JPH0717566B2 - Method for producing racemic-trans primary chrysanthemic acids - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION <Field of Industrial Application> The present invention relates to a method for producing racemic-trans primary chrysanthemic acid,
More specifically, the general formula (I) (In the formula, R represents a hydrogen atom, an alkyl group having 1 to 20 carbon atoms, a cycloalkyl group or an aralkyl group.) The racemic-cis or racemic-cis / trans mixed primary chrysanthemic acid is added with a peroxide. It also relates to a process for producing the corresponding racemic-trans primary chrysanthemic acid by reacting hydrogen bromide in the presence or absence of an azo compound.

<Problems to be Solved by Conventional Techniques and Inventions> Primary chrysanthemic acid constitutes the acid component of a low-toxic fast-acting insecticidal ester called so-called pyrethroid such as pyrethrin, allethrin, and phthalthrin. It is useful as a raw material for pyrethroid insecticides.

It is known that primary chrysanthemic acid has cis and trans geometrical isomers, and the insecticidal effect of trans-form ester is stronger than that of cis-form ester. Therefore, trans-transformation of the cis form into a trans form is far more advantageous from the viewpoint of insecticidal efficacy than using a cis form or an ester containing a large amount of cis form.

Conventionally, the primary chrysanthemic acid ester of the primary chrysanthemic acid is represented by the following formula, by the method of reacting 2,5-dimethyl-hexa-2,4-diene and diazoacetic acid ester, Is industrially produced by hydrolyzing the ester.

However, since the primary chrysanthemic acid obtained by the method is obtained as a mixture of the target trans-form and cis-form, the technique of converting cis or cis / trans mixed primary chrysanthemic acid into trans-form has important significance. .

Conventionally, a method for converting a cis-primary chrysanthemate to a trans-primary chrysanthemate is to add a cis-primary chrysanthemate to a lower alkyl primary alcoholate of an alkali metal in the presence of a lower alcohol of about 150. ℃ -200 ℃ method (Japanese Patent Publication No. 40-6457) or a method of treating with a special basic catalyst (Japanese Patent Publication No. 53-18495, Japanese Patent Publication No. 53-18496, etc.), and cis- First chrysanthemate, boron trifluoride etherate, iron chloride,
A method of using aluminum chloride or the like (JP-A-57-17)
No. 6930) is known.

Further, as a method of directly converting cis primary chrysanthemic acid into trans primary chrysanthemic acid, a method of heating cis primary chrysanthemic acid at a temperature of 180 ° C. or higher (JP-A-49-126650), or cis It is said that it can be trans-formed by reacting primary chrysanthemic acid with a nitrile complex catalyst of palladium dichloride (Tetrahedron Letters. 22 , 385 (1981)), but the former requires heating at high temperature and yield However, the latter has the drawback of requiring a relatively large amount of expensive reagents.

The inventors of the present invention have conducted extensive studies to find an excellent method for producing trans-primary chrysanthemic acid, and as a result, have shown the above general formula (I).
It was found that the trans-formation proceeds unexpectedly by allowing hydrogen bromide to act on the cis-primary chrysanthemic acids or the mixed cis / trans-primary chrysanthemic acids represented by Furthermore, they have found that by reacting hydrogen bromide in the presence of a peroxide or an azo compound, it can be converted into a corresponding trans form more smoothly and efficiently, and various studies have been conducted to arrive at the present invention.

<Means for Solving Problems> That is, the present invention provides a compound represented by the general formula (I). (In the formula, R represents a hydrogen atom, an alkyl group having 1 to 20 carbon atoms, a cycloalkyl group or an aralkyl group.) The cis or cis / trans mixed primary chrysanthemic acid represented by The present invention provides an industrially excellent method for producing trans-primary chrysanthemic acid, which comprises reacting with hydrogen bromide in the presence or absence to trans-form.

Next, the method of the present invention will be described in detail.

The general formula (I) used as a raw material in the present invention
The compound represented by, for example, primary chrysanthemic acid, methyl primary chrysanthemate, ethyl primary chrysanthemate, propyl primary chrysanthemate, butyl primary chrysanthemate, cyclohexyl primary chrysanthemate, cyclohexylmethyl primary chrysanthemate, Examples include benzyl primary chrysanthemate.

Further, the cis-primary chrysanthemic acid may be a cis isomer alone or a mixture with a trans isomer in any ratio, but in view of the object of the present invention, the cis isomer alone or the cis isomer is rich in cis-primary chrysanthemic acid. It goes without saying that the significance is exerted when using acids.

The hydrogen bromide used in the present invention may be gaseous or may be dissolved in a solvent, and in some cases lithium bromide, sodium bromide, potassium bromide and other bromides and sulfuric acid and other acids. It may be generated in the reaction system by using.

