JPH05163183A - 2-hydroxymethyl-menthol and 2-hydroxymethylmenthone - Google Patents

Abstract

PURPOSE:To provide the subject odorless compound having excellent effect and sustainability as a noxious organism repellent. CONSTITUTION:The objective compound, 2-hydroxymethyl-menthol of the formula. This compound can be obtained by producing 2-ethoxycarbonyl-menthone from menthone and diethyl carbonate followed by reducing the 2-ethoxycarbonyl- menthone.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a novel compound which is substantially odorless in itself and has an extremely long-lasting effect as a pest repellent.

[0002]

2. Description of the Related Art In order to protect oneself from pests such as mosquitoes, N as a pest repellent,
N-diethyltoluamide is widely used. Also,
It is known that 2-ethyl-1,3 hexanediol also has a strong repellent effect (USP2407205).

However, this N, N-diethyltoluamide has a peculiar odor and 2-ethyl-
1,3-hexanediol has problems such as lack of sustainability. Therefore, the development of new pest repellents has been desired. An object of the present invention is to provide a novel compound having an excellent pest repellent effect and useful as a pest repellent having no unpleasant odor.

[0004]

[Means for Solving the Problems] In view of the above circumstances, the present inventors have earnestly studied to develop a new pest repellent having a strong effect as a pest repellent and having no peculiar odor. Have succeeded in synthesizing a novel compound, and have found that the compound has an excellent pest repellent effect and its long-lasting effect. That is, the present invention relates to 2-hydroxymethyl-menthol and 2-hydroxymethyl-menthol represented by the following general structural formulas 3 and 4.

[Chemical 3]

[Chemical 4]

The details of the configuration of the present invention will be described below. The method for producing 2-hydroxymethyl-menthol (hereinafter abbreviated as HMMO) of the present invention includes:
2-Ethoxycarbonyl-from menthol and diethyl carbonate
It can be obtained by obtaining menthone and then reducing it. As a method for producing 2-hydroxymethyl-menthone (hereinafter abbreviated as HMMT) of the present invention, mentone and formaldehyde can be obtained by heating and stirring in methanol in the presence of potassium carbonate.

According to this synthetic method, 2-hydroxymethyl-
Menthol (HMMO) and 2-hydroxymethyl-menthone (HMMT) are obtained as colorless transparent oils with almost no odor. Further, each of the oily substances can be taken out as crystals by isolating stereoisomers by column treatment or the like. The present invention has been completed by finding the feature that all of these isomers have a strong repellent effect against pests such as mosquitoes.

Further, the HMMO and HMMT of the present invention are
Cosmetics that are usually used as pest repellents,
It can be used in the usual dosage forms of pharmaceuticals. The blending amount is 0.1% to 90%, preferably 3% to 20%. Further, the HMMO and HMMT of the present invention can be blended in a usual fragrance composition as a fragrance holding agent.

[0008]

EXAMPLES Examples will be described below. In addition, wt% shown in the examples means% by weight. Example 1 To 100 ml of dry benzene, 8 g of sodium hydride (containing 40% of liquid paraffin) was gradually added, and further 2
After adding 0 g of diethyl carbonate, the mixture was heated with stirring until reflux. A solution prepared by dissolving 15 g of menthone in 40 ml of dry benzene was gradually added dropwise to the reaction solution over about 2 hours. 2 more after dropping the whole amount
The heating and stirring were continued for an hour.

After cooling to room temperature, 20 ml of acetic acid was gradually added. After adding 100 ml of cold water, the organic layer was extracted. The aqueous layer was extracted twice with 100 ml of benzene, and then the above organic layers were mixed. The organic layer was washed with cold water, dried over anhydrous sodium carbonate, and then benzene was removed to obtain a crude reaction product. The crude reaction product was distilled under reduced pressure to obtain 16 g of a fraction mainly containing 2-ethoxycarbonyl-menthone.

This fraction was added to 20 ml of dry TH
After being dissolved in F (tetrahydrofuran), a solution prepared by dispersing 2 g of lithium borohydride in 120 ml of dry THF was gradually added dropwise under cooling and stirring. After completion of dropping, stirring was continued at room temperature for 4 hours. 50 under cooling and stirring
After gradually adding ml of ethyl acetate and 100 ml of water,
Further, a 10% aqueous sulfuric acid solution was added until the pH of the reaction solution reached about 2.

