Patent GB-781558-A (GB)
Title: Improvements in the production of amino-benzophenone-sulphones (amino-thioxanthone-s-dioxides)
IPC: C07D335/16
Filed: 1956-03-28
Abstract: Aminobenzophenone-sulphones are obtained by nitrating benzophenone-sulphones and either reducing the nitro compounds obtained or reacting them with ammonia or primary or secondary amines.  Unsubstituted benzophenone-sulphone may be employed, or its substitution products, e.g. halogen, alkyl, alkoxy or hydroxy, Mono- or dinitro compounds may be obtained, and they may be reduced with hydrosulphite, alkali sulphides or nascent hydrogen.  The products dye acetate rayon, nylon, polyurethanes, and polyesters.  In examples: (1) benzophenone-sulphone (i.e. thioxanthone-S-dioxide) is mono-nitrated to give 1-nitrobenzophenone-sulphone which is reduced with sodium sulphide or reacted with isopropylamine; (2) 2-methylbenzophenone sulphone is nitrated and the 1-nitro body is reduced with sodium sulphide or reacted with dimethylamine, methylamine, n-butylamine, or aniline; (3) 2-ethylbenzophenone sulphone is nitrated and the 1-nitro body is reduced with sodium hydrosulphite or reacted with hydroxyethylamine, or butylamine; (4) 2-methoxybenzophenone-sulphone or dibromobenzophenone-sulphone is nitrated and the nitro bodies reduced with sodium sulphide or hydrosulphite; (5) 2-chloro- and bromo-benzophenone are each dinitrated to give mixtures of nitro bodies which are separated by fractional precipitation and either reduced or reacted with hydroxyethylamine; (6) 1-nitro-2-ethyl- and 1-nitro-2-methyl-benzophenone-sulphone are each nitrated further, the dinitro bodies formed are separated by fractional precipitation, and either reduced or reacted with cyclohexylamine.ALSO:Various benzophenone-sulphones, viz. 2-methyl-, 2-ethyl, 2-methoxy- or 2-chlor-benzophenone-sulphone are obtained by condensation of thio- or dithio-salicyclic acid in concentrated sulphuric acid with toluene, ethylbenzene, anisol, or chlorbenzene respectively, and oxidizing the 2-methyl, ethyl, methoxy or chlorthioxanthones so obtained with hydrogen peroxide in glacial acetic acid or with a persulphate in concentrated sulphuric acid. Dibromobenzophenone-sulphone is obtained by bromination of thioxanthone in a melt of aluminum chloride and urea followed by oxidation.  Aminobenzophenone-sulphones are obtained by nitrating benzophenone-sulphones and either reducing the nitro compounds obtained or reacting them with ammonia or primary or secondary amines.  Unsubstituted benzophenone-sulphone may be employed, or its substitution products, e.g. halogen, alkyl, alkoxy or hydroxy. Mono- or dinitro compounds may be obtained, and they may be reduced with hydrosulphite, alkali sulphides, or nascent hydrogen.  The products dye acetate rayon, nylon, polyurethanes and polyesters.  In examples: (1) benzophenone-sulphone (i.e. thioxanthone-S-dioxide) is mono-nitrated to give 1-nitrobenzophenone-sulphone which is reduced with sodium sulphide or reacted with isopropylamine; (2) 2-methylbenzophenone sulphone is nitrated and the 1-nitro body is reduced with sodium sulphide or reacted with dimethylamine, methylamine, n-butylamine, or aniline; (3) 2-ethylbenzophenone sulphone is nitrated and the 1-nitro body is reduced with sodium hydrosulphite or reacted with hydroxyethylamine, or butylamine; (4) 2-methoxybenzophenone-sulphone or dibromobenzophenone-sulphone is nitrated and the nitro bodies reduced with sodium sulphide or hydrosulphite; (5) 2-chloro- and bromo-benzophenone are each dinitrated to give mixtures of nitro bodies which are separated by fractional precipitation and either reduced or reacted with hydroxyethylamine; (1) 1-nitro-2-ethyl-and 1-nitro-2-methylamine; (6) 1-nitro-2-ethyl- and 1-nitro-2-methylbenzophenone-sulphone are each nitrated further, the dinitro bodies formed are separated by fractional precipitation, and either reduced or reacted with cyclohexylamine.