fluoro-5-picoic acid pyridine; 2) using 2- Fluoro-5-formyl pyridinium and thionyl chloride or oxalyl chloride are refluxed in a chlorinated solvent. After the reaction is over, after the solvent is distilled under reduced pressure, add an alkane solvent to freeze and filter to obtain a 2-fluoro-5-formyl chloride pyridine solution. Rectification under reduced pressure gives 2-fluoro-5-formyl chloride pyridine. The invention has the advantages of high conversion rate, the purity of the obtained product is as high as 99.0 percent, the purity of the product is less than 0.5 percent, the production cost is low, and it is suitable for industrialized production.

Description

technical field [0001] The invention belongs to the field of organic synthesis, and in particular relates to a preparation method of 2-fluoro-5-formylchloropyridine. Background technique [0002] 2-Fluoro-5-formyl chloride pyridine (6-fluoro-3-formyl chloride pyridine), molecular formula C 6 h 3 ClFNO, CAS: 65352-94-5. This product is an important chemical intermediate raw material, which can further generate hydrazide, hydrazone and amide, and plays an important role in pesticides and medicines. Its application value and market prospect are very considerable, for example, it can be used to prepare 2-( 6-fluoropyridin-3-yl)-4,5-dihydropyridazole. [0003] At present, only reagent companies in the domestic market provide a small amount of samples, and the purity is usually only 98%. There is no very mature process technology report for obtaining high-purity products. Contents of the invention [0004] The object of the present invention is to provide a preparation metho...

Claims

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Application Information

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IPC IPC(8): C07D213/80C07D213/807C07D213/803
CPCC07D213/80C07D213/807C07D213/803
Inventor 柯有胜张孝朋刚宏辉
Owner 内蒙古佳瑞米精细化工有限公司
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