Design of mechanism-based inactivators of human placental aromatase

This article reviews the design and study, in our own laboratory and in other laboratories, of new 10 beta-substituted analogs of estr-4-ene-3,17-dione. These compounds, along with a number of known analogs, have been evaluated as reversible or irreversible inhibitors of human placental microsomal aromatase. The only irreversible inhibitors in the group surveyed here are the 10 beta-difluoromethyl, 10 beta-propargyl, and 10 beta-allenyl derivatives of estr-4-ene-3,17-dione. Possible mechanisms for the inactivation processes are discussed. The effects of incorporating the 19-methyl group of adrost-4-ene-3,17-dione into a ring of three, four, five or six carbons are also described.