JPH0521112B2 - - Google Patents

Description

Detailed Description of the Invention (Industrial Field of Application) The present invention relates to 2,6-bis(4-hydroxy-3,
Separation of 5-dimethoxyphenyl)-3,7-dioxabicyclo[3.3.0]octane, i.e., syringaresinol and its stereoisomers (hereinafter abbreviated as syringaresinols) at low cost and in good yield.・Related to methods of purification.

(Prior art) Syringaresinol, which is classified as a lignan, which is a type of plant component, exists in hardwoods and herbs together with its glycosides, although in small amounts.
It is known to be contained in lignin, which is one of the major chemical components of hardwoods and herbs.
Also, recently in our country, Eleuthero (Acantho-panax)
similar to Korean ginseng, which is widely used as a medicinal plant, it is attracting attention for its effectiveness in tonicity and enhancing biological defenses, but syringaresinol and its glycosides are active ingredients in Eleuthero. Its existence has been reported primarily by Soviet scientists. However, although syringaresinol has been attracting attention as a new physiologically active substance, no efficient and economical method for its production has been investigated, and only a few studies have been conducted on plant ingredient chemistry. Only laboratory separation methods have been reported in the field of research.

The present inventors have previously proposed a novel production method that allows syringaresinol to be obtained in good yield from inexpensive and easily available raw materials. That is, on the one hand, a plant body containing lignin containing syringyl cores, such as hardwood chips, is sealed in a pressure vessel, subjected to pressure and heat treatment in a water-containing state, and then rapidly discharged into a receiving tank under normal pressure. A method in which the wood chips are subjected to a so-called blasting treatment in which they are pulverized into fine particles, and then extracted with an organic solvent such as methanol, separated, and purified (Japanese Patent Application No. 58079/1989)
61-218590)). The other method involves cooking hardwood chips with aqueous acetic acid, and then extracting and dissolving the water-insoluble parts in the cooking reaction liquid with an organic solvent to separate and purify the chips.

These methods remove syringylglycerol-α and β-in lignin during blasting and cooking processes.
This is a two-pronged production method in which the allyl ether bond is cleaved, followed by the generation and polymerization of quinone methide radicals to produce a large amount of syringaresinol.
It can be said that these methods have made it possible for the first time to industrially produce syringaresinols.

(Problems to be Solved by the Invention) However, even when the above production method is adopted, as long as the extraction, separation, and purification steps are performed using conventional methods, there is a need to use large amounts of organic solvents, or However, there were still unresolved problems such as the complexity of operation.

The present invention aims to provide a method for efficiently separating and purifying syringaresinol produced by an explosion method and an acetic acid digestion method.

(Means for Solving the Problems) The present inventors further aimed to establish a more efficient and economical method for producing syringaresinol by the above-mentioned explosion method and hydrous acetic acid digestion method. As a result of our research, we found that a method for separating and purifying the syringaresinol component after organic solvent extraction following blasting treatment or acetic acid digestion treatment was to extract the syringaresinol portion with an alkaline aqueous solution, and then treat this extract with an adsorption resin. It was discovered that syringaresinol could be economically advantageously separated and purified with simple operations by eluating it with a water-soluble organic solvent and extracting and removing the water-soluble portion from the eluate, and completed the present invention. did.

The syringaresinol separation and purification process of the present invention involves treating a water-containing plant body containing lignin with a syringyl core, such as hardwood, as a component by a blasting method or an acetic acid digestion method, and then extracting the produced syringaresinol. a step of extracting and dissolving with an alkaline aqueous solution, a step of treating the extract with an adsorption resin to adsorb the target substance, and then eluting with a water-soluble organic solvent;
The process consists of a step of extracting and removing the water-soluble portion from the eluate concentrate and concentrating the syringaresinol, and a step of purifying the syringaresinol concentrated portion, and these steps will be described in detail below. explain.

The raw material plants used in the present invention include broad-leaved trees,
Any material containing lignin having a syringyl core, such as bamboo, straw, cottonseed shell, coconut shell, or almond shell, can be used. In addition, considering workability and processing efficiency, the shape of the raw material is preferably chips or small pieces of several centimeters or less.

In the case of blasting, the above-mentioned plant body is treated with superheated steam of 15-30 kg/cm ² for 5-30 minutes, and the resulting fine powdered water-containing plant body is added to an alkaline aqueous solution such as NaOH or KOH, either as is or in advance. After suspending in twice the amount of water and filtering, syringaresinol is extracted together with the lignin decomposition product by immersion. In this case, if water extraction is performed in advance, organic acids such as acetic acid and formic acid will be removed together with sugars and sugar-modified products, and in addition to the alkali necessary for extraction, these organic acids will be used to neutralize the organic acids. This method is more advantageous because not only can alkali be saved, but also contamination and deterioration of the resin in the subsequent resin adsorption step can be reduced.

