4,4‘-Dimethyldinaphtho[a,d]cycloheptane, a Naturally Occurring Polyaromatic Derivative Related to Triterpenoids of the Serratane Series

The polyaromatic hydrocarbon 4,4'-dimethyidinaphtho[a,d]cycloheptane (1a) has been identified by NMR studies after isolation from an Oligocene sediment. The original symmetrical structure of la, which bears a central seven-membered ring, is closely related to higher plant triterpenoid precursor(s) of the serratane series and is believed to have been formed in the subsurface by a microbially mediated aromatization process.