Attempted Synthesis and Unexpected β-Fragmentation of a Hindered β-Keto Nitroxide
Chris Edwards A , Peter C. Healy A , W. Ken Busfield A , Ezio Rizzardo B , San H. Thang B and Ian D. Jenkins C DA School of Natural Sciences, Griffith University, Brisbane, Qld 4111, Australia.
B CSIRO Materials Science and Engineering, Bayview Avenue, Clayton, Vic. 3168, Australia.
C Griffith Institute for Drug Discovery, Griffith University, Brisbane, Qld 4111, Australia.
D Corresponding author. Email: i.jenkins@griffith.edu.au
Australian Journal of Chemistry 70(10) 1106-1109 https://doi.org/10.1071/CH17203
Submitted: 11 April 2017 Accepted: 11 May 2017 Published: 31 May 2017
Abstract
The attempted synthesis of a β-keto imidazolidinone nitroxide by oxidation of the β-hydroxy imidazolidinone precursor with hydrogen peroxide and sodium tungstate led to an unexpected ring-opening reaction to produce 1,4-diazaspiro[4.5]dec-1-en-3-oxo-2-pentanoic acid 1-oxide (13) in high yield. The structure of 13 was confirmed by X-ray crystallographic analysis. A β-fragmentation mechanism is suggested for the oxidative ring-opening reaction.
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