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Process for the preparation of 1-(4-chlorophenyl)-pyrazolidin-3-ones

A technology of pyrazolidine and chlorophenyl, applied in the field of fungicides synthesis, can solve the problems of high safety risk, small amount of three wastes, large amount of three wastes, etc., and achieves the effects of high reaction safety and small amount of three wastes

Active Publication Date: 2022-04-12
NUTRICHEM LAB CO LTD
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  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

[0004] The purpose of the present invention is to provide a new preparation of 1-(4-chlorophenyl)-pyrazolidin-3-one in order to overcome the problems of high safety risk and large amount of three wastes caused by the use of p-chlorophenylhydrazine in the prior art. The method, which avoids steps such as diazotization and sodium sulfite reduction, has high reaction safety and a small amount of three wastes, and is suitable for industrial production

Method used

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  • Process for the preparation of 1-(4-chlorophenyl)-pyrazolidin-3-ones
  • Process for the preparation of 1-(4-chlorophenyl)-pyrazolidin-3-ones
  • Process for the preparation of 1-(4-chlorophenyl)-pyrazolidin-3-ones

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Experimental program
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Effect test

Embodiment 1

[0066] 1) Synthesis of compound 3

[0067] Add 25.7g of p-chloroaniline 1 and 100mL of toluene into the reaction bottle, raise the temperature to 80°C, add 16.0g of acrylic acid 2 dropwise, and continue to keep warm for 3 hours to complete the reaction. The reaction solution is directly used in the next reaction, and the reaction yield is 95% %. In addition, after the completion of the reaction, a sample was taken for mass spectrometry, and the results are as follows.

[0068] MS m / z: 200 (M+1).

[0069] 2) Synthesis of Compound 4

[0070] In the toluene solution containing 37.8g compound 3, add 27.7g content and be 30% by weight of hydrochloric acid, control temperature at 5-10 ℃, add dropwise the aqueous solution containing 13.9g sodium nitrite (sodium nitrite content is 33% by weight), After the dropwise addition was completed and the reaction was continued for 0.5 hours, the aqueous phase was separated, and the organic phase was directly used for the next reaction, and ...

Embodiment 2

[0080] 1) Synthesis of compound 3

[0081] Add 25.7g of p-chloroaniline 1 and 13mL of chlorobenzene into the reaction flask, keep the temperature at 20°C, add 21.8g of acrylic acid 2 dropwise, and continue to keep warm for 24 hours to complete the reaction. Rate 90%. In addition, after the completion of the reaction, a sample was taken for mass spectrometry, and the results are as follows.

[0082] MS m / z: 200 (M+1).

[0083] 2) Synthesis of Compound 4

[0084] In the chlorobenzene solution that contains 35.8g compound 3, add 26.3g content and be 30% by weight hydrochloric acid, control temperature at minus 10-0 ℃, add dropwise the aqueous solution that contains 15.1g sodium nitrite (sodium nitrite content is 35% by weight ), after the dropwise addition was completed and the insulation reaction was continued for 0.5 hours, the aqueous phase was separated, and the organic phase was directly used for the next step reaction, and the reaction yield was 95%. In addition, the or...

Embodiment 3

[0092] 1) Synthesis of compound 3

[0093] Add 25.7g of p-chloroaniline 1 and 257mL of dichloroethane into the reaction flask, raise the temperature to reflux, add 14.7g of acrylic acid 2 dropwise, and continue the heat preservation reaction for 1 hour to complete the reaction. The reaction solution is directly used in the next step reaction. Rate 90%. In addition, after the completion of the reaction, a sample was taken for mass spectrometry, and the results are as follows.

[0094] MS m / z: 200 (M+1).

[0095] 2) Synthesis of Compound 4

[0096] In the ethylene dichloride solution that contains 35.8g compound 3, add 26.3g content and be the hydrochloric acid of 30% by weight, control temperature at 10-20 ℃, add dropwise the aqueous solution that contains 16.9g sodium nitrite (sodium nitrite content is 20% by weight %), after the dropwise addition was completed and the insulation reaction was continued for 0.5 hours, the aqueous phase was separated, and the organic phase wa...

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Abstract

The invention relates to the field of fungicide synthesis and discloses a method for preparing 1-(4-chlorophenyl)-pyrazolidin-3-one. The method comprises: 1) reacting p-chloroaniline and acrylic acid to obtain an addition reaction product; 2) performing nitrosation reaction with nitrite after the addition reaction product is purified, or making the addition reaction product directly Carry out nitrosation reaction with nitrite to obtain a nitrosation reaction product; 3) use palladium carbon as a catalyst and hydrogen as a reducing agent to perform reduction to obtain a reduced product; 4) remove the catalyst from the reduced product and perform heat treatment to obtain 1 ‑(4‑Chlorophenyl)‑pyrazolidin‑3‑one. According to the method of the invention, steps such as diazotization and sodium sulfite reduction are avoided, the reaction safety is high, the amount of three wastes is small, and the method is suitable for industrial production.

Description

technical field [0001] The invention relates to the field of fungicide synthesis, in particular to a method for preparing 1-(4-chlorophenyl)-pyrazolidin-3-one. Background technique [0002] Pyraclostrobin is a new type of fungicide with high efficiency, low toxicity, broad spectrum, safety to non-target organisms, safety and friendliness to users and the environment, 1-(4-chlorophenyl)-pyrazolidine-3 -Kone is a key intermediate in the synthesis of pyraclostrobin. [0003] CN1190961A discloses a kind of method that takes p-chlorophenylhydrazine and ethyl acrylate as raw material synthesis 1-(4-chlorophenyl)-pyrazolidin-3-one, and the documents published later are all taken as a reference, inevitably p-Chlorophenylhydrazine was used. However, the synthesis of p-chlorophenylhydrazine requires reaction steps such as diazotization and sodium sulfite reduction, which have high safety risks and a large amount of three wastes. Contents of the invention [0004] The purpose of t...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): C07D231/08
CPCC07D231/08
Inventor 吴坤王磊倪肖元汪韬曹璐李辛夷
Owner NUTRICHEM LAB CO LTD
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