Patent GB-773807-A (GB)
Title: Process for the manufacture of 2-cyanoethylated n-substituted imines
Filed: 1954-08-24
Abstract: The invention comprises 2 (b -cyano-ethylated) - N - substituted - aldoimines with at least one hydrogen atom on the a -carbon atom, and ketoimines, 2,2-di- and 2,2,2-tri-cyano-ethylated N-substituted aldoimines and 2,21-dicyanoethylated N - substituted ketoimines. Such compounds are obtained by reacting an N-substituted aldoimine or ketoimine having at least one hydrogen atom on the a -carbon atom with acrylonitrile.  Ketoimines usually add only one mol. of acrylonitrile on a given carbon atom.  With aldoimines as many mols. of acrylonitrile as there are hydrogen atoms on the a -carbon atom can be added.  The imines are obtainable by reacting the appropriate amine with aldehydes or ketones. Specified aldehydes are acetaldehyde, propionaldehyde, n- or iso-butyraldehyde, n- or iso-valeraldehyde, capronaldehyde, enanthaldehyde, succindialdehyde, formylcyclohexane, phenylacetaldehyde and hydrocinnamic aldehyde. Suitable ketones are acetone, methyl ethyl ketone, methyl n-propyl ketone, diethyl ketone, methyl isobutyl ketone, methyl n-amyl ketone, ethyl n-butyl ketone, methyl n-heptyl ketone, diiso-butyl ketone, methyl tert.-butyl ketone, acetylacetone, acetonyl acetone, acetophenone, propiophenone, cyclopentanone, cyclohexanone, 1-methyl - cyclohexanone - 2, 1 - cyclohexyl - cyclohexanone-2, cyclohexandione-1,4, acetyl-cyclohexanone, a -hydrindone and a -tetralone.  Suitable amines are methylamine, ethylamine, n- or isopropylamine, n-, sec.-, tert.- or iso-butylamine, isoamylamine, n-dodecylamine, ethylenediamine, hexamethylenediamine, cyclopentylamine, cyclohexylamine, 4 - methylcyclohexylamine, benzylamine, aniline, o-, m-or p-toluidine, o-, m- and p-chloranilidine, o-, m-and p-nitroaniline, benzidine and p-anisidine.  Suitable reaction temperatures are 20 DEG  to 250 DEG C. and increased pressures may be used.  The reaction may be accelerated by catalysts such as alkali metal or alkaline earth metal hydroxides, or quaternary ammonium compounds.  Polymerization inhibitors, e.g. hydroquinone, tert.-butylpyrocatechol or trinitrotoluene may be added to the reaction mixture.  In examples: (1) to (3) 2-(b -cyanoethyl)-N-cyclohexyl - n - butyraldoimine and 2,2-di-(b -cyanoethyl) - N - cyclohexyl - n - butyraldoimine are obtained by reacting N-cyclohexyl-n-butyraldimine and acrylonitrile in various proportions; (4) N-cyclohexyl-enanthaldoimine and acrylonitrile are reacted to give 2-(b -cyanoethyl) - N - N - cyclohexyl - enanthaldoimine; (5) N-cyclohexylacetaldoimine heated in an autoclave with 3 molecular proportions of acrylonitrile gives 2,2,2-tri-(b -cyanoethyl)-N-cyclohexyl -acetaldoimine; (6) N-cyclohexyl-cyclohexanonimine and acrylonitrile are reacted to give N-cyclohexyl-2-(b -cyanoethyl)-cyclohexanonimine; (7) N-cyclohexyl-cyclohexanonimine reacted with 2 molecular proportions of acrylonitrile gives N-cyclohexyl-2-(b -cyanoethyl) -cyclohexanonimine and N-cyclohexyl-2,6-di-(b -cyanoethyl)-cyclohexanonimine which are separated by vacuum distillation; (8) N-n-butyl - 2 - (b  - cyanoethyl) - cyclohexanonimine is prepared by reacting equimolecular amounts of acrylonitrile and N-n-butyl-cyclohexanonimine; (9) N-phenyl-cyclohexanonimine and acrylonitrile are reacted to give N-phenyl-2-(b -cyanoethyl) -cyclohexanonimine; (10) N-cyclohexyl methyl n-propylketoimine and acrylonitrile are reacted to give N-cyclohexyl-3-(b -cyanoethyl)-pentanone-2-imine.  For purposes of identification the products may be hydrolysed to the corresponding aldehydes or ketones.  Hydrolysis with acid of the products of Examples (1), (3), (6), (7), (9) and (10) gives 2-(b -cyanoethyl)-n-butyraldehyde, 2,2 - di - (b  - cyanoethyl) - n - butyraldehyde, 2 - (b  - cyanoethyl) - cyclohexanone, 2,6 - di - (b - cyanoethyl) - cyclohexanone, and 3 - (b  - cyanoethyl) - pentanone - 2 respectively.  2 - (b -Cyanoethyl) -n-butyraldehyde heated with 20 per cent caustic potash solution gives g -ethylvalerolactone and a -ethylglutaric acid. 2,2-Di-(b -cyanoethyl) - n - butyraldehyde heated with a mixture of concentrated sulphuric and nitric acids gives g -carboxy-g -ethyl-pimelic acid.