Method of preparing diacetyl rhein

A technology of diacetylrhein and rhein, applied in the preparation of carboxylic acid esters, preparation of organic compounds, chemical instruments and methods, etc., can solve the problems of high production cost, achieve low production cost, short production cycle, and product yield and the effect of high purity

Inactive Publication Date: 2009-08-19
ZHEJIANG UNIV OF TECH +1
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

Although the method is simple and has few steps, it needs to use

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  • Method of preparing diacetyl rhein
  • Method of preparing diacetyl rhein
  • Method of preparing diacetyl rhein

Examples

Experimental program
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Embodiment 1

[0023] Rhein (5.64g, 20mmol), zinc trifluoromethanesulfonate (0.04g, 0.1mmol) and acetic anhydride (12.25g, 120mmol) were put into a 100ml reaction vessel, and the temperature was raised to 138°C for 1h under stirring. After the reaction, the temperature of the reaction solution was lowered to room temperature, and solids were precipitated, filtered, and the filter cake was recrystallized with acetic acid and dried to obtain diacetyl rhein (7.05 g). The HPLC purity was 99.5%, and the yield was 95.2%.

Embodiment 2

[0025] Rhein (5.64g, 20mmol), zinc trifluoromethanesulfonate (0.04g, 0.1mmol) and acetic anhydride (12.25g, 120mmol) were put into a 100ml reaction vessel, and the temperature was raised to 138°C for 2h under stirring. After the completion of the reaction, the temperature of the reaction solution was lowered to room temperature, a solid was precipitated, filtered, and the filter cake was recrystallized with acetic acid and dried to obtain diacetyl rhein (7.14 g). The HPLC purity was 99.7%, and the yield was 96.6%.

Embodiment 3

[0027] Put rhein (5.64g, 20mmol), zinc trifluoromethanesulfonate (0.04g, 0.1mmol) and acetic anhydride (8.17g, 40mmol) into a 50ml reaction vessel, and heat to 138°C for 0.5h under stirring. . After the completion of the reaction, the temperature of the reaction solution was lowered to room temperature, a solid was precipitated, filtered, and the filter cake was recrystallized with acetic acid and dried to obtain diacetyl rhein (7.10 g). The HPLC purity was 99.4%, and the yield was 95.8%.

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Abstract

The invention discloses a method for the preparation of diacerein having a structure represented by the formula (II), comprising the steps of: feeding rhein having the structure presented by the formula (I), a catalyst and acetic anhydride into a reaction vessel, heating up to 50 to 140 DEG C under a stirring state for reaction for 0.5-8 hours, tracing the reaction progress by means of TLC, detecting the amount of the diacerein to measure a reaction endpoint, upon completion of the reaction, cooling the temperature of reaction solution to room temperature, separating out solid for filtering, and recrystallizing filter cakes with acetic acid to obtain the diacerein; the catalyst is metal triflates, the amount of substances in the catalyst is 0.1%-10% of the amount of substances in rhein. The invention only needs the catalytic amount of the metal triflates to complete acylation reaction and the catalyst can be recycled, therefore, the invention greatly lowers the production cost, has higher yield and purity, simple post-treatment and simple production period, and is a preparation method for diacerein having favorable popularization and application prospect.

Description

(1) Technical field [0001] The invention relates to a preparation method of diacetyl rhein. (2) Background technology [0002] Diacerhein (Diacerhein), also known as diacerein, is a new interleukin 1β (1L-1β) inhibitor, which is mainly used clinically to treat osteoarthritis and delayed-induced arthritis. Recent studies have found that it has a good effect on rheumatoid arthritis, osteoporosis, adult acute respiratory syndrome and emphysema. [0003] The structural formula of diacetyl rhein: [0004] [0005] The research on the preparation of diacetyl rhein has a history of nearly 20 years. The classic preparation methods mainly include full chemical synthesis and semi-chemical synthesis. [0006] The total chemical synthesis of diacetyl rhein is mainly based on 3-nitrophthalic anhydride as the starting material, undergoes Friedel-Crafts reaction with m-cresol, and then undergoes reduction, cyclization and diazotization to synthesize intermediate chrysophanol , And then acetyl...

Claims

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Application Information

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IPC IPC(8): C07C67/08C07C69/16B01J31/02
CPCY02P20/584
Inventor 苏为科朱兴一张志敏
Owner ZHEJIANG UNIV OF TECH
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