Synthesis method of 2, 3-dichloropyridine

A dichloropyridine and synthesis method technology, applied in the direction of organic chemistry, can solve the problems of high production cost, low synthesis yield, affecting the yield and purity of the final product, and achieve the effect of good quality and simple operation steps

Active Publication Date: 2020-09-04
SHIJIAZHUANG WANYE CHEM IND CO LTD
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Problems solved by technology

[0004] Chinese patent (CN102086174A) discloses a production method of 2,3-dichloropyridine, which uses 2-chloronicotinamide as a raw material to avoid the problem of many side reactions caused by 2-position chlorination, but 2 - Chloronicotinamide is not easy to obtain, so the industrialization prospect of this method is not high
This method has no selectivity to 2-position and 6-position chlorine in the hydrogenation process, so there are many side reactions, which seriously affect the yield and purity of the final product
[0009] Chinese patent (CN103145609A) discloses a kind of preparation method of 2,3-dichloropyridine, this method uses 2,3,6-trichloropyridine as starting material, uses ammonium formate as hydrogen donor, but the conversion of this method The yield is low, so the rectification method needs to be adopted in t

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  • Synthesis method of 2, 3-dichloropyridine
  • Synthesis method of 2, 3-dichloropyridine
  • Synthesis method of 2, 3-dichloropyridine

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Embodiment Construction

[0026] The technical solution of this patent will be further described in detail below in conjunction with specific embodiments.

[0027] One, the synthetic method of compound B

[0028] Put water (504.72g) and sodium hydroxide (60g, 1.5mol) into a 1000mL four-necked bottle, stir to dissolve, then add hydroxylamine hydrochloride (104.24g, 1.5mol) in batches, after the addition is complete, control the temperature at 20-30°C, add dropwise Cyclopentanone (84.12g, 1.0mol) was added dropwise for about 1 hour. After the drop was completed, the temperature was kept for 2.5 hours. The reaction mixture was extracted by adding dichloromethane, and the dichloromethane layer was taken for GC analysis. The residual cyclopentanone was less than 0.5%. . Add dichloromethane (504.72g), stir for 20min, let stand for 1h, separate the dichloromethane layer MC①, add dichloromethane (504.72g) for the water layer, stir for 20min, let stand for 1h, separate the dichloromethane layer MC②, Combine M...

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Abstract

The invention provides a synthesis method of 2, 3-dichloropyridine, which comprises the following steps: reacting cyclopentanone with hydroxylamine hydrochloride, and taking sodium hydroxide as an acid-binding agent to obtain a compound A; carrying out Beckmann rearrangement reaction on the compound A under the action of thionyl chloride to obtain a compound B; reacting the compound B with sodiumborohydride under the catalysis of cobalt acetate to obtain a compound C; reacting the compound C under the catalysis of ammonium chloride to obtain a compound D; reacting the compound D with chlorineunder the action of azodiisobutyronitrile to obtain a compound E; and reacting the compound E with tert-butyl hypobromite to obtain 2, 3-dichloropyridine. The method is simple in operation steps, theused reaction raw materials are cheap and easy to obtain, the total molar yield is 68.88%, the purity of the produced 2, 3-dichloropyridine is 98.0% or above, the product quality is good, and the method is suitable for industrial production.

Description

technical field [0001] The invention belongs to the technical field of synthesis of pesticide intermediates, in particular to a synthesis method of 2,3-dichloropyridine. Background technique [0002] 2,3-Dichloropyridine is an important fine chemical intermediate, which can be used as a key intermediate in the synthesis of a new type of insecticide - sulfbendamide. [0003] Chinese patent (CN103570609A) discloses a method for preparing 2,3-dichloropyridine, which uses nicotinamide as a raw material to react with sodium hypochlorite to prepare 3-aminopyridine, and then reacts hydrochloric acid and hydrogen peroxide to obtain 2-chloro-3-amino Pyridine, and finally the target product was obtained by Sandmeyer reaction. This method has more side reactions and lower yield. [0004] Chinese patent (CN102086174A) discloses a production method of 2,3-dichloropyridine, which uses 2-chloronicotinamide as a raw material to avoid the problem of many side reactions caused by 2-position...

Claims

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Application Information

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IPC IPC(8): C07D213/61
CPCC07D213/61
Inventor 李宝才潘光荣
Owner SHIJIAZHUANG WANYE CHEM IND CO LTD
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