The reaction solution was extracted twice with 100 ml of diethyl ether, dried over anhydrous sodium carbonate,
The crude reaction product was obtained by removing diethyl ether and THF. Silica gel column chromatography (developing solvent benzene / acetone = 8/1) produced colorless oil (8.3 g, yield 34.4%).
Got

The parent peak -18 (M-H ₂ O) was observed in the mass spectrum measurement of the obtained oily substance, and strong hydroxyl group absorption at 3380 cm -1 was confirmed in the IR measurement.
In addition, elemental analysis (theoretical values of C and H are C = 70.92%,
H = 11.90%, measured value C = 70.85%, H = 1
The production of HMMO was confirmed by 2.01%.

Example 2 20 g of menthone was dissolved in 50 ml of methanol, and then 1.6 g of potassium carbonate was added. The reaction solution is 65
14 ml of formalin solution was gradually added dropwise to the mixture with heating and stirring up to ℃. After adding the total amount of formalin solution, stirring was continued for 3 hours. After removing methanol from the reaction solution under reduced pressure, the reaction solution was extracted twice with 50 ml of diethyl ether. The diethyl ether layer was dried over anhydrous sodium carbonate and the diethyl ether was removed to obtain a crude reaction product. This crude reaction product was subjected to silica gel column chromatography (developing solvent: benzene /
Acetone = 8/1) was used to obtain 7.3 g of a colorless transparent oily substance (yield 30.5%).

A parent peak -18 (M-H2O) was observed in the mass spectrum measurement of the obtained oily product. Also TM
M + = 256 in mass spectrum measurement after conversion to S
The value of was confirmed. Furthermore, elemental analysis (theoretical values of C and H are C
= 71.69%, H = 10.94%, measured value C = 71.
43%, H = 11.08%) confirmed the production of HMMT.

Application Examples 1 and 2, Comparative Examples 1 and 2 (Liper Lotion) According to the formulations shown in Table 1 below, reper lotions of Application Example and Comparative Example were prepared. Note that N, N-diethyltoluamide has been conventionally used as a pest repellent. Further, 2-ethyl-1,3-hexanediol is a compound known to have a repellent effect.

[0016]

[Table 1]

The pest repellent effect and its effect persistence test method are as follows. <Blood repellent test for adult Aedes albopictus> In order to investigate the repellent effect of Aedes albopictus on adults, the following test was conducted in a constant temperature room at room temperature of 30 ° C. and humidity of 70%.
After applying 10 ml of each test sample to the left and right forearms, each arm was inserted into a bag-shaped 20 cm × 15 cm wire net containing 50 adult male and female adult Aedes albopictus 5 to 7 days after emergence for 15 minutes to absorb blood. Gave time. Do this for 30 minutes, 1 hour, 2 hours, 4 hours, 6 hours later,
The lower figure of the blood-sucking trace within the time of blood-sucking was obtained, and the repellency rate was calculated from the following formula.

[Equation 1] Repellent rate = [(XY) / X] × 100 (%) X: Number of blood-sucking traces when the test liquid is not applied Y: Number of blood-sucking traces when the test liquid is applied

With respect to these application examples and comparative examples, a blood-sucking repellent test was conducted on the adult Aedes albopictus, and application examples 1 and 2 were compared with comparative examples 1 and 2. The results are shown in Table 2. As is clear from Table 2, the HM of the present invention
MO and HMMT had an excellent pest repellent effect and also excellent durability.

[0019]

[Table 2]

[0020]

INDUSTRIAL APPLICABILITY As described above, 2-hydroxymethyl-menthol (HMM) which is a novel compound of the present invention is used.
O) and 2-hydroxymethyl-menthone (HMMT)
Can be provided as a pest repellent that is odorless and has an excellent persistent repellent effect against pests.

Claims (2)

[Claims] 1. 2-Hydroxymethyl-menthol represented by the following general structural formula. [Chemical 1] 2. 2-Hydroxymethyl-menthone represented by the following general structural formula: [Chemical 2]