New benzenogenic diene syntheses

3,8-Diphenylpyrene 5 and 3,10-diphenylpyrene 10 were synthesized from 1,5-dibenzylnaphthalene and 1,4-diphenylnaphthalene. Dibenzylnaphthalenes were dehydrogenated to the quinonoid compounds 2 and 7, followed by addition of maleic anhydride and dehydrogenation of the adducts to give the aromatic anhydrides 4 and 9. These were decarboxylated to the corresponding hydrocarbons. By an analogous sequence of reactions 3,9-diphenylanthranthrene and 4,9-diphenyl-1,12-benzoperylene were prepared starting from 3,8-dibenzylpyrene 12 and 3,10-dibenzylpyrene 17 respectively. 1,6-Diphenylcoronene was synthesized by a further benzenogenic diene synthesis starting from 4,9-diphenyl-1,12-benzoperylene.