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Updated: Jul 26, 2025

Synthesis of pH Dependent Pyrazole, Imidazole, and Isoindolone Dipyrrinone Fluorophores using a Claisen-Schmidt Condensation Approach
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Synthesis of pH Dependent Pyrazole, Imidazole, and Isoindolone Dipyrrinone Fluorophores using a Claisen-Schmidt Condensation Approach

Published on: June 10, 2021

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化学选择性 [2 + 2]/[3 + 2] 光环添加 1,4-二胺:实验和理论研究

Xiaokun Zhang1, Xiuqing Song1, Jiwen Shi1

  • 1Faculty of Environment and Life, Beijing University of Technology, Beijing 100124, P. R. China.

The Journal of organic chemistry
|June 12, 2023
PubMed
概括

在1,4-二二胺 (1,4-DHPs) 中的结构变化控制光环添加反应中的化学选择性. 固态阻碍有利于 [2+2] 反应,而性则促进 [3+2] 路径,使复杂化合物的向合成成为可能.

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The absorption of UV–visible light by conjugated systems causes the promotion of an electron from the ground state to the excited state. Consequently, photochemical electrocyclic reactions proceed via the excited-state HOMO rather than the ground-state HOMO. Since the ground- and excited-state HOMOs have different symmetries, the stereochemical outcome of electrocyclic reactions depends on the mode of activation; i.e., thermal or photochemical.
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