JPH0692281B2 - A chafer beetle attractant containing amino acid methyl ester as an active ingredient - Google Patents

Description

Detailed Description of the Invention

[0001]

FIELD OF THE INVENTION The present invention relates to the giant brown chafer belonging to the family Coleoptera Scarabaeidae (scientific name: Holothrichia).
L-isoleucine methyl ester, D-isoleucine methyl ester, L-allo as a sex attractant for P.
The present invention relates to the control of C. japonica using one or more selected from isoleucine methyl ester and D-allo-isoleucine methyl ester.

[0002]

[Background Art] In regard to Coleoptera, Scarabaeidae, larvae feed on the bases of agricultural crops such as taro, sweet potato, and strawberry, and adult larvae come to fruit trees such as cherry, peach, plum, and pear to remove leaves. To eat. Since larvae hide in the soil and adults fly away, effective control with insecticides is extremely difficult. Further, the use of insecticides is not only extremely harmful to the health of workers, but also causes a so-called pesticide residue problem, which is a serious social problem from the viewpoint of food safety.

Under these circumstances, in order to effectively control C. japonica, it is necessary to have a means for predicting the occurrence that is useful for accurately knowing the ecology of development, and a method for controlling general toxic insecticides. It is highly desirable to develop different control measures. One of the effective methods is to use an attractant, and the chemical structure of the sex pheromone has already been elucidated for some pests other than the black scutellaria, and it is possible to use the attractant sex pheromone to control the development of pests. It has become possible to conduct research efficiently. Furthermore, a method for controlling pests by using such a sex attractant to capture a large number of adult males or disrupt the mating behavior of males and females is being developed.

[0004]

DISCLOSURE OF THE INVENTION The present invention is directed to the giant brown chafer belonging to the Coleoptera Scarabaeidae (scientific name: Holotr).
The purpose of the present invention is to elucidate a sex attractant against ichia parallella, and to provide a method for controlling Pseudococcidae using it.

[0005]

Means for Solving the Problems In view of the above circumstances, the present inventor conducted a study on the sex pheromone of the blue scutellaria, and extracted a component substance having extremely high sexual attraction activity to males from the adult female of the black stag beetle, The substance (natural product) was analyzed by infrared spectroscopy, mass spectrometry, etc., and the chemical structure was estimated from the data.

On the other hand, a compound having the estimated chemical structure was synthesized, and the synthesized product was similarly analyzed by infrared spectroscopy, mass spectrometry and the like. Furthermore, it was found that chemically synthesized compounds also have an effective attracting action on males of the Japanese blue chafer.

[0007] The data of natural products and synthetic products were collated, and from the coincidence, the sex attractant of Rana orientalis was found to be methyl (2S, 3S) in the natural product state.
-2-amino-3 methylpentanoate [methyl
(2S, 3S) -2-amino-3-methylp
entanoate], that is, L-isoleucine
Methyl ester (L-isoleucine meth
ylester) and methyl (2R, 3R) -2-amino-3methylpentanoate [methyl (2R,
3R) -2-amino-3-methylpenta
noate], that is, D-isoleucine methyl ester (D-isoleucine methyl ester).
Ster) and methyl (2S, 3R) -2-amino-3
Methyl pentanoate [methyl (2S, 3R)-
2-amino-3-methylpentanoat
e], that is, L-allo-isoleucine methyl ester (L-allo-isoleucine me
tylester) and methyl (2R, 3S) -2
-Amino-3-methylpentanoate [methyl (2
R, 3S) -2-amino-3-methylpen
Tanoate], that is, D-allo-isoleucine methyl ester (D-allo-isoleuc
It was found to be a mixture with ine methyl ester).

These compounds may be a mixture of the above-mentioned four kinds of compounds (optical isomers), one kind of the compound alone, or a mixture of two or three kinds of compounds. It exhibits a strong attracting action and a sexual behavior stimulating action on the adult male of the blue chafer, so it is a very effective substance when used for the control of the blue chafer. The present invention has been completed based on these findings.

[0009] The present invention is based on the genus Coleoptera (Horotricia par) belonging to the family Coleoptera, Scarabaeidae.
Allele, Holotrichia paralera), which has a very high sex-inducing effect on adult males, is selected from L-isoleucine methyl ester, D-isoleucine methyl ester, L-allo-isoleucine methyl ester and D-allo-isoleucine methyl ester. To provide one or more selected compounds,
Further, the present invention provides a sex attractant for Rhododendron japonicus, which contains one or more kinds of the compounds as active ingredients, and a method for controlling the Rhododendron japonicus using the one or more compounds.

[0010]

EXAMPLES L-, D-, and L-a which are the active substances of the present invention
Ilo- and D-allo-isoleucine methyl esters are the corresponding four amino acids L-, D-, L.
It can be chemically synthesized by methyl-esterifying -allo- and D-allo-isoleucine by a conventional method.

