GB322184A - Process for the production of vat dyestuffs of the anthraquinone series and intermediate products therefor - Google Patents

Abstract

322,184. Johnson, J. Y., (I. G. Farbenindustrie Akt.-Ges.). July 23, 1928. Anthraquinone dithiazoles; arylmercaptoiminoanthraquinones.-The imidechlorides of 2.6-diaroyldiaminoanthraquinones are converted into C-diaryl-2.1-(S) : 6.5-(S)-anthraquinonedithiazoles by treatment with sulphur or agents yielding sulphur. If this treatment is carried out under mild conditions, for example at low temperatures, 2.6 - bis-arylmercaptomethylaminoanthraquinones are first obtained and may be converted to the above dithiazoles by treating with acid or alkaline dehydrogenating agents such as sulphuric acid, chlorsulphonic acid, to which substances may be added an oxidizing agent, or potassium hydroxide solution containing potassium ferricyanide. In examples, 2.6-bis-phenylmercaptomethyliminoanthraquinone is heated (1) in naphthalene with sulphur to give C-diphenyl-2.1- (S) : 6.5-(S)-anthraquinonedithiazole (2) with alcoholic potash saturated with sulphuretted hydrogen to yield 2.6-bis-phenylmercaptomethyliminoanthraquinone; the latter compound is converted to the dithiazole obtained (1) by heating with sulphuric acid or other oxidizing agent. The imidechlorides may be prepared by the action of phosphorus pentachloride on the 2.6-diaryldiaminoanthraquinones. Specification 21615/12 is referred to.