Method for preparing 2-aminopyridine and alkyl derivative

A technology for aminopyridine and derivatives, which is applied in the field of preparing 2-aminopyridine and its alkyl derivatives, can solve the problems of unsatisfactory product quality, high equipment requirements, low product yield and the like, and achieves easy operation and low equipment requirements. , the effect of simple reaction route

Inactive Publication Date: 2004-10-27
ZHEJIANG UNIV
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

Because this method will be carried out at the melting temperature, the equipment requirements are high, the operation is difficult, and the product yield is low, and the product quality is not ideal.

Method used

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  • Method for preparing 2-aminopyridine and alkyl derivative
  • Method for preparing 2-aminopyridine and alkyl derivative
  • Method for preparing 2-aminopyridine and alkyl derivative

Examples

Experimental program
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Effect test

Embodiment 1

[0024] Example 1: 2-aminopyridine

[0025] 1) 2-cyanopyridine (20.8g, 0.2mol) was dropped into a mixed solvent of water (50mL) and acetone (50mL), and 10% H was added dropwise within 15 minutes under stirring 2 o 2 (123.5mL), heated up to 50°C, continued to stir for 2.5 hours, stopped the reaction, refrigerated, filtered with suction, and dried to obtain 23.4g of white solid 2-amidopyridine, which was directly used in the next reaction.

[0026] 2) Put the white solid obtained in the previous step into 12% NaOH aqueous solution (200mL), and add Br dropwise at 0°C 2 (10.5mL), keep the temperature at about 0°C, after the dropwise addition is complete, raise the temperature to 60°C for 0.5 hour reaction, and stop the reaction. The reaction solution was cooled, extracted twice with ethyl acetate (50 mL), the organic phase was washed twice with water (50 mL), dried, and concentrated to give a red liquid, which was distilled under reduced pressure (20 mmHg, 82-83° C.) to give 16.6...

Embodiment 2

[0027] Example 2: 2-Aminopyridine

[0028] The acetone was replaced with ethanol (50ml), and the rest was the same as in Example 1 to obtain 16.2g of white solid with a yield of 86.1% and a melting point of 60-61°C.

Embodiment 3

[0029] Example 3: 2-amino-3-picoline

[0030] The process was as in Example 1, using 2-cyano-3-picoline as raw material. The crude product was distilled under reduced pressure (20mmHg, 107-108.5°C) to obtain a white solid with a yield of 87.4% and a melting point of 33.5°C.

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Abstract

A process for preparing 2-amino pyridine and its alkyl derivative from 2-cyanopyridine or its alkyl derivative includes incomplete hydrolysis and Hofmann degradation. Its advantage is high output rate (80%) and purity up to 99% or more.

Description

technical field [0001] The invention relates to a preparation method of 2-aminopyridine, an intermediate of medicine, pesticide and dye, and its alkyl derivative. Background technique [0002] 2-Aminopyridine and its alkyl derivatives (formula I) are important medicine, pesticide and dye intermediates, and are applied in many aspects. Currently reported synthetic methods mainly contain the following: [0003] [0004] Where: R 1 ,R 2 ,R 3 ,R 4 stands for H, CH 3 or CH 2 CH 3 . [0005] 1. Obtained by directly reacting pyridine or its alkyl derivatives with sodium amide. Since the ammonification reaction with sodium amide must have 2-, 4-, and 6-position isomers, the product is difficult to purify and the yield is low; [0006] 2. It is obtained by Chichibabin's amination reaction of pyridine or its alkyl derivatives. The reagents used in this method are rare, the reaction conditions are also relatively harsh, and the yield is not high;...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C07D213/73
Inventor 戴立言王晓钟陈英奇
Owner ZHEJIANG UNIV
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