The structure of 4, 5, 6, 7-tetrahydrocyclohepta [jk] phenanthrene has been established by two independent syntheses. The synthesis of 7, 8, 9, 10-tetrahydrocyclohepta [delnaphthalene (VIII) from benzosuberone has been improved and it has been shown that VI11 is attacked in position 2 or 3 bv succinic anhydride.
