Synthesis and structure-activity relationships of new non-steroidal progesterone receptor ligands

In order to study structure-activity relationships, a series of new non-steroidal progesterone receptor ligands based on PF1092A 1) was synthesized with structural modifications (mostly introduction or removal of a methyl group) at the 3-, 4-, 5-, 7- or 9-position in the 6-acetoxy-4a, 5, 6, 7-tetrahydro-3, 4a, 5-trimethylnaphtho[2, 3 -b]furan-2(4H)-one 2) skeleton. Critical positions for high binding affinity to the progesterone receptor were identified.