JPH0350740B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a novel method for producing halogenated vinyl ethers.

Halogenated vinyl ethers can be used, for example, in pharmaceuticals,
It is a compound that is useful as a raw material for agricultural chemicals, and various proposals have been made for its production.

For example, Volume 50 of Chemical Abstracts,
In 2428h, α-chloro-β,β-dimethoxypropionic acid was treated with thionyl chloride to produce α-chloro-β-, which is a type of halogenated vinyl ether.
Proposals have been made regarding methods for producing methoxyacrylic acid.

The present inventors aimed to develop an industrially advantageous manufacturing method for halogenated vinyl ethers,
I conducted extensive research. As a result, they discovered that the objective could be achieved by reacting inexpensive and easily available vinyl ethers with halogens and then treating the reaction product with a base, that is, halogenated vinyl ethers could be produced extremely easily. Ta.

Vinyl ethers, which are raw materials in the present invention, can be represented by the general formula R ¹ OCH=CH-Y.

In this formula, R ¹ is methyl, ethyl, n-propyl, i-propyl, n-butyl, i-butyl, sec-butyl, tert-butyl, n-pentyl,
Mention may be made of alkyl groups having 1 to 8 carbon atoms such as n-hexyl, n-heptyl, n-octyl and the like. In the formula, Y is a -CN group or -
COOR ² group (wherein R ² is selected from the alkyl groups defined for R ¹ above).

Further, as the halogen used in the present invention, chlorine and bromine are particularly preferred.

It is presumed that the reaction between these vinyl ethers () and halogen () proceeds according to the following formula, and a dihalide represented by () is obtained as a reaction product.

The reaction is usually carried out in a solvent. Solvents include hexane, cyclohexane, petroleum ether,
Preferred are hydrocarbons such as benzene and toluene, halogenated hydrocarbons such as carbon tetrachloride, chloroform, methylene chloride, and dichloroethane, and further aprotic solvents such as dioxane and tetrahydrofuran.

The halogen is usually used in an amount equal to or more than the mole of vinyl ethers, preferably 1 to 10 moles per mole of vinyl ethers. There are no particular restrictions on the method of supplying the halogen, but gaseous or liquid halogen can be directly introduced into the reaction solution, or a halogen solution dissolved in the same solvent as the reaction solvent can also be introduced into the reaction solution.

Further, the reaction can be carried out at a temperature at which the reaction system remains in a liquid state, but from the viewpoint of reaction efficiency, it is desirable to carry out the reaction at a temperature of 80°C or lower, preferably at a temperature of -10 to 30°C.

Next, by treating the obtained dihalide with a base, the target halogenated vinyl ether represented by the formula () can be synthesized.

(However, in the formula, R ¹ , X and Y have the same meanings as above.) This treatment can also be carried out by directly adding a base to the system after the completion of the reaction, but the solvent can be removed from the system after the completion of the reaction. The reaction can also be carried out by dissolving the residue obtained by removing unreacted raw materials in a solvent and adding a base to the solution. The treatment operation can be carried out at a temperature ranging from room temperature to heating to reflux.

Bases that can be used include alkali metal salts of lower saturated fatty acids such as sodium acetate, potassium acetate, and sodium propionate; alkali metal carbonates such as sodium carbonate, potassium carbonate, lithium carbonate, sodium hydrogen carbonate, and potassium hydrogen carbonate; Examples include salts and organic bases such as triethylamine, trimethylamine, pyridine, and morpholine. The amount of these bases is 0.5 mol or more, preferably 1 mol or more, per 1 mol of vinyl ethers.
~10 mol is used.

After the treatment, the target halogenated vinyl ether can be isolated and purified by appropriately performing normal operations such as vacuum distillation and solvent extraction.

Next, examples of the present invention will be given.

Example 1 25ml with addition funnel, reflux condenser and thermometer
β- as vinyl ethers in an Erlenmeyer flask.
4.20 g of methoxyacrylonitrile and 10 ml of carbon tetrachloride were charged. Cool the outside with an ice-water bath,
After stirring, 2.56 ml of bromine was slowly added dropwise so that the reaction temperature did not exceed 10°C, and stirring was continued for an additional 30 minutes. Then add 4.5g of sodium acetate,
After heating under reflux for 1 hour, the mixture was cooled and the precipitate was removed. The liquid was distilled under reduced pressure to remove carbon tetrachloride and acetic acid, yielding a yellow liquid. The yellow liquid was further distilled under reduced pressure to obtain 6.5 g of a colorless liquid which was a mixture of cis and trans α-bromo-β-methoxyacrylonitrile.

Example 2 An experiment was conducted in the same manner as in Example 1, except that dioxane was used as a solvent instead of carbon tetrachloride. As a result, 6.1 g of mixed cis and trans α-bromo-β-methoxyacrylonitrile was obtained.

Example 3 After reacting β-methoxyacrylonitrile with bromine in the same manner as in Example 1, 5.0 g of sodium carbonate was added, followed by stirring at room temperature for 10 minutes. The subsequent operations were carried out in the same manner as in Example 1, and a mixture of cis and trans α-bromo-β-
4.3 g of methoxyacrylonitrile was obtained.

Example 4 A 50 ml Erlenmeyer flask equipped with a blow tube and a thermometer was charged with 4.20 g of β-methoxyacrylonitrile and 20 ml of carbon tetrachloride. The outside was cooled with an ice-water bath, and chlorine gas was bubbled through at a rate of 7/hr for 10 minutes while stirring, followed by stirring for 30 minutes. After carbon tetrachloride and unreacted chlorine were distilled off under reduced pressure, 20 ml of carbon tetrachloride was added to the residue to dissolve it. Next, 4.5 g of sodium acetate was added, and after heating under reflux for 1 hour, the mixture was cooled and the precipitate was removed. The liquid was distilled under reduced pressure to obtain 2.5 g of mixed cis and trans α-chloro-β-methoxyacrylonitrile.

Example 5 An experiment was carried out in the same manner as in Example 1, except that 6.33 g of β-n-butoxyacrylonitrile was used as the vinyl ether. As a result, 7.1 g of mixed cis and trans α-bromo-β-n-butoxyacrylonitrile was obtained.

Example 6 An experiment was carried out in the same manner as in Example 1, except that 5.80 g of methyl β-methoxyacrylate was used as the vinyl ether. As a result, 7.2 g of mixed cis and trans methyl α-bromo-β-methoxyacrylate was obtained.

Example 7 After reacting β-methoxyacrylonitrile with bromine in the same manner as in Example 1, a solution of 6.0 g of triethylamine dissolved in 10 ml of methylene chloride was added and stirred at room temperature for 1 hour. The subsequent operations were carried out in the same manner as in Example 1, and 5.9 g of mixed cis and trans α-bromo-β-methoxyacrylonitrile was obtained.

Claims (1)

[Claims] 1 General formula R ¹ OCH=CH-Y (R ¹ represents an alkyl group having 1 to 8 carbon atoms,
Y represents a -CN group or a ^-COOR2 group (wherein ^R2 is selected from the alkyl groups defined for ^R1 above). ) and a halogen represented by the general formula X ₂ (X is a halogen atom), and then the reaction product is treated with a base. (R ¹ , X and Y are the same as above.) A method for producing halogenated vinyl ethers.