Retinoic Acid Receptor β,γ-Selective Ligands: Synthesis and Biological Activity of 6-Substituted 2-Naphthoic Acid Retinoids

In search for retinoic acid receptor (RAR) selective ligands, a series of 6-substituted 2-naphthoic acid retinoids were synthesized and evaluated in vitro in a transactivation assay and a competition binding assay for all RARs. These derivatives, in general, showed RAR β,γ selectivity. Among these naphthoic acids, oxime derivative 12 was identified as a potent RAR γ-selective retinoid, while olefinic derivative 11 was found to be comparable to retinoic acid and slightly RAR β,γ selective. For the bioassays, a general correlation was observed between the binding affinity of the ligand to the receptors and the potency of the compounds in the transactivation assay. The structure−activity relationship of these naphthoic acids will be discussed.