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Updated: Mar 10, 2026

Synthesis of pH Dependent Pyrazole, Imidazole, and Isoindolone Dipyrrinone Fluorophores using a Claisen-Schmidt Condensation Approach
Published on: June 10, 2021
Recent advances in decorating the meta-position of pyridines through a temporary dearomatization strategy
Xin-Ming Xu1, Xiaoxu Chen1, Xuyue Wei1
1School of Chemistry and Chemical Engineering, Yantai University, Yantai, 264005, China. xin_mingxu@163.com.
Abstract:
The pyridine moiety is a privileged skeleton structure, playing an indispensable role in medicinal, chemical and materials science. Site-selective C-H functionalization of pyridines provides a straightforward approach to access valuable substituted pyridines. Compared to direct ortho- and para-functionalization, selective functionalization at the meta-position of pyridine has long posed a significant challenge due to the inherent electronic properties. Although lots of methods such as traditional electrophilic aromatic substitution, metalation, and transition metal-catalyzed reactions have been developed for meta-C-H functionalization, such reactions remain limited and highly challenging. In recent years, innovative strategies based on a dearomatization-rearomatization sequence for meta-selective C-H functionalization of pyridines, involving dihydropyridine, oxazino-pyridine, Zincke imine and radical ion intermediates, were accomplished. This review summarizes the latest advancements in the meta-C-H functionalization of pyridines using a temporary dearomatization strategy. According to the types of dearomatized intermediates, we discuss the advantages as well as limitations of these current methods and hope to inspire further progress in this important field.
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