DD244819A1 - METHOD FOR THE PRODUCTION OF SUBSTITUTED MALONONITRILES - Google Patents

Abstract

The aim of the invention is to develop a process for the preparation of 4-alkylthio-6-aryl-3-cyano-1,2-dihydro-pyridin-2-ylidene-malononitriles. The substituted Malononitrile of the general formula II, in which R is an optionally alkoxy-, alkyl-, nitro- or halogen-substituted phenyl radical or a fur-2-yl radical and R 1 is an alkyl radical, can be prepared by reacting the butadiene carbonitriles of the general formula I in which R and R1 have the abovementioned meaning, with which 1-amino-2-cyanoethylidene-malononitrile is prepared in the presence of bases. These substituted malononitriles can be used as organic intermediates for further syntheses. They are particularly suitable for the preparation of specific condensed heterocycles.

Description

For this 1 page formulas

Field of application of the invention

The invention relates to a process for the preparation of 4-alkylthio-6-aryl-3-cyano-1 ^ -dihydro-pyridin ^ -ylidenemalononitriles.

These substituted malononitriles can be used as organic intermediates for further syntheses. They are particularly suitable for the preparation of specific condensed heterocycles.

Characteristic of the known technical solutions

^ Alkylthio-e-aryl ^ -cyano-i ^ -dihydro-pyridine ^ -ylidene-malononitriles are not yet known.

Object of the invention

The aim of the invention is to develop a process for the preparation of these substituted malonitriles.

Explanation of the essence of the invention

The substituted Malononitrile of the general formula II in which R is an optionally alkoxy-, alkyl-, nitro- or halogen-substituted phenyl radical or a fur-2-yl radical and R ^{1 is} an alkyl radical can be prepared by reacting the Butadiencarbonitrile the general formula I, in which R and R ^{1 have} the above meaning, are prepared with the 1-amino-2-cyanoethyliden-malononitrile in the presence of bases.

The reactions are carried out in a water-miscible, aprotic solvent, preferably dimethylformamide. As bases alkali hydroxides or alkali carbonates, preferably potassium carbonate can be used. It is expedient to use an excess of base and to stir the reaction mixtures.

The reaction temperatures are 20-80 ° C, the reaction times range depending on the reaction temperatures of 10 minutes to 2 hours.

After completion of the reaction, the reaction mixtures are mixed with water and acidified with dilute mineral acid. The crude products can be recrystallized from organic solvents after filtration and washing with water for further purification.

embodiments Embodiment 1

3-cyano-4-methylthio-6-phenyl-1,2-dihydro-pyridin-2-ylidene-malononitrile

To a solution of 0.01 mol of 4,4-bis (methylthio) -2-phenyl-buta-1,3-diene-1,1-dicarbonitrile and 0.01 mol of i-amino-2-cyanoethylidene-malononitrile in 10 ml Dimethylformamide is added to 2 g of potassium carbonate. The mixture is stirred at 50 ^° C. for 20 minutes. The reaction mixture is then allowed to cool to 2O ⁰ C, it is mixed with 100 ml of water and then acidified with dilute mineral acid. The precipitate is filtered off, washed with water and recrystallized from methanol. Yield: 86% of theory. Melting point: 247-248 ⁰ C (dec.)

C ₁₆ H ₁₀ N ₄ S (290.4) Ber. C 66.18 H 3.47 N 19.19

C 66.30 H 3.50 N 19.06 IR (KBr): NH 3250, CN 2220, 2215, 2190 cm ^-1 ; ¹ H-NMR (DMSO-d ₆ ): CH ₃ S 2.65 (s ), CH 6.90 (s), aromatic protons 7.55-8.25ppm.

Embodiment 2

6- (p-Chloro-phenyl) -3-cyano-4-methylthio-1,2-dihydro-pyridin-2-ylidene-malononitrile 0.01 mol 2- (p-chloro-phenyl) -4,4-bis (Methylthio) -buta-1,3-diene-1,1-dicarbonitrile and 0.01 mol of i-amino-2-cyano-ethylidenmalononitrile are reacted as described in Example 1.

Yield: 57% of theory. Melting point: AB300 ⁰ CZers.

Embodiment 3

3-Cyano-6- (p -methoxyphenyl) -4-methylthio-1,2-dihydro-pyridin-2-ylidene-malononitrile 0.01 mol 2- (p-methoxy-phenyl) -4,4-bis (Methylthio) -buta-1,3-diene-1,1-dicarbonitrile and 0.01 mol of i-amino-2-cyano-ethylidenmalonitrile are reacted as described in Example 1.

Yield: 49% d. Th. Melting point: from 150 ⁰ C dec.

(N0) ₂ C = C (R) -O (H) = C (SE ¹ ) ₂

-R ¹ SH

-CH ₂ (CN) ₂

SE ¹

H-C

II

Claims (1)

-1-invention claim: A process for the preparation of substituted malononitriles of the general formula II in which R is an optionally alkoxy-, alkyl-, nitro- or halogen-substituted phenyl radical or a fur-2-yl radical and R ^{1 is} an alkyl radical, characterized in that Butadiencarbonitrile of the general formula I in which R and R ^{1 have} the above meaning, are reacted with the 1-amino-2-cyano-ethylidene-malononitrile in the presence of bases.