Patent GB-457621-A (GB)
Title: Improvements in the manufacture and production of condensation products
IPC: C07D235/06
Filed: 1935-07-27
Abstract: N-(o -cyanoethyl) derivatives of compounds containing one or more NH groups in heterocyclic combination are prepared by treating such compounds with acrylic nitrile in an alkaline medium.  Specified heterocyclic starting materials are pyrrole and its hydrogenation products and C-substitution products, such as 2-methylpyrrole, indole and its hydrogenation products and C-substitution products, such as 2 : 3-dihydroindole, 2-phenylindole, 2-, 3- or 5-methylindole, and 2 : 3-dimethylindole, carbazole and its hydrogenation products and C-substitution products, such as tetra- and hexa - hydrocarbazole, tetrahydroquinoline, tetrahydroisoquinoline, piperidine, imidazole and its substitution products, such as benzimidazole, dihydroacridine, morpholine, perimidine and C-methylperimidines, hydrogenated thiazines such as thiodiphenylamine, piperazine, hydropyrimidines and hydroperimidines.  As agents for rendering the medium alkaline, use may be made of alkali oxides, hydroxides, alcoholates, phenolates or naphtholates or of free alkali metals, but when the heterocyclic starting material, e.g. piperidine, is sufficiently strongly alkaline, addition of another alkaline agent may be unnecessary.  Substances which promote the reaction and/or restrain the nitrile from polymerizing may be present, mention being made of copper compounds, such as copper acetate, oleate or borate or cuprous chloride, and phenols such as phenol, hydroquinone or resorcinol.  The reaction is preferably effected at a raised temperature and at atmospheric or raised pressure in a solvent or diluent which may be an excess of acrylic nitrile, an alcohol such as butanol, a hydrocarbon such as benzine, benzene or cyclohexane, pyridine, acetonitrile, or ethyl acetate.  The products may be converted into the corresponding carboxylic acids or their salts or amides by saponification, or into amines by catalytic hydrogenation, or into esters by acid saponification in the presence of an alcohol; the esters may also be obtained by way of the free acids.  Examples are given in which, by addition of acrylic nitrile, (1) pyrrole yields N-(o -cyanoethyl)pyrrole; (2) piperidine yields N-(o -cyanoethyl)piperidine; (3) 2-methylindole yields N-(o -cyanoethyl)-2-methylindole and, as a by-product N : 3-di(o -cyanoethyl)-2-methylindole; these products may be saponified to yield the corresponding mono- and di-carboxylic acids; (4) 2-phenylindole yields N-(o -cyanoethyl)-2-phenylindole, which may be saponified to yield the corresponding acid; N : 3-di(o -cyanoethyl) - 2 - phenylindole may also be obtained; (5) carbazole yields N-(o -cyanoethyl)carbazole, which may be saponified to yield the corresponding acid; (6) decahydroquinoline yields N-(o -cyanoethyl)decahydroquinoline; (7) perimidine yields N-(o -cyanoethyl)perimidine; (8) indole yields N-(o -cyanoethyl)indole; (9) piperazine yields N : N<1>-di(o -cyanoethyl)piperazine; (10) 2 : 3-dimethylindole yields N-(o -cyanoethyl)-2 : 3-dimethylindole; (11) 5-methoxy-2 : 3-dimethylindole yields N - (o  - cyanoethyl) - 5 - methoxy - 2 : 3-dimethylindole; (12) benzimidazole yields N-(o -cyanoethyl)benzimidazole.