JPS60116648A - Production of halogenated acetal - Google Patents

Abstract

PURPOSE:To produce the titled compound useful as a raw material of pharmaceuticals, agricultural chemicals, etc., by reacting halogen with a vinyl ether available easily at a low cost, and contacting the reaction product with an alcohol. CONSTITUTION:A vinyl ether is made to react with a halogen (preferably chlorine or bromine) in a solvent such as hexane, chloroform, etc. at <=80 deg.C, especially at -10-+30 deg.C. The amount of the halogen is preferably 1-10mol per 1mol of the vinyl ether. The reaction product is made to contact with an alcohol to obtain the objective compound. The vinyl ether used as a raw material is represented by the formula R<1>OCH=CH-Y (R<1> is 1-8C alkyl such as methyl, n- octyl, etc.; Y is CN, etc.). The alcohol is the compound of formula R<3>OH wherein R<3> is preferably the same alkyl group as the R<1> of the vinyl ether.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a novel method for producing rhodanized acetals.

Halogenated acetals are compounds useful as raw materials for medicines, agricultural chemicals, etc., and various proposals have been made for their production methods.

Pharmaceutical Journal, 73 126 (1'953) describes the reaction of methyl chloroacetate and methyl formate in the presence of sodium methylate, and the resulting sodium salt of methyl α-chloroformylacetate reacted with hydrogen chloride in anhydrous methanol. let α-Chloro-, a type of halogenated acetal
Regarding the production method of methyl β,β-dimethoxypropionate,
Suggestions have been made.

Also, Bull, Sac, C! him, Fr.
1970 (2) 787-791, methyl α,α-dichloro-β-methoxypropionate is reacted with sodium methylate. A method for producing methyl α-chloro-β, β-dimethoxypropionate is disclosed.

These known methods require expensive raw materials.

The reaction process is long and is not necessarily industrially satisfactory.

The present inventors conducted extensive research with the aim of developing an industrially advantageous manufacturing method for pentahalogenated acetals.

As a result, after reacting a halogen with an inexpensive and easily available vinyl ether, one can contact the reaction product with an alcohol.

It has been found that this objective can be achieved, that is, that halogenated acetals can be produced extremely easily.

The vinyl ethers that are the raw materials in the present invention are as follows.

It can be represented by the general formula R"OC!H=OH-Y.

11. In the formula, R1 is methyl, ethyl, n-propyl, 1-propyl, n-butyl, 1-butyl, 5e
c-butyl, 1nert-butyl, n-pentyl, n
Mention may be made of alkyl groups having 1 to 8 carbon atoms, such as -hexyl, n-heptyl, n-ocfyl, and the like.

These alkyl groups may have a substituent such as an alkoxy group or a halogen atom that does not inhibit the 9 reaction. In the formula, Y is -ON group or 100OR
” group (wherein R2 is selected from the alkyl groups defined for R1 above).

Further, the halogen that can be used in the present invention includes:

Particularly preferred are chlorine and bromine. The halogen is usually used in an amount equal to or more than the mole of the vinyl ether, preferably 1 to 10 moles per mole of the vinyl ether.

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

X R'0OH=OH7Y +x,,→R10C! HCH-
Y...■(1) (n) (III) The reaction is usually carried out in a solvent. Solvents include hexane, cyclohexane, and petroleum ether.

Preferred are aprotic solvents such as hydrocarbons such as benzene and toluene, or halogenated hydrocarbons such as carbon tetrachloride, chloroform, methylene chloride, and dichloroethane. The reaction can be carried out at a temperature at which the two reaction systems remain in a liquid state, but from the viewpoint of the efficiency of the two reactions, it is desirable to carry out the reaction at a temperature of 80°C or lower, preferably at a temperature of -10°C to 0°C.

Next, the obtained dihalide and alcohol are brought into contact. The contact can also be carried out by directly adding alcohol to the system after the completion of the reaction.

The reaction can also be carried out by adding alcohol to the residue obtained by removing the solvent, unreacted raw materials, etc. from the system after the completion of the reaction.

The catalytic reaction between the dihalide (■) and the alcohol (■) proceeds according to the ninth-order formula (■), and the target product (V), a rhodanated acetal, is synthesized.

(11) (IV) (V) However, in the Narcol used, R3 in 1'j30H is preferably the same alkyl group as R1 in the vinyl ether (1). The alcohol is used in an amount equal to or more than the mole of the dihalogenated acetal, preferably 2 to 100 times the mole.

The catalytic reaction is carried out at a temperature usually between -10°C and 80°C.

Preferably, it can be carried out at a temperature of 0°C to 60°C.

Further, in the catalytic reaction, hydrogen halide (HX) is produced as is clear from the reaction formula (2) above.

The hydrogen halide can be reacted while being released out of the system as a gas, or can be removed by neutralizing it by adding a base to the reaction system. Bases that can be used include alkali or alkaline earth metal hydroxides, carbonates, and acetates such as sodium hydroxide, potassium hydroxide, magnesium hydroxide, calcium hydroxide, sodium carbonate, sodium bicarbonate, and sodium acetate. Further examples include organic bases such as triethylamine, trimethylamine, and pyridine.

Next, two examples of the present invention will be described.

Example 1 In a 25-proof Erlenmeyer flask equipped with a dropping funnel and a thermometer,
As vinyl ethers, 4.20 S' of β-methoxyacrylonitrile and 10 WLl of carbon tetrachloride were charged. While cooling the outside in an ice-water bath and stirring, add 2.56 m of bromine.
After adding J slowly and dropwise so that the reaction temperature did not exceed 10°C, stirring was continued for an additional 30 minutes at a temperature of 10°C or lower. After carbon tetrachloride and some unreacted bromine were then distilled off under reduced pressure.

Cool and maintain at approximately 10°C, add 20ml of methanol to the residue.
was added, and further 4.57 g of sodium acetate was added and stirred for 30 minutes. After removing the precipitate, the P liquid is distilled under reduced pressure,
B, 6f α-promo β, β-dimethoxypropionitrile was obtained.

Example 2 Carbon tetrachloride and bromine were not distilled off from the reaction system of β-methoxyacrylonitrile and bromine.

An experiment was conducted in the same manner as in Example 1, except that methanol was directly added.

As a result, 7.17 of α-bromo-β,β-dimethoxypropionitrile was obtained.

Example 6.25 g of β-butoxyacrylonitrile was used instead of β-methoxyacrylonitrile, and n-butanol 201111 was used instead of methanol.

An experiment was conducted in the same manner as in Example 1. the result.

10.5 g of α-bromo-β,β-di-n-butquine acrylonitrile was obtained.

Example 4 Example 1 except that methyl β-methoxyacrylate 5.805' was replaced with β-methoxypropionitrile and chlorine was blown in instead of bromine at a rate of 5.0 L/hr for 15 minutes. The experiment was carried out using the same procedure. the result,
Methyl α-chloro-β,β-dimethoxypropionate was obtained at 7.27 ml.

Patent applicant Ube Industries Co., Ltd.

Claims (1)

[Claims] After reacting vinyl ethers with norogen. A method for producing halogenated acetals, which comprises bringing a reaction product into contact with an alcohol.