Verfahren zur Herstellung von reaktiven Disazofarbstoffen

The invention comprises reactive disazo dyestuffs corresponding to the general formula in which the benzene nuclei A and B can contain further non-water solubilizing substituents and in the nucleus B one of the hydrogens of the position indicated by the bracket is replaced by the azo link, wherein X represents hydrogen or an alkyl group having 1 to 4 carbon atoms, n represents a positive whole number of at most 2, m represents a positive whole number of at least 1, Y represents the radical of a 1-aryl-5-pyrazolone compound which is coupled in the o-position to the enolic hydroxy group and Z represents an acyl residue capable of reacting with cellulose fibrous material to form a chemical bond. Such dyes are produced by reacting the corresponding compounds represented by the above formula when 2 represents hydrogen with 1 mol. of a functional derivative of an acid whose acyl residue is capable of reacting with cellulose fibrous material to form a chemical void. The rings A and B may contain alkyl groups having 1 to 4 carbon atoms, alkoxy groups, acylamino groups e.g. acetylamino or carbomethoxyamino groups, halogen atoms e.g. fluorine, chlorine or bromine. Acylating agents specified for use in introducing the reactive acyl group include b -chlorocrotonic chloride, b -chloropropionic chloride, acrylic chloride, b -bromoacrylic chloride, 2,4,5,6 - tetrachloro-, 2,4,6 - trichloro -, 2,4,6 - trichloro - 5 - acetyl pyrimidine, 2 - (21 - sulphophenylamino) - 4,6-dichloro - 1,3,5 - triazine; 2 - methylamino-4,6 - dibromo - 1,3,5 - triazine, 2 - methoxy-4,6 - dichloro - 1,3,5 - triazine and cyanuric chloride. Examples are furnished.