Refining method for pentoxifylline recycling products

A technique for refining pentoxifylline, which is applied in the field of refining recovered pentoxifylline products, and can solve problems such as unreachable single impurity, failure to meet finished product standards, poor impurity removal effect, etc.

Active Publication Date: 2019-03-22
CSPC INNOVATION PHARMA
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0008] It can be seen from the above-mentioned patents that the refining of xanthine products mainly adopts dissolution in an alkaline environment, adding carbon and decolorizing with a reducing agent, and then acidifying and crystallizing to obtain the finished product. The inventor used the above two methods to refine the recovered product of pentoxifylline. Unable to reach below 0.1%
[0009] The above-mentioned refining method is not effective in removing impurities, and it still cannot reach the finished product standard in the Pharmacopoeia after several times of refining

Method used

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  • Refining method for pentoxifylline recycling products
  • Refining method for pentoxifylline recycling products
  • Refining method for pentoxifylline recycling products

Examples

Experimental program
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Embodiment 1

[0030] Dissolve 20 g of the recovered product of pentoxifylline (maximum single impurity 4.02%, total impurity 8.25%) in water, add 30% liquid caustic soda to adjust the pH value to 12, add reducing agent sodium triacetoxyborohydride 1.0 g, and keep warm at 80°C for 1 hour. After filtering, cool down to below 20°C to obtain an alkaline solution. This alkaline solution was mixed with chloroform, allowed to stand for layers, and the organic phase was evaporated to obtain a viscous liquid. Then add methanol to dissolve the viscous liquid, add charcoal and keep it at reflux temperature for 1 hour, remove the charcoal by hot filtration, and a large amount of pentoxifylline will be precipitated at room temperature, and the finished product will be obtained after cold filtration and drying. The yield is 81.2%, the maximum single impurity is 0.06%, and the total impurity is 0.40%.

Embodiment 2

[0032] Dissolve 20 g of pentoxifylline recovered product (maximum single impurity 3.81%, total impurity 7.63%) in water, add 30% potassium hydroxide solution to adjust the pH value to 14, add reducing agent sodium triacetoxyborohydride 0.50 g, and keep warm at 80°C After 1h, filter and cool down to below 20°C to obtain an alkaline solution. The alkaline solution was mixed with dichloromethane, and the layers were separated after standing. After the organic phase was evaporated, a viscous liquid was obtained. Then add methanol to dissolve the viscous liquid, add charcoal and keep it at reflux temperature for 1 hour, remove the charcoal by hot filtration, and a large amount of pentoxifylline will be precipitated at room temperature, and the finished product will be obtained after cold filtration and drying. The yield is 80.9%, the maximum single impurity is 0.07%, and the total impurity is 0.44%.

Embodiment 3

[0034] Dissolve 20 g of pentoxifylline recovered product (maximum single impurity 4.63%, total impurity 8.37%) in water, add 50% sodium carbonate solution to adjust pH value to 10, add reducing agent sodium triacetoxyborohydride 0.75 g, keep at 80°C for 1 hour , After filtering, cool down to below 20°C to obtain an alkaline solution. Mix this alkaline solution with toluene, let it stand for layers, and evaporate the organic phase to obtain a viscous liquid. Then add chloroform to dissolve the viscous liquid, add charcoal and keep it at the reflux temperature for 1 hour, remove the charcoal by hot filtration, and a large amount of pentoxifylline will be precipitated at room temperature, and the finished product will be obtained after cold filtration and drying. The yield is 83.6%, the maximum single impurity is 0.09%, and the total impurity is 0.41%.

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Abstract

The invention discloses a refining method for pentoxifylline recycling products. The content of impurities in the pentoxifylline recycling products can be reduced, after the recycling products are refined, the maximum single impurities are reduced to be 0.1% or below, the total impurities are 0.5% or below, the standard of finished pentoxifylline is met, the integral yield is improved, and the reaction cost is reduced. The refining method comprises the following steps: (1) adding water in the pentoxifylline recycling products under the condition of heating, dissolving, adding alkaline liquid to regulate a pH value to be 10-14, adding a reducing agent, insulating, and then cooling and filtering to obtain an alkaline solution, wherein the single impurities in the pentoxifylline recycling products are less than 5%, and the total impurities in the pentoxifylline recycling products are less than 10%; (2) fully mixing the alkaline solution obtained in step (1) with an organic solvent A, thenstanding for layering, and removing an organic phase by evaporation to obtain viscous liquid; and (3) adding an organic solvent B to dissolve the viscous liquid, adding activated carbon, after insulating, filtering the activated carbon, cooling filtrate to the temperature of 20 DEG C or below, and filtering and drying to obtain pentoxifylline.

Description

technical field [0001] The invention belongs to the field of organic synthesis, and in particular relates to a method for refining recovered pentoxifylline products. Background technique [0002] Pentoxifylline (Pentoxifylline) is an agent for improving cerebral circulation and peripheral vascular circulation disorders. It has the effect of dilating cerebral blood vessels and peripheral blood vessels, and improves blood circulation in the brain and extremities. In addition, it can improve the oxidation capacity of hypoxic tissues. It is mainly used for the improvement of cerebral circulation after ischemic stroke, and it can also be used for the treatment of peripheral vascular diseases, such as chronic obliterative vasculitis with intermittent claudication, etc. It can also be used for the treatment of duodenal ulcer and viral hepatitis , lower extremity venous ulcers and other diseases, widely used clinically. [0003] Pentoxifylline is a crude product obtained by conden...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C07D473/10
CPCC07D473/10
Inventor 冯志军谢丽莎赵旭祁文敏解聪聪
Owner CSPC INNOVATION PHARMA
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