In addition, in the case of acetic acid digestion, the above plants are heated at 150 to 200°C for 1 to 5 minutes in an acetic acid solution containing less than 50% water.
After concentrating the cooking reaction solution containing syringaresinols for a period of time, the insoluble portion obtained by adding it to water is extracted and dissolved in the aqueous alkali solution.

By this alkali treatment, lignin decomposition products having free phenolic hydroxyl groups, including syringaresinols, are extracted as water-soluble alkali salts.

A suitable alkali for extracting syringaresinols is an alkali metal hydroxide. The concentration used can be diluted, but if the pH is below 10, a large amount of alkaline solution is required, the extraction efficiency is low, and the yield of syringaresinol is also low.
Additionally, if the concentration of the alkaline solution is extremely high, the extraction solution must be
It becomes necessary to adjust the pH, which requires the use of a large amount of acid, which complicates the process and is economically disadvantageous. Therefore, the appropriate concentration of alkaline solution to be used is 0.1 to 10%, but if the pH is adjusted to within the range of 10 to 14 in the final stage of extraction, it can be sent directly to the subsequent resin process, increasing efficiency. It is true.

The extract of lignin decomposition products containing syringaresinols is extracted with alkali while stirring.
The remaining plant matter or insoluble parts are separated by filtration or centrifugation. This extract contains macromolecules with a molecular weight of several thousand to small molecules with a molecular weight of about 100.

If the pH of this extract exceeds 14, it is adjusted to 14 or less, and then passed through a column filled with an adsorption resin made of a copolymer of styrene and divinylbenzene together with water. The part consisting mainly of low-molecular decomposition products, including syringaresinol, is adsorbed by the resin, while the high-molecular part passes through the column without being adsorbed. In this case, the speed at which the liquid is passed through the column varies depending on the processing conditions and extraction conditions of the raw material plant, but the hardwood material is heated under a pressure of 25 to 30 kg/ ^cm2 .
After being blasted for 10 minutes and extracted with hot water, the weight of the material was
When extracted with 20 times the volume of 1% NaOH aqueous solution,
Appropriately, the volume should be about 10 times or less of the resin filling capacity, and it is not appropriate to pass the liquid at 20 times or more, as there is a risk that some of the syringaresinol may pass through without being adsorbed. After finishing the liquid passage, the resin is washed with water about 3 to 5 times the amount of resin.

The adsorption resin used in the present invention is a copolymer with a giant network structure, and copolymers of styrene and divinylbenzene are well known, such as Amberlite XAD-2 (trade name) manufactured by Organo Corporation and Mitsubishi Chemical Corporation. Available as Diaion HP20 (product name).

Next, in order to elute the syringaresinol adsorbed on the resin, a water-soluble organic solvent such as methanol or acetone is passed through the column. The appropriate rate of liquid flow is 5 times or less the filling volume of the resin per hour. If the flow rate is 10 times or more, the replacement of adsorbed substances between the solvent and resin will be insufficient, and a large amount of elution solvent will be required to completely elute the syringaresinol, which is not efficient. .
The total amount of liquid to be passed requires approximately 2 to 5 times the volume of the filled resin. After the elution operation is completed, the resin is regenerated by passing water to replace the elution solvent.

The eluate is concentrated and the solvent is distilled off to obtain a brown solid containing syringaresinols. The amount of solids obtained is about 1/4 of the solid content of the extract passed through the resin under the above blasting treatment conditions,
Syringaresinol is concentrated 4 times. Moreover, most of this solid material is a water-soluble alkali salt, but syringaresinol is not an alkali salt but is free syringaresinol itself. Therefore, it is not necessary to treat this portion with an acid or the like to liberate it, and pure syringaresinol can be obtained by directly purifying it by a method such as column chromatography. However, as it is, it contains many impurities and requires a large amount of carrier and solvent when subjected to column chromatography, etc. Therefore, after removing water-soluble parts such as alkali salts from this product, purification is performed. It's better to get old. To remove the water-soluble portion, suspend the solid in water, stir well, and then collect the insoluble portion, or suspend the solid in an organic solvent that is poorly soluble in water, such as chloroform, stir well, and then collect the insoluble portion. There are two methods: collecting the dissolved portion, adding water, shaking, and washing, and distributing the solution using a one-liquid system such as water-ethyl acetate. With these methods, the content of syringaresinol in the solid material obtained after excluding the water-soluble portion reaches 10 to 40%. If this concentrated fraction is purified by various methods such as chromatography, pure crystals of syringaresinol can be obtained efficiently.

