New preparation method for anthelmintic fenbendazole

A kind of technology of fenbendazole and new method, applied in the field of preparation of fenbendazole, can solve the problems of low condensation yield and the like, and achieve the effects of high quality, simple and efficient new synthesis process and less pollution

Inactive Publication Date: 2013-08-14
CHANGZHOU YABANG QH PHARMACHEM
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0010] Chinese patent CN102241635A reports the above preparation route, and the condensation yield of this route is low

Method used

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  • New preparation method for anthelmintic fenbendazole
  • New preparation method for anthelmintic fenbendazole
  • New preparation method for anthelmintic fenbendazole

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0033] Step 12, the preparation of 4-dichloronitrobenzene

[0034] In a 500ml four-necked flask with a thermometer and a stirring device, start stirring, add 100.0g m-dichlorobenzene, 0.5 times the weight ratio of concentrated sulfuric acid, drop nitric acid in a molar amount that is 1.05 times m-dichlorobenzene, and control the dropping temperature at 10-15°C, after the dropwise addition is completed, keep the temperature at 10-15°C for 3 hours, follow the reaction by HPLC, remove the lower waste acid layer, add 100g of 15% sodium carbonate aqueous solution, stir and wash, and separate the lower layer to obtain 2,4- Dichloronitrobenzene 127.0g was directly used in the next step reaction. This step yield is 97.2%, and content is 98.1%.

[0035] Step 22 - Preparation of nitro-5-chloroaniline

[0036] Add 250.0g of 2,4-dichloronitrobenzene obtained in the previous step into a 1000ml autoclave, 2.5 times the weight ratio of 2,4-dichloronitrobenzene toluene, 12 times the weight ...

Embodiment 2

[0045] Step 1 Preparation of 2,4-dichloronitrobenzene

[0046] In a 500ml four-neck flask equipped with a thermometer and a stirring device, start stirring, add 100.0g m-dichlorobenzene, 0.9 times the weight ratio of concentrated sulfuric acid, and the molar amount is 1.1 times m-dichlorobenzene nitric acid, and keep warm at 5-10°C After 3 hours, HPLC traced the reaction to be complete. The lower waste acid layer was separated, and 100 g of 5% sodium hydroxide aqueous solution was added to stir and wash. The lower layer was separated to obtain 125.0 g of 2,4-dichloronitrobenzene, which was directly used in the next reaction. This step yield is 95.7%, and content is 98.7%.

[0047] The preparation of step 2 2-nitro-5-chloroaniline

[0048] In a 1000ml autoclave, add 100.0g of 2,4-dichloronitrobenzene obtained in the previous step, methanol with a weight ratio of 3.5 times 2,4-dichloronitrobenzene, and 10 times 2,4-dichloronitrobenzene Benzene molar amount of ammonia water, th...

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Abstract

The invention discloses a new preparation method for anthelmintic fenbendazole, and provides a new synthetic route for fenbendazole. Fenbendazole is obtained by taking m-dichlorobenzene as a starting raw material through the reactions of nitration, amination, condensation, reduction and cyclization. The new preparation method is characterized in that m-chloroaniline serving as the starting raw material in the conventional industrial route is changed into m-dichlorobenzene which is low in cost; and a reduction process which uses sodium sulfide is changed into a clean and efficient reduction process. The new synthetic process is simple and efficient, low in pollution, high in quality and applicable to industrial production.

Description

technical field [0001] The invention belongs to the field of chemistry or medicinal chemistry, and in particular relates to a preparation method of fenbendazole. Background technique [0002] Fenbendazole (Fenbendazole) is also known as benzimidazole, and its chemical name is 5-phenylthio-1H-benzimidazole-2-carbamate methyl ester. Fenbendazole is a broad-spectrum, high-efficiency, low-toxic new benzimidazole anthelmintic drug, which was successfully developed by Hoechst in the 1970s. It not only has high anthelmintic activity against adult and larvae of animal gastrointestinal nematodes, but also has a Caucus, Dicoela lanceolata, Fasciola and tapeworms are also effective. In foreign countries, fenbendazole is not only used for various animals, but also has special preparations for wild animals. [0003] Since the mid-1970s, there have been many reports on the synthetic route of fenbendazole at home and abroad, and its existing synthetic route can be mainly summarized as th...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C07D235/32
Inventor 苏文杰刘祥宜王四香朱伟王学成
Owner CHANGZHOU YABANG QH PHARMACHEM
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