File:Revised pathway map 1.gif

Finasteride is well know compound for treatment of alopecia. Which inhibit the Type II 5-α-reductase activity. The figure shows the basic SAR for 4-azasteroids at 5- -reductase (published in a review by Kenny et al). In general, a ketone in the 3-position is preferred. Lipophilic substituents in the 17-position are thought to bind in a lipophilic pocket of the receptor. Small lipophilic groups are tolerated around the ring as well as expanding the A-ring from six to seven-membered. The size and shape of the amide substituents at C-17 may influence both selectivity between types I and II and potency at both isoforms. Other structural classes of molecules are known to bind to 5 -R including 10 and 6-azasteroids, benzoquinolinones, benzoylaminophenoxybutanoic acid derivatives, and polyunsaturated fatty acids