GB879050A - New derivatives of benzoic acid and processes for their preparation - Google Patents

Abstract

The invention comprises compounds of the formula <FORM:0879050/IV (b)/1> wherein X1, X2 and X3 may be the same or different and represent hydrogen, a non-toxic metal cation, the ammonium radical or the radical of an organic base, for example a trialkylammonium or triaralkylammonium base such as triethylammonium and their preparation by reacting 3 : 5-diaminobenzoic acid or a salt thereof with chlorosulphonic acid in the presence of a tertiary organic base such as pyridine, preferably containing some pyridinium sulphonic acid. Alternatively the compounds may be prepared by reacting 3 : 5-dinitrobenzoic acid with a mixture of a sulphite and a bisulphite. The resulting 3 : 5-disulphamino-benzoic acid is extracted from the reaction mixture by conversion to a water-insoluble organic salt, for example a quaternary salt formed from a long chain alkyl or aralkyl quaternary ammonium derivative, for example N-(p-ditertiarybutylphenoxyethoxyethyl)- N-benzyl-N : N-dimethyl ammonium chloride. The long chain quaternary ammonium salt may then be converted into products wherein X1, X2 and X3 are hydrogen, a non-toxic metal cation or ammonium by first forming the triethylammonium salt by addition of triethylamine and converting this to the desired products, e.g. the sodium or potassium salts, by double decomposition.