An Efficient Synthesis of 11β-(4-Aminophenyl)spiro[estr-4-ene-17β,2′(5′H)-furan]-3,5′-dione

An efficient synthesis has been developed affording 11β-(4-aminophenyl)spiro[estr-4-ene-17β,2′(5′H)-furan]-3,5′-dione (2), main metabolite of antiprogestin (Z)-11β-[4-(dimethylamino)phenyl]-17β-hydroxy-17α-(3-hydroxyprop-1-enyl)estr-4-en-3-one (1), in an overall yield of 21%.