Amino compounds derived from 5-acetoacetylamino-benzimidazolones

Abstract

The invention relates to aminoazo compounds of the formula I ##STR1## in which X and Y are identical or different and denote hydrogen, chlorine, bromine, methyl, methoxy, ethoxy, nitro, trifluoromethyl, carbomethoxy or carboethoxy, A represents hydrogen, methyl or ethyl, and Z in the 6- or 7-position of the heteroaromatic ring system is hydrogen, chlorine or bromine, methyl, methoxy, ethoxy, carbomethoxy, carboethoxy or nitro. The compounds of the formula I are prepared by coupling a monodiazotized p-diaminobenzene substituted by X and Y analogously to the formula I with a 5-acetoacetylaminobenzimidazolone which carries the radicals A and Z analogously to the formula I. In the case where X, Y or Z does not denote a nitro group, it is possible to use in place of the p-diaminobenzene derivative a p-aminonitrobenzene derivative which is disubstituted by X and Y in the 2- and 5-positions. In this case, the product after diazotization and coupling is initially a nitro compound which can be converted by reduction into the aminoazo compound of the formula I. The aminoazo compounds are used as starting materials for preparing disazo compounds, preferably disazo pigments, through diazotization in conventional manner and coupling onto compounds which are capable of coupling, for example onto 5-acetoacetylaminobenzimidazolones. The disazo pigments are distinguished by high tinctorial strength, excellent fastness to solvents and migration, and high thermostability.