Abstract: A water-insoluble azo dyestuff of the formula:- ##SPC1##Wherein R is lower alkyl; the ring A is unsubstituted or is substituted by chlorine, bromine or nitro; Y is hydrogen, lower alkyl or lower alkoxy; Z is hydrogen, lower alkyl, lower alkoxy, chlorine or a group of the formula --NHCOR.sup.1 wherein R.sup.1 is lower alkyl; and X.sup.1 and X.sup.2 are independently selected from hydrogen, lower alkyl, hydroxy lower alkyl, lower alkylcarbonyl lower alkyl, cyano lower alkyl, lower alkoxycarbonyl lower alkyl, lower alkoxy lower alkyl, lower alkylcarbonyloxy lower alkyl, lower alkoxy lower alkoxycarbonyl lower alkyl, cyano lower alkoxy lower alkyl, chloro lower alkyl, phenoxy lower alkyl, phenyl, lower alkylcarbonylamino lower alkyl, cyano lower alkoxycarbonyl lower alkyl and lower alkylcarbonyloxy lower alkoxy carbonyl lower alkyl, a process for the manufacture of the said dyestuff and its use for colouring synthetic textile materials.