DD244749A1 - PROCESS FOR THE PREPARATION OF DIHYDROPYRIDINYLIDENE MONONONITRILES - Google Patents

Abstract

The invention relates to a process for the preparation of Dihydropyridinylidenmalononitriles. The aim of the invention is to develop a process for the preparation of 6-aryl-3-cyano-1,2-dihydro-pyridin-2-ylidene-malononitriles. The Dihydropyridinylidenmalononitrile of the general formula II in which R is an optionally alkoxy-, alkyl-, nitro- or halogen-substituted phenyl, can by reaction of Butadiencarbonitrile the general formula I, in which R has the above meaning and X is a cyano or Alkoxycarbonylgruppe be prepared with the 1-amino-2-cyano-ethylidene-malononitrile in the presence of bases. The Dihydropyridinylidenmalononitrile can be used as organic intermediates for further syntheses. They are particularly suitable for the construction of condensed heterocyclic compounds.

Description

Field of application of the invention

The invention relates to a process for the preparation of e-aryl-S-cyano-i ^ -dihydro-pyridin ^ -ylidene-malononitriles. These dihydropyridinylidene-malononitriles can be used as organic intermediates for further syntheses. They are particularly suitable for the construction of condensed heterocyclic compounds.

Characteristic of the known technical solutions

6-Aryl-3-cyano-1,2-dihydro-pyridin-2-ylidene-malononitriles are not yet known.

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Object of the invention

The aim of the invention is to develop a process for the preparation of these dihydropyridinylidene-malononitriles.

Explanation of the essence of the invention

The Dihydropyridinylidenmalononitrile of the general formula II, in which R is an optionally alkoxy-, alkyl-, nitro- or halogen-substituted phenyl, can be prepared by reacting the Butandiencarbonitrile of the general formula I, in which R has the above meaning and X is a cyano or Alkoxycarbonylgruppe are prepared with the i-amino-2-cyano-ethylidenmalononitrile in the presence of bases.

The reactions are carried out in organic solvents, preferably in dimethylformamide, in the presence of bases, preferably potassium carbonate. It is expedient to use the base in excess. If the bases do not completely dissolve in the solvents used, it is necessary to stir the reaction mixtures.

The reaction temperatures are 10-35 ⁰ C, the reaction times range depending on the reaction temperatures of 30 minutes to 4 hours.

After completion of the reaction, the reaction mixtures are mixed with water and acidified with dilute mineral acid. The crude products are filtered off, washed with water and recrystallized from organic solvents for purification.

embodiments

Embodiment 1 *

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

One dissolves successively 0.01 mol of 4-chloro-4-phenyl-1,3-butadiene-1,1-dicarbonitrile and 0.01 mol of i-amino-2-cyano-ethylidene, malononitrile in 10 ml of dimethylformamide. After adding 2 g of potassium carbonate to this mixture, it is stirred for one hour at 25 ° C. The reaction mixture is then added successively while stirring with 100 ml of water and 5 ml of half-concentrated hydrochloric acid. The precipitate is filtered off, washed with water and recrystallized from glacial acetic acid. Yield: 70% d. Th. Melting point: 280-283 ° C (decomp.)

C ₁₅ H ₈ N ₄ (244.3) Calc .: C 73.75 H 3.30 N 22.93

Found: C, 72.86, H, 3.70, N, 21.97

IR (KBr): NH 3120, CN 2225,2220,2190 cm ^-1 , ¹ H-NMR (DMSO-d ₆ ): aromatic protons 7.50 (m), CH 6.82 (d), 8.02 (d) , NH 8.95 (s) ppm.

Exemplary embodiments 2

e-fp-chloro-phenyD-S-cyano-i ^ -dihydro-pyridin ^ -ylidene-malononitrile

0.01 mol of 4-chloro-4- (p-chloro-phenyl) -1-cyano-buta-1,3-diene-1-carboxylic acid ethyl ester and 0.01 mol of T-amino-2-cyano-ethylidenmalononitrile implemented as described in Example 1.

Yield: 80% of theory. Melting point: 285-287 (Zers.) , '

C ₁₅ H ₇ CIN ₄ (287.7) Ber. C 64.64 H 2.53 N 20.10

Gef. C 64.50 H 2.90 N 20.27

IR (KBr): NH 3220, CN 2230, 2220, 200 cm "¹;

¹ H-NMR (DMSO-de): aromatic protons 7.55-7.75 (q), CH 6.85 (d), 8.07 (d), NH 7.35 (s) ppm.

Embodiment 3

3-cyano-6- (p-methoxy-phenyl) -1,2-dihydro-pyridine-2-ylidene-malononitrile

0.01 mol of 4-chloro-4- (p-methoxyphenyl) -buta-1,3-diene-1,1-dicarbonitrile and 0.01 mol of i-amino-2-cyano-ethylidene-malononitrile are reacted, as described in Example 1.

Yield: 60% d. Th. Melting point: 300-303 ⁰ C (dec.)

Claims (1)

Invention claim: A process for the preparation of Dihydropyridinylidenmalononitrilen of the general formula II in which R is an optionally alkoxy-, alkyl-, nitro- or halogen-substituted phenyl radical, characterized in that Butadiencarbonitrile of the general formula I, in which R has the above meaning and X is a Cyano or alkoxycarbonyl group is reacted with the i-amino-2-cyano-ethylidene, malononitrile in the presence of bases. For this 1 page formulas