GB558225A - Improvements in and relating to the acylation of sulphonamides - Google Patents

Abstract

558,225. Sulphonacylamides. KATSCHER, E., and WARD, BLENKINSOP & CO., Ltd. June 22, 1942, No..8541. Sample furnished. [Class 2 (iii)] Salts of acyl derivatives of sulphonamides are made by treating sulphonamides in the form of their N-salts with carboxylic acid amides. The sulphonamide group may be attached to an alkyl aryl aralkyl or heterocyclic residue and the carbamido group of the acid amide may be attached to hydrogen or to an alkyl aryl or aralkyl residue. The hydrogen atoms of the carbamide group may be free or one or both may be substituted by the same or different groupings. If the sulphonamide contains addition free or substituted amino group there is a tendency for this group also to become acylated, a tendency which increases with the temperature. The free acylated sulphonamide may be liberated from the salt by treatment with an acid ; and where two acylation products are produced, these may be separated by differences in their solubility. In examples (1) Anhydrous sodium sulphanilamide and acetamide are melted together until the evolution of ammonia has ceased when the reaction mixture is taken up with acid and the two products N 1 -acetylsulphanilamide and N 1 N 4 -diacetylsulphanilamide are separated. (2) Anhydrous sodium sulphanilamide and acetamide are heated together and the excess of acetamide removed under reduced pressure, to give a product consisting only of N 1 -acetylsulphanilamide. (3) Sodium N 4 -acetylsulphanilamide is melted with N 4 -acetylsulphanilamide and the product extracted with acid, to give N 1 N 4 -diacetylsulphanilamide and N 4 -acetylsulphanilamide. (4) Molten sulphanilamide is stirred with sodium hydroxide and acetamide added, the heating being continued while ammonia is evolved. There are obtained N 1 -acetylsulphanilamide, N 4 -acetylsulphanilamide and N 1 N 4 - diacetylsulphanilamide which are separated by means of their varying solibility in dilute acid. A sample has been filed under Sect. 2 (5) of formyl sulphanilamide prepared by heating sodium sulphanilamide and formamide together until no more ammonia is evolved and treating the sodium salt so formed with free formic acid. Specification 541,958 is referred to.