These active substances are used as they are or as a solution by dissolving them in a suitable organic solvent such as dichloromethane, and adsorbing them on a suitable carrier such as plastic such as polyethylene or rubber, or a capsule or a capillary tube made of plastic. It can be formulated into a practical form of a sex attractant by encapsulating in, or filling a glass capillary tube with one end sealed, using a suitable material or instrument depending on the usage form.

Example 1 Isolation and Identification of Active Substances The present inventors isolated and identified these active substances as follows. To track active substances, changes in nerve potentials produced by the tactile sensation of the blue-spotted beetle when the active substance was received using a bioassay for examining attractants against male adults of the blue-spotted beetle in the field and a bioelectric detector directly connected to a gas chromatograph. It depends on the method of detecting.

First, the secretory glands at the abdominal end of about 80 adult females of the blue-spotted beetle collected from the field were treated with dichloromethane 50
Extracted with ml. 50 extracts were fractionated by column chromatography using silica gel. That is, hexane was flowed in the order of 5%, 10%, 20%, 50% -ether / hexane and ether. The cotton wool containing 1 to 5 of each fraction was shown to the adults of the field blue chafer, and a large number of male adults were attracted to the ether fraction.

Gas chromatographic analysis of this active fraction revealed a single peak. That is, strong polarity column DB-23 (30 m × 0.25 mm; 0.25
μm) and hold at 50 ° C for 1 minute, then 8 ° C / min
When the temperature was raised to 210 ° C. at the rate of 10 minutes and held at that temperature for 10 minutes, a single peak was observed at 9.50 min. In addition, the non-polar column HP-1 (25m x 0.2m
m; 0.33 μm), the temperature was maintained at 50 ° C. for 1 minute, then the temperature was raised to 210 ° C. at a rate of 8 ° C./min, the temperature was maintained for 10 minutes, and then 230 ° C. at a rate of 20 ° C./min.
When heated to ℃ and held for 10 minutes, 12.56 m
A single peak was observed in.

Using a bioelectric detector directly connected to the gas chromatograph, male antennae showed a clear response to this component. The female antennae did not show any reaction to this component.

This fraction was injected into a Fourier transform infrared spectrophotometer directly connected to a gas chromatograph and analyzed.
55cm ^{- 1} (rC = O) a strong absorption carbonyl group was observed, also, 1173Cm ^{- 1} carbons (rC-O) strong absorption - the presence of oxygen binding was shown (Figure 1).
Considering the absorption patterns of the two, the substance was considered to be a methyl ester. Besides that, 1622
cm ^{- 1} weak absorption observed (δNH _2), the presence of amino groups was considered from this absorption.

When this component was injected into a gas chromatograph directly coupled mass spectrometer and analyzed (GC-MS analysis), a molecular ion peak m / z 145 and a base ion peak m / z were obtained.
z86 was found. Other characteristic ion peaks were m / z 74, 88, 146 (M + 1). The molecular weight is m / z 146 (M + 1), 16 by mass spectrometry by a chemical ionization method using ammonia.
3 (M + 18), when using isobutane, m / z 14
Since 6 (M + 1) and 186 (M + 41) were respectively observed, it was determined to be 145. Next, since m / z 86 and 88 were recognized as fragments, it was presumed to be the methyl ester of α-amino acid.

After reacting this component with acetyl chloride, GC-MS analysis revealed that the molecular ion peak m /
z186 and base ion peak m / z128 were recognized. Therefore, it was confirmed that the original amino acid was α-amino acid.

Regarding the alkyl group in this amino acid, three kinds of amino acids, namely leucine (leuc) are used.
ine), isoleucine, and norleucine were considered to be structures, which were confirmed by synthesis. That is, thionyl chloride was dissolved in methanol at -10 ° C, and each amino acid was added little by little. The temperature was gradually raised to 40 ° C. and then left for 2 hours. Excess methanol was distilled off, a small amount of water and ether were added in a cold state, aqueous ammonia was further added to make the aqueous layer basic, and the mixture was extracted with ether. The ether layer was washed 6 times with water.

The amino acid methyl ester thus obtained by the chemical synthesis is a strongly polar column DB-WAX.
(30 m × 0.25 mm; 0.25 μm), 50
After holding at 0 ° C for 1 minute, the temperature was raised to 180 ° C at a rate of 4 ° C / min, and after holding at that temperature for 1 minute, further 10 ° C / m.
The analysis was performed under the condition that the temperature was raised to 210 ° C. at a rate of in and the temperature was maintained for 10 minutes. Leucine methyl ester (le
The retention time of ucine methyl ester is 15.49 min, norleucine methyl ester (n
In the case of orleucine methyl ester), it was 17.40 min. Since the retention time of the natural product was 15.95 min under the same conditions, it was clearly different from both. This was supported by the fact that the intensity of fragment ion peak m / z 88 was significantly weaker than that of the natural product as a result of GC-MS analysis of both.
Isoleucine methyl ester (isoleucine)
In the case of methyl ester), its GC retention time and mass spectrum were in good agreement with those of the natural product.

