PT  - JOURNAL ARTICLE
AU  - D Mastropaolo
AU  - A Camerman
AU  - N Camerman
TI  - Hydrogen bonding interaction of diphenylhydantoin and 9-ethyladenine.
DP  - 1983 Mar 01
TA  - Molecular Pharmacology
PG  - 273--277
VI  - 23
IP  - 2
4099  - http://molpharm.aspetjournals.org/content/23/2/273.short
4100  - http://molpharm.aspetjournals.org/content/23/2/273.full
SO  - Mol Pharmacol1983 Mar 01; 23
AB  - 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.