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Preparation method of 7-bromo-4-hydroxy-3-quinoline carboxylic acid

A quinoline carboxylic acid and hydroxyl technology, which is applied in the field of preparation of 7-bromo-4-hydroxy-3-quinoline carboxylic acid, can solve the problems of low product purity, troublesome post-processing, low product yield and the like, and achieves Overcome the effects of many by-products, easy separation and simple operation

Active Publication Date: 2014-12-31
BEIJING GREENCHEM TECH
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

Specifically, because of the presence of lye, the bromine on the ethyl 7-bromo-4-hydroxyl-3-quinolinecarboxylate is removed, and finally 4,7-dihydroxyl-3-quinolinecarboxylate is obtained acid, ethyl 4,7-dihydroxy-3-quinolinecarboxylate and many other by-products, resulting in low product yield, troublesome post-processing, low product purity and many other disadvantages

Method used

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  • Preparation method of 7-bromo-4-hydroxy-3-quinoline carboxylic acid
  • Preparation method of 7-bromo-4-hydroxy-3-quinoline carboxylic acid

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preparation example Construction

[0032] The preparation method of 7-bromo-4-hydroxyl-3-quinoline carboxylic acid provided by the invention comprises:

[0033] 7-bromo-4-hydroxyl-3-quinoline carboxylic acid (C 1～3 ) Alkyl ester

[0034]

[0035] Among them, R 1 It is methyl, ethyl, n-propyl or isopropyl, and an organic solvent such as absolute ethanol or absolute methanol and a hydrochloric acid aqueous solution with a concentration of 1-2mol / L are added to the reaction vessel, wherein the amount of the solvent is based on each gram 7-bromo-4-hydroxyl-3-quinolinecarboxylic acid (C 1～3 ) Alkyl ester needs to add in the ratio of 25mL of solvent, 7-bromo-4-hydroxyl-3-quinolinecarboxylic acid (C 1～3 ) The molar ratio of alkyl ester to hydrochloric acid is 1:3-5, stirring and heating to reflux for 0.5-2 hours, preferably 1-1.5 hours, a large amount of solid products are precipitated, after the reaction is completed, filter, and the filtrate is concentrated until solids are precipitated , combined filter cake...

Embodiment 1

[0053] Preparation of 7-bromo-4-hydroxy-3-quinolinecarboxylic acid

[0054] Add 28.7g of analytically pure ethyl 7-bromo-4-hydroxy-3-quinolinecarboxylate (commercially available), 720mL of anhydrous methanol and 147mL of 1mol / L hydrochloric acid aqueous solution into the reaction flask, stir and heat to reflux for 1.5h, There is a large amount of solid product to separate out, after the reaction is completed, filter, the filtrate is concentrated until the solid is separated out, the combined filter cake is washed 3 times with methanol, and after drying, 22.7g of white solid 7-bromo-4-hydroxyl-3-quinolinecarboxylic acid is obtained , The calculated yield was 87.5%, and the purity of 7-bromo-4-hydroxyl-3-quinolinecarboxylic acid obtained by Agilent1100 liquid chromatography was 99.0%.

Embodiment 2

[0056] (1) Preparation of diethyl(3-bromoanilinomethylene)malonic acid

[0057] Add 30 g of analytically pure m-bromoaniline and 49 g of analytically pure diethyl ethoxymethylenemalonate into the reaction flask, stir, and heat slowly. When the reaction temperature rises to 110 ° C, stir for 1.5 h; after the reaction is completed, put The reaction solution is directly concentrated, and the ethanol generated by the reaction is removed, and the obtained thick product is purified by column chromatography, and after drying, 56.1 g of diethyl (3-bromoanilino methylene) malonic acid is obtained, and the calculated yield is 94%. The purity of diethyl (3-bromoanilinomethylene) malonic acid obtained by Agilent1100 liquid chromatography was 99.0%.

[0058] (2) Preparation of ethyl 7-bromo-4-hydroxy-3-quinolinecarboxylate

[0059] Under stirring, add 280 mL of diphenyl ether into the reaction flask, and when the temperature rises to 240°C, add 56.1 g of the above-prepared diethyl(3-bromo...

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Abstract

The invention relates to a preparation method of 7-bromo-4-hydroxy-3-quinoline carboxylic acid. The preparation method comprises that hydrochloric acid serves as a catalyst to catalyze 7-bromo-4-hydroxy-3-quinoline carboxylic acid (C1-3) alkyl ester for carrying out hydrolysis reaction, specifically, the preparation method comprises the following steps of: heating and refluxing 7-bromo-4-hydroxy-3-quinoline carboxylic acid (C1-3) alkyl ester, an organic solvent and 1-2 mol / L hydrochloric acid aqueous solution for 0.5-2 hours under stirring, and then filtering and washing filter cake to obtain 7-bromo-4-hydroxy-3-quinoline carboxylic acid. In an embodiment of the invention, 7-bromo-4-hydroxy-3-quinoline carboxylic acid (C1-3) alkyl ester is obtained by condensation and cyclization of m-bromoaniline and (C1-2) alkoxy methylene malonic acid bi(C1-3) alkyl ester. The preparation method is few in side reactions, simple in after-treatment, liable to separate the product, high in yield and high in product purity, so that the preparation method is suitable for industrial production.

Description

technical field [0001] The invention relates to a preparation method of 7-bromo-4-hydroxyl-3-quinoline carboxylic acid, which belongs to the technical field of organic synthesis. Background technique [0002] 7-Bromo-4-hydroxy-3-quinoline carboxylic acid is an important medicine, dye and pesticide intermediate, mainly used in the synthesis of antimalarial drugs, synthetic textile dyeing auxiliary agents and hair, fur dyes and in agriculture Used in the synthesis of pesticides and preservatives for vegetables and fruits. [0003] At present, the method for preparing 7-bromo-4-hydroxy-3-quinolinecarboxylic acid is to use m-bromoaniline as a raw material, and undergo condensation, cyclization, and hydrolysis under alkaline conditions to obtain the product. The product yield of this method is relatively low, mainly because the hydrolysis of last step 7-bromo-4-hydroxyl-3-quinolinecarboxylate ethyl ester is carried out under alkaline condition, produced a lot of by-products. Sp...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): C07D215/56
Inventor 宫宁瑞
Owner BEIJING GREENCHEM TECH
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