Preparation method of favipiravir

A technology of favipiravir and reaction solution, which is applied in the field of drug synthesis, can solve the problems of cost, increased processing difficulty, heterogeneous reaction, etc., and achieve the effect of reducing post-processing steps, avoiding drug safety, and mild reaction conditions
CN113248450APending Publication Date: 2021-08-13BEIJING SIHUAN PHARMA +2
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Patent Information

Authority / Receiving Office
CN · China
Patent Type
Applications(China)
Current Assignee / Owner
BEIJING SIHUAN PHARMA
Publication Date
2021-08-13

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Abstract

The invention relates to a preparation method of favipiravir, which comprises the following steps of: reacting 3,6-difluoro-2-cyanopyrazine under an alkaline condition at the temperature of between 40 and 70 DEG C to obtain 6-fluoro-3-hydroxy-2-cyanopyrazine, and then conducting a next-step reaction basically without treatment, and conducting reaction with inorganic alkali and hydrogen peroxide at 45-65 DEG C to obtain favipiravir. The preparation method avoids use of precursor control reagents or dangerous preparations, reduces dangerous factors in production, and has the advantages of simplicity and convenience in operation, high yield, high purity of the prepared product, safety, environmental protection, low cost, suitability for industrial production and the like.
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Description

technical field

[0001] The invention belongs to the field of drug synthesis, and in particular relates to a preparation method of Favipiravir. Background technique

[0002] Favipiravir (trade name AVIGAN) is an RNA-dependent RNA polymerase (RdRp) inhibitor broad-spectrum antiviral drug developed by Japan Fukuyama Chemical Co., Ltd. Bioterrorism attacks have important practical significance.

[0003]

[0004] CN1418220A discloses the preparation method of Favipiravir, comprising the following steps:

[0005]

[0006] This method has the following problems in the process of preparing 6-fluoro-3-hydroxyl-2-cyanopyrazine (compound II): one, heterogeneous reaction, stirring difficulty, increase processing difficulty; pH, extraction, washing, and drying and decompression to remove the solvent are cumbersome and costly. Third, column chromatography is used for purification, which is not suitable for industrial production. Fourth, the yield of this step is only 45.6%, and th...

Claims

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