Synthetic method of fenbendazole

A synthesis method and technology for fenbendazole, applied in the field of synthesis of fenbendazole, can solve the problems of difficulty in separation, environmental pollution, and high production costs, and achieve the effects of reducing product quality decline, low cost of three wastes, and mild conditions

Active Publication Date: 2021-08-13
SHANDONG GUOBANG PHARMA +1
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

This method needs to use tetrabutylammonium bromide to increase the cost, the three wastes produced by ferric chloride reduction pollute the environment, and the synthesis cost of hydrazine hydrate process is relatively high, although using methyl cyanocarbamate as cyclizing agent can reduce the cost, it will Ammonium chloride is produced, which is difficult to separate after mixing with the sodium ...

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  • Synthetic method of fenbendazole

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Experimental program
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Effect test

Embodiment 1

[0028] Example 1 Preparation of intermediate 5-phenylthio-2-nitroaniline

[0029] Add 172.57g of 5-chloro-2-nitroaniline, 517.71g of n-propanol, 8.00g of sodium hydroxide, and 858.00g of sodium thiophenate aqueous solution into a 1000ml four-necked bottle, stir evenly, and then heat up to 88°C (reflux temperature ), after 5 hours of heat preservation, the temperature was lowered to 0°C while stirring, and filtered after cooling and precipitation, and the filter cake was dried in an oven at 60°C for 5 hours to constant weight to obtain 218.64 g of 5-phenylthio-2-nitroaniline. The yield is 86.14%, and the purity is 97.03%.

[0030] The mass fraction of the sodium thiophenate aqueous solution is 20%.

Embodiment 2

[0031] Embodiment 2 prepares intermediate 5-phenylthio-2-nitroaniline

[0032] Add 172.67g of 5-chloro-2-nitroaniline, 517.71g of n-propanol, 8.00g of sodium hydroxide, and 858.00g of sodium thiophenate aqueous solution into a 1000ml four-necked bottle, replace the system with nitrogen three times and then stir evenly to raise the temperature to 88 ℃, after 5 hours of heat preservation, the temperature was lowered to 0 ℃ while stirring, cooled and precipitated, filtered, and the filter cake was dried in an oven at 60 ℃ for 5 hours to constant weight to obtain 243.50 g of 5-phenylthio-2-nitroaniline. The rate is 98.87%, and the purity is 100%.

[0033] The mass fraction of the sodium thiophenate aqueous solution is 20%.

[0034] Known from embodiment 1, 2, when reacting, system is not carried out nitrogen protection, can cause the yield of 5-phenylthio-2-nitroaniline to obviously reduce, and reason is that sodium thiophenate is easy to deteriorate in air and water, 5-chloro-2...

Embodiment 3

[0035] Embodiment 3 prepares intermediate 5-phenylthio-2-nitroaniline

[0036] Add 172.67g of 5-chloro-2-nitroaniline, 517.71g of n-propanol, 8.00g of sodium hydroxide, and 792.00g of sodium thiophenate aqueous solution into a 1000ml four-necked bottle, replace the system with nitrogen three times, and stir evenly to raise the temperature to 88 ℃, keep warm for 5h, cool and precipitate, then filter, put the filter cake in an oven at 60°C and dry for 5h to constant weight to obtain 242.81g of 5-phenylthio-2-nitroaniline, with a yield of 98.59% and a purity of 100%.

[0037] The mass fraction of the sodium thiophenate aqueous solution is 20%.

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Abstract

A synthetic method of fenbendazole belongs to the technical field of insect repellents, and specifically comprises the following steps: carrying out condensation reaction on 5-chloro-2-nitroaniline and a sodium thiophenol aqueous solution in a mixed solution of n-propyl alcohol and water to obtain 5-thiophenyl-2-nitroaniline; carrying out reduction reaction on the 5-thiophenyl-2-nitroaniline in a high-pressure kettle under the catalysis of raney nickel to generate 4-thiophenyl o-phenylenediamine; and mixing the 4-thiophenyl o-phenylenediamine and N-(trichloromethyl) methyl carbamate for a cyclization reaction to obtain fenbendazole; the method has the advantages that conditions are mild, operation is easy and convenient, ammonium chloride can be prevented from being generated in the cyclization process, and the three-waste cost is low; the generation of amine salt is avoided, and the treatment cost of three wastes is greatly reduced; and the yield of the fenbendazole can reach 84.27% to 89.99%, and the purity of the fenbendazole can reach 96.39% to 99.71%.

Description

technical field [0001] The invention relates to the technical field of insect repellants, in particular to a synthesis method of fenbendazole. Background technique [0002] Fenbendazole belongs to the class of benzimidazoles. It is a low-toxicity, high-efficiency, and broad-spectrum anthelmintic. It can drive away parasites such as hookworms, roundworms, whipworms, some tapeworms, and strongyloids in the gastrointestinal tract of animals. , and has a strong insecticidal egg effect, with long-lasting efficacy, safety and low toxicity, and good palatability. [0003] Patent US3954791 discloses a synthetic method for preparing benzimidazole compounds. The method first prepares 5-phenylthio-2-nitroaniline by refluxing 5-chloro-2-nitroaniline and thiophenol in DMF, and then It is reduced to 4-phenylthio-o-phenylenediamine with tin chloride, and finally cyclized with S-methylisothiouronate methyl ester to obtain benzimidazole. This method requires the use of DMF as a solvent, whi...

Claims

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Application Information

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IPC IPC(8): C07D235/32
CPCC07D235/32
Inventor 李琦斌于童程贺肖兵陈士刚
Owner SHANDONG GUOBANG PHARMA
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