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Technique for preparing diacerein by two-step oxidation process

A technology of diacerein and oxidation synthesis, which is applied in the direction of oxidative preparation of carboxylic acid, organic compound preparation, carboxylate preparation, etc., which can solve the problems of complex separation and purification of products

Inactive Publication Date: 2008-01-16
SHANGHAI PUYI CHEM CO LTD +1
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

Patent EP 0636602 (1994) also discloses a one-step oxidation method (flow process 4) without separation and re-oxidation from aloin (I) after acetylation, but needs to adopt a large excess of chromic anhydride oxidizing agent by 5-10 times
The problems of the above two methods are the use of highly toxic chromium oxidizers. The toxicity of chromium oxidizers is a difficult problem for industrialization, which poses environmental pollution and labor protection, and the separation and purification of products is also very complicated.

Method used

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  • Technique for preparing diacerein by two-step oxidation process
  • Technique for preparing diacerein by two-step oxidation process
  • Technique for preparing diacerein by two-step oxidation process

Examples

Experimental program
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Effect test

Embodiment 1

[0056] Example 1: Put 100 grams of 90% aloin into a 2-liter four-necked bottle, then add 800 milliliters of aqueous solution of 924 grams of ferric chloride, heat up to 98°C under stirring, keep the temperature for 7 hours, cool naturally to room temperature, and filter , the obtained filter cake was washed with water, and dried to obtain 80 grams of aloe-emodin crude product. The above crude product was repeatedly extracted with toluene, the combined extracts were concentrated and the resulting residue was recrystallized with 200 ml of acetic acid to obtain 45.9 g of aloe-emodin with a melting point of 216-218°C.

Embodiment 2

[0057] Example 2: 100 grams of 90% aloin was put into a 2-liter four-necked bottle, and then 1000 milliliters of aqueous solution of 1000 grams of ferric chloride was added, and the temperature was raised to 80° C. under stirring, and the reaction was kept for 10 hours, cooled naturally to room temperature, and filtered , the resulting filter cake was washed with water, and dried to obtain 85 grams of aloe-emodin crude product. The above crude product was repeatedly extracted with toluene, the combined extracts were concentrated and the resulting residue was recrystallized with 200 ml of acetic acid to obtain 50 g of aloe-emodin with a melting point of 216-218°C.

[0058] (2) Preparation of rhein III

[0059] Embodiment 1: 10 grams of aloe-emodin were put into a 1000 milliliter four-neck flask equipped with 40 grams of PCC with a stirrer and a reflux condenser, 800 milliliters of dichloroethane was added, and the reflux reaction was carried out under vigorous stirring for 10 h...

Embodiment 3

[0061] Example 3: Put 10 grams of aloe-emodin into a 1000 ml four-neck flask equipped with 40 grams of manganese dioxide with a stirrer and a reflux condenser, add 1000 ml of acetone, and reflux for 20 hours under vigorous stirring. Concentrate by filtration to obtain 5.8 g of rhein III.

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Abstract

The invention relates to a novel method to prepare diacerein which is an active ingredient for synthesizing medicine for knee osteoarthritis. The invention is characterized in that two steps of oxidation are adopted, firstly, the aloe-emodin is oxidated to rhubarb aldehyde and is acetylated for protection, secondly the intermediate product of the rhubarb aldehyde is oxidated, in this way, the final product diacerein can be obtained. The oxidation process of the invention is easy to control with a friendly environment and the quality of the products is greatly improved, thus the invention is suitable for large-scale production.

Description

technical field [0001] The invention relates to a new synthesis method of diacerein, an active ingredient of medicine for treating arthritis. Background technique [0002] Diacerein is a new interleukin (IL)-1 inhibitor. At present, the drug is mainly used to treat osteoarthritis, and the effective rate of treating osteoarthritis is 72-83.3%, with few adverse reactions. Diacerein has the following structure: [0003] [0004] The earliest patent DE 2,711,493 (1977) discloses that the method for preparing diacerein is to use potassium dichromate as an oxidizing agent to directly oxidize the benzylic hydroxyl group of aloe-emodin (II) to a carboxylic acid group at one time, forming an intermediate The product (VI) is then acetylated to obtain diacerein (scheme 2). Although this process has fewer reaction steps, due to the use of potassium dichromate as an oxidizing agent, the oxidation conditions are relatively severe, and the hydroxyl group in the anthraquinone structur...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C07C66/02C07C51/16C07C51/347
Inventor 张仰明周电根王文捷王博
Owner SHANGHAI PUYI CHEM CO LTD
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