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Process for purifying diacerein

A technology of diacerein and aloe-emodin, which is applied in chemical instruments and methods, preparation of organic compounds, separation/purification of carboxylic acid esters, etc., can solve the problems of expensive solvents, equipment and time, complicated operation and reduced yield And other issues

Inactive Publication Date: 2006-01-04
SYNTECO SPA
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

[0018] Yet obviously these two kinds of methods are loaded down with trivial details to operate, and make diacerein pure product significantly reduce relative to the productive rate of diacerein crude product
And, not only in the aspect of obtaining the pure product of diacerein, but also in recovering the aspects of diacerein lost in each step and a large amount of methoxyethanol and dimethylacetamide, these two methods require solvent, equipment very expensive in terms of time and

Method used

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Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0042]Add the suspension of 15.6kg diacerein crude product in the mixture of 80 liters of acetone and 80 liters of water, add 4.27kg triethylamine simultaneously, wherein the aloe-emodin of about 500ppm is contained in the diacerein crude product. The resulting solution was extracted with 4 aliquots of butyl acetate (100 L each); the organic phases were combined and the butyl acetate was recovered and recycled to the process. The diacerein salt solution was acidified with dilute HCl; the precipitated diacerein was centrifuged, fully washed with water and dried to obtain 14.8 kg of diacerein whose aloe-emodin content was not higher than 2 ppm. Subsequent crystallization from acetic anhydride / acetic acid followed the method reported above.

Embodiment 2

[0044] The same method as in Example 1 was carried out, and the number of extractions was limited to three times (the final aloe-emodin content was ~45ppm) or two times (the final aloe-emodin content=85ppm).

Embodiment 3

[0046] Follow the same method as in Example 1, using toluene as the extraction solvent. After five consecutive extractions, diacerein contains no more than 3ppm of aloe-emodin (about 33ppm after four extractions).

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PUM

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Abstract

A process for obtaining diacerein with an aloe-emodine content lower than 100 ppm, preferably of 0-5 ppm, is herein disclosed. The process comprises subjecting an an aqueous-organic solution of a diacerein salt with a weak base to extraction with a water immiscible or sparingly water-miscible solvent, such as toluene, acetates of C2-C4 alcohols, halohydrocarbons and the like.

Description

technical field [0001] The present invention relates to a method for purifying diacerein, which makes it possible and easy to obtain diacerein with a low aloe-emodine content (less than 100 ppm, or 0 to 5 ppm if necessary). Background technique [0002] Diacerein (1,8-diacetoxy-3-carboxy-anthraquinone) is a compound known to have anti-arthritic activity and can be obtained in various ways (see "The Merck Index", XIII, 2979; EP 0 243 698; EP 0 520 414; EP 636 602; PCT EP 00 / 03691, PCT EP 01 / 06019), usually via aloin (10-glucopyranosyl-1,8-dihydroxy-3-hydroxymethyl It is obtained by acetylation of the group-9(10H)-anthrone; "The Merck Index", XIII, 304) followed by chromium oxidation of the acetylated derivative. This method was disclosed about one hundred years ago by R. Robinson and J. L. Simonsen (Journal of the Chemical Society (Transactions), 1909, 1085-1095). In the above paper aloin is mentioned by its synonym aloin (see "The Merck Index", XIII, 304); an essentially i...

Claims

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Application Information

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IPC IPC(8): C07C69/00C07C67/48C07C67/58C07C67/60
CPCC07C67/58C07C67/60C07C69/16C07C67/48
Inventor D·马吉
Owner SYNTECO SPA
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