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A kind of preparation method of fenbendazole

A technique for preparing fenbendazole and its preparation steps, which is applied in the field of preparation of fenbendazole, can solve problems such as low condensation yield, and achieve the effects of high quality, simple and efficient synthesis process, and less pollution

Active Publication Date: 2016-04-20
CHANGZHOU YABANG QH PHARMACHEM +2
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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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  • A kind of preparation method of fenbendazole
  • A kind of preparation method of fenbendazole
  • A kind of preparation method of 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] Preparation of step 22-chloro-4-phenylthionitrobenzene

[0036] In a 500ml four-necked flask with a thermometer and a stirring device, start stirring, add 90.8g of 2,4-dichloronitrobenzene, 1.02 times the molar amount of thiophenol, a...

Embodiment 2

[0045] Step 12, the preparation of 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] Preparation of step 22-chloro-4-phenylthionitrobenzene

[0048] In a 500ml four-necked flask with a thermometer and a stirring device, start stirring, add 90.8g of 2,4-dichloronitrobenzene, 1.5 times the molar amount of thiophenol, and 3 times the amount of 2,4-dichloronitronitrobenzene Toluene...

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Abstract

The invention discloses a preparation method of fenbendazole and provides a brand-new synthesis route of the fenbendazole. The fenbendazole is prepared from m-dichlorobenzene as a starting material through the steps of nitrification, condensation, amination, reduction and cyclization. The preparation method is characterized in that the starting material m-chloroaniline in the existing industrial route is changed to the cheap m-dichlorobenzene; the existing reduction technology with sodium sulfide dihydrate is changed to the clean and high-efficiency reduction technology; and the new synthesis technology is concise and simple, high in efficiency, slight in pollution, high in quality, and suitable 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 Patents(China)
IPC IPC(8): C07D235/32
Inventor 朱建民王学成吴建才琚泽沁
Owner CHANGZHOU YABANG QH PHARMACHEM
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