Estrogen receptor β-subtype selective tetrahydrofluorenones: Use of a fused pyrazole as a phenol bioisostere

Synthesis of a series of fused pyrazole tetrahydrofluorenone analogs which are potent, ERβ subtype selective ligands is described. Analogs possessing subnanomolar ERβ binding, greater than 100-fold ERβ-selectivity, and oral bioavailability are reported.