JPS6210492B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for producing 3-phenoxybenzyl 2-(4-alkoxyphenyl)-2-methylpropyl ethers represented by formula ().

formula() [In formula (), R is a lower alkyl group, X ₁ ,
X ₂ is a hydrogen atom or a fluorine atom. ] Recently, certain compounds of 3-phenoxybenzyl ether derivatives, including the compound represented by the formula (), have extremely high insecticidal and acaricidal activity, and are also excellent in immediate and residual effects. It has been found that it has low toxicity not only to humans and animals but also to fish and the like, and an excellent pest control composition has been provided.

JP-A-56-154427 discloses a 3-phenoxybenzyl ether derivative represented by the formula (). [In formula (), R is a methyl group or an ethyl group,
R' is a hydrogen atom, a halogen atom, or a lower alkyl group, and R'' is a halogen atom or a lower alkyl group] In addition, in JP-A-57-72928 and JP-A-57-64632, there are In addition to a halogen atom or a lower alkyl group, R' or R'' may be a lower alkoxy group, or even if each benzene nucleus of a 3-phenoxybenzyl group is substituted with a halogen atom, etc. Good compounds have been disclosed.

The present inventors found that among the compounds disclosed in the above-mentioned publication, one of R' and R'' in formula () is 4.
These compounds are substituted with a lower alkoxy group at the 4-position, and R is a methyl group, that is, 3-phenoxybenzyl ether compounds having a neophyl group substituted at the 4-position with a lower alkoxy group. Among them, we found that it has a particularly large insecticidal effect. At that time, it was also found that if the benzene nucleus of the neophyl group was substituted with a halogen atom or an alkyl group, the excellent effect would be reduced.

The present invention provides a method for producing a compound of formula () having no halogen atom or alkyl group in the benzene nucleus of the neophyl group and only an alkoxy group at the 4-position of the benzene nucleus.

In the above-mentioned Japanese Patent Application Laid-Open No. 56-154427 and other publications, the formula ()
A method for producing the compound represented by formula () is also described, and the compound represented by formula () is a compound represented by formula (),
or its salt [In formula (), R′, R′, R″ are the same as the above formula ()] and 3-phenoxybenzyl halides or alcohols are condensed, or a compound represented by formula () [In the formula (), X is a halogen atom R, R', R'' are the same as in the above formula ()] and 3-phenoxybenzyl alcohol. Also, the above publication describes Although formula () and methods for producing compounds of formula () are also described, the synthesis of compounds of formula () requires a long reaction route, and therefore it is difficult to use industrially when using a compound of formula () as a raw material for a compound of formula (). disadvantageous to

On the other hand, the compound of formula () can be prepared by, for example, the following method. However, when R′ and R″ are an alkoxy group and a hydrogen atom, and one of them is substituted with a lower alkoxy group at the 4-position, the above (1)
In the method described above, the nuclear chlorination reaction proceeds preferentially, so that the desired 4-alkoxyneofyl chlorides are hardly obtained. In addition, in method (2) above,
High purity 4-alkoxyneofyl chlorides are Since it can only be obtained in extremely low yields and the obtained 4-alkoxyneofyl chlorides are unstable compounds, there are many difficulties in storing and handling them on an industrial scale. accompany.

From the above, when industrially producing the compound of the formula (), it is not advisable to use a method of causing a condensation reaction between 4-alkoxyneofyl chlorides and 3-phenoxybenzyl alcohols.

Based on these findings, the present inventors have conducted intensive studies on an industrially inexpensive manufacturing method for 3-phenoxybenzyl 2-(4-alkoxyphenyl)-2-methylpropyl ethers, and have developed the present invention. This is the completion of the invented method.

That is, the method of the present invention takes a compound represented by the above formula (), which is a compound having a particularly remarkable effect as an insecticide, by adding a chlorine or bromine atom to at least one position ortho to the alkoxy group of the compound of formula (). It is produced from a compound represented by the substituted formula (), and the compound of formula () is preferably reacted with hydrogen in the presence of a hydrogenation catalyst to eliminate the fluorine atom, cleave the ether bond, etc. The elimination reaction of only chlorine and bromine atoms proceeds selectively with almost no side reactions, resulting in 3-phenoxybenzyl 2-(4-alkoxyphenyl)-2-methyl represented by the formula (). This method allows propyl ethers to be obtained in good yields.

It is already known that certain compounds can be produced by a method in which a halogen atom bonded to a benzene nucleus is eliminated by a catalytic hydrogenation reaction. From the compound represented by the formula () that has a simple ether bond,
The method of selectively dehalogenating only chlorine or bromine to produce the 4-alkoxy neophylether derivative represented by the formula () is a completely new technology, and the method of producing the 4-alkoxy neophylether derivative represented by the formula ( In addition to its usefulness, it has extremely high industrial utility value.

