Soluble and Stable Zethrenebis(carboximide) and Its Quinone

Key words

zethrene - polycyclic aromatic hydrocarbons - quinones

Significance

Despite first being synthesized decades ago by Clar and co-workers, zethrene only recently began attracting major interest due to its potentially interesting optoelectronic properties. Poor air and light sensitivity of unsubstituted zethrene would not have aided its cause. A more convenient route to zethrene was found in the 1960’s during attempts to synthesize and isolate the unstable tetradehydrodinaphtho[10]annulene, a precursor of zethrene. This was not successfully done until last year.

Comment

Employing the same strategy discovered by Staab and Sondheimer in the 1960’s, the authors take advantage of the automatic transannular cyclization of the tetradehydrodinaphtho-[10]annulene to form the butadiene core of the zethrene. Meanwhile, the overall improved stability of 1 no doubt makes it an interesting compound for further optoelectronic studies. Extremely notable as well is that attempts to brominate 1 using N-bromosuccinimide in the presence of DMF unexpectedly leads to the formation of the respective quinone 2.