Patent GB-341612-A (GB)
Title: Manufacture of ortho-anilinesulphonic acids
IPC: C07C309/46
Filed: 1929-11-13
Abstract: 1-Aminobenzene-2-sulphonic acids substituted in the 3, 4 and 6 positions by alkyl, O-alkyl, O-aryl, O-aralkyl, CO-aryl, SO2-aryl, NO2, SO3, H, COOH or halogen groups are made by treating the corresponding amine with a halogen sulphonic acid in the presence or absence of a diluent but in the complete absence of water.  As diluents high-boiling aliphatic hydrocarbons, aliphatic substitution products of aliphatic hydrocarbons and of benzene, toluene, xylene, carbon tetrachloride, o-dichlorbenzene and nitrobenzene are used. Either chloro or fluoro sulphonic acids are suitable sulphonating agents.  Acids are described resulting from the sulphonation of 4-6-dichloro-3-amino-1-toluene, 2-5-dichloro-4-amino - 1 - toluene, 4-5-dichloro-2-amino-1-toluene, pseudocumidene, 1-amino-3-methyl-4-methoxy-6-chlorobenzene, 1 - amino- 2 - methoxy - 4 - chloro - 5-methylbenzene, 1 - amino -3 - chloro - 4 - methyl -6-methoxybenzene, 5 - methyl - 4 - chloro - 2 - amino-diphenyl ether, 4,5 - dichlor - 2 - amino - diphenyl ether, 5-methoxy-4-methyl-2-amino-diphenyl ether, 5 - methyl - 4-chloro - 2 - aminophenyl - benzyl ether, 2 - amino - 4 - chloro - 5 - methyldiphenylsulphone, 2 - amino - 4 - methyl - 5 - methoxydiphenylsulphone, 3 - methyl - 4 - amino - 6 - chlorodiphenylsulphone, 1-amino-2-4-dimethoxy-5-methylbenzene, 2-4-5-trichloroaniline, 2-5-dichloro-4-aminobenzophenone, 4 - 5 - dichloro - 2 - aminobenzophenone, 3-amino-4-chloro - 6 - methoxybenzophenone, 1 - amino - 3 - 6 - dimethyl - 4 - chlorobenzene, 2 - 5 - dichloroaniline-4-sulphonic acid, 2-5-dichloro-4-nitro-1-aminobenzene, 2-5-dichloro-4-amino-1-benzoic acid.  Specification 175,019, [Class 2 (iii), Dyes &c.], is referred to.  1-Amino-2-chloro-4-methoxy-5-methylbenzene is obtained by the chlorination of 1-acetamino-4-methoxy - 5 - methylbenzene and the subsequent elimination of the acetyl group. 1-Amino-2-methoxy-4-chloro-5-methylbenzene is obtained in a similar way from 1-acetamino-2-methoxy-5-methylbenzene. 2-Amino-4-5-dichlordiphenyl ether is obtained by the condensation of 3-5-6-trichloro-2-nitrobenzene with phenol and subsequent reduction of the nitro group. p  2-Amino-4-chloro-5-methylphenyl-1-benzyl ether is obtained by the condensation of 5-methyl-4-chloro-2-nitro-1-oxybenzene with benzyl chloride and subsequent reduction of the nitro group. 2 - Amino - 4 - methyl - 5 - methoxydiphenyl ether is obtained by nitrating 4-benzenesulphamino-1-methyl-2-methoxybenzene, eliminating the benzenesulpho group, converting into 4-chloro-5-nitro-1-methyl-2-methoxybenzene by Sandmeyer's reaction, condensing with phenol and reducing to the amino compound. 2-Amino - 4 - chloro - 5 - methyldiphenylsulphone is obtained by the condensation of 2,5-dichloro-4-nitro-1-methylbenzene with benzene sulphonic acid and the subsequent reduction of the nitro group. 2-Amino - 4 - methyl - 5 - methoxydiphenylsulphone and 3-methyl-4-amino-6-chlorodiphenylsulphones are similarly obtained from 2-methyl-5-chloro-4-nitro-1-methoxybenzene (obtained by nitrating 5-amino-2-methyl-1-methoxybenzene and replacing the amino group by chlorine by Sandmeyer's reaction) and 4-5-dichloro-2-methyl-1-nitrobenzene. 1-Amino-2-4-dimethoxy-5-methylbenzene is obtained by treating 4-6-dichloro-3-nitro-1-methylbenzene with sodium ethylate and subsequent reduction of the nitro group. 2-5-Dichloro-4-aminobenzophenone is obtained by oxidizing 2-5-dichloro-4-nitro-1-methylbenzene to the carboxylic acid, converting this to the acid chloride and condensing with benzene and subsequently reducing the nitro group. 3-Amino-4-chloro-6-methoxybenzophenone is obtained by treating 4-6-dichlor-3-nitro-1-benzoic acid with thionyl chloride, condensation with benzene, replacement of a chlorine atom by the methoxy and reduction of the nitro group. 2-Amino-4-5-dichlorbenzophenone is obtained by oxidizing 3-4-dichloro-6-nitro-1-methylbenzene to the carboxylic acid, conversion to the acid chloride and condensation with benzene and subsequent reduction of the nitro group. 2-5-Dichloroaniline-4-sulphonic acid is obtained by baking 2-5-dichloroaniline with sulphuric acid. 2-5-Dichloroaniline-4-amino-1-benzoic acid is obtained by oxidizing the methyl group of 2-5-dichlor-4-acetylamino-1-methylbenzene and saponifying.