Patent GB-486497-A (GB)
Title: Process for the manufacture of sulphonic acid amide compounds
IPC: C07C311/37
Filed: 1936-08-29
Abstract: The process described in the parent Specification in which carboxylic and/or sulphonic groups are introduced into p-amino-benzene sulphonic acid arylides, the amino group of which may be substituted and the aryl radical of which contains at least p  one sulphonic acid and/or carboxylic group, no other substituent being present in the aryl radical, is modified in that it is applied to p-aminobenzene sulphonic acid arylides which are substituted in the aromatic nucleus by alkyl, halogen, amino and/or nitro groups.  The amino group in the para position may be free or substituted.  The preferred substituents are acyl radicals of the various aliphatic and aromatic, if desired substituted, carboxylic and sulphonic acids.  The sulphonic acid and carboxylic acid radicals may be present in the aryl radical once or several times.  In examples: (1) 1.4-diaminobenzene 3.5-disulphonic acid is condensed with 4-acetylaminobenzene sulphochloride to give the acid sodium salt of 4-(para-acetylaminobenzene-sulphonamide)-1-aminobenzene 2 : 6-disulphonic acid which on alkaline hydrolysis gives 4-(para-aminobenzene-sulphonamido)-1-aminobenzene 2 : 6-disulphonic acid; (2) 4-acetylaminobenzene sulphonic acid amide is condensed with 2-chloro-5-nitrobenzoic acid to give 2 - (para - acetylaminobenzene - sulphonamido)-5-nitrobenzoic acid; (3) 4-acetylaminobenzene sulphonic acid amide is condensed with the sodium salt of 4-chloro-3 : 5-dinitrobenzene sulphonic acid to give 4-(para-acetylaminobenzene-sulphonamido) - 3 : 5 - dinitrobenzene sulphonic acid; (4) sodium 6-aminotoluene-3-toluene-3-sulphonate is stirred in the presence of sodium acetate with 4-nitrobenzene sulphonic acid to give 3-methyl-4-(p-nitro-benzenesulphonamido) benzene sulphonic acid which is reduced with iron filings to the corresponding p-amino compound; (5) sodium 5-amino-toluene-2-sulphonate is condensed with azobenzene sulphochloride and the 2-methyl-4-(p-azobenzene - sulphonamido) - benzene sulphonic acid reduced with sodium hydrosulphite to 2 - methyl - 4 - (p - aminobenzene - sulphonamido) benzene sulphonic acid; (6) 4-acetyl-aminobenzene sulphonic acid o-toluidide is reacted with chlorsulphonic acid to give 4-methyl-3-(p-acetyl - aminobenzene - sulphonamido) - benzene sulphochloride which is then hydrolyzed with hydrochloric acid to 4 - methyl - 3 - (p - aminobenzene - sulphonamido) - benzene sulphonic acid; (7) the hydrochloride of 2-amino-4-mercapto-1-methyl benzene is reacted with 4-acetylamino benzene sulphonic chloride to give 4 - methyl - 3 - (p - acetyl aminobenzenesulphonamido) thiophenol which is converted with potassium permanganate to 4-methyl-3-(p-aminobenzene - sulphonamido) - benzene sulphonic acid; (8) 4-acetylamino-benzene sulphochloride is reacted with 4-chloro-2-amino benzonitrile in pyridine solution to give 4-chloro-2-(p-acetylaminobenzene - sulphonamido) - benzonitrile which is hydrolyzed with alkali to 4-chloro - 2 - (p - aminobenzene sulphonamido)-benzoic acid.  The starting materials for carrying out the process of the present invention are prepared as described in the parent Specification. Specifications 20192/14, 278,037, [both in Class 2 (iii)], 470,461, 474,423, and 482,524 are referred to.