Potentially carcinogenic cyclopenta[a]phenanthrenes. Part 11. Synthesis of the 1-methyl, 1,11-methano, and 7,11-dimethyl derivatives of 15,16-dihydrocyclopenta[a]phenanthren-17-one

15,16-Dihydro-1-methylcyclopenta[a]phenanthren-17-one has been prepared starting from testosterone, and in addition by a multi-stage synthesis from a correctly substituted naphthalene. The latter route has also been employed for the synthesis of the 7,11-dimethyl-17-ketone, and the 1,11-methano-17-ketone containing a bridged bay region.