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Updated: May 22, 2026

Microwave-Assisted Preparation of 1-Aryl-1H-pyrazole-5-amines
Published on: June 23, 2019
Hydrazine-mediated cyclization of Ugi products to synthesize novel 3-hydroxypyrazoles
Arthur Y Shaw1, Jonathan A McLaren, Gary S Nichol
1Department of Pharmacology and Toxicology, College of Pharmacy, BIO5 Oro Valley, The University of Arizona, 1580 E. Hanley Blvd., Oro Valley, AZ 85737, USA.
Abstract:
This report discloses a novel concise synthesis of a series of 3-hydroxypyrazoles 5 via a tandem Ugi/debenzylation /hydrazine-mediated cyclization sequence. Herein, n-butyl isocyanide 4b was utilized as an alternative to classical convertible isocyanides enabling high yielding hydrazine-mediated cyclization. Taken together, a novel class of 3-hydroxypyrazoles 5a-5i was synthesized with potential to be of interest in future library enrichment strategies.
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