Preparation method for anthelmintic benzimidazole fenbendazole

A technology of benzimidazole and benzimidazole, which is applied in the field of preparation of anti-parasitic raw material drug benzimidazole, can solve the problems of difficult operation, great impact on the environment, and high cost, and achieve the effect of safe operation

Inactive Publication Date: 2011-11-16
JIANGSU BAOZONG & BAODA PHARMACHEM
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0010] The above three routes mainly have disadvantages such as high ...

Method used

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  • Preparation method for anthelmintic benzimidazole fenbendazole
  • Preparation method for anthelmintic benzimidazole fenbendazole
  • Preparation method for anthelmintic benzimidazole fenbendazole

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0032] Step 1: Preparation of 2-nitro-1,4-dichlorobenzene

[0033] In a 500 ml four-necked flask with a thermometer and a stirring device, start stirring, add 120.0 g of p-dichlorobenzene, 0.8 times the weight ratio of concentrated sulfuric acid, and drop nitric acid with a molar weight of 1.04 times that of dichlorobenzene, and control the dropping temperature At 20-25°C, the dropwise addition is completed, and the reaction is kept at 35-40°C for 1 hour, and the GC tracks the reaction completely, and the lower waste acid layer is separated; the weight ratio of p-dichlorobenzene is added to purify and wash, and the water layer is separated; Neutralize to neutral with liquid caustic soda, discard the water layer. 153.1 g of 2-nitro-1,4-dichlorobenzene was obtained, which was directly used in the next reaction. This step yield is 97.7%.

[0034] Step 2: Preparation of 2-nitro-4-chloroaniline

[0035] 153.1g of 2-nitro-1,4-dichlorobenzene obtained in the previous step, 2.2 ti...

Embodiment 2

[0043] Step 1: Preparation of 2-nitro-1,4-dichlorobenzene

[0044] In a 500 ml four-necked flask with a thermometer and a stirring device, start stirring, add 120.0 g of p-dichlorobenzene, 0.8 times the weight ratio of concentrated sulfuric acid, and drop nitric acid with a molar weight of 1.04 times that of dichlorobenzene, and control the dropping temperature At 20-25°C, the dropwise addition is completed, and the reaction is kept at 35-40°C for 1 hour, and the GC tracks the reaction completely, and the lower waste acid layer is separated; the weight ratio of p-dichlorobenzene is added to purify and wash, and the water layer is separated; Neutralize to neutral with liquid caustic soda, discard the water layer. 153.4 g of 2-nitro-1,4-dichlorobenzene was obtained, which was directly used in the next reaction. This step yield is 97.9%.

[0045] Step 2: Preparation of 2-nitro-4-chloroaniline

[0046]153.4g of 2-nitro-1,4-dichlorobenzene obtained in the previous step, 2.2 tim...

Embodiment 3

[0054] Step 1: Preparation of 2-nitro-1,4-dichlorobenzene

[0055] In a 1000 ml four-necked flask with a thermometer and a stirring device, start stirring, add 240.0 g of p-dichlorobenzene, 0.8 times the weight ratio of concentrated sulfuric acid, dropwise add nitric acid with a molar mass of 1.04 times that of p-dichlorobenzene, and control the dropwise Adding temperature is 20-25°C, dropwise is completed, keep warm at 35-40°C for 1 hour, GC tracks the reaction is complete, remove the lower waste acid layer; add p-dichlorobenzene at a weight ratio of 1 times for purification and washing, and remove the water layer ; Then use liquid caustic soda to neutralize, discard the water layer. 307.2 g of 2-nitro-1,4-dichlorobenzene was obtained, which was directly used in the next reaction. This step yield is 98.0%.

[0056] Step 2: Preparation of 2-nitro-4-chloroaniline

[0057] 307.2g of 2-nitro-1,4-dichlorobenzene obtained in the previous step, 2.2 times the weight ratio of 2-ni...

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Abstract

The invention discloses a preparation method for anthelmintic benzimidazole fenbendazole. The method is characterized in that: p-dichlorobenzene is used as a starting raw material which is subjected to nitration, amination, condensation, reduction and ring-closure reactions so as to obtain fenbendazole (the content of the final product being 98% to 101%). The novel preparation method has the characteristics of a simple and highly efficient process and safe operation, 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 antiparasitic raw material drug benthimazole. Background technique [0002] Benthimazole, also known as fenbendazole, chemically named 5-phenylthiobenzimidazole-2-methyl carbamate, is a broad-spectrum and highly effective anti-parasitic drug for veterinary use. Benthimazole is used to drive and kill animal gastrointestinal parasites. It not only has high anthelmintic activity against animal gastrointestinal roundworms, hookworms, whipworms, some tapeworms and strongyloides, but also has high anthelmintic activity against some bronchial tree and pulmonary parasites. (feline lungworm and paragonimiasis) also have better curative effect. Benthimazole has the advantages of broad repellent spectrum, low toxicity, good tolerance, wide safety range and good palatability. [0003] Benthimazole was initially successfully developed b...

Claims

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Application Information

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IPC IPC(8): C07D235/32
Inventor 朱志勇陈荣倪林明张智红
Owner JIANGSU BAOZONG & BAODA PHARMACHEM
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