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Improved method of synthesizing emodin

A technology of emodin and cyclization, which is applied in the field of synthesis and improvement of the main component emodin, can solve the problem of low yield and achieve the effect of increasing the total yield

Inactive Publication Date: 2007-09-12
NANJING RALLY BIOCHEM
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

[0010] (2) 3,5-dimethoxyphthalic acid method (G.D.Graves, Roger Adams, J.Amer.Chem.Soc., 45, 2439, 1923), with 3,5-dimethoxyphthalic acid Diformic anhydride and m-cresol as starting materials, after Friedel-Crafts reaction, cyclization and demethylation, the yield is too low

Method used

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Embodiment 1

[0021] Embodiment 1, the preparation of 2-(2-hydroxyl-4-methylbenzoyl)-3,5-dinitrobenzoic acid

[0022] Take by weighing 3,5-dinitrophthalic anhydride 119.0g (0.5mol) and m-cresol 400g (3.7mol), drop into and be equipped with sealed stirrer, anhydrous calcium chloride drying tube and reflux condenser In a 2L three-neck flask, cool the flask in an ice-water bath, add 200g (1.5mol) of powdered anhydrous aluminum trichloride at a time, start stirring, heat up, heat to 100-110°C, and stir vigorously for 3 hours until the release of hydrogen chloride stops , a viscous reddish-brown substance is produced. Ice was added while stirring until the excess chromium trichloride passed through the addition of 150ml of concentrated hydrochloric acid, the product coagulated and the solution was clarified. After filtration, the filter cake was treated with 50 g of sodium carbonate, filtered, and dried to obtain 154.8 g of white crystal 2-(2-hydroxyl-4-methylbenzoyl)-3,5-dinitrobenzoic acid, y...

Embodiment 2

[0023] Embodiment two, the preparation of 2-(2-hydroxyl-4-methylbenzoyl)-3,5-diaminobenzoic acid

[0024] Put 346g (1mol) of 2-(2-hydroxy-4-methylbenzoyl)-3,5-dinitrobenzoic acid, 300ml of absolute ethanol and 5g of Raney nickel into a 1L autoclave. Close the autoclave, feed hydrogen, raise the temperature to 25°C to make the pressure 3.5Mpa, stir at a medium speed, rapidly raise the temperature to 90°C, stop heating, and maintain the reaction at 90-100°C for 8 hours. Cool, depressurize, and filter the catalyst. Ethanol was distilled off, and the residue was recrystallized to obtain 269 g of amino compounds, with a yield of 94.1%, mp: 232-234°C, and content (HPLC) ≥ 96.5%.

Embodiment 3

[0025] Example 3, Preparation of 1-hydroxyl-6,8-diamino-3-methylanthraquinone

[0026] Add 2-(2-hydroxyl-4-methylbenzoyl)-3,5-diaminobenzoic acid 28.6g (0.1mol) in the 500ml three-necked bottle, oleum 136ml, boric acid 65g, slowly heat up to React at 120°C for 1 hour, then raise the temperature to 150-160°C to make the solution transparent, neutralize with 10% sodium hydroxide solution, extract with ethyl acetate, evaporate to dryness, and then recrystallize with acetone and water to obtain 21.2 g of dark orange crystals , yield 79.1%, mp: 300-307°C, content (HPLC) ≥ 96.0%.

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Abstract

This invention relates a synthesizing and reforming method for rheum emodin, which takes 3, 5-dinitroalizaric acid as the starting material to be reacted through Ke Fu acylation, recovery, circulation and diazo reactions to get the total yield of 50.8%, in which, nitryl is recovered by catalyzation and hydrogenation, oil of vitriol and acetic acid as the medium, glycol mono-aether as the assistant solvent to increase the reaction yield rate of diazo reaction.

Description

field of invention [0001] The invention relates to the field of organic and medicinal chemistry, in particular, the invention relates to an improved method for synthesizing emodin, the main component of rhubarb, a traditional Chinese medicine. Background technique [0002] Emodin is one of the main components extracted from the rhizome of Rheum palmatum, a plant of the Polygonaceae family. It has antibacterial, anticancer activities, catharsis and diuretic effects. Emodin is the main raw material for the synthesis of hypericin. [0003] Emodin, also known as 1,3,8-trihydroxy-6-methylanthraquinone, English name: Emodin, its structural formula is as follows: [0004] [0005] Emodin [0006] Since rhubarb contains various components such as chrysophanol, rhein, emodin and aloe-emodin, the process of extracting and separating monomer emodin from rhubarb, or obtaining emodin by hydrolyzing the extract aloe-emodin is cumbersome and costly. High...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C07C46/00C07C50/18
Inventor 陈新王凯文
Owner NANJING RALLY BIOCHEM
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