GB1091376A - Substituted diphenylamines - Google Patents

Abstract

The invention relates to compounds of the general formula <FORM:1091376/C2/1> in which R is an alkyl group having 1 to 8 carbon atoms or a cyclo alkyl group having 5 to 8 carbon atoms. Compounds claimed per se are 4 - amino - 41 - methylaminodiphenylamine, 4 - amino - 41 - isopropylaminodiphenylamine, 4 - amino - 41 - sec - octylaminodiphenylamine, 4 - amino - 41 - cyclohexylaminodiphenylamine. The compounds may be prepared by formylating the selected N-alkyl or N-cycloalkyl p-phenylene diamine to produce N,N1-diformyl-N alkyl - p - phenylenediamine or N,N1-diformyl - N - cycloalkyl - p - phenylenediamine which is condensed with p-chloronitrobenzene in the presence of alkali-metal carbonate using a polar aprotic solvent such as dimethylformamide. The crude N-alkyl-N-formamido-N1-nitrodiphenylamine or N - cycloalkyl - N-formamido - N1 - nitrodiphenylamine thus produced is subject to ethanolic sodium hydroxide to remove the formyl group, and the resulting N - alkylamino - N1 - nitrodiphenylamine or N - cycloalkylamino - N1 - nitrodiphenylamine is hydrogenated using a suitable hydrogenation catalyst such as palladium-on-carbon to obtain the desired 4-amino-4-alkyl-aminodiphenylamine or the 4-amino-41-cycloalkylaminodiphenylamine. In the case of 4-amino - 41 - sec - alkylaminodiphenyl - amines (in which the alkyl radical has 3 to 8 carbon atoms) and 4 - amino - 41 - cycloalkylaminodiphenylamines (in which the cycloalkyl radical has 5 to 8 carbon atoms), the 4-amino-41-mono-substituted aminodiphenylamines may be prepared by the reductive alkylation of 4,41-diaminodiphenylamine with one equivalent of the appropriate dialkyl ketone or cycloalkanone in an alcohol solvent, in the presence of a hydrogenation catalyst, such as palladium-on-carbon to produce a mixture of the 4-amino-41-sec-alkylaminodiphenylamine and the 4,41-di-sec - alkylaminodiphenylamine, or the 4-amino - 41 - cycloalkylaminodiphenylamine and the 4,41 - dicycloalkylaminodiphenylamine from which the 4-amino-41-mono-substituted aminodiphenylamine may be recovered by distillation or chromatography.