abstract |
Bis(indolyl)ethylene aldehydes of the general formula <IMAGE> I in which R1 denotes hydrogen, alkyl, aralkyl or aryl, R2 denotes hydrogen, alkyl or aryl, R3 denotes hydrogen, alkyl, alkenyl, COOH or aryl and R4 denotes hydrogen, alkyl, alkoxy, cycloalkoxy or halogen, and these substituents themselves can carry non-ionic radicals or a carboxyl group, are dyestuff intermediates. |