GB305140A - - Google Patents

Abstract

305,140. I. G. Farbenindustrie Akt.- Ges. Jan. 31, 1928, [Convention date]. o-Carboxylicacidamide-mercapto- and thioglycollic acid aryl compounds; thioindigo dyes.- In order to prepare o-carboxylicacidamidoaryl thioglycollic acids, which are intermediates for thioindigo dyestuffs, o-cyanarylsulphocyanogen compounds (see Specification 306,575) are first submitted to acid hydrolysis, and are then condensed with chloracetic acid in alkaline solution. The first step replaces the cyanide group by a carboxylicacidamide group, but in some cases the sulphocyanogen group is replaced by the group -S.CO.NH2, which on further hydrolysis by means of alkali, advantageously in the presence of a reducing agent, gives the mercapto group. In one example. 1-methyl-2-cyano-3-sulphocyano- 5-chlorbenzene, by treatment with sulphuric acid in the cold, yields the partially hydrolyzed product, which is then treated with caustic soda in the presence of sodium hydrosulphate or zinc dust, in order to give 1-methyl-3-mercapto-5- chlorbenzene-2-carboxylacidamide, and finally with chloracetic acid to give the corresponding o-carboxylicacidamidethioglycollic acid. According to further examples, 1-cyano-2-sulphocyano-4- chlorbenzene and 1-cyano-2-sulphocyano-4-ethoxybenzene are similarly hydrolyzed to the corresponding o-mercaptocarboxylicacidamides, which are then condensed with chloracetic acid in order to give the corresponding o-carboxylicacidamidethioglycollic acids. 1-Cyano-2-sulphocyanogen-4-chlorbenzene is prepared from 1-amino-4-chlorbenzene, by treating with alkali thiocyanate and a halogen (see Specification 303,813), and converting the resulting 1-amino-2-sulphocyano-4-chlorbenzene according to Specification 306,575 to the corresponding 1-cyano derivative.