GB604693A - Improvements in or relating to the production of sulphonamides - Google Patents

Abstract

p-Acylaminobenzenesulphonyl guanidines of the general formula <FORM:0604693/IV(b)/1> (in which RCO is an acyl group and R1 and R2 are the same or different and represent H or aliphatic, alicyclic or heterocyclic radicals) are made by heating the ammonium or substituted ammonium salts of the formula <FORM:0604693/IV(b)/2> in the absence of ammonia or any other ammonium compound. The heating may take place in a liquid medium, e.g. water, ethyl alcohol, anisole or acetamide. Temperatures above 130 DEG C. are preferably used. Ammonium and substituted ammonium salts of acylaminobenzenesulphonyl cyanamides may be prepared from the corresponding calcium salts by reaction with ammonia or a primary or secondary amine in the presence of carbon dioxide. In examples: (1) the ammonium salt obtained by double decomposition between the calcium salt of p-acetylamino-benzenesulphonyl cyanamide and ammonium carbonate is heated to 150-170 DEG C. to yield p-acetylamino-benzenesulphonylguanidine; (2) a 50 per cent aqueous solution of the ammonium salt of p-acetylamino-benzenesulphonyl cyanamide is heated to 150-155 DEG C. to yield the same product; (3) the same product is obtained by heating to 150-160 DEG C. a suspension of p - acetylamino - benzenesulphonyl cyanamide in ethyl alcohol; (4) the methylamine salt of p-acetylamino-benzenesulphonyl cyanamide, prepared by double decomposition between methylamine carbonate and the calcium salt of p-acetylamino-benzenesulphonyl cyanamide, is heated to 170 DEG C. to yield p-acetylamino - benzenesulphonyl methylguani - dine; and (5) the diethylamine salt of p-acetylamino-benzenesulphonyl cyanamide, prepared from the calcium salt of p-acetylamino-benzenesulphonyl cyanamide, diethylamine and carbon dioxide, is heated to 170 DEG C. to yield p-acetylamino - benzenesulphonyl diethylguanidine. Samples have been furnished under Sect. 2 (5) of (a) p-acetylamino-benzenesulphonyl cyclohexylguanidine and (b) p-acetylamino-benzenesulphonyl pyridylguanidine, prepared by analogous methods. Specifications 563,766 and 595,472 are referred to. In the Specification as open to inspection under Sect. 91, R1 and R2 in the general formula may also be aromatic radicals, or together with the nitrogen atom may form a closed ring. This subject-matter does not appear in the Specification as accepted.