GB731020A - Process for the manufacture of 4-(p-aminobenzenesulphonyl)-aminopyrimidines - Google Patents

Abstract

4 - (p - Aminobenzene - sulphonyl) - aminopyrimidines are made by reacting one mol. of 4-aminopyrimidine under anhydrous conditions with at least 1 1/2 mols. of a benzene sulphohalide containing a substituent convertible by hydrolysis or reduction to an amino group in the p-position to the sulpho group, in presence of a non-hydroxylic organic solvent and of at least 1 1/2 mols. of an acid binding agent consisting of trimethylamine and another tertiary base having at least the same capacity for binding hydrogen halide, splitting off one benzenesulphonyl radical from the bis-(benzenesulphonyl)-aminopyrimidine produced, and converting the p-substituent referred to to an amino group by hydrolysis or reduction. The tertiary amine other than trimethylamine is preferably a trialkylamine in which no alkyl group contains more than 4 carbon atoms while at least one alkyl group contains more than 1 carbon atom, and preferably 1-50 per cent trimethylamine is used with 99-50 per cent of the other tertiary amine. Examples describe the production of 4-(p-aminobenzenesulphonyl)-amino-2,6-dimethylpyrimidine from 4-amino-2,6 - dimethyl - pyrimidine and (1) p - acetylsulphanilic acid chloride in methylene chloride in presence of a mixture of trimethylamine with triethylamine, dimethylethylamine, or diethylmethylamine, followed by hydrolysis of the product with caustic soda; or (2) p-nitrobenzenesulphochloride in methylene chloride in presence of a mixture of trimethylamine and triethylamine, followed by combined reduction and hydrolysis with iron and hydrochloric acid; or (3) p-chlorbenzenesulphochloride as in (2), followed by hydrolysis in alcoholic caustic soda and reaction with ammonia. Other solvents specified are ethylene chloride, chloroform, or acetone.