Synthesis of perylene‐3,4‐dicarboximides — Novel highly photostable fluorescent dyes

Perylene‐3,4‐dicarboximides 2 are obtained by a decarboxylizing condensation of moderately sterically hindered primary amines with perylene‐3,4,9,10‐tetracarboxylic 3,4:9,10‐bisanhydride ( 3 ) in the presence of water. Perylene‐3,4‐dicarboxylic anhydride ( 4 ) is prepared by hydrolysis of the imides with KOH in tert ‐butyl alcohol. The anhydride may be condensed with any primary amine to the corresponding imide. The imides are highly fluorescent and very photostable dyes.