TY - JOUR T1 - Hydrogen bonding interaction of diphenylhydantoin and 9-ethyladenine. JF - Molecular Pharmacology JO - Mol Pharmacol SP - 273 LP - 277 VL - 23 IS - 2 AU - D Mastropaolo AU - A Camerman AU - N Camerman Y1 - 1983/03/01 UR - http://molpharm.aspetjournals.org/content/23/2/273.abstract N2 - A hydrogen-bonded complex of diphenylhydantoin (DPH) and 9-ethyladenine (EtAd) crystallizes from 2,4-pentanedione with the asymmetrical unit consisting of two DPH molecules, one EtAd molecule, and one solvent molecule. The crystal structure was solved by direct methods and refined to a residual of R = 0.054. Structure determination reveals that one DPH hydrogen-bonds to EtAd in a Watson-Crick scheme while the second DPH N(3)--H bonds to EtAd N(3) to form a 2:1 DPH-EtAd complex. Comparisons are made with barbiturate-adenine complexes and with an earlier postulation of a 1:1 DPH-EtAd complex derived from NMR and IR data. The 2,4-pentanedione molecule adopts the keto-enol configuration with an asymmetrical intramolecular hydrogen bond. ER -