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CATALYTIC HYDROGENATION OF NITRILES

20200039936 ยท 2020-02-06

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    Abstract

    The present invention relates to a novel catalytic hydrogenation of substituted 2-methyl cyanopyridyl derivatives, in particular 3-chloro-5-(trifluoromethyl)pyridin-2-yl]acetonitrile [=Py-CN] to substituted 2-ethylaminopyridine derivatives, in particular 2-[3-chloro-5-(trifluoromethyl)pyridin-2-yl]ethanamine [=Py-ethanamine] or salts thereof in the presence of Raney catalysts, in particular Raney nickel or cobalt.

    Claims

    1. A process (A) for preparing substituted 2-ethylaminopyridine derivatives of formula (III) and corresponding salts thereof, ##STR00008## Wherein p is an integer equal to 1, 2, 3 or 4; each substituent X is chosen, independently of the others, as being halogen, C.sub.1-C.sub.4 alkyl or C.sub.1-C.sub.4 haloalkyl; comprising hydrogenating a substituted 2-methyl cyanopyridyl derivative according to formula (II) ##STR00009## wherein p is an integer equal to 1, 2, 3 or 4; each substituent X is chosen, independently of the others, as being halogen, C.sub.1-C.sub.4 alkyl or C.sub.1-C.sub.4 haloalkyl; in the presence of a Raney catalyst.

    2. The process according to claim 1, further comprising (A2) after (A1) an isolated product according to formula (III) is reacted with a benzoyl halide according to formula (IV) ##STR00010## Wherein Hal is fluorine, chlorine or bromine; q is an integer equal to 1, 2, 3 or 4; each substituent Y is chosen, independently of the others, as being halogen, C.sub.1-C.sub.4 alkyl or C.sub.1-C.sub.4 haloalkyl; to the compound according to formula (I) ##STR00011## wherein p and X are defined as above; q is an integer equal to 1, 2, 3 or 4; each substituent Y is chosen, independently of the others, as being halogen, C.sub.1-C.sub.4 alkyl or C.sub.1-C.sub.4 haloalkyl;

    3. The process according to claim 1, Wherein p is 1 or 2; X is independently of the others, as being fluorine, chlorine, or difluoromethyl, trifluoromethyl, dichloromethyl, trichloromethyl; and the 2-pyridyl moiety is substituted by X in 3- and/or in 5-position.

    4. The process according to claim 1, Wherein the compound according to formula (III) is 2-[3-chloro-5-(trifluoromethyl)pyridin-2-yl]ethanamine.

    5. The process according to claim 1, Wherein the Raney catalyst is Raney Cobalt.

    Description

    EXAMPLES

    [0110] The examples shown below further illustrate the invention without limiting it.

    [0111] Examples regarding Process (A):

    Example 1: Hydrogenation with Raney Cobalt Catalyst

    [0112] The water-comprising Raney cobalt catalyst (Actimet Cobalt (BASF)) is washed three times with water and another three times with tert-butyl methyl ether (MTBE).

    [0113] An autoclave is charged with 30% (w/w) of the washed Raney cobalt catalyst and 66 g of [3-chloro-5-(trifluoromethyl)pyridin-2-yl]acetonitrile solved in 340 g of MTBE. Another 50 g of MTBE is added. The contents are then stirred at an elevated hydrogen pressure of 20 bar at 25 C. until the hydrogen uptake ceased after about three hours. Stirring is then continued for another hour. The reaction mixture is removed by filtration from the autoclave. The removed reaction mixture is analyzed by HPLC to quantify the content of amine.

    [0114] The product 2-[3-chloro-5-(trifluoromethyl)pyridin-2-yl]ethanamine was obtained at 76.59% yield in a first example, and at 74.74% in a second example.