Two-Step Synthesis of Blue Luminescent (Pyrrol-3-yl)-1<i>H</i>-(aza)indazoles Based on a Three-Component Coupling-Cyclocondensation Sequence
作者:Jan Nordmann、Svenja Eierhoff、Melanie Denißen、Bernhard Mayer、Thomas J. J. Müller
DOI:10.1002/ejoc.201500575
日期:2015.8
(Pyrrol-3-yl)-1H-(aza)indazoles can be efficiently prepared by a two-step process that consists of a consecutive three-component coupling–cyclocondensation synthesis to give ortho-halo-3-acylpyrrol-3-yl-substituted (hetero)arenes followed by a cyclization–condensation–SNAr sequence. Almost all derivatives display an intense blue emission upon excitation in the near UV with enormous Stokes shifts (6500–8300
(Pyrrol-3-yl)-1H-(aza)indazoles 可通过两步法有效制备,该法由连续的三组分偶联-环缩合合成得到 ortho-halo-3-acylpyrrol-3-yl-取代的(杂)芳烃,然后是环化-缩合-SNAr序列。几乎所有衍生物在近紫外激发时都显示出强烈的蓝色发射,具有巨大的斯托克斯位移 (6500–8300 cm–1) 和相当高的荧光量子产率 (Φf = 0.28–0.46)。通过对 DFT 优化几何结构执行的 TD-DFT 计算,可以合理地合理化电子跃迁。可逆质子化导致在窄 pH 范围内静态荧光猝灭,这使标题化合物成为有利的 ON/OFF 荧光切换系统。