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Preparation of 2,4-dichloroquinazoline

A technology of dichloroquinazoline and quinazoline dione, applied in 2 fields, can solve the problems of high production cost, low reaction yield, unsuitable for industrialized production and the like, and achieves a technology with low production cost, low solvent toxicity and high yield. Effect

Inactive Publication Date: 2009-07-08
太仓浦源医药原料有限公司
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0010] The raw materials of route 1 are not easy to obtain and are not suitable for industrial production; although the raw materials of route 2 are easy to obtain, the reaction yield is low, the production cost is high, and dimethylaniline is more toxic

Method used

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  • Preparation of 2,4-dichloroquinazoline
  • Preparation of 2,4-dichloroquinazoline

Examples

Experimental program
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Effect test

Embodiment 1

[0023] A kind of preparation method of 2,4-dichloroquinazoline, comprises the steps successively:

[0024] (1), anthranilic acid reacts with potassium cyanate to generate 2,4-quinazolinedione

[0025] Take a dry 500ml four-neck flask, install a thermometer and a cooling tube, add 41g (0.3mol) anthranilic acid and 100ml water to form a mixture, then add dropwise 200ml aqueous solution of 55g (0.68mol) potassium cyanate, and stir for half an hour Add 36g of 0.5mol / L sodium hydroxide aqueous solution dropwise, control the temperature of the solution within 40°C, stir for half an hour, heat up to 85°C, keep it warm for 2 hours, cool to 0°C, add 30% hydrochloric acid to acidify, and adjust the pH to 2~3 , the temperature was kept at about 0° C., filtered and dried to obtain 42 g of 2,4-quinazolinedione, and the molar yield was 86.3% based on 2,4-quinazolinedione.

[0026] (2), 2,4-quinazoline diketone chlorination obtains 2,4-dichloroquinazoline

[0027] Take a 500ml dry four-nec...

Embodiment 2

[0029] A kind of preparation method of 2,4-dichloroquinazoline, comprises the steps successively:

[0030] (1), anthranilic acid reacts with potassium cyanate to generate 2,4-quinazolinedione

[0031] Take a dry 500ml four-neck flask, install a thermometer and a cooling tube, add 41g (0.3mol) anthranilic acid and 100ml water to form a mixture, then add dropwise 200ml aqueous solution of 60g (0.74mol) potassium cyanate, and stir for half an hour Add 60g of 0.3mol / L sodium hydroxide aqueous solution dropwise, control the temperature of the solution within 40°C, stir for half an hour, heat up to 90°C, keep it warm for 2.5 hours, cool to 0°C, add 30% hydrochloric acid to acidify, and adjust the pH to 2~3 , the temperature was kept at about 0° C., filtered and dried to obtain 45 g of 2,4-quinazolinedione, and the molar yield was 92.5% based on 2,4-quinazolinedione.

[0032] (2), 2,4-quinazoline diketone chlorination obtains 2,4-dichloroquinazoline

[0033] Get a 500ml dry four-ne...

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Abstract

The invention relates to a method for preparing 2,4-dichloroquinazoline. The method comprises the following steps that: (1) ortho-aminobenzoic acid reacts with potassium cyanate to generate 2,4-quinazoline diones; and (2) the 2,4-quinazoline diones and a chlorinating agent undergo a chlorination reaction to generate the 2,4-dichloroquinazoline. Particularly, in step (1), the mass ratio of the ortho-aminobenzoic acid to the potassium cyanate is 1:1-3, the reaction uses water as a solvent, and is performed at a temperature of between 20 and 100 DEG C with pH of between 9 and 12; and in step (2), the chlorination reaction uses fatty amine as a solvent. The method uses non-toxic solvent and accessible raw materials, has high reaction yield, and is applicable to industrial production.

Description

technical field [0001] The invention relates to a preparation method of 2,4-dichloroquinazoline. Background technique [0002] 2,4-Dichloroquinazoline is an important organic intermediate, which is mainly used in the fields of medicine, pesticide, dyestuff and organic synthesis. In recent years, with the application and popularization of downstream products of 2,4-dichloroquinazoline, the demand has increased, and its market prospect is very broad. [0003] In the prior art, the synthesis of 2,4-dichloroquinazoline mainly contains the following two synthetic routes: [0004] Route 1: aniline / phenoxycarbonyl isocyanate method, the reaction equation is as follows: [0005] [0006] In the US 04 / 02885 patent, the synthetic route is described, and the total yield of the synthetic route is about 58%. [0007] Route 2: anthranilic acid / potassium cyanate method, the equation is as follows: [0008] [0009] Anthranilic acid reacts with potassium cyanate in acetic acid sys...

Claims

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Application Information

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IPC IPC(8): C07D239/95
Inventor 周富荣
Owner 太仓浦源医药原料有限公司
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