Process for the preparation of pyrazole azo dyestuffs

摘要

New pyrazole azo dyestuffs of the formula (I) (I) in which R1 denotes hydrogen or an acyl radical, R2 denotes hydrogen, alkyl, alkenyl, cycloalkyl, aralkyl, aryl or a heterocyclic radical which is optionally bonded via alkylene, R3 denotes hydrogen, halogen, alkyl or alkoxy, R4 denotes hydrogen, halogen, hydroxyl, amino, nitro, cyano, alkyl, alkoxy, acylamino, acyloxy or alkoxy-carbonyl, R5 and R6 independently of one another in each case denote hydrogen, alkyl, aralkyl or aryl or NR5R6 together denotes a hydrogenated heterocyclic radical which is bonded via the nitrogen and optionally contains further hetero atoms, it being possible for all the alkyl, alkenyl, cycloalkyl, aralkyl, aryl, alkoxy and heterocyclic radicals present to be optionally substituted by nonionic substituents, a novel process for their preparation and their use for dyeing and printing materials.