Patent GB-511845-A (GB)
Title: Improvements in the manufacture and production of sulphonamides of carboxylic acid imides
IPC: C07D209/48
Filed: 1938-02-19
Abstract: 511,845. Sulphonamide compounds. JOHNSON, G. W. (I. G. Farbenindustrie Akt.-Ges.). Feb. 19, 1938, No. 5235. [Class 2 (iii)] Sulphonamides of o-dicarboxylic acid imides are prepared by treating o-halogencarboxylic acids with chlorsulphonic acid, reacting the resulting, sulphonic acid chlorides with ammonia or amines or cyclic bases, and heating the products with cuprous cyanide. Alternatively, sulphonamides of cyclic halogen compounds having an alkyl or aldehyde or trihalogenmethyl group in o-position to the halogen are subjected to oxidation in the case of alkyl- or aldehyde-containing compounds or to saponification in the case of the trihalogenmethyl-containing compounds and the products heated with cuprous cyanide. In the reaction with cuprous cyanide, a substance such as pyridine or quinoline is preferably added in order to render it soluble in the mixture. In place of cuprous cyanide may be used a mixture of a copper salt and an alkali cyanide. The saponification of the trihalogenmethyl groups may be effected by heat treatment with dilute sulphuric acid. Some of the products are useful as medicaments or dyestuffs. According to the examples, (1) phthalimide-4- sulphonamide is prepared by heating 2-chlorbenzoic acid with chlorsulphonic acid, converting the 5-sulphochloride with ammonia into the 5-sulphonamide, and heating with cuprous cyanide and pyridine ; (2) phthalimide- 4-sulphonic acid phenylamide is obtained when 2-brombenzoic acid is heated with chlorsulphonic acid, the product reacted with aniline and the resulting 2-brombenzoic acid- 5-sulphonic acid phenylamide heated with cuprous cyanide or a mixture of cuprous chloride and sodium cyanide; 2-fluoro or iodo-benzoic acid-5-sulphochloride may be used for reaction with the aniline, and the latter replaced by benzylamine ; (3) phthalimide-4- sulphonic acid piperidide results when 2-chlorbenzoic acid-5-sulphochloride is heated with piperidine and the product treated with cuprous cyanide; (4) the disulphonic acid dimethylamide of 2 : 3-naphthalene-carboxylic acid imide is prepared from 2-chlornaphthalene-3-carboxylic acid by reaction first with chlorsulphonic acid, then with dimethylamine and finally with cuprous cyanide ; starting from 2-chlorquinoline-3-carboxylic acid a sulphonic acid dimethylamide of quinoline-2:3-dicarboxylic acid imide is similarly obtained ; (5) phthalimide-4-sulphonic acid methylphenylamide is formed by heating 2-fluorbenzoic acid with chlorsulphonic acid, reacting the 5-sulphochloride with monomethylaniline, and treating the amide with cuprous cyanide ; (6) phthalimide-4-sulphonic acid diphenylamide and carbazolylamide are formed when 2-chlorbenzoic acid-5-sulphochloride is heated with diphenylamine or potassium carbazole and the product reacted with cuprous cyanide ; (7) phthalimide- 4-sulphonamide is prepared by treating 2- cblortoluene-5-sulphonamide with potassium permanganate in sodium hydroxide solution, and heating the resulting 2-chlorbenzoic acid-5- sulphonamide with cuprous cyanide. The use of tetrahydroquinoline as a reactant is also referred to, whilst the Provisional Specification adverts to the use of hydrazine and its derivatives and hydroxylamins in the same connection. 2-Iodobenzoic acid- 5-sulphochloride is prepared by adding potassium iodide to diazotized 2-aminobenzoic acid and treating the 2-iodobenzoic acid thus obtained with chlorsulphonic acid.