Related Experiment Video
Updated: Aug 30, 2026

Synthesis of pH Dependent Pyrazole, Imidazole, and Isoindolone Dipyrrinone Fluorophores using a Claisen-Schmidt Condensation Approach
Published on: June 10, 2021
Spiro-fused (C2)-azirino-(C4)-pyrazolones, a new heterocyclic system. Synthesis, spectroscopic studies and X-ray
Wolfgang Holzer1, Rosa M Claramunt, Marta Pérez-Torralba
1Department of Pharmaceutical Chemistry, University of Vienna, Althanstrasse 14, A-1090 Vienna, Austria. holzer@merian.pch.univie.ac.at
Abstract:
Reaction of 1-substituted 4-acyl-5-hydroxy-3-methyl-1H-pyrazoles (2) with hydroxylamine gives the corresponding "oximes" 3, which are mainly present as (Z)-2,4-dihydro-4-[(hydroxyamino)methylene]-3H-pyrazol-3-ones. Treatment of compounds 3 with trichloroacetyl isocyanate/potassium carbonate in anhydrous diethyl ether affords 7-methyl-1,5,6-triazaspiro[2.4]hepta-1,6-dien-4-ones (4). The structure of compounds 4 was elucidated by means of single-crystal X-ray analysis (4f, 4h) and confirmed by NMR spectroscopic investigations ((1)H, (13)C).
Related Concept Videos
Five-Membered Heterocyclic Aromatic Compounds: Overview
Frost Circles for Different Conjugated Systems
Stereoisomerism of Cyclic Compounds
Aromatic Hydrocarbon Anions: Structural Overview
Due to the absence of continuous overlap of p...
Aryldiazonium Salts to Azo Dyes: Diazo Coupling
Hybridization of Atomic Orbitals I
![Solid-phase Synthesis of [4.4] Spirocyclic Oximes](/_next/image?url=https%3A%2F%2Fcloudfront.jove.com%2FCDNSource%2Fteasers%2F58508.jpg&w=3840&q=50)
