A comparison of steroidal and non-steroidal inhibitors of human steroid 5α-reductase: New tricyclic aryl acid inhibitors of the type-1 isozyme

A series of 9,10-dihydrophenanthrene-2-carboxylic acids has been prepared and evaluated in vitro as inhibitors of human recombinant steroid 5α-reductase. 7-Bromo-9,10-dihydrophenanthrene-2-carboxylic acid, 8c, is a potent and selective non-steroidal inhibitor of human type-1 steroid 5α-reductase (Ki,app 26 nM). The inhibitory activity relationships of steroidal and non-steroidal inhibitors, with 4-aza, 6-aza, diene acid, aryl acid and nitro-alkenes functionalities, are considered.