Niu Cong, Yang Jianjing, Yan Kelu, Xie Jiafang, Jiang Wei, Li Bingwen, Wen Jiangwei
Institute of Medicine and Materials Applied Technologies, College of Chemistry and Chemical Engineering, Qufu Normal University, Qufu, Shandong 273165, P. R. China.
Shandong Key Laboratory of Biophysics, Institute of Biophysics, Dezhou University, Dezhou 253023, P. R. China.
iScience. 2022 Apr 15;25(5):104253. doi: 10.1016/j.isci.2022.104253. eCollection 2022 May 20.
A straightforward and practical strategy for pyridylation of inert N-heterocycles, enabled by ammonium cation and electrochemical, has been described. This protocol gives access to various N-fused heterocycles and bidentate nitrogen ligand compounds, through dual-proton-coupled electron transfer (PCET) and radical cross-coupling in the absence of exogenous metal and redox reagent. It features broad substrate scope, wide functional group tolerance, and easy gram-scale synthesis. Various experiments and density functional theory (DFT) calculation results show the mechanism of dual PCET followed by radical cross-coupling is the preferred pathway. Moreover, ammonium salt plays the dual role of protonation reagent and electrolyte in this conversion, and the resulting product 9-(pyridin-4-yl)acridine compound can be used for fluorescence recognition of Fe and Pd with high sensitivity.
一种由铵阳离子和电化学实现的惰性氮杂环吡啶化的直接实用策略已被报道。该方案通过双质子耦合电子转移（PCET）和自由基交叉偶联，在无外源金属和氧化还原试剂的情况下，可获得各种氮稠合杂环和双齿氮配体化合物。它具有底物范围广、官能团耐受性强、易于克级规模合成的特点。各种实验和密度泛函理论（DFT）计算结果表明，双PCET随后自由基交叉偶联的机理是首选途径。此外，铵盐在该转化中起到质子化试剂和电解质的双重作用，所得产物9-（吡啶-4-基）吖啶化合物可用于对铁和钯的高灵敏度荧光识别。
