JPH0764779B2 - Stilbene-2-carboxylic acid, 3-hydroxy, 5-methoxy, a method for producing the same, and a herbicide containing the same as an active ingredient - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to stilbene-2-carboxylic acid, 3-hydroxy, 5-methoxy, a method for producing the same and a herbicide containing the same as an active ingredient. Since this substance is of natural origin and has a plant growth inhibitory effect,
It is useful as a pesticide with low toxicity.

[0002]

BACKGROUND OF THE INVENTION Most of the herbicides commercialized to date are organic synthetic agents, and their adverse effects on the environment have become a serious problem. Therefore, there is a strong demand for the development of naturally-occurring low-toxic pesticides that can be easily metabolized and decomposed in the natural material cycle.

However, the only natural herbicide that has been commercialized as a herbicide is the herbicide of microbial (actinomycete) origin, Bialaphos (trade name: Herbiace, manufactured by Meiji Seika Co., Ltd.), which is plant-derived. There are no examples of herbicides. Therefore, it is an object of the present invention to provide natural, low toxicity pesticides of plant origin.

Regarding the plant growth inhibitory action of stilbene derivatives, a report by Hashimoto et al. (Journal name, number of volumes,
1988), it is pointed out that the inhibitory action of the stilbene-2-carboxylic acid derivative represented by the following formula (2) is mainly germination inhibition, but inhibition on roots and aboveground parts The effect is small, and no inhibitory effect on the roots and above-ground parts is observed at a concentration of 150 ppm.
In addition, as a result of comparison of the inhibitory activities of several dozen stilbene derivatives, it is concluded that the substitution of the phenolic hydroxyl group at the 3rd and 4'positions is essential for the expression of the plant growth inhibitory activity.

[0005]

[Chemical 2]

[0006]

That is, the present invention provides the following formula (1):

[0007]

[Chemical 3]

Stilbene-2-carboxylic acid represented by
With respect to 3-hydroxy-5-methoxy, the above stilbene-2-carboxylic acid, 3-hydroxy-5, characterized in that the extract obtained by subjecting the leaves of Kimame to extraction treatment with methanol or ethanol is extracted with ethyl acetate. −
The present invention relates to a method for producing methoxy and a herbicide containing the stilbene-2-carboxylic acid, 3-hydroxy, 5-methoxy as an active ingredient.

The stilbene derivative is a general term for compounds having a basic skeleton represented by the following formula (3), and is a compound widely distributed in the plant kingdom.

[0010]

[Chemical 4]

However, there are few isolated examples of the stilbene-2-carboxylic acid derivative, and the compound represented by the above formula (1), which was isolated by the present inventor at this time, is a novel compound which has not been published in the literature.

The stilbene-2-carboxylic acid, 3-hydroxy, 5-methoxyl represented by the formula (1) can be obtained by an extraction method using leaves and / or stems of Kimame. Kimame is a legume crop cultivated for food or feed in tropical countries, but its components have not been clarified and other uses have not yet been developed.

The method for producing stilbene-2-carboxylic acid, 3-hydroxy, 5-methoxy of the present invention will be described below. One kind of solvent selected from methanol, ethanol and acetone is used at a ratio of 2 to 6 liters, preferably 3 to 5 liters per 1 kg of Kimame leaves and / or stems, and 15 to 40 ° C., preferably 25-
Extraction is performed at 30 ° C. for 1 to 48 hours, preferably 6 to 24 hours. Suitably, this operation is repeated 2 to 5 times,
Obtain the extract.

After the extracts are combined, they are concentrated if necessary, then the concentrated solution is dissolved in water as necessary, and the pH is adjusted to about 2 to 3 with an acid such as hydrochloric acid. Then, 2 to 20 ml of ethyl acetate, preferably 1 to 10 ml of this concentrated solution is used.
Extract again using 0-15 ml. It is desirable to repeat this extraction operation 2 to 5 times. The ethyl acetate layer thus obtained is extracted with a 3-5% aqueous sodium bicarbonate solution. If further purification is desired, known techniques such as an ion exchange method can be applied for purification. Further, as another preferable method, the pH of the sodium bicarbonate layer is adjusted to about 2 to 3 with an acid such as hydrochloric acid, and then 2 to 6 volumes, preferably 3 to 5 volumes of ethyl acetate are added. It is extracted again and redissolved.

The obtained ethyl acetate layer can be used as a herbicide as it is, but it is usually used after further purification. That is, the ethyl acetate layer is concentrated under reduced pressure and then purified by column chromatography using silica gel or the like. Elution is performed using an organic solvent, for example, a mixed solvent of benzene and ethyl acetate. When this mixed solvent is used, specifically, 500 ml of ethyl acetate in benzene is eluted at a concentration of 5%, and further 10% is 500 ml,
Elute 500 ml at 15% sequentially. The eluent is, for example, 5
Fractions of 0 ml each are fractionated by a fraction collector to obtain a fraction containing a target plant growth inhibitor.

After the fractions containing the target substance are collected and combined, the solvent is removed and recrystallized from, for example, methanol and a water-methanol mixed medium to isolate the plant growth inhibitor as needle crystals.

