GB560661A - Manufacture of para-aminobenzene sulphonacylamides - Google Patents

Abstract

Para-aminobenzene sulphonacylamides of the general formula <FORM:0560661/IV/1> where R1 is an alkyl- and/or alkoxy-, or alkylthiosubstituted benzene residue which may contain further substituents. R2 is hydrogen, alkyl or aralkyl and R3 is hydrogen or alkyl are prepared by reacting a sulphonamide of the benzene series containing in the para position a group containing nitrogen, with an alkyl-, and/or alkoxy-, or alkylthio-substituted carboxylic acid of the benzene series or a functional derivative thereof. If desired the nitrogen containing group in the para position may finally be converted into an amino group. Nitrogen containing groups mentioned include nitroso-, azo-, azoxy-, hydrazo-, and acyl such as acetyl or carbomethoxy groups. Sulphonamides mentioned include p-aminobenzenesulphonamide, p - alkyl or p - aralkylaminobenzene-sulphonamides, p - acylaminobenzene sulphonamides, as acids there are mentioned o-, m-, or p-toluic acid, 2 : 4-dimethylbenzoic acid, 3 : 4-dimethyl-benzoic acid, 2 : 5-dimethylbenzoic acid, 4-chloro-5-methylbenzoic acid, 5 - chloro - 4 - methylbenzoic acid, 4 - methoxybenzoic acid, 4-ethoxybenzoic acid, 3 : 4-dimethoxybenzoic acid, 4 - methoxy - 5 - methylbenzoic acid, 5-nitro-4-methylbenzoic acid, the trimethyl ether of gallic acid, 3-acetylamino-4-methylbenzoic acid, 4-methylmercaptobenzoic acid, 3-methylmercaptobenzoic acid, 4-ethylmercaptobenzoic acid, 4 - isopropylmercaptobenzoic acid, 3-methyl-4-methylmercaptobenzoic acid, and 3 - methylmercapto - 4 - methylbenzoic acid. Instead of the free acids, their functional derivatives may be used, in which case acid binding or condensing agents may be present. In examples: (1) copper powder is added to a chlorbenzene solution of p-nitrobenzenesulphonamide and 4-methoxybenzoic acid chloride and the product treated with iron powder and glacial acetic acid to reduce the nitro group. (2) As in example (1) using 3 - methyl - 4 - methoxybenzoic acid chloride. (3) Anhydrous aluminium chloride is added to a nitrobenzene suspension of p-nitrobenzenesulphonamide and 4-methylbenzoyl chloride added. Catalytic hydrogenation of the product results in 4-aminobenzene-N-(4-methylbenzoyl)sulphonamide. (4) As in example (3) but using 2-methyl-benzoyl chloride. (5) As in example (3) but using 2 : 4-dimethyl-benzoyl chloride. (6) 4-Methylmercapto-benzoic acid chloride are added to a nitrobenzene suspension of sodium-p-nitrobenzenesulphonamide and the product worked up by treatment first with water and then with dilute acid. (7) 3-Methyl-4-methylmercapto-benzoic acid chloride is added to a pyridine solution of p-nitrobenzene-sulphonamide, and the nitro-compound reduced with iron powder and glacial acetic acid. (8) 4-Isopropylmercaptobenzoic acid chloride is added to a pyridine solution of p-nitrobenzene-sulphonamide and the nitro compound reduced with iron powder and glacial acetic acid. 3 - Methyl - 4 - methylmercaptobenzoic acid is prepared from 3-methyl-4-aminobenzoic acid by diazotization followed by treatment first with potassium xanthate and then with dimethyl sulphate. Specification 541,958 is referred to.