Quinolines are a ubiquitous heterocyclic aromatic scaffold, which can be found in many natural and synthetic products. They are highly valued for their pharmacological and electrochemical properties, encouraging the discovery of new routes for quinoline synthesis and diversification. Polyaryl-substituted quinolines have recently surged as useful substrates for a wide variety of applications, yet their synthetic routes remain difficult and inefficient. Herein, we report a rapid and novel mechanochemical Friedländer synthesis of polyaryl-substituted quinolines under basic conditions using ball milling. Optimized reaction conditions result in moderate to excellent yields ranging from 69% to >95% and demonstrates broad functional group tolerance at 1 hour reaction times. We further demonstrate a new route for the synthesis of photocatalyst DPQN2,4-di-OMe and photo-ligand PPQN2,4-di-OMe as well as OLED donor-acceptor pCzPPQ, electron transport material oligoquinoline TQB and organic semiconductor DPA. A gram-scale reaction was also achieved using Resonant Acoustic Mixing (RAM), providing an isolated yield of 87% after a simple recrystallization in ethanol.

中文翻译：

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颠覆弗里德兰德反应：快速、可扩展的多芳基取代喹啉机械化学合成


喹啉是一种普遍存在的杂环芳香支架，可以在许多天然和合成产品中找到。它们因其药理学和电化学特性而受到高度重视，鼓励发现喹啉合成和多样化的新途径。多芳基取代的喹啉最近已成为多种应用的有用底物，但其合成路线仍然困难且低效。在此，我们报道了在碱性条件下使用球磨进行多芳基取代喹啉的快速、新颖的机械化学弗里德兰德合成。优化的反应条件可实现中等至优异的产率，范围为 69% 至 >95%，并在 1 小时反应时间内表现出广泛的官能团耐受性。我们进一步展示了光催化剂DPQN2,4-di-OMe和光配体PPQN2,4-di-OMe以及OLED供体-受体pCzPPQ、电子传输材料寡喹啉TQB和有机半导体DPA的合成新路线。使用共振声学混合 (RAM) 也实现了克级反应，在乙醇中简单重结晶后分离产率为 87%。