Azoalkene chemistry provides practical access to 5-aminopyrazoles selectively protected at the N-1 position

Azoalkene chemistry provides practical access to 5-aminopyrazoles selectively protected at the N-1 position Full article

Journal

Tetrahedron Letters
ISSN: 0040-4039 , E-ISSN: 1873-3581

Output data

Year: 2026, Volume: 178, Article number : 155987, Pages count : DOI: 10.1016/j.tetlet.2026.155987

Authors

Kokuev Aleksandr O. ¹ , Sukhorukov Alexey Yu. ¹

Affiliations

1	Laboratory of Organic and Metal−Organic Nitrogen−Oxygen Systems (LOMONOS), N. D. Zelinsky Institute of Organic Chemistry, Russian Academy of Sciences, Leninsky prosp. 47, Moscow 119991, Russian Federation

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 α-cyanohydrazones. The process utilizes readily available α-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.

Kokuev A.O. , Sukhorukov A.Y.
Azoalkene chemistry provides practical access to 5-aminopyrazoles selectively protected at the N-1 position
Tetrahedron Letters. 2026. V.178. 155987 . DOI: 10.1016/j.tetlet.2026.155987 WOS Scopus OpenAlex

Submitted:	Dec 5, 2025
Published online:	Feb 6, 2026

Web of science:	WOS:001686950400001
Scopus:	2-s2.0-105029418407
OpenAlex:	W7126379577

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