DE3148155A1 - METHOD FOR PRODUCING FORMYL BUTTERIC ACID DERIVATIVES - Google Patents

Description

3U8155

-1-

Troisdorf, November 24, 1981

OZ: 81075. (4101) Dr.Sk/Ce

DYNAMIT NOBEL AKTIENGESELLSCHAFT Troisdorf, District Cologne

Process for the preparation of formylbutyric acid derivatives

The present invention is a process for the preparation of formylbutyric acid derivatives of the general Formula (I)

HC - CH ₀ -CC- COOR ⁴
0 R 'E ^ B ^?

and their dialkyl acetals. The in the claimed procedure alkyl-substituted formylbutyric acid ester dialkyl acetals formed as intermediates previously unknown compounds.

Alkyl-substituted formylbutyric acid esters are described, for example, in DE-OS 28 10 031. They are used for manufacturing of pesticides based on substituted hexene carboxylic acid esters. The production this ester is described in the aforementioned property right

and stated that the formylbutyric acid ester necessary as intermediate products by ozonolysis of the corresponding 3 »3-dialkylhexene-5-carboxylic acid ester obtained can be. The procedure described there has the Disadvantage that considerable equipment requirements are required and that it is carried out with starting compounds whose: Production is also very expensive.

There was therefore the task of using the formyl butter mentioned to produce acid derivatives in a simple way and use starting materials that are more easily accessible than the above-mentioned dimethylhexenecarboxylic acid esters.

In fulfilling this task, a method has now been developed Preparation of formylbutyric acid derivatives of the formula

HC - CH ₀ -C - CH - COOR ⁴ " ,

in which R, R and R * represent hydrogen and / or alkyl groups with 1 to 10 carbon atoms and R is hydrogen. or a Alkyl radical with 1 to 4 carbon atoms can be found, which is characterized in that a 3,4-dihydro-ol-pyrone the formula

HC HC - R ^ Ht O'

in which R, R and R ^ have the meaning given above, preferably in the presence of acidic substances, with water or an alcohol of the formula R ^4- OH (R ^^ - alkyl) and water.

In the procedure according to the invention, "in which the dihydro-ÖH? Yron is reacted with alcohols, the dialkyl acetal of the desired aldehyde is formed as an intermediate. This intermediate is a previously unknown substance; it can be easily fractionated if necessary Isolate distillation.

The ring cleavage of the dihydro-OL-pyrone according to the invention takes place / preferably in the presence of acidic compounds both in the reaction with water and in the reaction with the alcohols mentioned. Mainly Lewis and Brönsted acids come into consideration as acidic compounds. Examples of Lewis acids that can be used include AlCl ,,, ZnClp, BF ^, FeCl ^. The following Brönsted acids may be mentioned: HpSO ^, ILJ ³ Ov, p-toluenesulphonic acid, trichloroacetic acid or acidic ion exchangers.

The amount of acidic compounds that can be used can vary within wide limits. Quantities as low as 0.0001% by weight, based on the φ-pyrone, show a catalytic effect. In general, however, amounts between 0.001 and 0.1% by weight, based on the 01-pyrone, are used.

If water is used as the reactant, the substituted formylbutyric acid is obtained directly. If gegen.as reaction partner uses an alcohol, the above-mentioned acetal of the substituted is formed as an intermediate Formylbutyric acid ester. The ester and acetal radicals (denoted by R in the above formula) are included Residues with the same number of carbon atoms. The acetal obtained as an intermediate is then known per se Way converted into the corresponding formal by treatment with water, isolation of the Acetals, if this is to be converted directly into the aldehyde, is generally not necessary. In the

Hydrolysis of the acetal into the aldehyde, the ester grouping on the carboxylic acid residue is generally retained if mild hydrolysis conditions are maintained. This hydrolysis is therefore preferably carried out at temperatures between 0 and 50 ^° C. in the presence of the abovementioned amounts of acid. ·

The ring cleavage of the ol-pyrones with water or alcohols generally takes place at temperatures between 20 and 200 ^° C. Preference is given to working in the temperature range between 20 ^° C. and the boiling point of the alcohol used.

