DE1793594B2 - Process for the production of substituted acrylonitriles - Google Patents

Description

NH ₂

in which Ar is a phenyl, p-methylphenyl or p-ChlorphcisyJgruppe and R a low molecular weight Alkyl group means, characterized in that a nitrotoluene derivative is first used the formula

15th

NH ₂

in which Ar is a phenyl, p-methylphenyl or p-chlorophenyl group and R is a low molecular weight alkyl. is characterized in that nitrotoluene derivative of the formula

group

one first

a

CH ₃

y v

NO,

OR

OR

in which R stands for a low molecular weight alkyl group

stands, with an alkali metal polysulphide in one in which R stands for a low molecular weight alkyl group, Alcohol ζ; · an aminobenzaldehyde of formula 30 with an alkali metal polysulfide in an alcohol

to an aminobenzaldehyde of the formula

OHC

OHC

/ V

NH,

35 OR

in which R stands for a low molecular weight alkyl group, reacts and then the same, without separating it from the reaction mixture, with phenyl-, p-methylphenyl- or p-chlorophenylacetonitrile condensed.

45

A process for the preparation of acrylic acid derivatives is already known, which is part of a process for the production of S-phenyl-V-acyamino-coumarins is (US-PS 28 81 186). It consists in that a benzaldehyde derivative, that in position 2 is a hydroxyl group or one which can be converted into a hydroxyl group Substituents and in position 4 a substituted amino group or one which can be converted into an amino group Has substituents, with an acetic acid derivative which is a phenyl or substituted in the α-position Has phenyl radical, is condensed to the corresponding «-Phenylacrylsäurederivat.

However, the starting material used for this process is difficult to manufacture. Furthermore must a chemically unstable aldehyde derivative isolated and the amino group in position 4 protected by acylation will. Finally, in order to get the desired connection, it is still necessary to use the To remove acyl group by an appropriate method.

The method shown is therefore technically difficult to carry out and has a high level of chemicals the R stands for a low molecular weight alkyl group, allows to react and then the same without him separated from the reaction mixture, condensed with phenyl-, p-methylphenyl- or p-chlorophenylacetonitrile.

The process according to the invention is carried out in two stages, each stage being an analogous one Mode of operation (Journal of the Chemical Society, 1944, pp. 4 and 5 for the first stage and US-PS 28 81 186, column 2, paragraph 2, lines 6 to 9 for the second stage). With regard to this state of the art when carrying out the process according to the invention it was not so readily foreseeable that the reaction product of the first stage without separation directly with the derivatives of phenylacetic acid could be condensed in the oxidation-reduction medium, as pointed out in US Pat. No. 2,881,186 is that because of troublesome side reactions no free amino group in the 4-position of the benzaldehyde should be present.

The technical progress of the process according to the invention can be seen in the fact that the free amino group does not have to be protected and therefore a subsequent cleavage of the protective group is not necessary.

A particular nilrotoluene derivative is 2-methoxy-4-nitrotoluene suitable.

The alcohols that can be used as the reaction medium are, for example, methanol, ethanol, Propanol, isopropanol and mixtures thereof.

As alkali metal polysulfides, for example, the polysulfides of potassium, sodium, lithium

tttiums, of the rubidium. Of it the polysulphides of potassium and sodium are particularly preferred.

The process products are valuable intermediates for the production of 3-phenyl-7-aminocuciarines, from which optical brighteners can be made.

example 1

A solution of 18 g of crystalline sodium sulfide, 16.5 g of sodium hydroxide, 8.5 g of sulfur and 200 g of water is stirred and boiled over the course of 2 hours to give 200 g of 95% alcohol, which contains 30 g of 2-methoxy-4- containing nitro-toluene. At the same temperature for further 6 hours is stirred and then cooled to 40 ⁰ C. To the solution are added 21.1 g Benzylcyauid, and it is stirred for 3 hours at 40 ° C. It is then cooled and the salted-out product is filtered. The precipitate is washed with water and a little ethanol. 25.5 g of a-phenyl - /} - (2-methoxy-4-aminophenyl) acrylonitrile are obtained in the form of yellow crystals with a melting point of 138 to 139 ° C.

Example 2

A solution of 18 g of crystalline sodium sulfide, 16.5 g of sodium hydroxide, 8.5 g of sulfur and 200 g Water is added dropwise with stirring and boiling over 2 hours. 200 g of 95% isopropyl alcohol added to the 30 g of 2-methoxy-4-nitiotoluene contains. The mixture is stirred for a further 6 hours at the same temperature and then cooled to 40.degree. 23.6 g of p-methylphenylacetonitrile are added, and it is stirred at the same temperature for 3 hours. It is then worked up as described in Example 1. It becomes a- (4-methylphenyl) -0- (2-methoxy-4-aminophenyl) -acrylonitrile ic form of yellow crystals with a melting point of 172 to 174 ° C.

Example 3

A solution of 18 g of crystalline sodium sulfide, 16.5 g of sodium hydroxide, 8.5 g of sulfur and 200 g of water is added dropwise to 200 g of 95% methyl alcohol over the course of 2 hours with stirring and boiling, which contains 30 g of 2-methoxy- Contains 4-nitrotoluene. At the same temperature for further 6 hours is stirred and then cooled to 40 ⁰ C. 27.3 g of p-chloro-phenylacetonitrile are added. The resulting solution is allowed to react for a further 3 hours at the same temperature. A- (4-chlorophenyl) - / J- (2-methoxy-4-aminophenyl) acrylonitrile is obtained in the form of yellow crystals with a melting point of 226 to 228 ° C.

Claims (1)

Claim: Process for the preparation of substituted Acrylic nitriles of the formula hen consumption, is economically unfavorable and has long reaction and work-up times. It is therefore not technically advantageous. It has now been found a method that the disadvantages of the known Procedure does not have. The process according to the invention for the preparation of acrylic mitrils of the formula