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Updated: Feb 27, 2026

Synthesis of pH Dependent Pyrazole, Imidazole, and Isoindolone Dipyrrinone Fluorophores using a Claisen-Schmidt Condensation Approach
Published on: June 10, 2021
Cascade Reaction of In Situ Generated N-Heteroiminophosphoranes with α,β-Unsaturated Compounds: A Direct Entry to
Liu Song1, Dandan Zhu1, Fei Yu1
1Department of Chemistry and Chemical Engineering, Chongqing University of Science and Technology, Chongqing 401331, People's Republic of China.
Abstract:
An efficient method for the in situ generation of N-heteroiminophosphoranes through the electrophilic addition of the terminal N-atom of oxindole diazocompounds to triphenylphosphine has been developed. The subsequent Wittig/6π 1,5-electrocyclization/1,3-H shift cascade reaction of N-heteroiminophosphoranes with α,β-unsaturated aldehydes, ketoesters, and ketones proceeded smoothly in one pot. A series of functionalized pyrazoles bearing an oxindole unit and atropisomeric biarylpyrazoles have been afforded by this tool with good yields and high functional group tolerance under mild conditions.
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