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A kind of refining method of penclosamide

A technology of pentaclosamide and a refining method, which is applied in the refining field, can solve the problems of difficult removal, residual pigment, and insignificant adsorption effect, and achieves the effects of convenient operation and good effect.

Active Publication Date: 2015-12-02
CHANGZHOU YABANG QH PHARMACHEM
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0003] The key intermediate in the synthesis of penclosamide is 2-amino-4,6-dichlorophenol, which contains amino and phenolic hydroxyl groups in its structure. During the reaction, it is easily oxidized by air to nitro or even azo Colored substances cause the final product to be pink or brown instead of the original light yellow, and the colored oxides generated during the synthesis process are similar to the finished product in terms of structure and polarity. In the subsequent separation and extraction process, if it is difficult to remove by conventional refining process, it will affect the appearance and color of the final product
At present, the decolorization method commonly used in industry mainly uses activated carbon adsorption for decolorization. The disadvantage is that this method can only absorb fine particles insoluble in solvents, but the adsorption effect on its substances is not obvious, and it cannot fundamentally solve the problem of pigment residues.
Patent CN101891646A reports that methanol with a weight ratio of 6.4 times the crude product of penclosamide is used as a solvent, and 5% activated carbon is used as a decolorizing agent, and the yield is too low, only 64.7%

Method used

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Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0021] In a 500ml four-neck flask equipped with a thermometer and a stirring device, add 60g of pink penclosamide crude product, butanone with a weight ratio of 4 times, start stirring, heat up and reflux until dissolved, filter with suction, and cool the filtrate to 50°C , add thiourea dioxide whose weight ratio is 0.1% times of the crude product of pentachlorosamide, heat and stir for 1 hour, add dropwise water with a weight ratio of 1.5 times of the crude product of pentachlorosamide, after the addition is completed, cool to 20°C, stir for 1 hour, and pump After filtering, the filter cake was washed with 30 ml butanone, and dried at 95° C. to obtain 56.5 g of a light yellow solid with a yield of about 94.2% and an HPLC content of 99.8%.

Embodiment 2

[0023] In a 500ml four-neck flask equipped with a thermometer and a stirring device, add 60g of brown pentaclosamide crude product, acetone with a weight ratio of 9 times, start stirring, heat up and reflux until dissolved, filter with suction, cool the filtrate to 50°C, add Sodium bisulfite whose weight ratio is 10% times that of the crude product of pentaclosamide is kept and stirred for 2 hours, and water whose weight ratio is 5 times that of the crude product of penclosamide is added dropwise. After filtering, the filter cake was washed with 30ml (acetone / water=1:1), sucked dry and dried at 95°C to obtain 55.8g of a light yellow solid with a yield of about 93% and an HPLC content of 99.7%.

Embodiment 3

[0025] In a 500ml four-neck flask equipped with a thermometer and a stirring device, add 60g of brown pentachlorosamide crude product, methanol with a weight ratio of 3 times, start stirring, heat up and reflux until dissolved, filter with suction, cool the filtrate to 50°C, add Ascorbic acid whose weight ratio is 3% times of pentaclosamide crude product, heat preservation and stirring for 2 hours, dropwise add water whose weight ratio is 3 times of pentaclosamide crude product, drop the temperature to 20 ℃, stir for 1h, suction filter, filter The cake was washed with 30 ml of methanol, and dried at 95° C. to obtain 57 g of a light yellow solid with a yield of about 95% and an HPLC content of 99.8%.

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PUM

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Abstract

The invention discloses a refining method of oxyclozanide, which comprises the following steps: (1) dissolving oxyclozanide crude products in a solvent, heating and reflowing till clarifying, and then carrying out suction filtration; (2) cooling the filtrate to be 40-55 DEG C, adding a reducing decolorising agent, and keeping the temperature for 0.5-2 h; (3) dropwise adding water in a destaining solution to separate out crystals, sufficiently mixing, cooling to the room temperature, carrying out suction filtration, washing, and drying to obtain the product. The refining method has the advantages that the reducing decolorising agent is adopted to decolor oxyclozanide, the refined product is better in appearance and is buff; the HPLC content of the refined product is larger than 99.7%, the individual impurity content of the refined product is smaller than 0.2%, and the yield of the refined product is can be higher than 93%.

Description

technical field [0001] The invention relates to a refining method, in particular to a new method for decolorizing penclosamide. Background technique [0002] Oxyclozanide (Oxyclozanide), also known as oxyclosamide, hydroxyclosanilide and oxyclozanide, belongs to halogenated salicylanilide compounds, and is a salicylanilide anthelmintic drug. For the treatment and control of trematodes in animals such as cattle and sheep. [0003] The key intermediate in the synthesis of penclosamide is 2-amino-4,6-dichlorophenol, which contains amino and phenolic hydroxyl groups in its structure. During the reaction, it is easily oxidized by air to nitro or even azo Colored substances cause the final product to be pink or brown instead of the original light yellow, and the colored oxides generated during the synthesis process are similar to the finished product in terms of structure and polarity. In the subsequent separation and extraction process, if it is difficult to remove by conventio...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): C07C235/64C07C231/24
Inventor 王学成苏文杰张峥朱伟朱建民
Owner CHANGZHOU YABANG QH PHARMACHEM