Synthesis of 8-bromo-5,12-tetracenequinone and 2-bromotetracene derivatives

A series of bromotetracenequinones 1 and bromotetracenes 2 were prepared from 4-bromophthalic anhydride. The parent tetracenequinone 1a and tetracene 2a were sparingly soluble in organic solvents. In contrast, dipropyl-substituted tetracenequinone 1b and tetracene 2b were a little more soluble. Preparation of dihexyl-substituted tetracene 2c proved to be difficult. Sonogashira coupling of 1b with trimethylsilylacetylene afforded the corresponding product.