Synthesis and structure–activity relationship of 3-arylbenzoxazines as selective estrogen receptor β agonists

A series of 3-aryl-7-hydroxybenzoxazine analogues have been prepared and evaluated as ligands for the two estrogen receptor subtypes (ERα and ERβ). From the radioligand binding assay, compounds with more than a 10-fold binding selectivity toward the ERβ subtype have been identified. These compounds have also been shown to be potent full agonists in the functional assay by activation of ERE promoted transcription, with the best compound being 20-fold more potent than genistein.