GB508393A - The manufacture of vat dyestuffs - Google Patents

Abstract

508,393. Dyes. CARPMAEL, A. (I. G. Farbenindustrie Akt.-Ges.). Jan. 25, 1938, No. 2422. Addition to 487,380. [Class 2 (iii)] Vat dyestuffs of the general formula where R is the radicle of a vattable ring system, or the. corresponding imidazole, oxazole or. thiazole derivatives, are manufactured by converting such N-aroyl derivatives of amines of vattable ring systems (or their, imidazole, oxazole or thiazole derivatives) as contain in the aroyl radicle an amino or nitro group, by an oxidation or reduction process respectively, into the corresponding azo compounds. In examples : (1) 1-(3<1>-nitrobenzoylamino).-anthraquinone is reduced by means of, zinc dust and aqueous ammonia in dioxane solution ; the product dyes cotton from a red vat lemon yellow shades; (2) Á-(4<1>-aminophenyl)-2 :1 (N)- oxazoloanthraquinone is oxidized by means of sodium hypochlorite in aqueous sodium carbonate solution ; (3) Á.-(3<1>-aminophenyl)-1(S) : 2(N)-thiazolanthraquihone is similarly oxidized; the product dyes cotton from a violet-red vat yellow shades ; (4) 1-(4<1>-aminobenzoylamino)- anthraquinone is oxidized by means of sodium bichromate in aqueous acetic acid solution. Specification 478,700 is referred to. 1 - (3<1>- Nitrobenzoylamino) -anthraquinone is obtainable by condensing 1- aminoanthraquinone with 3-nitrobenzoyl chloride in the presence of o-dichorobenzene.