Stable azaheterocyclic derivatives of pentalene have been reported by the group of Hafner in the 1970s. However, these structures remained of low interest until recently, when they started to be investigated in the context of organic light-emitting diodes’ (OLEDs’) development. Herein, we revisit the synthesis of stable azapentalene derivative 1,3-bis(dimethylamino)-2-azapentalene and further explore its properties both computationally and experimentally. Beyond the reproduction and optimization of some previously reported transformations, such as formylation and amine substitution, the available scope of reactions was expanded with azo-coupling, selective halogenations, and cross-coupling reactions.

中文翻译：

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重温哈夫纳的氮杂戊二烯：1,3-双(二甲氨基)-2-氮杂戊二烯的化学

Hafner 小组在 20 世纪 70 年代报道了稳定的氮杂环戊二烯衍生物。然而，直到最近，当人们开始在有机发光二极管（OLED）开发的背景下对它们进行研究时，这些结构仍然没有引起人们的兴趣。在此，我们重新审视稳定的氮杂五环戊二烯衍生物1,3-双(二甲氨基)-2-氮杂五环戊二烯的合成，并通过计算和实验进一步探讨其性质。除了复制和优化一些先前报道的转化（例如甲酰化和胺取代）之外，可用的反应范围还通过偶氮偶联、选择性卤化和交叉偶联反应得到了扩展。