Eureka AIR delivers breakthrough ideas for toughest innovation challenges, trusted by R&D personnel around the world.

Preparation method of key intermediate of 3-bromo-1-(3-chloro-2-pyridyl)-1H-imidazole-5-carboxylic acid

A technology of pyridyl and intermediates, which is applied in the field of new preparation of key intermediates, can solve problems such as low reaction temperature, gas explosion, and slow reaction progress, and achieve the effects of reducing production costs, reducing safety hazards, and improving production efficiency

Active Publication Date: 2021-06-25
杭州新桂实业有限公司
View PDF4 Cites 2 Cited by
  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

In the process of throwing ammonium persulfate, the reaction temperature is low or the speed of adding ammonium persulfate is too slow, which will make the reaction proceed very slowly. The reaction proceeds rapidly in an instant and produces a large amount of gas, which may cause an explosion if it cannot be released in time

Method used

the structure of the environmentally friendly knitted fabric provided by the present invention; figure 2 Flow chart of the yarn wrapping machine for environmentally friendly knitted fabrics and storage devices; image 3 Is the parameter map of the yarn covering machine
View more

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0021] Add 2,3-dichloropyridine to a 500ml reaction bottle, then add hydrazine hydrate, reflux at 100°C for 10 hours, then cool down to 10°C and centrifuge to obtain 3-chloro-2-pyridyl wet product, dry it in a drying oven and then Put into ethanol and heat up to 20°C, pour diethyl maleate and sodium ethylate into reaction at 60°C, cool down to 10°C and centrifuge to obtain 2-(3-chloro-2-pyridyl)-5-oxo-3-pyrazolidine. 2-(3-Chloro-2-pyridyl)-5-oxo-3-pyrazolidine reacts with bromide of phosphorus oxybromide in acetonitrile to generate 3-bromo-1-(3-chloro-2-pyridyl )-4,5-dihydro-1H-pyrazole-5-carboxylic acid ethyl ester wet product.

[0022] Add 3-bromo-1-(3-chloro-2-pyridyl)-4,5-dihydro-1H-pyrazole-5-carboxylic acid ethyl ester wet product: 94g (dried to 80g) in a 500ml reaction bottle, Then successively drop into 320g of process water and then drop into 60g of sodium overflow acid. Slowly raise the temperature to 100°C and keep it warm for 3 hours to prepare 3-bromo-1-(3-chlor...

Embodiment 2

[0024] Put 2,3-dichloropyridine into a 500ml reaction bottle, then add hydrazine hydrate, reflux at 105°C for 15 hours, then cool down to 20°C and centrifuge to obtain 3-chloro-2-pyridyl wet product, dry it in a drying oven and then Put into ethanol and heat up to 20°C, pour diethyl maleate and sodium ethoxide into reaction at 70°C, cool down to 10°C and centrifuge to obtain 2-(3-chloro-2-pyridyl)-5-oxo-3-pyrazolidine. 2-(3-Chloro-2-pyridyl)-5-oxo-3-pyrazolidine reacts with bromide of phosphorus oxybromide in acetonitrile to generate 3-bromo-1-(3-chloro-2-pyridyl )-4,5-dihydro-1H-pyrazole-5-carboxylic acid ethyl ester wet product.

[0025] Add 3-bromo-1-(3-chloro-2-pyridyl)-4,5-dihydro-1H-pyrazole-5-carboxylic acid ethyl ester wet product: 94g (dried to 80g) in a 500ml reaction bottle, Then successively drop into 320g of process water and then drop into 60g of sodium overflow acid. Slowly raise the temperature to 105°C and keep it warm for 1.5 hours to prepare 3-bromo-1-(3-c...

Embodiment 3

[0027] Put 2,3-dichloropyridine into a 500ml reaction bottle, then add hydrazine hydrate, reflux at 102°C for 12 hours, then cool down to 15°C and centrifuge to obtain 3-chloro-2-pyridyl wet product, dry it in a drying oven and then Put into ethanol and heat up to 20°C, pour diethyl maleate and sodium ethoxide into reaction at 65°C, cool down to 10°C and centrifuge to obtain 2-(3-chloro-2-pyridyl)-5-oxo-3-pyrazolidine. 2-(3-Chloro-2-pyridyl)-5-oxo-3-pyrazolidine reacts with bromide of phosphorus oxybromide in acetonitrile to generate 3-bromo-1-(3-chloro-2-pyridyl )-4,5-dihydro-1H-pyrazole-5-carboxylic acid ethyl ester wet product.

