Synthesis of new benzo[c]phenanthridine derivatives

Three-component condensation of naphthalen-1-amine with triethyl orthoformate and dimedone or cyclopentane-1,3-dione, as well as the reaction of naphthalen-1-amine with 2-acetyl-5,5-dimethylcyclohexane-1,3-dione, gave the corresponding 2-[1-(α-naphthylamino)alkylidene]cycloalkane-1,3-diones which underwent intramolecular cyclization to 7,8,9,10-tetrahydrobenzo[c]phenanthridin-7-one derivatives on heating in polyphosphoric acid. 9,9-Dimethyl-7,8,9,10-tetrahydrobenzo[c]phenanthridin-7-one was reduced to 9,9-dimethyl-7,8,9,10-tetrahydrobenzo[c]phenanthridin-7-ol with sodium tetrahydridoborate.