Institute of Natural Sciences and Mathematics, Ural Federal University, 620000 Ekaterinburg, Russia.
Molecules. 2022 Dec 16;27(24):8996. doi: 10.3390/molecules27248996.
A straightforward approach for the construction of the new class of conjugated pyrans based on enamination of 2-methyl-4-pyrones with DMF-DMA was developed. 2-(2-(Dimethylamino)vinyl)-4-pyrones are highly reactive substrates that undergo 1,6-conjugate addition/elimination or 1,3-dipolar cycloaddition/elimination followed by substitution of the dimethylamino group without ring opening. This strategy includes selective transformations leading to conjugated and isoxazolyl-substituted 4-pyrone structures. The photophysical properties of the prepared 4-pyrones were determined in view of further design of novel merocyanine fluorophores. A solvatochromism was found for enamino-substituted 4-pyrones accompanied by a strong increase in fluorescence intensity in alcohols. The prepared conjugated structures demonstrated valuable photophysical properties, such as a large Stokes shift (up to 204 nm) and a good quantum yield (up to 28%).
开发了一种基于 2-甲基-4-吡喃酮与 DMF-DMA 烯胺化反应构建新型共轭吡喃的直接方法。2-（2-（二甲氨基）乙烯基）-4-吡喃酮是高反应性的底物，可经历 1,6-共轭加成/消除或 1,3-偶极环加成/消除，随后在不打开环的情况下取代二甲氨基。该策略包括选择性转化，可得到共轭和异噁唑基取代的 4-吡喃酮结构。鉴于进一步设计新型甲川菁荧光染料，测定了所制备的 4-吡喃酮的光物理性质。发现烯胺取代的 4-吡喃酮具有溶剂变色性，并在醇中荧光强度大大增强。所制备的共轭结构表现出有价值的光物理性质，例如大斯托克斯位移（高达 204nm）和良好的量子产率（高达 28%）。
