DE962071C - Process for the preparation of esters, amides or nitriles of ª ‡ -Cyan-ª ‡, ª ‰ -dichloropropionic acids - Google Patents

Description

Process for the preparation of esters, amides or nitriles of α-cyano-α, ß-dichloropropionic acids It it was found that one.by the action of chlorine on α-cyanoacrylic acid esters, amides or nitriles, which in the ß-position at least one alkyl, cycloalkyl, aralkyl or aryl radical, the corresponding a-cyano-a, ß-dichloropropionic acid derivatives in smooth reaction receives.

The implementation succeeds in many cases without further ado by introducing gaseous chlorine in the substances mentioned. In other cases it is advantageous to to promote the chlorination process by adding catalysts. Come for this namely salts of organic bases, e.g. B. the salts of hydrogen chloride, phosphoric acid, sulfuric acid, toluenesulfonic acid or dichloroacetic acid, e.g. B. with dimethylamine, Triethylamine, dimethylaniline, benzyldimethylamine, pyridine, quinoline, isoquinoline, Quinaldine and picoline, further z. B. carbazole, azo- and hydrazodiisobutyric acid nitrile and benzoyl peroxide in question, in amounts from about 0.1 to about 50 / ,, in particular from about 1 to 201 ,, can be added.

If desired, the addition of chlorine to the double bond can occur by adding a trace of iodine, e.g. B. in amounts of about 0.01 to 0.1 O / o, furthermore can still be accelerated.

Optionally, solvents such. B.

Chloroform, carbon tetrachloride, o-dichlorobenzene or tetrachloroethane, be used.

The reaction already takes place at room temperature. In some cases however, moderately elevated temperatures can also be used.

On α-cyanoacrylic acid esters and amides suitable for the process or nitriles of the type indicated are z. B. called ß-methyl-a-cyanoacrylic acid methyl ester, fl-methyl-a-cyanoacrylonitrile, ß "S-di- methyl-α-cyanoacrylonitrile, ß-phenyl-α-cyanoacrylonitrile, ß, ß-pentamethylene-α-cyanoacrylonitrile, ß-phenyl-α-cyanoacrylic acid ethyl ester, ß-phenyl-α-cyanoacrylic acid methyl ester, ß-phenyl-α-cyanoacrylic acid amide, ß-ethyl-ß-methyl-α-cyanoacrylonitrile, ß, ß-diethyla-cyanoacrylonitrile, ß-ethyl-a-cyanacrylnikil and ß-methyl-ß-phenyl-α-cyanoacrylonitrile.

The smooth course of the reaction was surprising, since chlorine, in contrast to bromine, already in Äthylenmononitrile, z. B. acrylonitrile, only with difficulty attaches. Since the starting materials for the present process are either compounds with a nitrile group and an ester or amide group on a carbon atom of the double bond or around dinitriles, in which both nitrile groups sitting on such a carbon atom was not to be expected Implementation with chlorine would succeed at all.

The products of the process can be used as intermediates for novel organic syntheses are used.

B e i s p i e l 1 In 39 parts by weight of α-cyanocrotonitrile a rapid stream of chlorine is initiated at room temperature. The temperature is rising in the reaction mixture to 45 ° within 1 hour. With little hydrogen chloride development, which ceases completely after 3 hours, the dinitrile absorbs chlorine. After 4 hours if the introduction of chlorine is interrupted, the reaction mixture is brought to room temperature cooled and by introducing dry air of excess chlorine and of Freed hydrogen chloride. The total chlorine uptake is 24 parts by weight. That The reaction mixture is fractionated in a high vacuum. This gives 53.2 parts by weight a-cyano-a, fl-dichlorobutyronitrile (boiling point 32 ° 1 0.2 mm): calculated ... Cl 43.5; found ... Cl 43.2.

Example 2 50 g of β-phenyl-a-cyanoacrylonitrile are mixed with 1 g of quinoline hydrochloride added and placed in a three-necked flask equipped with a stirrer, thermometer and reflux condenser heated to 85 °. A moderate stream of chlorine is now passed through the liquid melt, so that an internal temperature of 900 is not exceeded. Towards the end of the reaction the chlorine flow can be increased somewhat. The excess chlorine is with air marketed, The a-cyano-α, ß-dichloro-ß-phenylpropionic acid nitrile crystallized after cooling and can be recrystallized from a little methanol. Melting point 59 to 60 °, the raw yield is practically quantitative.