Structural analysis of the obtained substance is carried out by mass spectrometry, infrared spectroscopic analysis and nuclear magnetic resonance analysis. This compound is stilbene-2-carboxylic acid, 3-hydroxy, 5-
It was determined to be methoxy. Figure 1 shows the mass spectrum of this compound, Figure 2 shows the infrared absorption spectrum, and Figure 3 shows ¹ H.
-NMR spectrum, Fig. 4 shows ¹³ C-NMR spectrum, respectively. In addition, this substance is searched by CAS (1962-1
990), the description in the literature was not recognized and it was determined to be a new compound.

The main mechanism of action of this substance is inhibition of root elongation, as will be described later. As described above, in the past knowledge, the inhibitory action of the stilbene-2-carboxylic acid derivative is a germination inhibitory action, whereas this substance shows almost no germination inhibitory action, and it is mainly the inhibition of radicle elongation. It is clearly different from the action of the known compound in that it has a plant growth inhibitory action even though it is not substituted with a hydroxyl group at the 4'position. Moreover, this substance is 500 μM (135 ppm)
It has an action of inhibiting the growth of lettuce radicles by about 80% at the concentration of 1, and is superior to the known ones even at the concentration showing the activity.

[0019]

EXAMPLES The present invention will now be described with reference to examples, but the present invention is not limited thereto.

Example 1 5 kg of fresh leaves of kimame were extracted with 20 liters of methanol at room temperature. This operation is repeated 3 times, and after the extracts are combined,
Concentrated to obtain total extract. About 400 ml of this total extract
After dissolving in water, adjust the pH to 2.5 with hydrochloric acid,
Extraction was performed 3 times with 400 ml of ethyl acetate to obtain an ethyl acetate layer.

The resulting ethyl acetate layer was extracted with a 5% aqueous sodium bicarbonate solution to obtain a sodium bicarbonate layer, which was adjusted to pH 2.5 with hydrochloric acid and then extracted with 3 volumes of ethyl acetate to obtain ethyl acetate. Layers were obtained.

After concentration of the ethyl acetate layer under reduced pressure, 200 g
Silica gel column chromatography was performed using the above silica gel to purify. Elution was carried out using a mixed solvent of benzene and ethyl acetate at an ethyl acetate concentration of 5% in benzene.
00 ml, 500 ml at 10% and 5 at 15%
It was carried out by sequentially eluting with 00 ml. Eluent is 5
Fractionation of 0 ml each with a fraction collector
It was found that substances having a plant growth inhibitory effect were present in the 2 to 15 fractions.

After these fractions were combined, the solvent was removed under reduced pressure and recrystallized from methanol and a water-methanol mixed medium to isolate a plant growth inhibitor as needle crystals. The structure of this substance was examined by mass spectrometry, infrared spectroscopy and nuclear magnetic resonance analysis. As a result of mass spectrometry, the molecular weight of this substance was found to be 270. In addition, as a result of infrared spectroscopy analysis and nuclear magnetic resonance analysis, the structure of this substance was stilbene-
It was determined to be 2-carboxylic acid, 3-hydroxy, 5-methoxy.

Example 2 When the methanol extract of the fresh leaves of the soybeans in Example 1 was examined for its inhibitory effect on plant growth, the results shown in Table 1 were obtained.

[0025]

[Table 1]

As is clear from the results shown in Table 1, the action of inhibiting the growth of plants in the extract, especially the action of inhibiting the elongation of radicles was observed.

Example 3 The plant growth inhibitory effect of stilbene-2-carboxylic acid, 3-hydroxy, 5-methoxy obtained in Example 1 was assayed by a lettuce growth test. Results are shown in FIG. As is clear from the figure, this substance inhibits the elongation of lettuce radicles by 50% at a concentration of 2.3 × 10 ⁻⁴ M. However, since the inhibitory effect on hypocotyl elongation and germination is small, it was revealed that the main mechanism of action of this substance is root elongation inhibition.

[0028]

The stilbene-2-carboxylic acid of the present invention,
3-Hydroxy, 5-methoxy is a naturally-derived substance obtained from a specific plant as a raw material and has a plant growth inhibitory action, and is therefore useful as a low-toxic pesticide.

[Brief description of drawings]

FIG. 1 shows a mass spectrum of a compound of the present invention.

FIG. 2 shows an infrared absorption spectrum of the compound of the present invention.

FIG. 3 shows the ¹ H-NMR spectrum of the compound of the present invention.

FIG. 4 shows a ¹³ C-NMR spectrum of the compound of the present invention.

FIG. 5 is a graph showing the plant growth inhibitory effect of the compound of the present invention.

Claims (3)

[Claims] 1. A stilbene represented by the following formula (1):
2-carboxylic acid, 3-hydroxy, 5-methoxy. [Chemical 1] 2. The extract obtained by subjecting leaves and / or stems of Kimame to extraction treatment with methanol, ethanol or acetone is extracted with ethyl acetate.
Process for producing stilbene-2-carboxylic acid, 3-hydroxy, 5-methoxy as described. 3. A herbicide containing the stilbene-2-carboxylic acid, 3-hydroxy, 5-methoxy according to claim 1 as an active ingredient.