Verfahren zur Herstellung von wasserunloeslichen Monoazofarbstoffen

摘要

The invention provides water-insoluble monoazo dyes of formula in which the group R-HN-O2S- is in a position other than ortho to the azo group, R is a hydrogen atom or alkyl, hydroxyalkyl, alkenyl, cycloalkyl or aralkyl group or an aryl or acetyl group which may be substituted by non-ionic radicals and the benzene nuclei B and C may be substituted by alkyl or alkoxy groups or halogen atoms, the dyes being prepared by coupling diazo compounds of amines of formula with acetoacetyl compounds of 5-amino-benzimidazolones of formula Coupling is carried out by conventional processes if desired in presence of a surface-active agent and optimum grain structure may be obtained by after treating in organic liquids. Red-yellow colours are obtained.