The 3 »4-dihydro-A-pyrones used as starting materials can be prepared, for example, by thermolysis of substituted dihydro-5-hydroximethyl- (3H) -furanones (DE-OS 29 52 068).

3U8155

example 1

12.6 g of 3,4-dihydro-4,4-dimethyl-ol-pyrone were mixed with 9 g of HpO and this mixture was refluxed for 4 hours under nitrogen in the presence of 0.1 g of p-toluenesulfonic acid. Excess water and unreacted starting material were separated off by distillation and the residue obtained was recrystallized from carbon tetrachloride. 11.0 g (75.2%) of 4-formyl-3,3-dimethyl-butyric acid (melting point 59 ^° C.) were obtained.

Example 2

11.0 g of 3,4-dihydro-4,4-dimethyl- _{pyrone were refluxed with 18.3 g of methanol and 0.1 g of H 2} SO 4 (96%) for 4 hours. The methanol was then distilled off. There were

1513.3 g of 4-formyl-3,3-dimethylbutyric acid / methyl ester dimethylacetal obtain. The crude acetal was stirred for 6 hours with 18 g of ILpO under nitrogen at room temperature. After that it was the org. Phase separated and distilled. The 4-pormyl-3,3-dimethylbutyric acid methyl ester distilled at 138

20 to 140 ⁰ C at 16 * 10 "^ bar (yield 7.1 g).

MMR spectrum of methyl 4-formyl-3,3-dimethylbutyrate, dimethylacetal (GCl ^, ^ O MHZ): / = 1.05 (6H); 1.65 (d, 2H); 2.25 (2H); 3.30 (6H); 3.65 (3H); 4.5 (t, 1H). 25th

Claims (1)

3H8155 - 1 - Troisdorf, November 24th, 1981 OZ: "107? (4.101) Dr.Sk/Ce patent claims:
Ml Process for the preparation of formylbutyric acid derivatives of the formula HC - CH ₀ -C - CH - COOR ⁴
9! £ Α \ pt χ
O RRR- ^ in which the Rer.te R, R "and R-" 'h'ir hydrogen and / or Alkyl groups with 1 to 10 carbon atoms are and R is hydrogen or an alkyl radical with 1 to 4 carbon atoms can be, characterized in that a 3,4-dihydro - & - pyrone of the formula η ¹ y X, HC MG - U ' HC 1 ? 5
in which R ₁ R "and W have the meaning given above, reacts with water or an alcohol dor formula R OH (R = C ^^ - alkyl) and water. ? 52. Method ζχχτ ITersiollunp; from Aoetalon the Ροπή oil R ⁴ O CH - CH ₀ - "C - CH - COOR ⁴ 1 2 3 4 in which the radicals R, R, R and R are the above Have meaning, characterized in that one ^, 4-dihydro-ol -p.yron of the formula R ¹ R ² HC HC-R? > v S ^ O 12-5
xn the R, R and R- ^ have the meaning given above, with alcohols of the formula R OH. 3. Process for the preparation of lOrmylbutyric acid derivatives according to claim 1 or 2, characterized in that the reaction in the presence of an acidic Catalyst is carried out. 4. Process for the preparation of formylbutyric acid derivatives according to claim 1 and 2 and of acetals according to claim 2 and 3 »characterized in that Lewis or Brönsted acids are used as acidic compounds. 5. Alkyl-substituted 4-formylbutyric acid alkyl ester acetals the formula ΕγΛ DD \ J Xl / CH - CH ₀ -C - C - COOR ^4. \ J Xx ta Sx. in which R, R and Br represent identical or different alkyl radicals with 1 to 10 carbon atoms and R represents identical alkyl radicals with 1 to 4 carbon atoms.