The 4-alkoxy neophylether derivative produced by the method of the present invention is represented by the formula (). [In formula (), R is a lower alkyl group,
X ₁ X ₂ is a hydrogen atom or a fluorine atom. ] Specifically, R is a methyl group, an ethyl group, n
-propyl group, i-propyl group, n-butyl group,
Examples include t-butyl group and i-butyl group.

Next, representative examples of 3-phenoxybenzyl 2-(4-alkoxyphenyl)-2-methylpropyl ethers represented by the formula () produced by the method of the present invention are shown, but of course, only those exemplified are shown. Examples include, but are not limited to, 3-phenoxybenzyl 2-(4-methoxyphenyl)-2-methylpropyl ether, 3-phenoxy-4-fluorobenzyl 2-(4-methoxyphenyl)-2-methyl Propyl ether, 3-(4-fluorophenoxy)benzyl 2-(4-methoxyphenyl)-
2-Methylpropyl ether, 3-(4-fluorophenoxy)-4-fluorobenzyl 2-(4-
methoxyphenyl)-2-methylpropyl ether, 3-phenoxybenzyl 2-(4-ethoxyphenyl)-2-methylpropyl ether, 3-
Phenoxy-4-fluorobenzyl 2-(4-ethoxyphenyl)-2-methylpropyl ether, 3-(4-fluorophenoxy)benzyl 2
-(4-ethoxyphenyl)-2-methylpropyl ether, 3-(4-fluorophenoxy)-4-
Fluorobenzyl 2-(4-ethoxyphenyl)-
2-methylpropyl ether, 3-phenoxy-
6-fluorobenzyl 2-(4-ethoxyphenyl)-2-methylpropyl ether, 3-(2-fluorophenoxy)benzyl 2-(4-ethoxyphenyl)-2-methylpropyl ether, 3-
Phenoxybenzyl 2-[4-(i-propoxy)
phenyl]-2-methylpropyl ether, 3-
Phenoxy-4-fluorobenzyl 2-[4(i
-propoxy)phenyl]-2-methylpropyl ether, 3-phenoxybenzyl 2-[4-(1
-methylpropoxy)phenyl]-2-methylpropyl ether, 3-phenoxybenzyl 2-
[4-(n-butoxy)phenyl]-2-methylpropyl ether, 3-phenoxybenzyl 2-
[4-(t-butoxy)phenyl]-2-methylpropyl ether, 3-phenoxybenzyl 2-
Examples include compounds such as [4-(n-pentyloxy)phenyl]-2-methylpropyl ether.

These compounds are obtained from compounds corresponding to formula () compounds having chlorine or bromine atoms at the 3-position or 3-position and 5-position of the benzene nucleus of a 4-alkoxyneophyl group as shown in the formula (); () compound is, for example, a compound of formula () [In the formula (), R, Y ₁ , Y ₂ are the same as in the above formula ()] and 3-phenoxybenzyl alcohol were mixed with caustic soda, dimethyl sulfochloride, etc. as described in the above publication. It can be easily obtained by condensation in a reaction medium such as a side.
Moreover, the compound of formula () is, for example, By the above-described method, it is possible to preferentially react only the para-position with respect to the alkoxy group in high yield. The obtained compound of formula () is 4-
Since it is not an unstable compound like alkoxy neophyl chloride, it is advantageous in condensation reactions with 3-phenoxybenzyl alcohols and in purification of target products.

In the method of the present invention, the compound of formula () can be obtained from the compound of formula () by catalytic hydrogenation, hydrogenation using a reducing agent such as lithium aluminum hydride, or dehalogenation using metals in an aprotic polar solvent. Among these methods, a hydrogenation method, particularly a catalytic hydrogenation method, can be most advantageously implemented industrially. The compound of formula () can be produced by the catalytic hydrogenation method, for example, as follows.

A compound represented by the formula () is reacted with hydrogen in the presence or absence of a base and a medium at a specified temperature in the presence of a catalyst at normal pressure or under pressure, and then separated from the reaction mixture by an appropriate separation method. A compound represented by the formula () is obtained.

Bases used include alkali metal hydroxides, carbonates, acetates and alcoholates, such as potassium hydroxide, sodium hydroxide, potassium carbonate, sodium carbonate, sodium acetate and sodium methylate, alkaline earth metal hydroxides. substances, such as calcium hydroxide, and fatty acids, aromatic or heterocyclic bases, such as triethylamine, ethylenediamine, diethylaniline,
Pyridine and 1,5-diazabicyclo[5.
4.0] undec-5-ene (commonly known as DBU), etc., but alkali metal hydroxides are particularly preferred, and sodium hydroxide is particularly advantageous from an economic point of view. Although the amount of the base to be used can be selected within a wide range, it is generally used in a molar ratio of 0 to 10, preferably 1 to 6, per mole of the compound represented by the formula () as a raw material.

