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Updated: Jun 17, 2026

Synthesis of pH Dependent Pyrazole, Imidazole, and Isoindolone Dipyrrinone Fluorophores using a Claisen-Schmidt Condensation Approach
Published on: June 10, 2021
Electrochemically Driven [3+3] Tandem Cyclization of 3-Substituted Indoles with Amidines to Access Polysubstituted
Ying Gao1, Chaosen Guo1, Qihai Zhao1
1Key Laboratory of Chemistry in Ethnic Medicinal Resources, School of Ethnic Medicine, Yunnan Minzu University, Kunming 650500, China.
Abstract:
A simple and environmentally friendly electrochemical method is reported for accessing polysubstituted pyrimido[4,5-b]indoles via the cyclization of 3-substituted indoles with amidines. By employing tetrabutylammonium iodide (nBu4NI) as the electrolyte and 2,2,6,6-tetramethylpiperidinooxy (TEMPO) as a redox mediator, the target heterocycles were efficiently synthesized in moderate to good yields. Mechanistic studies demonstrated that both TEMPO and nBu4NI are indispensable redox mediators and essential for achieving high selectivity in this transformation.
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