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Preparation method of 2-bromine-5,6-diphenyl pyrazine

A technology of diphenylpyrazine and hydroxyl group, applied in the field of preparation of 2-bromo-5,6-diphenylpyrazine, can solve the problems of low yield and product purity, complicated process and high cost, and achieve product quality Stable, high-purity, and fast results

Pending Publication Date: 2017-05-10
陕西友帮生物医药科技有限公司
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Problems solved by technology

However, the traditional preparation method has complex process, high cost, low yield and product purity

Method used

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  • Preparation method of 2-bromine-5,6-diphenyl pyrazine

Examples

Experimental program
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Effect test

Embodiment 1

[0018] Dissolve 5-hydroxy-2,3-diphenylpyrazine (1.0g, 4.0mmol) in 10mL tetrahydrofuran, according to the molar ratio of 5-hydroxy-2,3-diphenylpyrazine and phosphorus oxybromide 1:1.2 Proportionally add phosphorus oxybromide (1.35g, 4.8mmol), and react at 65°C for 3 hours. After the reaction is detected by TLC, slowly pour the reaction solution into 20g of ice-water mixture while it is hot, and continue stirring for 20 minutes. Adjust the pH value to 8.0 with saturated potassium carbonate solution, extract 20mL*3 times with ethyl acetate, wash with 10mL saturated brine, dry over anhydrous sodium sulfate, and remove the solvent by rotary evaporation to obtain the crude product of 2-bromo-5,6-diphenylpyrazine , the crude product was recrystallized with methanol to obtain 1.02 g of pure product 2-bromo-5,6-diphenylpyrazine, the product yield was 82%, and the product purity was 98%.

Embodiment 2

[0020] Dissolve 5-hydroxy-2,3-diphenylpyrazine (1.0g, 4.0mmol) in 10mL of benzene, according to the molar ratio of 5-hydroxy-2,3-diphenylpyrazine and phosphorus oxybromide 1:2 Proportionally add phosphorus oxybromide (2.25g, 8.0mmol), react at 80°C for 2.5 hours, TLC detects that the reaction is complete, slowly pour the reaction solution into 20g of ice-water mixture while it is hot, continue to stir for 20 minutes, and use saturated Adjust the pH value to 8.0 with potassium bicarbonate solution, extract 20mL*3 times with ethyl acetate, wash with 10mL of saturated brine, dry over anhydrous sodium sulfate, and remove the solvent by rotary evaporation to obtain the crude product of 2-bromo-5,6-diphenylpyrazine , the crude product was recrystallized with methanol to obtain 1.05 g of pure product 2-bromo-5,6-diphenylpyrazine, the product yield was 84%, and the product purity was 98%.

Embodiment 3

[0022] Dissolve 5-hydroxy-2,3-diphenylpyrazine (1.0g, 4.0mmol) in 10mL toluene, according to the molar ratio of 5-hydroxy-2,3-diphenylpyrazine and phosphorus oxybromide 1:5 Add phosphorus oxybromide (6.22g, 20.0mmol) in proportion, react at 85°C for 2.0 hours, TLC detects that the reaction is complete, slowly pour the reaction solution into 30g of ice-water mixture while it is hot, continue to stir for 20 minutes, and use saturated Adjust the pH value to 8.0 with sodium bicarbonate solution, extract 30 mL*3 times with ethyl acetate, wash with 20 mL of saturated brine, dry over anhydrous sodium sulfate, and remove the solvent by rotary evaporation to obtain the crude product of 2-bromo-5,6-diphenylpyrazine , the crude product was recrystallized with methanol to obtain 1.10 g of pure product 2-bromo-5,6-diphenylpyrazine, the product yield was 88%, and the product purity was 98%.

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Abstract

The invention relates to a preparation method of 2-bromine-5,6-diphenyl pyrazine. The preparation method of the 2-bromine-5,6-diphenyl pyrazine comprises the following steps: performing reaction on 5-hydroxyl-2,3-diphenyl pyrazine serving as a starting material, a reaction solvent comprising at least one of benzene, methylbenzene and tetrahydrofuran, and phosphorus oxybromide according to a certain proportion at 65 to 85 DEG C for 1 to 3 hours to prepare 2-bromine-5,6-diphenyl pyrazine, pouring the system slowly into ice water after the reaction, continuously stirring for 20 minutes, adjusting the pH value by using a saturated carbonate solution to be 8.0, performing ethyl acetate extraction, washing with a saturated salt solution, drying with anhydrous sodium sulfate, performing rotary evaporation and concentration to obtain a 2-bromine-5,6-diphenyl pyrazine crude product, and performing recrystallization on the crude product to obtain a pure product. The preparation method of the 2-bromine-5,6-diphenyl pyrazine is mild in reaction condition, high in speed, easy to operate and control and simple in aftertreatment, and the product has stable quality and high purity.

Description

[0001] (1) Technical field [0002] The invention belongs to the field of organic synthesis, and in particular relates to a preparation method of 2-bromo-5,6-diphenylpyrazine. [0003] (2) Background technology [0004] 2-Bromo-5,6-diphenylpyrazine is an important intermediate in organic synthesis, mainly used in pharmaceutical intermediates, organic synthesis, and also in pesticide production. However, the traditional preparation method has complex process, high cost, low yield and product purity. [0005] (3) Contents of the invention [0006] The problem to be solved in the present invention is to provide a preparation method of 2-bromo-5,6-diphenylpyrazine in view of the prior art, which is simple and reasonable, low in cost, high in yield and product purity, and suitable for experiments Laboratory and industrial production. [0007] The present invention is achieved through the following technical solutions: [0008] A preparation method of 2-bromo-5,6-diphenylpyrazine...

Claims

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Application Information

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IPC IPC(8): C07D241/16
CPCC07D241/16
Inventor 王雷李娟杨蕊程伟来新胜来超来子腾
Owner 陕西友帮生物医药科技有限公司
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