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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
General Approach to 5,6-Dihydropyridin-2-ones: Annulation Of Imines with 1,4-Ambiphilic Crotonic Acids
Ekaterina Levashova1, Leonard Beiderwieden1,2, Andrey Firsov1
1Institute of Chemistry, Saint Petersburg State University, Saint Petersburg 199034, Russia.
Abstract:
Herein, we describe a regio- and diastereoselective metal-free approach for the assembly of densely functionalized 3,6/5,6-dihydropyridin-2-ones from γ-EWG-substituted crotonic acids and imines under 1,1'-carbonyldiimidazole (CDI) activation. The method developed offers the advantages of a wide range of functionalities in easily accessible substrates, mild reaction conditions, and generally high yields. The synthetic utility of this method has been extended to some core and functional group transformations. Additionally, the reaction mechanism was studied by DFT calculations.
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