Mastropaolo D, Camerman A, Camerman N
Mol Pharmacol. 1983 Mar;23(2):273-7.
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.
二苯乙内酰脲（DPH）与9-乙基腺嘌呤（EtAd）的氢键复合物从2,4-戊二酮中结晶出来，其不对称单元由两个DPH分子、一个EtAd分子和一个溶剂分子组成。晶体结构通过直接法解析，最终残余因子R = 0.054。结构测定表明，一个DPH以沃森-克里克模式与EtAd形成氢键，而第二个DPH的N(3)-H与EtAd的N(3)键合，形成2:1的DPH-EtAd复合物。将其与巴比妥酸盐-腺嘌呤复合物以及根据核磁共振和红外数据对1:1 DPH-EtAd复合物的早期推测进行了比较。2,4-戊二酮分子采用酮-烯醇构型，具有不对称的分子内氢键。
