The synthesis of 6,7-Dihydrocyclohepta[opqr]benzo[c]phenanthrene

Abstract

6,7-Dihydrocyclohepta[opqr]benzo[c]phenanthrene, the first example of a hydrocarbon containing a seven-membered ring with four contiguously fused aromatic rings, has been prepared. A preliminary examination of the n.m.r, spectrum shows the signal from the four aliphatic protons coalesce to a sharp singlet at temperatures above -40º. Attempts to dehydrogenate this compound to the fully unsaturated hydrocarbon were unsuccessful.