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Azoalkene chemistry provides practical access to 5-aminopyrazoles selectively protected at the N-1 position
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DOI：10.1016/j.tetlet.2026.155987.png)
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Abstract
En 中文
5-Aminopyrazoles are extensively used as building blocks in medicinal chemistry. However, selective protection of endo- and exocyclic nitrogen atoms is challenging. Here, we describe a convenient protocol for the synthesis of 1-Boc-protected 5-aminopyrazoles through Michael addition of cyanide to azoalkenes followed by spontaneous cyclization of the resulting alpha-cyanohydrazones. The process utilizes readily available alpha-halohydrazones, acetone cyanohydrin as a safer substitute for cyanide, and aqueous DMSO as the reaction medium. The method enables further synthetic diversification of the resulting 1-Boc-5-aminopyrazoles through reactions with electrophilic agents.
Keywords:
Aminopyrazoles
Azoalkenes
Halohydrazones
Acetone cyanohydrin
Cyanide addition
Journal
T
IF:
1.5
Papers:
148
Citations:
4.2W
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Cited Papers