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Preparation method of fenbendazole which is benzimidazole anti-helminthic drug

A technology of medicine benthiimazole and benzimidazole, which is applied in the field of preparation of antiparasitic raw material benthiimazole, can solve the problems of difficult operation, high cost, large environmental impact and the like, and achieves the effect of safe operation

Inactive Publication Date: 2017-02-15
JIANGSU BAOZONG & BAODA PHARMACHEM
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0007] Route 3: The above three routes mainly have the disadvantages of high cost, difficult operation of some links, and great impact on the environment.

Method used

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  • Preparation method of fenbendazole which is benzimidazole anti-helminthic drug
  • Preparation method of fenbendazole which is benzimidazole anti-helminthic drug
  • Preparation method of fenbendazole which is benzimidazole anti-helminthic drug

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0030] Step 1: Preparation of 2-nitro-1,4-dichlorobenzene

[0031] In a 500ml four-necked flask with a thermometer and a stirring device, start the stirring, add 120.0g of p-dichlorobenzene, 0.8 times the weight ratio of concentrated sulfuric acid, and add 1.04 times the molar amount of dichlorobenzene to nitric acid, and control the temperature of the drop. After the dripping is completed at 20~25℃, keep the reaction at 35~40℃ for 1 hour, GC will track the reaction to complete, and separate the lower waste acid layer; add p-dichlorobenzene to 1 times the weight ratio for purification and wash, and then separate the water layer; Neutralize to neutral with liquid caustic soda and discard the water layer. 153.1 g of 2-nitro-1,4-dichlorobenzene was obtained, which was directly used in the next reaction. The yield in this step was 97.7%.

[0032] Step 2: Preparation of 2-nitro-4-chloroaniline

[0033] Add 153.1g 2-nitro-1,4-dichlorobenzene obtained in the previous step, 2.2 times the ...

Embodiment 2

[0041] Step 1: Preparation of 2-nitro-1,4-dichlorobenzene

[0042] In a 500ml four-necked flask with a thermometer and a stirring device, start the stirring, add 120.0g of p-dichlorobenzene, 0.8 times the weight ratio of concentrated sulfuric acid, and add 1.04 times the molar amount of dichlorobenzene to nitric acid, and control the temperature of the drop. After the dripping is completed at 20~25℃, keep the reaction at 35~40℃ for 1 hour, GC will track the reaction to complete, and separate the lower waste acid layer; add p-dichlorobenzene to 1 times the weight ratio for purification and wash, and then separate the water layer; Neutralize to neutral with liquid caustic soda and discard the water layer. 153.4 g of 2-nitro-1,4-dichlorobenzene was obtained, which was directly used in the next reaction. The yield in this step was 97.9%.

[0043] Step 2: Preparation of 2-nitro-4-chloroaniline

[0044] Add 153.4g of 2-nitro-1,4-dichlorobenzene, 2.2 times the weight ratio of 2-nitro-1,4...

Embodiment 3

[0052] Step 1: Preparation of 2-nitro-1,4-dichlorobenzene

[0053] In a 1000 ml four-necked flask with a thermometer and a stirring device, turn on the stirring, add 240.0g p-dichlorobenzene, 0.8 times the weight ratio of concentrated sulfuric acid, dropwise add nitric acid 1.04 times the molar amount of p-dichlorobenzene, control the drop Adding temperature is 20~25℃, after dripping, keep incubating at 35~40℃ for 1 hour, GC will track the reaction to completion, and remove the lower waste acid layer; add p-dichlorobenzene to 1 times the weight ratio for purification and washing, and remove the water layer ; Then neutralize to neutral with liquid caustic soda, discard the water layer. 307.2 g of 2-nitro-1,4-dichlorobenzene was obtained, which was directly used in the next reaction. The yield in this step was 98.0%.

[0054] Step 2: Preparation of 2-nitro-4-chloroaniline

[0055] Add 307.2g 2-nitro-1,4-dichlorobenzene obtained in the previous step, 2.2 times the weight ratio of 2-n...

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Abstract

The invention discloses a preparation method of fenbendazole which is a benzimidazole anti-helminthic drug. Fenbendazole is obtained by taking p-dichlorobenzene as a raw material through nitration, amination, condensation, reduction and ring-closure, and the final product content is 98-101%. The preparation method is simple and efficient, is safe to operate, and is suitable for industrial production.

Description

Technical field [0001] The invention relates to a new method for preparing a benzimidazole anthelmintic, in particular to a new method for preparing an anti-parasitic raw material medicine Fenzimidazole. [0002] 2. Background technology [0003] Fenbendazole, also known as fenbendazole, is chemically named 5-phenylthiobenzimidazole-2-methyl carbamate. It is a broad-spectrum and highly effective antiparasitic drug for veterinary use. Fenzimidazole is used to repel animal gastrointestinal parasites. It not only has high anthelmintic activity against animal gastrointestinal roundworms, hookworms, whipworms, some tapeworms and strongyloides, but also against some bronchial tree and lung parasites. (Cat lungworm and lung fluke) also have better effects. Fenzimidazole has the advantages of wide anthelmintic spectrum, low toxicity, good tolerance, wide safety range, and good palatability. [0004] Fenthiamidazole was first developed by Hoechst in the 1970s. The synthetic routes reported...

Claims

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Application Information

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IPC IPC(8): C07D235/32
CPCC07D235/32
Inventor 陈荣
Owner JIANGSU BAOZONG & BAODA PHARMACHEM
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