Patent GB-595965-A (GB)
Title: Improvements relating to the manufacture of amidines
IPC: C07D213/78
Filed: 1945-07-11
Abstract: Amidine thiocyanates of the general formula <FORM:0595965/IV/1> wherein R represents an alkyl, aryl or substituted aryl, aralkyl, alicyclic or heterocyclic group, and R1 and R2 each represent hydrogen or an alkyl or aralkyl radical or together form an alkylene chain, are manufactured by heating a nitrile R.CN at about 180-240 DEG  C., if desired in the presence of a solvent, with ammonium thiocyanate, thiourea, a thiocyanic acid salt of a monoamine NHR1R2, or an unsymmetrical alkylthiourea. The products may be converted into the free amidines, and salts with other acids may be prepared from the latter, or, in some cases, by adding the appropriate acid to a solution of the thiocyanate.  In examples: (1) heptyl cyanide is heated with ammonium thiocyanate and the product is treated with aqueous sodium hydroxide, extracted with ether and the ethereal solution mixed with an alcoholic picric acid solution to form caprylamidine picrate; (2) phenylacetamidine picrate is prepared from benzyl cyanide as in (1), except that chloroform is used for the extraction; (3) benzamidine picrate is prepared from benzonitrile as in (2); (4) p-bromobenzonitrile is heated with ammonium thiocyanate to produce p-bromobenzamidine thiocyanate; (5) as in (4), but with conversion of the thiocyanate to the picrate by treating an aqueous solution of the former with an alcoholic picric acid solution; (6) p-cyanophenol is heated with ammonium thiocyanate and the product is treated with aqueous ammonia to liberate p-hydroxybenzamidine dihydrate; (7) anisonitrile is heated with ammonium thiocyanate and anioamidine is liberated by means of aqueous sodium hydroxide solution, dissolved in dilute hydrochloric acid, and sodium picrate solution is added, producing anioamidine picrate; (8) p-cyanophenyl methyl sulphone is heated with ammonium thiocyanate, if desired in the presence of glycerol, or with thiourea, and the product is converted into p-amidinophenyl methyl sulphone hydrochloride via the free base; (a) m-methylsulphonylbenzonitrile is heated with ammonium thiocyanate to give m - methylsulphonylbenzamidine thiocyanate; (10) p-sulphamidobenzonitrile is heated with ammonium thiocyanate and the product is converted to p-sulphamidobenzamidine hydrochloride; (11) p-cyanophenyl methyl sulphone is heated with benzylamine thiocyanate and the product is converted to N-benzyl-p-methylsulphonylbenzamidine reineckate via the free base and its hydrochloride; (12) benzonitrile is heated with piperidine thiocyanate and the product is converted to N : N-pentamethylenebenzamidine picrate; (13) benzonitrile is heated with dimethylamine thiocyanate, and the product is converted to N : N-dimethylbenzamidine reineckate via the hydrochloride, the free base and its benzenesulphonate; (14) p-methylsulphonylbenzonitrile is heated with dimethylamine thiocyanate, and the product is converted to N : N - dimethyl - p - methylsulphonylbenz - amidine; (15) p-methylsulphonylbenzonitrile is heated with methylamine thiocyanate and the product is converted to N-methyl-p-methylsulphonylbenzamidine benzenesulphonate; (16) 2-naphthonitrile is heated with ammonium thiocyanate or thiourea and the product is converted to 2-naphthamidine picrate; (17) 2-cyanopyridine is heated with ammonium thiocyanate and the product is converted to 2-amidinopyridine picrate; (18) 4 : 41-dicyano-a  : g -diphenoxypropane is heated with ammonium thiocyanate and the product is converted to 4 : 41 - diamidino - a  : g  - diphenoxypropane hydrochloride; (19) p : p1 - dicyanodiphenyl ether similarly yields p : p1-diamidinodiphenyl ether dihydrochloride dihydrate; (20) 4 : 41-dicyanostilbene similarly yields 4 : 41-diamidinostilbene dihydrochloride dihydrate.