DE1134365B - Process for the preparation of functional derivatives of ª ‡, ª ‡ -dihalogenglutaric acids - Google Patents

Description

Process for the preparation of functional derivatives of α, α-dihalogiutaric acids a, a-Dihaloglutaric acids and their functional derivatives have so far been in the literature not described.

It has now been found that dihaloglutaric acid compounds can be easily obtained by addition of dihaloacetic acid derivatives, e.g. B. esters, nitriles, etc., to functional derivatives of a, ß-olefinically unsaturated carboxylic acids in the presence of a Alkali alcoholates and an inert solvent or diluent, preferably tert-butanol or toluene, can be obtained at a moderately elevated temperature.

So you get z.ti. from methyl acrylate and methyl dichloroacetate in the presence of an alkali alcoholate, the a, a-dichloro-glutaric acid dimethyl ester. At Instead of the acrylic acid ester, acrylonitrile, methacrylic acid ester and the like can also be used. use. So react z. B. methyl dibromoacetate or dichloroacetonitrile in the same way with acrylonitrile.

Potassium tertiary butoxide is primarily suitable as the alkali metal alcoholate. Catalytic amounts are sufficient for the addition; at reaction temperature but you can also use a larger amount of alkali metal alcoholate without side reactions occur.

The course of the reaction according to the invention is surprising because one either ester condensations or a preferred reaction of the halogen compounds should expect with the alcoholate.

The production of the α-dihaloglutaric acid esters is of great scientific nature and technical interest because these connections were previously unknown and because the inventive method the production of a, a-dihaloglutaric acids with defined position of the halogen and a further substituent in the a-position enables.

The compounds obtainable by the process according to the invention can be distilled without decomposition. They can be used as starting materials for numerous Serving syntheses.

Example 1 143 g of methyl dichloroacetate, 200 cc of tert-butanol and 95 g of methyl acrylate were slowly mixed with 5.4 g of solid sodium with stirring methylate added, the temperature not exceeding 500 C. After completing the registration was stirred for a longer time at room temperature.

After extracting the reaction mixture with ether, the ether solution became Washed neutral with dilute acid, the solvent evaporated and a, a-Dichloroglutaric acid dimethyl ester obtain. Bp.lo = 123 to 124 "C. Yield 170g - 750J0 of theory.

C7Hlo04cl2 (molecular weight 229.06).

Calculated ... C 36.69, H 4.40, C1 30.97; found . C 36.66, H 4.60, C1 30.87.

The a, a-dichloro-glutaric acid diethyl ester was obtained in the same way (Bp 5 = 112 to 114 "C; yield 81010 of theory), from methyl dibromoacetate and methyl acrylate of methyl a, a-dibromoglutarate with a boiling point of 132 ° C and from 11 g of methyl difluoroacetate and 9.5 g of methyl acrylate 10 g of a, a-Difluorglutaric acid dimethyl ester of b.p. 20 = 125 ° C.

Example 2 157 g of ethyl dichloroacetate, 200 cc of tert-butanol and 60 g of acrylonitrile were slowly mixed with 11.2 g of potassium tert-butoxide, wherein the temperature was kept at 25 to 40 "C. After the end of the entry, over Stirred overnight and extracted with ether. After the ether layer had evaporated, the The residue is distilled and a, a-dichloro-glutaric acid ethyl ester mononitrile of boiling point s = 123 to 124 "C. Yield: 165 g = 75 ° / 0 In the same way, 100 g of methyl methacrylate and 143 g of methyl dichloroacetate of a, a-dichloro-a-methyl-glutaric acid methyl ester obtained of bp 15 = 123 to 125 "C. Yield 159 g = 65%.

Example 3 11 g of dichloroacetonitrile and 8.6 g of methyl acrylate were dissolved in 25 cm of toluene and 0.5 g of sodium methylate was added in portions, the temperature rising to 50 ° C. After the completion of the entry, it was cooled and distilled.

12 g of 2,2-dichloroglutaric acid nitrile (l) methyl ester (5) were obtained from Kp.15 = 106 to 1080 C.

Claims (2)

PATE NTANS PRUCHE: 1. Method of making functional Derivatives of the a, a-dihaloglutaric acids, characterized in that functional derivatives of dihaloacetic acids to functional derivatives of a, B-olefinically unsaturated carboxylic acids in the presence of an alkali alcoholate and an inert solvent or diluent accumulates at a moderately elevated temperature. 2. The method according to claim 1, characterized in that in Presence of an inert organic solvent or diluent, preferably tert-butanol or toluene works.