The amount used is usually 1/1000 for 1 mol of the primary chrysanthemic acid to be treated.
It is in the range of 1/4 mol. As the solvent for hydrogen bromide, any solvent which does not inhibit the racemization reaction may be used, and examples thereof include organic solvents such as carboxylic acids, saturated hydrocarbons, aromatic hydrocarbons, halogenated saturated hydrocarbons, halogenated aromatic hydrocarbons and the like. Water etc. can be mentioned.

As the peroxide, for example, t-butyl hydroperoxide, 1,1,3,3-tetramethylbutyl hydroperoxide, tetrahydrofuran, cumene hydroperoxide produced by oxidation of ethers such as dioxane, etc. , Hydroperoxides such as diisopropylbenzene hydroperoxide, diacyl peroxides such as benzoyl peroxide and lauroyl peroxide, t-butyl perbenzoate, t-butyl peracetate, diisopropyl peroxydicarbonate, dicyclohexyl peroxydicarbonate Peroxyesters such as, methyl ethyl ketone peroxide, ketone peroxides such as cyclohexanone peroxide,
Examples thereof include dialkyl peroxides such as di-t-butyl peroxide and dicumyl peroxide, peracids such as peracetic acid, and hydrogen peroxide. Of these, hydroperoxides, diacyl peroxides and peroxyesters are preferable, and hydroperoxides are more preferable.

The amount of peroxide used is usually 1/20 to 1 mol of hydrogen bromide.
The amount is 5 mol, preferably 1/10 to 2 mol.

Examples of the azo compound include azobisisobutyronitrile, 2,2′-azobis (2,4-dimethylvaleronitrile), 1,1′-azobis (cyclohexane-1-carbonitrile), 4,4′-azobis. -4-Cyanopentanoic acid, 2-phenylazo-2,4-dimethyl-4
-Azonitriles such as -methoxyvaleronitrile and 2-cyano-2-propylazoformamide, azoesters such as methyl azobisisobutyrate and ethyl azobisisobutyrate, and alkylazos such as azo-t-butane. Azonitriles and azoesters are preferably used.

The amount used is usually 1/10 to 5 per mol of hydrogen bromide.
It is in the range of 1/4 to 2 mol, preferably 1/4 to 2 mol.

Further, when carrying out the reaction, it is preferable to use an inert solvent, and as such a solvent, a saturated hydrocarbon,
Aromatic hydrocarbons, their halides, ethers, etc. can be mentioned.

The reaction temperature is arbitrary in the range of -30 ° C to the boiling point of the primary chrysanthemic acid (the boiling point of the solvent used when the solvent is used),
It is usually in the range of -20 ° C to 100 ° C.

The time required for the reaction may vary depending on the amount of the hydrogen bromide and the peroxide or the azo compound used and the reaction temperature, but usually several minutes to 10 hours is sufficient to achieve the purpose.

In carrying out the method of the present invention, hydrogen bromide is usually added to the primary chrysanthemic acid to be treated in the presence of a solvent. When using a peroxide or an azo compound, usually, the primary chrysanthemic acid to be treated is mixed with the peroxide or the azo compound in the presence of a solvent, and then the hydrogen bromide is added thereto, or The first chrysanthemic acid to be treated is dissolved in a solvent, and then a peroxide or an azo compound is poured together with hydrogen bromide.

Further, when using an aqueous solution of hydrobromic acid as hydrogen bromide and an organic solvent that is incompatible with water as a reaction solvent, for example, an aromatic hydrocarbon, the solubility in water is large and the reaction By allowing an inorganic salt that does not inhibit the reaction to exist in the reaction system, the target reaction can proceed more smoothly. Examples of such inorganic salts include lithium bromide, lithium chloride, calcium bromide, calcium chloride, magnesium bromide, magnesium chloride, magnesium sulfate, phosphorus pentoxide, and the like. Further, by mixing an aqueous solution of hydrobromic acid with water and an organic solvent inert to hydrogen bromide, such as acetic acid or dioxane, the desired reaction can be proceeded more smoothly.

The progress of the reaction can be obtained by sampling a part of the reaction solution and measuring the geometrical isomer ratio by gas chromatography or the like.

<Effects of the Invention> Thus, trans primary chrysanthemic acids are produced, but according to the present invention, trans primary chrysanthemic acids can be efficiently produced, and in addition, they are more general as industrial raw materials and moreover against moisture. Also brings advantages such as the fact that hydrogen bromide which is stable and easy to handle can be used.

<Examples> Next, the present invention will be described in more detail with reference to Examples, but the present invention is not limited thereto.

Example 1 5.0 g of cis primary chrysanthemic acid was dissolved in 20 ml of dioxane, and t
-Butyl hydroperoxide (0.03 g) and 25% hydrogen bromide-acetic acid (0.34 g) were added dropwise, and the mixture was stirred at the same temperature for 30 minutes.