When the reaction is carried out in the presence of a medium, water, alcohols such as methanol, polyhydric alcohols such as ethylene glycol, acetic acid and acetate esters, and various other organic solvents can be used as the medium. A mixture of a solvent and water can also be used. Particularly suitable are water and methanol. The amount of the reaction medium to be used can be selected between 0 and 100 parts by volume per 1 part by volume of the compound represented by formula () as the raw material, but the reaction rate and volumetric efficiency of the reaction container should be taken into consideration. Then, 2 to 10 parts by volume is desirable.

As a catalyst, nickel-based catalysts such as Raney nickel, palladium-based catalysts such as palladium-carbon, and other platinum-based catalysts are used, but palladium-carbon is particularly advantageous, and the amount used is based on the compound represented by the formula () of the raw material. 0.1 to 2.0 weight percent, preferably 2 to 7 weight percent.

Although the hydrodehalogenation reaction of the present invention can be carried out at normal pressure, it is preferably carried out under increased pressure, especially under increased pressure of 5 to 60 kg/cm ² .

Furthermore, the method of the invention can be carried out within a wide temperature range. It is generally carried out at a temperature of 50°C to 220°C, preferably 80°C to 150°C.

As described above, the method of the present invention is a method for producing a compound represented by formula () from a compound represented by formula (), but instead of the compound represented by formula (), for example, a compound represented by formula () It goes without saying that the present invention can also be applied to compounds having a substituent such as an alkyl group that does not affect the hydrodechlorination or hydrodebromination reaction to obtain the corresponding compounds of formula ().

Examples are shown below.

Example 1 In a 500 ml autoclave, 60.0 g (0.146
mol), 7.5 g (0.188 mol) of flaked caustic soda, 7.2 g of 5% palladium on carbon (50% Wet),
Charge 108 ml of methanol and 36 ml of water, and after sealing, replace the inside with nitrogen and then add 8 kg/cm ² G of hydrogen.
Fill up to 8-10 kg/cm ² G of hydrogen at an internal temperature of 110°C.
The reaction was completed by heating and stirring for 12 hours while replenishing with water.

After cooling the reaction solution to room temperature, the residual pressure was released,
120 ml of benzene was added into the autoclave to dissolve the oil layer. Next, insoluble matters were removed, and the resulting mother washing solution was washed with 30 ml of benzene, and the resulting mother washing solution was thoroughly shaken, and then allowed to stand for separation to obtain a benzene layer. Subsequently, the benzene layer was washed three times with 120 ml of water and separated, and then the benzene was distilled off under reduced pressure to obtain an oily substance. As a result of internal standard gas chromatography analysis, this oily substance was found to be 3-
Phenoxybenzyl 2-(4-ethoxyphenyl)-2-methylpropyl ether, 98.5%, 3-phenoxybenzyl 2-(3-
Contains 0.5% of chloro-4-ethoxyphenyl)-2-methylpropyl ether, and by ether bond cleavage, 3-phenoxytoluene and 4-ethoxyneofyl alcohol are respectively produced.
It was less than 0.2%.

Yield of oil: 53.6g, yield 96.0%.

The freezing point, elemental analysis values, and NMR spectrum of this oil were as follows.

Freezing point 31.2℃ Elemental analysis value C ₂₅ H ₂₈ O ₃ C H Theoretical value 79.75 7.50 Actual value 79.86 7.69 NMR spectrum δCDCl ₃ 1.25 (6H, s), 1.3 (3H, t), 3.35 (2H,
s), 3.92 (2H, q), 4.2 (2H, s), 6.6-7.4
(13H, m) ppm Example 2 3-Phenoxy-4-
Fluorobenzyl 2-(3-chloro-4-ethoxyphenyl)-2-methylpropyl ether
50.0g (0.117mol), flaked caustic soda 5.6
g (0.140 mol), 5%-palladium on carbon (50%
Wet) 5g, methanol 90ml and water 30ml were charged, and after sealing, the inside was replaced with nitrogen, and then hydrogen was added at 10kg/
Pressurize and fill to cm ² G, and at an internal temperature of 100℃, add 8~8% hydrogen.
The reaction was completed by heating and stirring for 15 hours while replenishing with 10 kg/cm ² G.

