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Updated: Jan 18, 2026

Preparation of Stable Bicyclic Aziridinium Ions and Their Ring-Opening for the Synthesis of Azaheterocycles
Published on: August 22, 2018
A Chemoselective and Copper-Catalyzed Azide-Alkyne Cycloaddition (CuAAC)/Ring-Cleavage/Cyclization Reaction Sequence
Xiaoling Su1, Zixin Huang1, Guozhao Feng1
1The Marine Biomedical Research Institute of Guangdong Zhanjiang, Guangdong Medical University, Zhanjiang, Guangdong, 524023, China.
None:
The privileged pyrimidin-4-imine scaffold is of interest in both chemical and pharmacological research. Herein, we detail the development of a chemoselective, copper-catalyzed azide-alkyne cycloaddition (CuAAC)/ring-cleavage/cyclization strategy for the synthesis of various pyrimidin-4-imine derivatives. At higher temperatures (80 °C), the copper(I)-catalyzed, three-component reaction of ynones, sulfonyl azides, and amidines selectively affords a cycloaddition/fragmentation product. In contrast, at room temperature (rt, ca. 25 °C), in water-miscible solvents, and in a remarkably chemoselective process, the formation of pyrimidin-4-imines is now favored.
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