After the reaction, 4.5 g of 40% sodium hydroxide aqueous solution was added, and the solvent was distilled off under reduced pressure. Water and toluene were added to the residue for extraction, and the aqueous layer was separated. The aqueous layer was neutralized with diluted sulfuric acid, extracted with toluene, and the organic layer was washed with water. Next, the organic layer was concentrated and distilled to obtain 4.8 g of distillate. (Boiling point 110-119 ° C
/2.5mmHg) It was confirmed from the infrared absorption spectrum that this was primary chrysanthemic acid. As a result of analysis by gas chromatography, the composition was 5.0% cis and 95.0% trans.

Example 2 25 g of primary chrysanthemic acid consisting of 20.1% cis isomer and 79.9% trans isomer
Was dissolved in 40 ml of toluene, and 3.0 g of lithium bromide was suspended. Toluene solution of t-butyl hydroperoxide 0.44g and 48% hydrobromic acid aqueous solution 2.23g with stirring at 20 ° C.
Was dripped.

After the reaction, dilute hydrochloric acid was added, and the mixture was stirred and separated.
A 0% caustic soda aqueous solution was added for extraction. Dilute sulfuric acid was added to the obtained aqueous layer to make it acidic, and then extracted twice with toluene.
After washing the toluene layer with water, the solvent was distilled off under reduced pressure, and the residual liquid was then distilled to give a boiling point of 110-119 ° C / 2.5 mmHg fraction 24.0 g.
Got It was confirmed from the infrared absorption spectrum that this product was chrysanthemic acid.

As a result of analysis by gas chromatography, cis isomer 4.0%,
The trans form was 96.0%.

Example 3 25 g of the same primary chrysanthemic acid used in Example 2 was added to 88 ml of toluene.
Dissolved in water, 0.75 g of t-butyl hydroperoxide was added, and hydrogen bromide gas 2.
Blow 02g in 30 minutes.

Thereafter, the same operation as in Example 2 was carried out to obtain 22.4 g of primary chrysanthemic acid.

As a result of analysis by gas chromatography, cis isomer 4.0%,
The trans form was 95.1%.

Example 4 Ethyl primary chrysanthemate comprising 20% cis and 80% trans 2.
50 g was dissolved in 10 ml dioxane, 115 mg of t-butyl hydroperoxide was added, and 410 mg of 25% hydrobromic acid acetic acid solution was added with stirring at room temperature.

After the reaction, 2% aqueous sodium hydroxide solution was added to neutralize, the solvent was distilled off under reduced pressure, and then hexane and 2 were added to the residue.
% Aqueous sodium hydroxide solution was added for extraction, and the organic layer was washed with water. The obtained organic layer was concentrated under reduced pressure and then distilled to obtain 2.25 g of a distillate having a boiling point of 85 to 88 ° C./10 mmHg.

It was confirmed from the infrared absorption spectrum that this was the ethyl ester of primary chrysanthemic acid. As a result of analysis by gas chromatography, cis isomer 5.0%, trans isomer 95.0
%Met.

Example 5 5.0 g of cis primary chrysanthemic acid and 59 mg of azobisisobutyronitrile were dissolved in 20 g of toluene. While stirring at 80 ° C, 0.35 g of 25% hydrobromic acid acetic acid solution was added dropwise and reacted for 30 minutes.

As a result of analysis by gas chromatography, cis 7.9%,
The composition was 92.1% of trans form.

Example 6 10.0 g of primary chrysanthemic acid having the same composition as used in Example 2 was dissolved in 100 g of toluene. Add to this 25% hydrobromide acetic acid solution at 20 ° C.
4.82 g was added and stirred for 1 hour. As a result of analysis by gas chromatography, cis isomer was 6.3% and trans isomer was 93.7%.

Example 7 320 mg of ethyl primary monochrysanthemate having the same composition as used in Example 4 was dissolved in 4 ml of toluene.

To this, 52 mg of a 25% hydrobromic acid acetic acid solution was added at 20 ° C., and the mixture was stirred for 30 minutes. As a result of analysis by gas chromatography, the cis isomer was 7.2% and the trans isomer was 92.8%.

Continuation of the front page (51) Int.Cl. ⁶ Identification number Office reference number FI technical display location C07C 69/747 // C07B 35/08 7419-4H 61/00 300

Claims (1)

[Claims] 1. A general formula (In the formula, R represents a hydrogen atom, an alkyl group having 1 to 20 carbon atoms, a cycloalkyl group or an aralkyl group.) The racemic-cis or racemic-cis / trans mixed primary chrysanthemic acid is added with a peroxide. Alternatively, a method for producing a racemic-trans primary chrysanthemic acid, which comprises reacting with hydrogen bromide for trans conversion in the presence or absence of an azo compound.