19F magnetic resonance probes for live-cell detection of peroxynitrite using an oxidative decarbonylation reaction

We report a newly discovered oxidative decarbonylation reaction of isatins that is selectively mediated by peroxynitrite (ONOO−) to provide anthranilic acid derivatives. We have harnessed this rapid and selective transformation to develop two reaction-based probes, 5-fluoroisatin and 6-fluoroisatin, for the low-background readout of ONOO− using 19F magnetic resonance spectroscopy. 5-fluoroisatin was used to non-invasively detect ONOO− formation in living lung epithelial cells stimulated with interferon-γ (IFN-γ).