The syringaresinol obtained in the present invention is syringaresinol and episyringaresinol, both of which are optically active substances.

(Examples) Hereinafter, the present invention will be specifically described based on Examples.

Example 1 Birch wood chips were dried in a pressure vessel (withstand pressure 40 kg/cm ² , capacity 2) which had a steam blowing pipe and an air discharge pipe at the top, a discharge pipe with a ball valve at the bottom, and was connected to a receiving tank with a silencer. as weight
200g was enclosed. Next, the air exhaust pipe was opened, and saturated steam of 2 kg/cm ² gauge was blown into the tube for 2 to 3 seconds each time to exhaust the air, and this operation was repeated three times. After steam replacement, close the air exhaust pipe and 30Kg/
cm ² gauge saturated steam was introduced into the pressure vessel and jacket to rapidly heat and pressurize it. The maximum temperature reached inside the container was 235°C. Immediately after reaching 235°C, the introduction of saturated steam was stopped, and this state was maintained for 8 minutes. Thereafter, the lower ball valve was opened, and the contents of the pressure vessel were discharged into the receiving tank within a very short time. The ejection time is almost instantaneous.
The inside of the receiving tank was washed with water, and the discharged birch fine powder was collected as a suspension.

Approximately 80°C hot water was added to the obtained fine powder suspension to bring the total volume to 3, followed by stirring and suction filtration. Furthermore, the same operation was repeated twice. The residue was dispersed in a 1% NaOH aqueous solution of 2, stirred, and then filtered. The same treatment was repeated two more times, and a total of three alkaline extracts were combined. The pH of this alkaline extract was 11.8, and the solid content was 77 g.

This alkaline extract was passed through a column packed with 1 part of Amberlite XAD-2 manufactured by Argano Co., Ltd. together with water at a rate of 3 parts per hour. After passing the alkaline extract, water was passed through the resin at a rate of 3 to 5 hours per hour to wash the resin. The combined solid content of the passing liquid and washing liquid was 56 g.

Next, 3 methanol was passed through the tube at a rate of 1.5 per hour, and the eluate was collected. The obtained eluate was concentrated to dryness to obtain 21.5 g of solid matter. This solid was ground, dispersed in 400 ml of water, and then extracted with 100 ml of ethyl acetate. The ethyl acetate extraction was performed three times and the total extracted solids was 5.5 g.

This solid was charged to a column packed with silica gel C-200 manufactured by Wako, and eluted with a mixture of ethyl acetate:benzene/1:3 (volume ratio).
The episyringaresinol and syringoresinol portions were collected while monitoring by silica gel thin layer chromatography. A portion consisting only of episyringaresinol and syringaresinol and a mixed portion of both were obtained. The mixed portion was subjected to silica gel column chromatography again under the same conditions to separate episyringalesinol and syringalesinol. The crude crystals of episyringaresinol and syringoresinol obtained from two rounds of column chromatography were 1.7 g and 1.2 g, respectively.

Recrystallizing each crude crystal from dichloromethane-n-hexane yields 1.3 g and 1.0 g of pure crystals of episyringaresinol and syringaresinol, respectively.
were obtained, and the infrared absorption spectra and melting points matched those of each sample. In addition, no drop in melting point was observed in the blending test with each sample.

Example 2 Cottonseed husks with a dry weight of 200 g were treated according to the equipment and procedure of Example 1 using saturated steam of 25 kg/cm ² gauge, maximum temperature of about 220°C, and maximum temperature holding time of 12 minutes. , a fine powder suspension was obtained.

The obtained fine powder suspension was subjected to hot water extraction treatment in the same manner as in Example 1, and the excess residue was extracted as in Example 1.
Extraction was carried out with an aqueous NaOH solution under the same conditions and procedures as above. The pH of the obtained extract was 11.6. This extract was passed through a column packed with Mitsubishi Kasei Diaion HP20 1 together with water under the same conditions as in Example 1, and further washed with water.
It was eluted with ethanol. Ethanol was distilled off from the eluate and dried to obtain 26 g of solid. This solid was crushed, 300 ml of dichloromethane was added, and the mixture was stirred and extracted for 3 hours. Thereafter, centrifugation was performed to remove the residue, and 100 ml of water was added to the resulting dichloromethane solution, which was shaken and washed. The solvent was distilled off from this dichloromethane solution, and the residue was purified under the same conditions as in Example 1. It was subjected to silica gel column chromatography to obtain syringaresinol and epixyringaresinol moieties. Recrystallization was carried out using dillolomethane-n-hexane to obtain 0.8 g and 1.0 g of pure syringaresinol and episyringaresinol crystals, respectively. The obtained syringaresinol and episyringaresinol had infrared absorption spectra and melting points that matched those of each sample, and did not show any decrease in melting point in a mixing test with each sample.

