Cyclic 1,4-diazadiene (2,3-dihydro-5-methyl-6-phenylpyrazine) and diketone (1-phenyl-1,2-propanedione) yielded two products via dehydration–condensation of the diamine and diketone moieties when a mixture of H2O and MeOH was used as the solvent. The structures of the new products were established by 2D NMR analysis. Single-crystal X-ray structural characterization and density functional theory calculations allowed us to determine that this reaction took place via reaction of the enamine tautomer.

中文翻译：

---

环状1,4-二氮杂二烯的烯胺互变异构体与二酮的反应活性

环状1,4-二氮杂二烯（2,3-二氢-5-甲基-6-苯基吡嗪）和二酮（1-苯基-1,2-丙二酮）通过脱水-二胺和二酮部分的缩合反应生成两种产物用1 H 2 O和MeOH作为溶剂。通过2D NMR分析确定了新产品的结构。单晶X射线结构表征和密度泛函理论计算使我们能够确定该反应是通过烯胺互变异构体的反应发生的。