CS233994B1 - Process for preparing 2,4,6-trisubstituted 3-cyanopyridines - Google Patents

Abstract

The process for producing the 2,4,6-trisubstituted 3-cyanopyridines of the invention makes it possible to obtain products which are readily isolated from the reaction mixture and refine crystallization, while the requirements for the process equipment are low, which is economically advantageous. The products obtained are potential scintillators and photo stabilizers of plastics. The process consists in reacting the compounds of the formula C8H5 --CH.dbd.C (CN) - - COC8H4H with aromatic ketones of the formula XCqH4COCH3 in the presence of a suitable oxidant, at elevated temperature, in an organic solvent and in the presence of condensing agents. X and Y are hydrogen, phenyl or 4-biphenylyl.

Description

The present invention relates to a process for the preparation of 2,4,6-trlavyl-3-cyanopyridines or formula I

who X and Y represent a hydrogen atom, a fomyl or a 4-biphenynyl group,

Only a derivative in which both the X and Y subetiments are hydrogen atoms, from 1,3-diphonyl propenone and bonzoylaoetonitrile nobo 3-animo-3-Yenylprepenitrile, has been prepared from the compounds of formula I so far. The present method of preparation is demanding in terms of the availability of starting materials, so that the substances or formula Z, who X and Y are not hydrogen atoms, are very difficult to access. Known production methods provide products with unreliable, variable yields, and also isolation is more difficult.

These disadvantages are overcome by the process for the preparation of the 2,4,6-trisubstituted 3 cyanopyridines according to the invention, which consists in reacting the compounds of the formula II: - CH = cCCNj-COCgH4Y and aromatic ketones of the formula III: XO4H3 ^ COCB4 in The presence of condensation agents and a suitable oxidizing agent at elevated temperature in the organic solvent is preferred. The alcohols, glycols and glyoorols or other hydroxydivatives may preferably be used, the condensation being carried out at a satisfactory boiling point of these solvents, i.e. between 50 and 250 ° C. Condensation agents which may be used are:

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- 2 ammonium salts of carboxylic acid mineral acids used · Molecular oxygen alone, possibly mixed with an inert gas, nitro compound no alkali metal oxides ·

The advantage of the novel process for the preparation of the 2,4,6-trisubstituted-3-cyanopyridines according to the invention lies in the use of the more readily available type II and H1 fractants, especially for the virtually insignificant cases where the X and Y groups are not hydrogen atoms. jo which LOPE případoeh than reported in the literature, the products to be readily isolated from roakč- ₄ ni mixture and refined crystallization. Also, the requirements for this type of equipment are low, indicating an economic advantage.

The process for the preparation of hot-oxygen-ring compounds of the formula I will be explained in more detail in several embodiments.

A process for the preparation of 6- (4-biphonylyl) -2,4-diphonyl-3-cyanopyridine

Mixture 0.4? * benzylidene-benzoyl-acetonitrile, 0.39 g of 4-aootyl-biphenyl-0.15% ammonium isotonate and 7 ml of ethanol were heated to boiling for 8 hours in a slow stream of air. After cooling to room temperature, 0.42 g of melting point 210 DEG-212 DEG C. (otanol-benzene) is obtained.

Example 1 a d 2

A process for the preparation of 2- (4-Biphonylyl) -4,6-diphenyl-3-cyanopyridine

A mixture of 0.52 g of bonzylidoa-4-phonylbonzoylaootonitrile, 0.20 g of aootophonone, 0 * 13 g of ammonium oetane and 7 ml of ethanol was heated for 10 hours in the presence of aerated oxygen and after 2 hours began to precipitate insoluble product. aspirate to room temperature, wash with water and methanol. 0.40 g of melting point product 225-227 ° C (ethanol: benzene) was obtained.

Example 1 and d 3

A process for the preparation of 2,4,6-triphonyl-3-cyanopyridine

A mixture of 2.33 g of benzylidenebenzoylaoetonitrile, 1.20 g of aoetophenone, 0.75 g of ammonium ethane, 1 ml of nitrobonzone and 10 ml of ethanol was heated for 8 hours, after which the insoluble product began to precipitate after 30 minutes. · 1.4 g of product, m.p. 223 DEG-225 DEG C., crystallized from ethanol-bonzone (III), were obtained.

- 3 Example 4

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2- (4-Biphenylyl) -4-phenyl-3-cyano-6- [4- (p-terphenylyl)] pyridine

A mixture of 0.27 g of 4-acetylphenyl, 0.31 g of benzylidenebenzoylaoetonitrile, 0.08 g of ammonium acetate, 2 ml of dimethylformamide and 10 ml of ethanol was heated to reflux for 16 hours under atmospheric oxygen. the precipitate is filtered off with suction, washed with water and ethanol and recrystallized from toluene. 0.25 β of the desired product is obtained, which is purified by chromatography on an eloupoi of 50 β silica gel eluting with chloroform, melting point »269-271 ° C *

Said 2,4,6-trieubstituted 3-cyanopyridines are potential plastic sointillators and photostabilizers.

Claims (4)

A process for the preparation of 2,4,6-> trisubstituted 3-cyanopyridines of the formula I wherein X and Y are hydrogen, phenyl or 4-biphenylyl, characterized in that the bonzylidone bonzoylaootonitrile of the formula II can be reacted C ₆ H ₅ - CH SC (CN) - COC ₆ H ₄ Y (II), who Y is as defined above with aromatic ketones of formula III x c ₆ h ₄ Coch ₃ (HI), who X eA is as defined above, the presence of a condensing agent and oxidizing agent in an organic rozpeuétědle as a ^ £ ° and examples below, ^ Ucpholy, glycols and glyosroly, wherein the condensation is carried out at reflux Jbemf téobto rezpouétédol, yes in the range from 50 to 25Ο OFMET C. _T /> e ^ o vxowe! 2 · Method for the preparation of 2,4,6-trisubstituted 3. A compound according to claim 1, wherein the condensation agent is an ammonium salt of a carboxylic acid or a minor acid of the formula I. 3. A process for the preparation of 2,4,6-trisubstituted 3-cyanopyridines according to claim 1, wherein the oxidizing agent used is molecular oxygen alone, optionally mixed with an inert gas, nitric acid or alkali metal trihydrate. of metals. , ebecvte / te i / eorc 4. A process for the preparation of 2,4,6-trisubstituted 3-cyanopyridines according to claim 1, characterized in that aliphatic hydroxy derivatives having a boiling point in the range of from 50 to 250 [deg.] C. are used as solvents.