Synthesis of functionalized tetracene dicarboxylic imides

For the first time, a synthesis of tetracene dicarboxylic imides was established with 1,2,3,4-tetrahydrotetracene (1) instead of tetracene as the starting material. Mono-bromination of 1 by CuBr2 followed by a Friedel–Crafts reaction, oxidation, and imidization gave the tetrahydrotetracene carboxylic imides 5a–b. Subsequent oxidative dehydrogenation of 5a–b with DDQ afforded the functional tetracene dicarboxylic imide monobromides 6a–b, which can be further functionalized to provide functional materials such as the ‘donor–acceptor’ type compounds 7a–b.