[0028] Add 3-bromo-1-(3-chloro-2-pyridyl)-4,5-dihydro-1H-pyrazole-5-carboxylic acid ethyl ester wet product: 94g (dried to 80g) in a 500ml reaction bottle, Then successively drop into 320g of process water and then drop into 60g of sodium overflow acid. Slowly raise the temperature to 102°C and keep it warm for 2.5 hours to prepare 3-bromo-1-(3-c...

the structure of the environmentally friendly knitted fabric provided by the present invention; figure 2 Flow chart of the yarn wrapping machine for environmentally friendly knitted fabrics and storage devices; image 3 Is the parameter map of the yarn covering machine
Login to View More

PUM

No PUM Login to View More

Abstract

The invention discloses a preparation method of a key intermediate of 3-bromo-1-(3-chloro-2-pyridyl)-1H-imidazole-5-carboxylic acid. The method comprises the following steps: by taking 2,3-dichloropyridine as an initial raw material, carrying out a hydrazine hydrate reflux reaction, and then conducting cooling and centrifuging to obtain a 3-chloro-2-pyridyl wet product; then, enabling the 3-chloro-2-pyridyl wet product to react with diethyl maleate and sodium ethoxide to generate 2-(3-chloro-2-pyridyl)-5-oxo-3-pyrazolidine; then carrying out bromination reaction on the 2-(3-chloro-2-pyridyl)-5-oxo-3-pyrazolidine and phosphorus oxybromide to produce a 3-bromo-1-(3-chloro-2-pyridyl)-4,5-dihydro-1H-pyrazole-5-carboxylic acid ethyl ester wet product; putting the 3-bromo-1-(3-chloro-2-pyridyl)-4,5-dihydro-1H-pyrazole-5-carboxylic acid ethyl ester wet product into water, adding sodium persulfate, and carrying out a reaction so as to obtain 3-bromo-1-(3-chloro-2-pyridyl)-1H-pyrazole-5-carboxylic acid ethyl ester; and conducting hydrolysis in water to obtain 3-bromo-1-(3-chloro-2-pyridyl)-1H-imidazole-5-carboxylic acid. The method can greatly improve the production efficiency and reduce the production cost, and can be directly used for the next reaction without drying treatment.

Description

technical field [0001] The invention relates to a new preparation method of a key intermediate of the insecticide chlorantraniliprole, in particular to a 3-bromo-1-(3-chloro-2-pyridyl)-1H-imidazole-5- A new preparation process of the key intermediate of formic acid. Background technique [0002] 3-Bromo-1-(3-chloro-2-pyridyl)-1H-imidazole-5-carboxylic acid as a key intermediate of the novel ryanodine receptor insecticide chlorantraniliprole. Its follow-up products have a wide range of uses and a large market demand. This product uses 2,3-dichloropyridine 2-(3-chloro-2-pyridyl)-5-oxo-3-pyrazolidinidine as the starting material, after amination, cyclization, bromination, oxidation, Made by hydrolysis reaction. In the past industrial production, oxidative dehydrogenation, an important one-step reaction, had a relatively high hidden danger in safe production and operation. The specific steps are to put the dried 3-bromo-1-(3-chloro-2-pyridyl)-4,5-dihydro-1H-pyrazole-5-carbox...

Claims

the structure of the environmentally friendly knitted fabric provided by the present invention; figure 2 Flow chart of the yarn wrapping machine for environmentally friendly knitted fabrics and storage devices; image 3 Is the parameter map of the yarn covering machine
Login to View More

Application Information

Patent Timeline
no application Login to View More
IPC IPC(8): C07D401/04
CPCC07D401/04
Inventor 张更真张国庆丁业久汪军挥
Owner 杭州新桂实业有限公司
Who we serve
  • R&D Engineer
  • R&D Manager
  • IP Professional
Why Eureka
  • Industry Leading Data Capabilities
  • Powerful AI technology
  • Patent DNA Extraction
Social media
Eureka Blog
Learn More
PatSnap group products

Browse by: Latest US Patents, China's latest patents, Technical Efficacy Thesaurus, Application Domain, Technology Topic, Popular Technical Reports.

© 2024 PatSnap. All rights reserved.Legal|Privacy policy|Modern Slavery Act Transparency Statement|Sitemap|About US| Contact US: help@patsnap.com