Patent GB-608492-A (GB)
Title: Amino-alkyl esters of diphenylamine 2-mono-carboxylic acids
Filed: 1945-05-07
Abstract: Disubstituted aminoalkyl esters of diphenylamine-2-monocarboxylic acids of the general formula <FORM:0608492/IV(b)/1> wherein R represents hydrogen or an alkyl, aryl or aralkyl group, R1 and R2 represent alkyl, aryl or aralkyl groups, e.g., they may both represent alkyl groups, and n is an integer, e.g. not greater than 6, are prepared by reacting diphenylamine-2-monocarboxylic acid halides of the general formula <FORM:0608492/IV(b)/2> wherein X represents halogen and R has the above significance, with an N-disubstituted-amino-alcohol of the general formula HO.CnH2n.NR1R2, wherein R1, R2 and n have the above significance.  The esters may also be prepared by heating the anhydride of the diphenylamine-2-carboxylic acid with the amino-alcohol, or by heating the free acid with the amino-alcohol in the presence of an agent which removes water from the reaction mixture.  Either of the benzene nuclei of the diphenylamine-2-monocarboxylic acid used may contain one or more substituents, e.g. halogen, substituted amino such as acetylamino, methylamino, dimethylamino, phenylamino, diphenylamino or benzylamino, nitro, alkoxy such as methoxy or ethoxy, aryloxy such as phenoxy, aralkoxy such as benzyloxy, alkyl, substituted alkyl, aryl and substituted aryl groups.  The benzene nucleus not containing the carboxylic group may contain a monocyclic aryl substituents, e.g. in the 41 position, and may comprise a phenyl group directly linked to the carbon atom in the 41 position or linked thereto through another atom, e.g. a nitrogen or oxygen atom, and may be a phenylamino, a phenoxy or a phenylmercapto group which may or may not contain additional substituents such as alkyl groups present in any position.  The aminoalkyl esters may be converted into water soluble salts thereof such as the hydrohalide, acetate, lactate, methane sulphonate or isethionate salts.  Suitable diphenylamine-2-carboxylic acids may be prepared by the interaction of a 2-halogenobenzoic acid with aniline or a homologue thereof, generally in the presence of copper powder and/or an acid acceptor, or by the condensation of a 2-aminobenzoic acid or a substituted aminobenzoic acid with a halogeno benzene or a substituted halogeno benzene and the following diphenylamine-2-monocarboxylic acids are specified: p N-phenylanthranilic acid or a substituted N-phenylanthranilic acid such as 21, 31- and 41 - chlorodiphenylamine-, 21 : 41 - dichlorodiphenylamine - 5 - chloro - 41 - methoxy - diphenylamine-, 5-chloro-41-methoxy-21-nitrodiphenylamine-, 41-chloro-21 : 61 - dinitrodiphenylamine-, 41-bromo-diphenylamine-, 21-hydroxy-diphenylamine-, 21 and 31-methoxy-diphenylamine-, 21-, 31- and 41-nitro-diphenylamine-, 41-chloro-21 : 61-dinitrodiphenylamine-, 21 : 41 : 61-trinitro-diphenylamine-, 41-dimethylamino-5-chlorodiphenylamine-, 21-, 31-and 41-methyldiphenylamine-, 41-phenol-diphenylamine -, 41 - phenylamino - diphenylamine- and 41-phenoxy-diphenylamine-2-carboxylic acids, N-substituted diphenylamine-2-carboxylic acids such as N-methyl diphenylamine- and triphenylamine-2-carboxylic acids. There may also be used homonuclear or heteronuclear polyhalogeno diphenylamine-2-carboxylic acids obtained by the condensation of a polyhalogeno benzoic acid with a mono- or polyhalogenated aniline, e.g. 21 : 41-4 : 6-tetrachlorodiphenylamine- or 41 : 3 : 5-trichloro-diphenylamine-2-carboxylic acids.  The acids may be converted into their acid chlorides with the customary reagents, e.g. phosphorus trichloride or pentochloride or carbonyl chloride, but preferably thionyl chloride.  The N-disubstituted amino-alcohols used are preferably but not necessarily straight chain amino alcohols, and preferably contain a small number of carbon atoms, e.g. N-disubstituted ethanolamines, propanolamines, butanolamines and hexanolamines such as b -dimethylamino-ethanol, b -diethylamino-ethanol, b -di-n-propylamino-ethanol, -diethylamino-n-propanol and 4-diethylamino-n-butanol.  In examples: (1) to (7) b -diethylaminoethyl-, b -diethylaminoethyl 5-chloro-41-methoxy-, b -diethylaminoethyl 41-phenyl-, b -diethylaminoethyl 41-phenoxy -, b  - diethylaminoethyl - 41 - phenylamino-, g -dipropylaminopropyl- and d -diethylamino - n - butyl - diphenylamine - 2 - carboxylates are prepared as their hydrochloride salts, using the acid chloride of the corresponding diphenylamine-2-carboxylic acid (obtained by the action of thionyl chloride on the free acid).