Fused/condensed rings Heterocyclic rings systems that are formally derived by fusion with other rings, either carbocyclic or heterocyclic, have a variety of common and systematic names. For example, with the benzo-fused unsaturated nitrogen heterocycles, pyrrole provides indole or isoindole depending on the orientation. The pyridine analog is quinoline or isoquinoline. For azepine, benzazepine is the preferred name. Likewise, the compounds with two benzene rings fused to the central heterocycle are carbazole, acridine, and dibenzoazepine. Thienothiophene are the fusion of two thiophene rings. Phosphaphenalenes are a tricyclic phosphorus-containing heterocyclic system derived from the carbocycle phenalene.
Fused/condensed rings Heterocyclic rings systems that are formally derived by fusion with other rings either carbocyclic or heterocyclic have a variety of common and systematic names For example with the benzo-fused unsaturated nitrogen heterocycles pyrrole provides indole or isoindole depending on the orientation The pyridine analog is quinoline or isoquinoline For azepine benzazepine is the preferred name Likewise the compounds with two benzene rings fused to the central heterocycle are carbazole acridine and dibenzoazepine Thienothiophene are the fusion of two thiophene rings Phosphaphenalenes are a tricyclic phosphorus-containing heterocyclic system derived from the carbocycle phenalene