GB587334A - New monoazo dyestuffs - Google Patents

Abstract

Monoazo dyes are manufactured by coupling a diazotized 2-aminophenol-6-sulphonic acid, substituted in the 4-position by a chlorine atom or a methyl radical, with a 1 - phenyl - 5 - pyrazolone-3-carboxylic amide in which the phenyl radical may carry halogen or alkyl substituents and in which the nitrogen atom of the amide group carries a single substituent which is either a phenyl radical carrying one or more halogen or alkyl substituents or an a -naphthyl radical. The products yield bordeaux dyeings on wool by the chromate (metachrome) process. Examples describe the preparation of the dyestuffs 4-chloro-2-aminophenol-6-sulphonic acid --> 1 - phenyl - 5 - pyrazolone - 3 - carboxylic a -naphthylamide, 21 : 51- or 31 : 41-dichloranilide, o- or p-toluidide, 21 : 41-dimethylanilide, p-xylidide or p-chloranilide; and 4-methyl-2-aminophenol-6-sulphonic acid --> 1-phenyl-5-pyrazolone-3-carboxylic p-toluidide or p-chloranilide. Additional coupling components specified are 1 - phenyl - 5 - pyrazolone - 3 - carboxylic m-toluidide and o- and m-chloranilide. Specifications 344,250 and 584,255 are referred to. Samples have been furnished under Sect. 2 (5) of the dyestuffs 4 - chloro - 2 - aminophenol - 6 - sulphonic acid --> 1-p-tolyl- and 1-p-chlorophenol-5-pyrazolone-3-carboxylic o-toluidide. The pyrazolone derivatives employed as coupling components are obtainable by treating the corresponding 1 - phenyl - 5 - pyrazolone - 3 - carboxylic acid with the appropriate amine in an inert solvent, e.g. toluene, in the presence of phosphorus trichloride.