Facile synthesis and sulfonylation of 4-aminopyrazoles

This paper describes the synthesis of alkyl- and naphthyl-substituted 4-aminopyrazoles by mild reduction of nitrosopyrazoles. Several amines are available in nearly quantitative yield. Sulfonamide derivatives were obtained based on 4-aminopyrazoles. The structure of 15 synthesized previously unknown compounds was proved by NMR, IR spectroscopy, elemental analysis, and mass spectrometry. Quantum-chemical calculations made it possible to establish the spatial structure of their most stable conformers. (C) 2021 Elsevier B.V. All rights reserved.

Automated summary

This study describes the synthesis of alkyl- and naphthyl-substituted 4-aminopyrazoles by mild reduction of nitrosopyrazoles with high yields. Sulfonamide derivatives were obtained based on these 4-aminopyrazoles, and the structures of 15 synthesized previously unknown compounds were confirmed. Quantum-chemical calculations were used to determine the spatial structure of their most stable conformers.