Analysis for C10H6N2Cl2 (molecular weight 225, I): calculated. C 53.35, H 2.69, N 12.45, C1 3I.5; found .. C 52.84, H 2.75, N 12.1, C1 30.8, 52.74, 2.86, 12.1 30.8.

Example 3 20 parts by weight of α-cyano-β-benzylcrotononitrile become Slurried in 100 parts by volume tetrachlorethylene. - 0.2 parts by weight are added to this Pyridine hydrochloride and 0.01 part by weight of iodine. One leads into this mixture slow heating to 600 chlorine. After about 10 minutes the dinitrile goes into Solution. The introduction of chlorine is continued for 3 hours at 70 to 80 °. The excess chlorine is then blown out of the reaction mixture with air. The tetrachlorethylene is then distilled from the in a water jet vacuum formed dichloro compound.

There remain 32 parts by weight of a-cyano-a, ß-dichloro-ß-benzylcrotononitrile, which gradually solidifies into yellowish-white crystal glands. Recrystallized from cyclohexane, it is obtained as a pure white crystal powder with a melting point of 110 to 1120 Decomposition.

Analysis for Cl2HloN2Cl2 (molecular weight 253, I): calculated. C 56.90, H 3.98, N 11.05, Cl 28.10; found . C 56.54, H 4.0I, NIO, g3, Cl 28.67.

Example 4 62 g of β-methyl-α-cyanoacrylic acid methyl ester become with 9.3 g of pyridine hydrochloride and 0.05 g of iodine and stirred at 70 to 800 charged with a moderate stream of chlorine until no more chlorine is absorbed. The excess chlorine is displaced by air and the reaction product in a high vacuum fractionated, the ß-methyl-α, ß-dichloro-a-cyanopropionic acid methyl ester boils with boiling point 0.1 = 59 to 620. Yield 88.2 g = 91.8% of theory.

Analysis for C6H7NO2Cl2 (molecular weight 196): calculated. C 36.76, H 3.60, N 7, I5, Cl 56, I7; found .. C 36.87, H 3.64, N 6.77-, Cl 35.90, 37.14, 3.64, 6.88, 36, Io.

Example 5 48.6 g of β, β-pentamethylene-α-cyanoacrylonitrile become chlorinated as in Example 4. The reaction product, ß, ß-pentamethylene-α, ß-dichloro-α-cyanopropionic acid nitrile, is distilled in vacuo. Kp. 5 = 114 to 116 °. Yield 60.5 g = 84% of theory.

Analysis for C9HloN2Cl2 (molecular weight 2I7, I): calculated. C 49.79, H 4.64, N I2.9I, Cl 32.66; found .. C 50, I6, H 4.85, N I2.0, Cl 32.6 50.24, 5.15, 12.0, 32.7.

Example 6 20 parts by weight of benzylidenecyanoacetic anilide become Slurried in 100 parts by weight of glacial acetic acid.

To this are added 0.2 part by weight of pyridine hydrochloride and 0.01 part by weight Iodine. While stirring vigorously, a vigorous stream of chlorine is first passed into the Mixture, heating to 70 °. After about 15 minutes the anilide is in Solution gone, whereupon the mixture with the slow addition of chlorine 2112 Is post-chlorinated for hours at 70 to 75 °.

Then the excess chlorine is displaced with air and steamed the glacial acetic acid in a vacuum. The a-cyano-a, ß-dichloro-ß-phenylpropionic acid anilide remains as a viscous, yellowish oil.

Yield 32g. It is difficult to recrystallize from cyclohexane clean. A white crystal powder with a melting point of 80 to 85 ° is obtained with decomposition.

Analysis for C16H12N2OCl2 (molecular weight 319.2): calculated. C1 = 22.30; found .. C1 = 22.78.

Claims (1)

P A T E N T A N S P R U C H: Process for the production of esters, Amides or nitriles of a-cyano-a, ß-dichloropropionic acids, which are in the ß-position at least contain an alkyl, cycloalkyl, aralkyl or aryl radical, characterized in that that chlorine on the corresponding a-cyanoacrylic acid derivatives, optionally in The presence of catalysts and / or a trace of iodine can act.