Synthesis of nitrogen-containing derivatives of 17(20)-pregnenoic, 17β-hydroxypregnanoic, and 17α-hydroxypregnanoic acids as new potential antiandrogens

A general scheme for the synthesis of oxazoline and benzoxazole derivatives of [17(20)E]-21-norpregnene differing in the structure of the steroid moiety as well as amides of 17β-hydroxy-3-oxopregn-4-en-21-oic and 17α-hydroxy-3-oxopregn-4-en-21-oic acids was developed. The scheme involved synthesis of the steroid building blocks (appropriately protected derivatives of pregn-17(20)-en-21-oic, 17β-hydroxypregnan-21-oic, and 17α-hydroxypregnan-21-oic acids) and subsequent transformation of these building blocks into the target compounds. Following the developed scheme, synthesis of new nitrogen-containing steroid derivatives exhibiting antiandrogenic activity was enabled.