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Method for producing substituted pyrazolecarboxylic acid chlorides

A pyrazole carbonyl chloride, unsubstituted technology, applied in botany equipment and methods, animal repellent, biocide, etc., can solve the problems of low space-time yield and unfavorable safety technology

Inactive Publication Date: 2014-08-13
BAYER IP GMBH
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

The method has a low space-time yield and is unfavorable from a safety-technical point of view due to the hydrogen peroxide involved

Method used

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  • Method for producing substituted pyrazolecarboxylic acid chlorides
  • Method for producing substituted pyrazolecarboxylic acid chlorides
  • Method for producing substituted pyrazolecarboxylic acid chlorides

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0064] To a solution of 48.5 g of 5-chloro-1,3-dimethyl-1H-pyrazole-4-carbaldehyde in 230 ml of chlorobenzene was added 36 g of sodium carbonate. Subsequently, at 60° C., 3.9 g of 2,2-azobyronitrile (AIBN) were added, 24 g of chlorine gas were passed through within 4 hours and a further 6 g of AIBN were added. After the gas sparging was complete, the reaction solution was stirred for an additional 30 minutes. The solid was filtered off and washed with a little chlorobenzene. After solvent removal, 5-chloro-1,3-dimethyl-1H-pyrazole-4-carbonyl chloride was obtained in 74% yield.

Embodiment 2

[0066] To a solution of 48 g of 5-chloro-1,3-dimethyl-1H-pyrazole-4-carbaldehyde in 230 ml of chlorobenzene was added 36.5 g of sodium carbonate. Subsequently, 1.2 g of di(t-butylcyclohexyl) peroxycarbonate was added at 20°C, and the resulting mixture was heated to 40°C. 24 g of chlorine gas was introduced within 4 hours. After the gassing was complete, the reaction solution was stirred at 40° C. for a further 30 minutes. The solid was filtered off and washed with a little chlorobenzene. After solvent removal, 5-chloro-1,3-dimethyl-1H-pyrazole-4-carbonyl chloride was obtained in 68% yield.

Embodiment 3

[0068] To a solution of 48 g of 5-chloro-1,3-dimethyl-1H-pyrazole-4-carbaldehyde in 230 ml of chlorobenzene was added 51.8 g of potassium carbonate in the presence of protective gas. Subsequently, 24 g of chlorine gas was introduced at 20° C. for 4 hours under irradiation with a mercury lamp. After the gassing was complete, the reaction solution was stirred for a further 20 minutes at 20° C. under irradiation. The solid was filtered off and washed with a little chlorobenzene. After solvent removal, 5-chloro-1,3-dimethyl-1H-pyrazole-4-carbonyl chloride was obtained in 95% yield.

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Abstract

The invention relates to a method for producing substituted pyrazole acid chlorides by chlorination of the aldehydes of formula (II) under radical conditions.

Description

[0001] This application is a divisional application of the 200880002458.3 patent application for invention filed on January 9, 2008, entitled "Method for Preparing Substituted Pyrazole Carbonyl Chlorides". technical field [0002] The present invention relates to a process for the preparation of substituted pyrazolyl chlorides by chlorination of aldehydes of formula (II) under free radical conditions. Background technique [0003] Pyrazolyl chlorides are important units for the preparation of active crop protection ingredients. [0004] Pyrazolyl chlorides are usually prepared by reacting carboxylic acids with a chlorinating agent. An advantage of this method is based on the fact that the corresponding carboxylic acids are readily prepared and thus commercially available. The preparation of substituted pyrazolyl chlorides does not meet this prerequisite because the corresponding carboxylic acids are not readily available. [0005] For example, pyrazole-4-carboxylic acid is...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C07D231/16
CPCC07D231/16A01N43/56
Inventor N·卢J-D·海因里希A·斯特劳布T·沃尔M·J·福特
Owner BAYER IP GMBH