Department of Chemistry, Ludwig-Maximilians-Universität , Butenandtstr. 5-13, 81377 Munich, Germany.
Center for NanoScience (CeNS), University of Munich , 81377 Munich, Germany.
Org Lett. 2016 Jul 1;18(13):3158-61. doi: 10.1021/acs.orglett.6b01373. Epub 2016 Jun 20.
Pyridonaphthyridines (triazaphenanthrenes) were prepared in 4 steps and in 13-52% overall yield using Negishi cross-couplings between iodopicolines and 2-chloro-pyridylzinc derivatives. After chlorination, Gabriel amination and spontaneous ring-closure, the final aromatization leading to the triazaphenanthrenes was achieved with chloranil. This heterocyclic scaffold underwent a nucleophilic addition at position 6 leading to further functionalized pyridonaphthyridines. The influence of these chemical modifications on the optical properties was studied by steady-state and time-resolved optical spectroscopy. While the thiophene-substituted heterocycles exhibited the most extended absorption, the phenyl- and furan-substituted compounds showed a stronger photoluminescence, reaching above 20% quantum yield and lifetimes of several nanoseconds.
嘧啶并萘啶(三嗪并菲啶)经四步反应合成,产率为 13%-52%,采用的是碘化吡啶与 2-氯吡啶基锌衍生物之间的 Negishi 交叉偶联反应。氯代、Gabriel 氨化和自发环化后,利用重氮萘醌将最后一步芳构化得到三嗪并菲啶。这个杂环骨架在 6 位发生亲核加成反应,得到进一步功能化的嘧啶并萘啶。通过稳态和时间分辨光谱研究了这些化学修饰对光学性质的影响。噻吩取代的杂环化合物表现出最宽的吸收,而苯基和呋喃取代的化合物则表现出更强的光致发光,量子产率超过 20%,寿命达数纳秒。