DE1278433B - Process for the preparation of nitriles of substituted cycloaliphatic or heterocyclic carboxylic acids - Google Patents

Description

Process for the preparation of nitriles of substituted cycloaliphatic or heterocyclic carboxylic acids The invention comprises a process for the preparation of nitriles of substituted cycloaliphatic or heterocyclic carboxylic acids of the general formula in which Ar is an aryl radical, such as QHs, p-CH, C, HS, or a heterocyclic substituent, such as 3-pyridyl or 2-thienyl, Z is (- CH2) n = or - (CH,) "" - Y is (CH2) na group, where Y is a divalent atom or a divalent atomic group, such as - O -, - S -, - N (CHa) -, n = 2, 3, 4, 5 or 6 and n , = na = 1, 2, 3, and where the hydrogen in one or more methylene groups is optionally replaced by an alkyl or aryl group, by reaction of dihaloalkanes of the general formula X (CH2) nXi or X (CH2) n, - Y (CH2) naXl with carboxylic acid nitriles of the general formula ArCH, CN, in which X and X, are halogen atoms and Ar has the above meaning in the presence of basic condensing agents and is characterized in that one is made in the presence of at least 40% strength aqueous solutions of alkali metal hydroxides works as a condensing agent and quaternary ammonium compounds as catalysts.

The condensation is carried out at 20 to 100 ° C.

The amount of the catalyst is less than 0.1 mole per mole of nitrile. The type of addition (sequence) of the substances is arbitrary.

The process is usually carried out with molar amounts of substances that react with each other. The reaction medium can also be an inert one Contain diluents such as benzene.

Quaternary ammonium compounds can be replaced by ternary ones Amines as catalysts, which during the reaction with the alkylating agent supply the corresponding ammonium compounds.

The substituted ones made according to the present invention cycloaliphatic or heterocyclic carboxylic acid nitriles differ in their physical properties differ considerably from the starting materials, so that they are obtained in their pure form by means of distillation or crystallization can.

The following examples illustrate the present invention: Example 1 117 g (1 mol) of phenylacetonitrile are mixed with 350 g of 50% strength aqueous NaOH solution and then 3 g of tetramethylammonium hydroxide and 143 g (1 mol) of β, β'-dichlorodiethyl ether are added. The reaction mixture is stirred vigorously at 40 to 60 ° C. for 6 hours. After the reaction has ended, 127 g (68% yield) of 4-phenyl-4-cyanotetrahydropyran, boiling point = 110 ° 1 mm Hg, are separated off by vacuum distillation.

Example 2 131 g (1 mol) of p-methyl-phenyl-acetonitrile are mixed with 210 g (1 mole) 1,5-dibromopentane and 600 ml benzene mixed. Then 4 g of tetraethylammonium chloride are added and 400 ml of an aqueous 40% NaOH solution are added, and this mixture is added for 10 hours heated with stirring on the reflux condenser. After dilution with water, the organic layer 1 - (p - methylphenyl) - cyclohexanecarboxylic acid nitrile (105 g = 53% yield), bp = 135 ° C / 2 mm Hg distilled off.

Example 3 147g p-methoxyphenylacetonitrile, 215g 1,4-dibromobutane, 340 g of KOH, 280 ml of water and 6 g of trimethylbenzylammonium hydroxide ("Triton B") are used mixed together and stirred for 5 hours. After decomposition with water, the reaction mixture becomes distilled and 1- (p-methoxyphenyl) -cyclopentanecarboxonitrile (172 g = 85% Yield), bp = 140 ° C / 1 mm Hg.

Example 4 47 g of 2,2'-dichloroethylbenzylamine are mixed with 23.5 g of phenylacetonitrile. 120 ml of 50 ° / jger aqueous solution of NaOH and 0.5 g of triethylbenzylammonium chloride are added, and the reaction is carried out at a temperature of 60 to 70 ° C. over a period of 6 hours with vigorous stirring. The mixture is then diluted with water, the organic layer is extracted with benzene, the benzene extract is washed and 25 ml of concentrated hydrochloric acid are added. The product obtained is filtered, washed with water and then with benzene and dried. 39 g of 4-phenyl-4-cyano-N-benzylpiperidine hydrochloride with a melting temperature of 247 ° C. are obtained. The yield is 62%. The free base has a melting point of 75 ° C.

Claims (4)

Claims: 1. Process for the preparation of nitriles-substituted cycloaliphatic or heterocyclic carboxylic acids of the general formula in which Ar is an aryl or a heterocyclic substituent, Z is a (CH2) n = or - (CH2) n, - Y (CH2) na group, where Y is a divalent atom or a divalent atom group and n = 2, 3, 4, 5 or 6, n1 = n2 = 1, 2, 3 and where the hydrogen in one or more methylene groups is optionally replaced by an alkyl or an aryl group, by reaction of dihaloalkanes of the general formula X (CH2) nXi or X (CH2) nl - Y (CH2) naXi with carboxylic acid nitriles of the general formula ArCH2CN, in which X and X ,. Halogen atoms and Ar has the above meaning in the presence of basic condensing agents, characterized in that one works in the presence of at least 40% aqueous solutions of alkali metal hydroxides as condensing agents and quaternary ammonium compounds as catalysts. 2. The method according to claim 1, characterized in that that a compound is used as the quaternary ammonium compound, which only formed during the reaction from a tertiary amine and the dihalo compound will. 3. The method according to claim 1 and 2, characterized in that the quaternary Ammonium compound is used in amounts of not more than 0.1 mole per 1 mole of nitrile will. Documents considered: German Patent No. 812 669; J. At the. Chem. Soc., Vol. 54, 1932, pp. 2028-2037; H o u b e n - W e y 1, Methods derorganic chemistry, vol. 11I, 3rd edition, 1943, pp. 907, 915, 918, and vol. VIII, 4th edition, 1952, p. 339.