 Replacing the anilide with an alkene gives weakly active compounds, which can be attributed to the lack of intramolecular hydrogen binding or to poor hydrogen-bond donor capability.Various combinations of electron-withdrawing substitutions in the aniline ring of these drugs have not shown higher binding to the AR receptor, compared to compounds which have a chloro or trifluoromethyl group at the meta position (R1) and either a cyano or nitrogen group at the para position (R2).For hydroxyflutamide, a group of compounds that differed in the aromatic ring did not bind to the AR.