2-Arylindenes and 2-Arylindenones: Synthesis of Probes To Study the Binding Orientation of Unsymmetrical Nonsteroidal Ligands to the Estrogen Receptor

A set of 2-arylindene and -indenone systems, bearing a 3-ethyl or 3-aryl substituent and a single hydroxyl group either on the 6-position of the indene or 4'-position of the C-2 aryl group, have been synthesized in connection with a larger investigation of the orientation with which 2-arylindene nonsteroidal estrogens bind to the estrogen receptor. The 6-hydroxyl-substituted systems are prepared by a-benzylation or benzoylation of a benzyl ketone, followed by Friedel-Crafts cyclization to the indene or indenone. The 2-(4-hydroxyphenyl)-substituted systems were approached via a 2-arylindan-l,3-dione: Grignard addition-dehydration gave the corresponding indenones from which the indenes could be prepared by Wolff-Kishner reduction. 1,3-Diethyl-2-(4-hydroxyphenyl)indene was prepared by hydride reduction of a benzofulvene precursor. The molecular structures and estrogen receptor binding affinities of these 2-arylindene and -indenone systems will be presented elsewhere.