Abstract: Azo dyestuff having the formula ##STR1## in which A is an aromatic carbocyclic radical containing a CN substituent in the o-position to the azo group and K is the radical of a coupling component as well as the process for their production are disclosed. The process involves cyano exchange between a metal cyanide, e.g. CuCN and the corresponding dyestuff containing Cl or Br instead of CN, in an organic solvent particularly polar aprotic organic solvents, e.g. dimethyl sulfoxide. The dyestuffs are suitable for dyeing a variety of fiber material such as cotton, wool, silk as well as synthetic materials such as polyamide and polyethylene terephthalate to give dyeings which are characterized by great clearness and good general fastness properties.

Abstract: Azo dyestuff of the formula ##STR1## wherein R.sub.5 is H, CH.sub.3, OCH.sub.3, or OC.sub.2 H.sub.5 ;R.sub.6 is selected from the group consisting of H, OCH.sub.3 and OC.sub.2 H.sub.5 ;R.sub.7 and R.sub.8 are each selected from the group consisting of methyl, ethyl, n-butyl, and substituted ethyl wherein the substituent is selected from the group consisting of CN, Cl, carbomethoxy, methylcarbonyloxy, and methoxy-carbonyloxy;Y.sub.1 stands for ##STR2## these dyestuffs being useful for coloring hydrophobic fibers with good clarity and fastness.

Abstract: Disazo dyestuffs of the formulaA'--N.dbd.N--B'--N.dbd.N--Kare disclosed in whichA' is an aromatic carbocyclic or aromatic heterocyclic radical;B' is aromatic carbocyclic and at least one of A' and B' carries a cyano group ortho to the azo group; andK is the radical of a coupling component, e.g. parahydroxyaryl or N-substituted paraaminoaryl radicals.These dyestuffs are useful for dyeing synthetic hydrophobic materials such as polyesters, cellulose triacetate, polyamides, polyolefins, polyurethanes and polymers and copolymers of acrylonitrile to give greenish-blue to bluish-red shades with good fastness properties.

Abstract: Preparation of azo dyestuffs which possess at least one nitrile group in the ortho-position to the azo bridge, by reacting the corresponding ortho-halogenoazo compounds with CuCN or systems which for CuCN, in the presence of nitrogen bases and optionally of surface-active agents, in an aqueous medium, with replacement of at least one halogen substituent, which is in the orthoposition to the azo bridge, by a nitrile group. Preferably the reaction is carried out as one-pot-process. The dyestuffs prepared by the process, a substantial number of which are known, are useful in dyeing natural and synthetic fiber materials.