Patent GB-649981-A (GB)
Title: The manufacture of diamines and process of obtaining same
Filed: 1947-12-19
Abstract: Diamines of the general formula <FORM:0649981/IV (b)/1> wherein R is a hydrogen atom or a hydroxyl group, R1 is a hydrogen atom or a methyl group, Q is phenyl or a cyclohexyl group and n is zero or 1, at least one n being one, and salts thereof, are prepared by catalytically hydrogenating in one or more steps with intermediate acylation, if desired, on imidazolone of the general formula <FORM:0649981/IV (b)/2> or an acylated derivative thereof, to yield a compound of the formula <FORM:0649981/IV (b)/3> or an acylated derivative thereof, which is then hydrolysed by heating with a mineral acid or, after first protecting any nuclear hydroxyl groups in the group Q with benzyl groups by treatment with a benzyl halide, by heating with an alkali in order to open the imidazoline ring and remove any acyl groups present, and thereafter removing any such protecting benzyl groups by catalytic hydrogenolysis.  The hydrogenation may be carried out in the presence of platinum or palladium.  The hydrolysis may be carried out in two stages with dilute cold alkali, preferably an alkali metal hydroxide, in order to remove any acyl groups and with a mineral acid in order to open the imidazoline ring.  The diamines of the above general formula may be treated with alkylating or acylating agents to alkylate or acylate the amino and hydroxy groups, e.g. they may be methylated, ethylated, benzylated, acetylated, benzoylated or carbamylated.  In the examples the following compounds are prepared: 1-methyl - 4 - (3 - hydroxyphenyl) -, 1 - methyl - 4 - (3,4 - dihydroxyphenyl) -, 1 - methyl - 4 - (3,4 - dibenzyloxyphenyl) -, 3,4 - dimethyl - 5 - phenyl -, 4 - methyl - 5 - (p - hydroxyphenyl) -, 1 : 3 - diacetyl - 4 - methyl - 5 - (p - acetoxyphenyl) -, 4 - methyl - 5 - (p - hydroxyphenyl) -, 4 - methyl - 5 - cyclohexyl -, 4 - methyl - 5 - (a - hydroxybenzyl) -, 1,3 - diacetyl - 4 - methyl - 5 - benzyl -, 4 - cyclohexylmethyl - a  - hydroxy -, 4 - cyclohexylmethyl -, 1,3 - diacetyl - 4(or 5) - benzyl -, 1,3 - diacetyl -4(or 5) - a  - hydroxybenzyl -, and 4(or 5) - a  - hydroxybenzyl - 2 - imidazolidones; 1 - (3 - hydroxyphenyl) - N - methyl -, 1 - (3,4 - dibenzyloxyphenyl) - N2 - methyl - and 1 - (3,4 - dihydroxyphenyl) - N2 - methyl-ethylene diamines in the form of their hydrochloride salts; 1 - phenyl - N2 - methyl -, 1-(p-hydroxyphenyl)-, 1-cyclohexyl-, 3-cyclohexyl - 3 - hydroxy -, 3 - cyclohexylmethyl -, 3-phenyl-, and 3-phenyl-3-hydroxy-1 : 2-pro-panediamines in the form of their hydrochloride salts; 1-cyclohexyl-, 1-phenyl-1-hydroxy-, and 1-[henyl-2,3-butane diamines in the form of their hydrochloride salts and sulphate salts; 1 - 3 - (hydroxyphenyl) - N1,N2 - tetramethyl - ethylenediamine dihydrochloride; tribenzoyl derivative of 3 - cyclohexyl - 3 - hydroxy - 1,2 - propanediamine dihydrochloride. Imidazolones of the formula <FORM:0649981/IV (b)/4> where n is zero or 1, Q is a phenyl and R1 is hydrogen or methyl, are prepared by reacting aryl - a  - aminoalkyl ketones or aryl - a  - alkyl - aminoalkyl - ketones with an alkali - metal cyanate.  In the examples, 1-methyl-4-(3-hydroxyphenyl) -, 1 - methyl - 4 - (3,4 - di-hydroxyphenyl)-, 3,4-dimethyl-5-phenyl- and 4 - methyl - 5 - (p - hydroxyphenyl) - 2 - imidazolones are prepared.  1,3 - Diacetyl - 4 - methyl - 5 - (p - acetoxy-phenyl) - and 1,3 - diacetyl - 4 - methyl - 2 - imidazolones are prepared by reacting with acetic anhydride 4 - methyl - 5 - (p - hydroxyphenyl) - and 4 - methyl - 5 - benzyl - 2 - imidazolone, respectively.  Imidazolones of the formula <FORM:0649981/IV (b)/5> wherein n is 0 or 1 and R1 is hydrogen or methyl, and Q is phenyl or a hydrogenated phenyl nucleus, are prepared by a Friedel-Craft reaction from the corresponding substituted imidazolone and the corresponding acyl halide, e.g. 4 - methyl - 5 - benzoyl - 2 - imidazolone is prepared from 4-methyl-2-imidazolone and benzoyl chloride.  The Specification as open to inspection under Sect. 91 refers to the preparation of 4-methyl-5-benzyl-2-imidazolidone by the hydrogenation of 1,3-diacetyl-4-methyl-5-benzyl-2-imidazolone.  It also refers to the preparation of 1-phenyl-and 1-cyclohexyl-2 : 3-butane diamines in which the phenyl or cyclohexyl radical is substituted as by hydroxy, alkyl such as methyl, ethyl, propyl, isopropyl, or acyloxy such as acetyloxy or propionoxy groups. This subject-matter does not appear in the Specification as accepted.