Abstract: Water-soluble azo compounds of the formula (1) ##STR1## in which R is hydrogen or alkyl of 1 to 4 carbon atoms, X is alkyl of 1 to 6 carbon atoms substituted by carboxy or sulfo, or is phenyl substituted by 1 or 2 sulfo or carboxy or both, and Z is vinyl, .beta.-thiosulfatoethyl or .beta.-sulfatoethyl and M is hydrogen or the equivalent of a metal, and in which the second sulfo group in the naphthalene is bonded in the m-position or p-position relative to the acylated amino group. The new azo compounds are very valuable dyestuffs having fiber-reactive properties, and give color-fast and deep dyeings and prints on fiber materials made of cellulose or synthetic or natural polyamide fibers.

Abstract: It has been found that dyestuffs of the formula ##STR1## in which p stands for an integer of from 1 to 6, and W represents, as a water-solubilizing group, the sulfo group, the sulfato group (--OSO.sub.3 H), the thiosulfato group (--S--SO.sub.3 H), the carboxyl group, the phosphato group (--OPO.sub.3 H.sub.2), the phosphonic acid group (--PO(OH).sub.2) or the phosphonic acid-semi-ester group of the formula --PO(OR)OH, wherein R represents an alkyl radical of from 1 to 5 carbon atoms, preferably the methyl or ethyl radical, are very suitable in dyeing and printing processes of synthetic polyamide fiber materials and yield brilliant and very fast dyeings and prints on these materials, especially even dyeings of textured polyamide fibers which have differences in stretching.