Potentially carcinogenic cyclopenta[a]phenanthrenes (1,2-cyclopentenophenanthrenes). Part I. A new synthesis of 15,16-dihydro-17-oxocyclopenta[a]phenanthrene and the phenanthrene analogue of 18-norœstrone methyl ether

Abstract

15,16-Dihydro-17-oxocyclopenta[a]phenanthrene and its 3-methoxy, 11- and 12-methyl, and 11,12-dimethyl, derivatives have been synthesised by aromatisation of the 3-unsubstituted and 3-methoxy-11,17-diketones in which rings C and D are both saturated; the mechanism of the aromatisation is discussed.