Zhou You, Lei Shuang-Gui, Abudureheman Baihetiguli, Wang Li-Sheng, Yu Zhi-Cheng, Xiang Jia-Chen, Wu An-Xin
National Key Laboratory of Green Pesticide, International Joint Research Center for Intelligent Biosensor Technology and Health, College of Chemistry, Central China Normal University, Wuhan, P.R. China.
School of Chemistry and Chemical Engineering, Southeast University, Nanjing, P.R. China.
Nat Commun. 2024 Dec 30;15(1):10907. doi: 10.1038/s41467-024-55312-9.
Skeleton editing for heteroarenes, especially pyrazoles, is challenging and remains scarce because these non-strained aromatics exhibit inert reactivities, making them relatively inactive for performing a dearomatization/cleavage sequence. Here, we disclose a cycloaddition-induced scaffold hopping of 5-hydroxypyrazoles to access the pyrazolopyridopyridazin-6-one skeleton through a single-operation protocol. By converting a five-membered aza-arene into a five-unit spine of a 6/6 fused-bicyclic, this work unlocks a ring-opening reactivity of the pyrazole core that involves a formal C = N bond cleavage while retaining the highly reactive N-N bond in the resulting product. A [4 + 2] cycloaddition of a temporarily dearomatized 5-hydroxypyrrole with an in situ generated aza-1,3-diene, followed by oxidative C-N bond cleavage, constitutes the domino pathway. A library of pyrazolopyridopyridazin-6-ones, which are medicinally relevant nitrogen-atom-rich tricyclics, is obtained efficiently from readily available materials.
杂芳烃尤其是吡唑的骨架编辑具有挑战性且相关研究仍然较少，因为这些非张力芳烃表现出惰性反应性，使其在进行去芳构化/裂解序列时相对不活泼。在此，我们披露了一种5-羟基吡唑的环加成诱导的骨架跳跃反应，通过单一操作方案得到吡唑并吡啶并哒嗪-6-酮骨架。通过将五元氮杂芳烃转化为6/6稠合双环的五元骨架，本研究揭示了吡唑核心的开环反应性，该反应涉及形式上的C=N键裂解，同时在所得产物中保留高反应性的N-N键。临时去芳构化的5-羟基吡咯与原位生成的氮杂-1,3-二烯进行[4+2]环加成，随后进行氧化C-N键裂解，构成了多米诺反应途径。从易得的原料出发，高效地获得了一系列具有药物相关性的富含氮原子的三环化合物——吡唑并吡啶并哒嗪-6-酮。