Example 3 Beech wood chips weighing 700 g (dry weight) were placed in an autoclave, and acetic acid and water were added and sealed so that the liquid ratio was 6 and the acetic acid concentration was 90%. first 30
The mixture was heated to 180°C for 1 minute, held at 178-182°C for 3 hours, and then rapidly cooled. Thereafter, the internal solution was taken out, and the pulp and liquid were separated by filtration. The residue was immersed in 90% acetic acid in Step 5, disintegrated with a mixer, and then filtered again to separate the liquid and pulp.
It was concentrated together with the above solution. After concentrating to about 1.5%, it was added dropwise to 15ml of water, and the resulting precipitate was collected by centrifugation. After washing the collected precipitate with water, 1% NaOH9 was added to the precipitate to dissolve it. The pH of the alkaline solution was 12.3.

As in Example 1, this alkaline solution was passed through a column filled with 3 parts of Amberlite XAD-2 manufactured by Organo Co., Ltd. together with water at a rate of 3 parts per hour, and then 6 parts of water was passed at a rate of 3 parts per hour. The resin was washed. Thereafter, 6 methanol was passed through the solution at a rate of 3 per hour for elution. The solvent was distilled off from the resulting methanol eluate and dried to obtain 61 g of solid matter.

After dispersing this solid in water according to the procedure of Example 1,
Extracted with ethyl acetate. The ethyl acetate extract was subjected to silica gel column chromatography under the same conditions and operations as in Example 1, and then recrystallized from dichloromethane-n-hexane to obtain pure syringaresinol and episyringaresinol. 2.8 g and 3.1 g of crystals were obtained, respectively. Each of the obtained crystals was confirmed to be syringaresinol and episyringaresinol by comparison with a standard product.

(Effects of the Invention) According to the present invention, syringaresinol can be produced at an extremely high yield by using readily available and inexpensive plant bodies such as hardwood, bamboo, and coconut shells as raw materials by using the blasting method and the acetic acid cooking method. After being produced, it can be efficiently separated and purified. Moreover, neither the alkali extraction/dissolution step nor the resin treatment step requires complicated treatment equipment or operations, so industrialization is easy and high economic efficiency can be expected.

Claims (1)

[Claims] 1. A plant body containing lignin having a syringyl core as a component is (a) subjected to pressure and heat treatment in a water-containing state in a pressure vessel, and then rapidly discharged into a receiving tank under normal pressure and pulverized. or (b) after cooking with hydrous acetic acid in a pressure vessel, extracting the water-insoluble parts of the crushed plant material or the cooking solution with an alkaline aqueous solution, and adsorbing the extract with an adsorption resin; 2,6-bis(4-hydroxy-3,5-dimethoxyphenyl)-3, characterized in that it is eluted with a water-soluble organic solvent and the water-soluble portion is removed from the eluate.
Separation and purification method of 7-dioxabicyclo[3.3.0]octane. 2. 2,6-bis(4-hydroxy-3,5-dimethoxyphenyl)-3,7 according to claim 1, characterized in that a woody broad-leaved tree or a herbaceous plant is used as the plant. -Separation and production method of dioxabicyclo[3.3.0]octane. 3. 2, 6- as set forth in claim 1, characterized in that an alkaline aqueous solution with a pH of 10 or more is used.
A method for separating and purifying bis(4-hydroxy-3,5-dimethoxyphenyl)-3,7-dioxabicyclo[3.3.0]octane. 4. 2,6-bis(4-hydroxy-3,
Separation and purification method of 5-dimethoxyphenyl)-3,7-dioxabicyclo[3.3.0]octane. 5. 2,6-bis(4-hydroxy-3,5-dimethoxyphenyl)-3 according to claim 1, characterized in that a copolymer of styrene and divinylbenzene is used as the adsorption resin. Separation and purification method of 7-dioxabicyclo[3.3.0]octane. 6 As a water-soluble organic solvent, a saturated alcohol having 1 to 3 carbon atoms, dioxane, tetrahydrofuran,
or 2,6-bis(4-hydroxy-3,5-dimethoxyphenyl)-3,7- according to claim 1, characterized in that acetone is used.
Separation and purification method of dioxabicyclo[3.3.0]octane.