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Refining method of candesartan

A technology of candesartan and a refining method, which is applied to the refining field of intermediate candesartan, can solve the problems of high usage of organic solvent, difficulty in filtration of material and liquid, environmental waste of materials and the like, and achieves low usage of solvent, Excellent refining effect, easy filtering and drying effect

Pending Publication Date: 2017-05-24
ZHEJIANG HUAHAI PHARMA CO LTD
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  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0008] The known systems for refining the crude product of candesartan mainly include dimethyl sulfoxide and DMF. This system has problems such as high usage of organic solvents, low refining yield, difficulty in filtering the feed liquid, and difficulty in drying. The problem has greatly caused problems such as high production costs, waste of materials and environmental pollution.

Method used

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  • Refining method of candesartan
  • Refining method of candesartan
  • Refining method of candesartan

Examples

Experimental program
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Effect test

Embodiment 1

[0026] Take 20 g of crude candesartan, add 200 mL of 2 mol / L sodium hydroxide and 20 mL of tetrahydrofuran, and stir to dissolve. After cooling down to 15°C, add glacial acetic acid dropwise, adjust the pH to 6.5, stir and crystallize, continue to cool down to 5°C, add glacial acetic acid dropwise, adjust the pH to 5.5, stir and crystallize for 1 hour, suction filter, and dry to obtain a solid The white product was 17.6 g, and the purity of candesartan (HPLC) was 97.6%.

Embodiment 2

[0028] Take 20 g of crude candesartan, add 160 mL of 2 mol / L sodium hydroxide and 40 mL of tetrahydrofuran, and stir to dissolve. After cooling down to 10°C, add glacial acetic acid dropwise, adjust the pH to 6.0, stir and crystallize, continue to cool down to 0°C, add glacial acetic acid dropwise, adjust the pH to 5.0, stir and crystallize for 1 hour, filter and dry to obtain a solid White product 16.7g, candesartan purity (HPLC) 98.2%.

Embodiment 3

[0030] Take 20 g of crude candesartan, add 100 mL of 2 mol / L potassium hydroxide and 30 mL of tetrahydrofuran, and stir to dissolve. After cooling down to 13°C, add glacial acetic acid dropwise, adjust the pH to 6.2, stir and crystallize, continue to cool down to 3°C, add glacial acetic acid dropwise, adjust the pH to 5.3, stir and crystallize for 2 hours, suction filter, and dry to obtain a solid The white product was 16.0 g, and the purity of candesartan (HPLC) was 97.3%.

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Abstract

The invention provides a refining method of candesartan. The refining method includes the step of refining a candesartan crude product in a tetrahydrofuran or acetonitrile solvent with an acid-base crystallization method. The refining method is high in yield, low in cost, good in refining effect and very suitable for industrial production.

Description

technical field [0001] The invention relates to a method for refining candesartan, an intermediate of candesartan cilexetil. Background technique [0002] Candesartan cilexetil is a selective angiotensin Ⅱ receptor (AT1) antagonist, which antagonizes the vasoconstriction of angiotensin Ⅱ by binding to vascular smooth muscle AT1 receptor, thereby reducing peripheral vascular resistance. Candesartan is an important intermediate in the synthesis process of candesartan cilexetil, and its structural formula is as shown in formula I: [0003] [0004] At present, the synthesis of candesartan mainly uses cyclic compound (VI) and sodium azide as raw materials, forms a tetrazole structure through [3+2] cycloaddition reaction, and then uses sodium hydroxide solution to saponify-crystallize to obtain . [0005] [0006] The candesartan crude product synthesized by this route contains a large amount of impurities such as candesartan (II), candesartan isomer (III) and other impur...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C07D403/10
CPCC07D403/10
Inventor 胡佳兴黄文锋涂国良王安宇童志强
Owner ZHEJIANG HUAHAI PHARMA CO LTD
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