Synthesis 2024; 56(17): 2703-2708
DOI: 10.1055/s-0043-1775376
paper

Efficient Synthesis of Tetrahydropyrazolo[1,5-a]pyrimidines Based on the Recyclization of N-Arylitaconimides with Aminopyrazoles

Yuri A. Kovygin
,
Khidmet S. Shikhaliev
,
The study received financial support from the Ministry of Science and Higher Education of the Russian Federation within the framework of State Contract with universities regarding scientific research in 2022e2024, project No. FZGU-2022-0003.


Abstract

This article presents an efficient one-step synthesis of tetrahydropyrazolo[1,5-a]pyrimidines through the recyclization of N-arylitaconimides with aminopyrazoles. The heterocyclic system of pyrazolo[3,4-b]pyrimidine is known for its diverse biological properties, making its derivatives significant in pharmaceutical and medicinal chemistry. The study focuses on the regio- and chemoselective cascade reaction of N-arylitaconimides with 5-aminopyrazoles, demonstrating a new approach to synthesizing pyrazolo[1,5-a]pyrimidines and pyrazolo[3,4-b]pyridines. The methodology, involving boiling in isopropyl alcohol with acetic acid, yields selectively either pyrazolo[3,4-b]pyridines or pyrazolo[1,5-a]pyrimidines based on the substituents in the aminopyrazoles. The study elucidates the reaction mechanism, structural characterization using NMR spectroscopy, and confirms the structures via high-performance liquid chromatography and mass spectrometry. The simplicity and synthetic potential of this approach make it a valuable method for the preparation of these heterocyclic frameworks.

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Publication History

Received: 10 April 2024

Accepted after revision: 04 June 2024

Article published online:
20 June 2024

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