Isoleucine methyl ester (isol
Eucine methyl ester) has two asymmetric carbon atoms, and therefore four optical isomers are considered. Therefore, each optical isomer was synthesized by methyl esterification of the corresponding amino acid.

The substances thus obtained were compared and examined by chromatographic analysis using an optical isomer separation column. That is, the optical isomer resolution column CP-Cy
clodextrin β-2,3,6-M-19 (5
0 m × 0.25 mm; 0.25 μm) was analyzed under a low temperature condition of 95 ° C.
-Allo-isoleucine methyle
star: 24.109 min, D-allo-iso
leucine methyl ester: 24.4
65min, D-isoleucine methyl
ester: 24.865 min, L-isoleu
cine methyl ester: 25.479m
in (a in FIG. 2).

When a natural product was analyzed under the same conditions, L-
isoleucine methyl ester: 8
3.6% D-isoleucine methyl ester
r: 9.9%, D-allo-isoleucine
methyl ester: 4.5%, L-allo-
isoleucine methyl ester:
It was detected at a rate of 2.0% (FIG. 2b).

Each of the synthetic amino acid methyl ester and the natural product was mixed with acetyl (S) -lactyl chloride [acet].
yl (S) -lactyl chloride], and the resulting derivative was analyzed by GC. That is, strong polarity column DB-WAX (30 m × 0.25 mm; 0.25 μ)
m) was used and held at 100 ° C. for 1 minute, and then 4 ° C./mi
The temperature was raised to 220 ° C. at a rate of n and held for 10 minutes. The retention time of the derivative is D-allo-isoleucin.
e methyl ester: 25.66 min, D
-Isoleucine methyl ester:
25.97 min, L-allo-isoleucin
e methyl ester: 26.10 min, L
-Isoleucine methyl ester:
It was 26.42 min.

Analysis of the natural product under the same conditions gave results supporting the results obtained when using the optical isomer resolution column described above.

Based on the above results, it is worth noting that the giant brown chafer belonging to the Coleoptera Scarabaeidae (scientific name: Holorich)
ia paralera)
Is a substance (natural product) that has an extremely high sex-inducing effect on males of M. alba, methyl (2S, 3S) -2-amino-3methylpentanoate [methyl (2S, 3S) -2-a
mino-3-methylpentanoate],
That is, L-isoleucine methyl ester (L-i
soleucine methyl ester),
Methyl (2R, 3R) -2-amino-3 methylpentanoate [methyl (2R, 3R) -2-amino
-3-methylpentanoate], that is, D-isoleucine methyl ester (D-isol
eucine methyl ester) and methyl (2S, 3R) -2-amino-3 methylpentanoate [methyl (2S, 3R) -2-amino-3-
methylpentanoate], that is, L-
allo-isoleucine methyl ester (L-all
o-isoleucine methyl ester
r) and methyl (2R, 3S) -2-amino-3methylpentanoate [methyl (2R, 3S) -2-a
mino-3-methylpentanoate],
That is, D-allo-isoleucine methyl ester (D-allo-isoleucine methyl
It was determined to be a mixture with L.

The main component showing the sex-inducing activity is considered to be L-isoleucine methyl ester in view of the composition ratio in natural products.

[Example 2-Biological activity of active substance] A sex pheromone (L-isoleucine met) having a natural composition.
hyl ester: 83.6%, D-isoleuc
ine methyl ester: 9.9%, Da
Ilo-isoleucine methyl est
er: 4.5%, L-allo-isoleucine
about 1 μg of methyl ester (2.0%)
A piece of cotton wool that had been impregnated (corresponding to one female pheromone) was shown in the field giant blue-spotted chafer.
It was observed to continue the exploratory behavior for 3 minutes. It was observed that this behavior continued even when the pheromone source contained in the cotton wool pieces was randomly moved.

L-, D-, La obtained by chemical synthesis
Ilo- and D-allo-isoleucine methyl esters were subjected to similar field bioassays of one compound alone and a mixture of two to four compounds, again showing that a large number of male adult C. I was attracted.

[Brief description of drawings]

FIG. 1 is an absorption spectrum diagram of a natural product in a gas chromatograph directly coupled Fourier transform infrared spectrophotometer.

FIG. 2 shows data obtained by subjecting isoleucine methyl ester to an optical isomer resolution column and performing chromatographic analysis. a is a synthetic product and b is a natural product.

Claims (2)

[Claims] 1. L-isoleucine methyl ester, D
-Attractivity of Coleoptera Scarabaeidae belonging to the family Coleoptera Scarabaeidae characterized by containing one or more compounds selected from isoleucine methyl ester, L-allo-isoleucine methyl ester and D-allo-isoleucine methyl ester as an active ingredient. Agent. 2. L-isoleucine methyl ester, D
-A method for controlling a black beetle belonging to the family Coleoptera Scarabaeidae, which comprises using at least one compound selected from isoleucine methyl ester, L-allo-isoleucine methyl ester and D-allo-isoleucine methyl ester.