Method for synthesizing alpha-asarone

A technology of asarone and its mixture, which is applied in the field of synthesizing α-asarone, which can solve the problems of difficult removal, environmental pollution, separation and purification, etc., and achieve the effects of mild reaction, cost reduction and short synthesis route

Inactive Publication Date: 2008-07-09
HUNAN NORMAL UNIVERSITY
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

KOH is used as the isomerization reagent, but the amount of KOH is large (m α / β∶KOH =1:16), causing a lot of environmental pollution and reagent waste, and demethylation by-products are generated in the isomerization reaction, making separation and purification difficult
Although using PdCl 2 (CH 3 EN) 2 It can effectively convert β-asarone into α-asarone, but the cost of noble metal Pd catalyst is high, and the residual Pd in ​​the product is difficult to remove, thus affecting the quality and safety of medicines

Method used

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  • Method for synthesizing alpha-asarone

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Experimental program
Comparison scheme
Effect test

Embodiment 1

[0017] (1) Take 21.5g (0.11mmol) of 2,4,5-trimethoxybenzaldehyde, 61.25g (0.165mmol) triphenylethylphosphine bromide, 27.6g (0.20mmol) anhydrous K 2 CO 3 Powder, add 250ml dimethyl sulfoxide, stir and reflux for 24 hours. Stop the reaction, remove the solvent under reduced pressure, add 300ml petroleum ether and stir for 15 minutes, filter, wash the filtrate with 100ml (volume ratio 1: 1) of a mixed solution of ethanol and water, separate the oil layer, anhydrous Na 2 SO 4 After drying, the solvent was removed under reduced pressure to obtain 17.1 g of an oily mixture of α / β-asarone, with a yield of 60%. As determined by GC, α-asarone accounted for 43%, and β-asarone accounted for 57%.

[0018] (2) Get 5.0g (24.0mmol) of α / β-asarone mixture into a 100ml round bottom flask, add 25ml ethanol to dissolve; add catalyst I in the above solution 2 122.0mg (0.48mmol), stirred at room temperature for 12h, isomerization reached equilibrium, gas chromatography analysis trans / cis asa...

Embodiment 2

[0020] Get α / β-asarone mixture 5.0g (24mmol) in the 100ml round bottom flask, add 25ml ethyl acetate, add catalyst I 2 122.0mg (0.48mmol), stirred at room temperature for 30min, isomerization reached equilibrium, gas chromatography analysis showed trans / cis asarone=97.0 / 3.0, stop the reaction, the reaction solution was added successively 5% Na 2 S 2 o 3 solution and washed with water, anhydrous Na 2 SO 4 Drying, solvent removal, recrystallization with 7.5ml ethanol aqueous solution (V ethanol / V water=7: 3), obtains white crystal 3.65g, yield 73.0%, fusing point 60-61 ℃, GC analysis α-asarone content 98.0%.

Embodiment 3

[0022] Get α / β-asarone mixture 5.0g (24.0mmol) in the 100ml round bottom flask, add 25ml ethanol, add catalyst I 2 61.0mg (0.24mmol), stirred at room temperature for 24h, isomerization reached equilibrium, gas chromatography analysis trans / cis asarone = 95.0 / 5.0, stop the reaction, add 5% Na to the reaction solution 2 S 2 o 3 solution, after stirring for 30min, the solvent was removed, extracted three times with ethyl acetate, 30ml each time, washed with water, anhydrous Na 2 SO 4 Dry, extract solvent, recrystallize with 7.5ml ethanol aqueous solution (V ethanol / V water=7: 3), obtain white crystal 2.75g, yield 55% melting point 60-61 ℃, GC analysis α-asarone content is 98.0%.

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Abstract

The invention discloses a method for synthesizing alpha-asarone, including the alpha / beta-asarone mixture obtained from the wittig reaction in the existing technique, then employing the alpha / beta-asarone mixture as raw materials, according to the ratio of raw materials : solvent=1 : 1-100 to dissolve the alpha / beta-asarone mixture, adding 0.025mol%-5mol% iodine catalyst into the solution and changing cis-form asarone into anti-form asarone by stirring with the solvent reflux temperature of 0-120 DEG C. The invention can control the content of cis-form asarone which has toxic side-effect, thereby obtaining acceptable product. The invention has the advantages of short synthesizing line, mild reaction, simple and easy operation, which greatly reduces cost and is adapted for mess product in industry.

Description

technical field [0001] The invention relates to a method for synthesizing α-asarone. Background technique [0002] The chemical name of α-asarone is trans-2,4,5-trimethoxy-1-propenylbenzene, which mainly exists in the volatile oil of plants such as Shichangpu, and its cis isomer is called β-asarone brain. α-Asarone has been proven to have various pharmacological activities such as antitussive, phlegm-removing, asthma-relieving, antispasmodic, anti-convulsant, anti-ulcer, anti-cancer, and hypolipidemic. The α-asarone directly extracted from plants is very likely to be mixed with carcinogens such as xanthal, while the synthetic α-asarone has been confirmed to be free of xantalyl. The existing synthetic method of α-asarone is prepared by the addition of Grignard reagent ethylmagnesium iodide and 2,4,5-trimethoxybenzaldehyde, but Grignard reagent requires anhydrous operation and is not suitable for expanding production, and The reaction of dehydration of intermediates to prep...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C07C43/205C07C41/32
Inventor 张为刘长徐广宇徐建兵
Owner HUNAN NORMAL UNIVERSITY
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