| abstract |
A process for preparing quaterrylene-3,4:13,14-tetracarboximides of the general formula I n nin whichn nR, R′ are each independently hydrogen or optionally substituted C 1 -C 30 -alkyl, C 5 -C 8 -cycloalkyl or aryl or hetaryl;n nwhich comprises reacting a perylene-3,4-dicarboximide of the general formula IIan n nin the presence of a base-stable, high-boiling, organic solvent and of an alkali metal base or alkaline earth metal base, with a perylene-3,4-dicarboximide of the general formula IIbn n nin which X is hydrogen, bromine or chlorine. |