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Updated: Nov 4, 2025

Preparation of Stable Bicyclic Aziridinium Ions and Their Ring-Opening for the Synthesis of Azaheterocycles
Published on: August 22, 2018
Constructing fused N-heterocycles from unprotected mesoionic N-heterocyclic olefins and organic azides via diazo
Qiuming Liang1, Kasumi Hayashi1, Yimin Zeng1
1Davenport Chemical Research Laboratories, Department of Chemistry, University of Toronto, 80 St. George Street, Toronto, Ontario, M5S 3H6, Canada. d.song@utoronto.ca.
Abstract:
Mesoionic N-heterocyclic olefins (mNHOs) were first reported last year and their reactivity remains largely unexplored. Herein we report the reaction of unprotected mNHOs and organic azides as a novel synthetic route to a variety of pyrazolo[3,4-d][1,2,3]triazoles, an important structural motif in drug candidates and energetic materials. The only byproduct aniline can be easily recycled and converted back to the starting organic azide, in compliance with the green chemistry principle. The reaction mechanism has been explored through experimental and computational studies.
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