Method for hydrogenation reduction of 4-thiophenyl-2-nitroaniline through raney nickel

A technology of phenylthio-o-phenylenediamine and nitroaniline, which is applied in the field of Raney nickel hydrogenation reduction of 4-phenylthio-2-nitroaniline, can solve environmental pollution, unpleasant hydrogen sulfide gas, and affect products Quality and other issues

Inactive Publication Date: 2013-01-09
JIANGSU BAOZONG & BAODA PHARMACHEM
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0006] At present, the reducing agents that have been industrialized mainly include sodium sulfide and hydrazine hydrate, but the use of sodium sulfide as a reducing agent will produce unpleasan

Method used

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Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0020] Add 450g of methanol, 100g of 4-phenylthio-2-nitroaniline, 6.0g of Raney nickel, 2.0g of potassium hydroxide to a 2000ml autoclave, tighten the autoclave, start stirring, and use 0.5MPa of nitrogen Replacement three times, 0.5MPa hydrogen replacement three times, pressurize the hydrogen to 1.5MPa, slowly raise the temperature to 60°C, keep the pressure and temperature for 1.5 hours, take samples for HPLC analysis, if the reaction is not completed, continue to keep warm until the reaction is completed. After the reaction, the reaction kettle was cooled to room temperature, the hydrogen pressure was removed, the material was pressed out with nitrogen, the Raney nickel was removed by filtration, and the filtrate was concentrated with a rotary evaporator to obtain 86.0 g of off-white solid product with a purity of 99.95%. The rate is 98.0%.

Embodiment 2

[0022] Add 450g of methanol, 100g of 4-phenylthio-2-nitroaniline, 6.0g of Raney nickel, 3.0g of potassium hydroxide to a 2000ml autoclave, tighten the autoclave, start stirring, and 0.5MPa of nitrogen Replace three times, 0.5MPa hydrogen replacement three times, pressurize the hydrogen to 2.0MPa, slowly raise the temperature to 65°C, keep the pressure and temperature for 1.5 hours, take samples for HPLC analysis, if the reaction is not completed, continue to keep warm until the reaction is completed. After the reaction, the reactor was cooled to room temperature, the hydrogen pressure was removed, the material was pressed out with nitrogen, the Raney nickel was removed by filtration, and the filtrate was concentrated with a rotary evaporator to obtain 85.5 g of off-white solid product with a purity of 99.90%. The rate is 97.3%.

Embodiment 3

[0024] Add 900g of methanol, 200g of 4-phenylsulfanyl-2-nitroaniline, 12.0g of Raney nickel, 6.0g of potassium hydroxide to a 2000ml autoclave, tighten the autoclave, start stirring, and 0.5MPa of nitrogen Replace three times, 0.5MPa hydrogen replacement three times, pressurize the hydrogen to 1.5MPa, slowly raise the temperature to 65°C, keep the pressure and temperature for 1.5 hours, take samples for HPLC analysis, if the reaction is not completed, continue to keep warm until the reaction is completed. After the reaction was finished, the reactor was cooled to room temperature, the hydrogen pressure was removed, and the material was pressed out with nitrogen, and the Raney nickel removed by filtration was concentrated with a rotary evaporator to obtain 170.0 g of off-white solid product with a purity of 99.89%. The yield was 96.8%.

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PUM

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Abstract

The invention discloses a method for hydrogenation reduction of 4-thiophenyl-2-nitroaniline through raney nickel. The method is characterized in that reducing 4-thiophenyl-2-nitroaniline into 4-thiophenyl o-phenylenediamine is one of the necessary operations in the technology of producing fenbendazole at present. According to the invention, the method adopting hydrogenation reduction is provided to replace the existing reduction method, so the cost is reduced, and the energy saving and environmental protection can be ensured.

Description

technical field [0001] The invention relates to a method for the hydrogenation reduction of 4-phenylthio-2-nitroaniline by Raney nickel, in particular to the application of cocatalysts in the hydrogenation reduction of sulfur-containing compounds by Raney nickel, the adjustment of the pH value of the reaction, and the like. Background technique [0002] The chemical name of fenbendazole is 5-phenylthiobenzimidazole-2-methyl carbamate. It is a broad-spectrum and highly effective anti-parasitic drug for veterinary use. The common synthetic route is as follows: [0003] . [0004] The above route is mainly the third one which is more common and has been industrialized on a large scale. As can be seen from the above routes, each route is inseparable from the reduction reaction of 4-phenylthio-2-nitroaniline, and the reaction formula is as follows: [0005] . [0006] At present, the reducing agents that have been industrialized mainly include sodium sulfide and hydrazine ...

Claims

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Application Information

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IPC IPC(8): C07C323/37C07C319/20
Inventor 严家庆朱志勇王琳陈荣
Owner JIANGSU BAOZONG & BAODA PHARMACHEM
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