CN103360360A

CN103360360A - Method for preparing (+)-gallocatechin on basis of dihydromyricetin

Info

Publication number: CN103360360A
Application number: CN2012101127157A
Authority: CN
Inventors: 肖竹平
Original assignee: Individual
Current assignee: Individual
Priority date: 2012-04-10
Filing date: 2012-04-10
Publication date: 2013-10-23

Abstract

The invention provides a method for preparing (+)-gallocatechin on the basis of dihydromyricetin, which comprises the following steps: reacting at the room temperature of 40-70 DEG C for 1-15 hours by using dihydromyricetin and tetrahydrofuran (THF) or dioxane as a solvent and Et3SiH, Me3SiH or t-BuNH2.BH3 as a reducer; and distilling under reduced pressure recover the solvent, washing the solid with n-hexane or petroleum ether, and recrystallizing with ethanol chloroform to obtain the (+)-gallocatechin. The dihydromyricetin with abundant and stable sources is used as the raw material to synthesize the gallocatechin by a semisynthetic method, thereby greatly lowering the production cost, greatly enhancing the production capacity of the gallocatechin, and providing a new way for utilization of the dihydromyricetin.

Description

A kind of method based on dibydro myricetrin preparation (+)-l-Epigallocatechol

Technical field

The present invention relates to field of fine chemical, the molecular design preparation method of a kind of (+)-l-Epigallocatechol is provided.

Technical background

Natural product (+)-l-Epigallocatechol (GC) is one of important activity composition in the tea-polyphenol, is called as catechin compounds (catechins) with epigallocatechin, NVP-XAA 723 etc.Have widely biological activity, as have inhibition of cell proliferation (anticancer), anti-oxidant, anti-inflammatory, anti-cardiovascular disease isoreactivity; Also have the effects such as ultraviolet radiation preventing, fat-reducing, prevent diabetes, alleviation Parkinson's disease.But because the source is limited, thereby its application is greatly limited.

At present, various catechin monomeric compounds mainly all are to obtain by the tea leaf extract tea-polyphenol being carried out separation and purification.But since structural similitude between the various monomers of catechin, character close (such as l-Epigallocatechol and catechin, epigallocatechin and l-Epicatechol etc.), and so separating difficulty is large, cost is high, is difficult to realize suitability for industrialized production.Especially the content of l-Epigallocatechol in tealeaves is very low, less than 3%, is difficult to meet the need of market by produced in conventional processes.Thereby must seek new production ways, improve the production efficiency of l-Epigallocatechol.

Ampelopsis grossedentata is a kind of Wild Liane, in the most of provinces and regions of south China distribution is arranged all, is a kind of tame class tea plant resources that is easy to.Its main active ingredient is dibydro myricetrin (content nearly 30%), is easy to extract purifying, and market value is low.It is carried out structure of modification, and the derived product that changes into high added value is significant.

The present invention opens up the l-Epigallocatechol new process of production, take sufficient, the stable dibydro myricetrin of originating as raw material, adopts semisynthetic method to synthesize l-Epigallocatechol, greatly reduces production cost, has also greatly improved the throughput of l-Epigallocatechol.

Summary of the invention

The object of the invention is to, extract in the Ampelopsis grossedentata separate obtain flavonoid compound---dibydro myricetrin provides a kind of method for preparing (+)-l-Epigallocatechol as raw material, can greatly reduce production costs, improve throughput.

For achieving the above object, embodiment of the present invention are: the preparation method of a kind of (+)-l-Epigallocatechol is characterized in that (THF) Huo diox is as solvent, with Et take tetrahydrofuran (THF) with dibydro myricetrin ₃SiH, Me ₃SiH or t-BuNH ₂BH ₃Be reductive agent, with CF ₃CO ₂H is catalyzer, and at 40-70 ℃ of lower reaction 1-15h, vacuum distillation recovered solvent with a small amount of normal hexane or petroleum ether solid, gets (+)-l-Epigallocatechol with the ethanol Gossypol recrystallized from chloroform.

Technological line is as follows:

The condition of optimizing is that the mol ratio of dibydro myricetrin and reductive agent is 1: 3-1: 7.Under agitation and N ₂Protection is lower, adds reductive agent.

The present invention becomes methylene radical with chemical reducing agent with dibydro myricetrin 4-carbonyl reduction and does not affect the 3-hydroxyl, does not also affect the steric configuration of 2-carbon and 3-carbon simultaneously.The present invention adopts semisynthetic method to synthesize l-Epigallocatechol take sufficient, the stable dibydro myricetrin of originating as raw material, greatly reduces production cost, has improved greatly the throughput of l-Epigallocatechol.

Embodiment

Further describe the present invention by following examples, but scope of the present invention is not subjected to any restriction of these embodiment.

Use Et ₃SiH reduction dibydro myricetrin is l-Epigallocatechol: in the 250mL there-necked flask, add 32g (0.1mol) dibydro myricetrin, and anhydrous THF150mL, under agitation and N ₂Protection is lower, adds Et ₃SiH 63.4mL (0.4mol), 55 ℃ of lower reaction 12h, THF is reclaimed in underpressure distillation, divides 3 washings with products therefrom with the 90mL normal hexane, and drying with ethanol-Gossypol recrystallized from chloroform, gets white solid 20.4g, productive rate 67%.Fusing point: 188-190 ℃.

Claims

1. the preparation method of one kind (+)-l-Epigallocatechol is characterized in that, with dibydro myricetrin take tetrahydrofuran (THF) (THF) or diox as solvent, with Et ₃SiH, Me ₃SiH or t-BuNH ₂BH ₃Be reductive agent, at 40-70 ℃ of lower reaction 1-15h, vacuum distillation recovered solvent with normal hexane or petroleum ether solid, gets (+)-l-Epigallocatechol with the ethanol Gossypol recrystallized from chloroform.

2. the preparation method of (+) according to claim 1-l-Epigallocatechol is characterized in that, takes the molecular design method take dibydro myricetrin as precursor.

3. the preparation method of (+) according to claim 1-l-Epigallocatechol is characterized in that, the mol ratio of dibydro myricetrin and reductive agent is 1: 3-1: 7.