After cooling the reaction solution to room temperature, the residual pressure was released, and 100 ml of benzene was added to the autoclave.
The oily part was dissolved. Next, after removing insoluble matter by filtration, the resulting mother washing solution was washed with 20 ml of benzene, and the obtained mother washing solution was thoroughly shaken and then allowed to stand still for liquid separation to obtain a benzene layer. Subsequently, the benzene was washed three times with 100 ml of water, and then the benzene was distilled off under reduced pressure to obtain an oily substance. As a result of analysis by internal standard gas chromatography, this oily substance was found to be 3-phenoxy-4-
Fluorobenzyl 2-(4-ethoxyphenyl)-2-methylpropyl ether 97.2%, raw material 3-phenoxy-4-fluorobenzyl 2-
Contains 1.0% of (3-chloro-4-ethoxyphenyl)-2-methylpropyl ether, and 0.1% or less of 3-phenoxytoluene and 4-ethoxyneofyl alcohol each due to ether bond cleavage. It contained less than 0.5% of 3-phenoxybenzyl 2-(4-ethoxyphenyl)-2-methylpropyl ether, which is presumed to be produced as a result of hydrogenation of fluorine atoms.

Yield of oil: 45.1 g, yield: 95.0% The refractive index, elemental analysis, and NMR spectrum of this oil were as follows.

n ²⁰⁰ _D : 1.5635 Elemental analysis value C ₂₅ H ₂₇ FO ₃ C H F Theoretical value 76.12 6.90 4.82 Calculated value 75.95 6.98 4.69 NMR spectrum δCDCl ₃ 1.28 (6H, s), 1.39 (3H, t), 3.29 (2H,
s), 3.92 (2H, q), 4.32 (2H, s), 6.6~
7.4 (12H, m) ppm Example 3 In a 500ml autoclave, add 3-phenokibenzyl 2-(3-bromo-4-ethoxyphenyl)-2.
- 50.0 g (0.110 mol) of methyl propyl ether,
Flake caustic soda 4.8 g (0.121 mol), 5% -
Palladium on carbon (50% wet) 2.0g, methanol
Charge 90 ml and 30 ml of water, seal, replace the inside with nitrogen, then pressurize and fill with hydrogen up to 10 kg/cm ² G.
While replenishing hydrogen at 8-10Kg/ ^cm2G at an internal temperature of 80℃,
The reaction was completed by heating and stirring for 12 hours.

After cooling the reaction solution to room temperature, the residual pressure was released, and 100 ml of benzene was added to the autoclave.
The oily part was dissolved. Next, insoluble matters were removed by filtration under reduced pressure, and the resulting mother washing solution was washed with 20 ml of benzene, and the resulting mother washing solution was thoroughly shaken and then allowed to stand for separation to obtain a benzene layer solution. Subsequently, the benzene layer was washed three times with 100 ml of water, and then benzene was distilled off under reduced pressure to obtain an oil. As a result of analysis by internal standard gas chromatography, this oil was found to contain 98.5% of the target 3-phenoxybenzyl 2-(4-ethoxyphenyl)-2-methylpropyl ether and 3-phenoxybenzyl 2 of the raw material. Contains 0.3% -(3-bromo-4-ethoxyphenyl)-2-methylpropyl ether, and also contains 3% by ether bond cleavage.
-Phenoxytoluene and 4-ethoxyneofyl alcohol were each 0.2% or less.

Yield of oil: 41.2 g, yield: 98.0% The freezing point, elemental analysis, and NMR spectrum of this oil were as follows.

Freezing point 33.1℃ Elemental analysis value C ₂₅ H ₂₈ O ₃ C H Theoretical value 79.75 7.50 Actual value 79.50 7.22 NMR spectrum δCDCl ₃ 1.25 (6H, s), 1.3 (3H, t), 3.35 (2H,
s), 3.92 (2H, q), 4.2 (2H, s), 6.6-7.4
(13H, m) ppm

Claims (1)

[Claims] 1 Formula () [In formula (), R is a lower alkyl group, X ₁ ,
X ₂ is a hydrogen atom or a fluorine atom. ] In the method for producing 3-phenoxybenzyl 2-(4-alkoxyphenyl)-2-methylpropyl ethers represented by the formula () [In formula (), R is a lower alkyl group, X ₁ ,
X ₂ is a hydrogen atom or a fluorine atom, Y ₁ , Y ₂
is a hydrogen atom, a chlorine atom, or a bromine atom,
At least one of Y ₁ and Y ₂ is a chlorine atom or a bromine atom. ] 3-phenoxybenzyl 2-(4-
Alkoxy-3-halogenophenyl)-2-methylpropyl ethers or 3-phenoxybenzyl 2-(4-alkoxy-3,5-dihalogenophenyl)-2-methylpropyl ethers by hydrogenation reaction. A method for producing 3-phenoxybenzyl 2-(4-alkoxyphenyl)-2-methylpropyl ethers, which comprises dechlorinating or debrominating to obtain a compound represented by formula ().