Trifluoromethoxy-benzylated ligands improve amyloid detection in the brain using 19F magnetic resonance imaging

The chemical properties of probes that improve amyloid detection by non-invasive 19F magnetic resonance imaging (MRI) are of interest. We synthesized benzoxazole compounds with trifluoromethoxy groups, and found that these compounds displayed sharp 19F nuclear magnetic resonance (NMR) signals in an assay buffer. However, the intensities of the 19F NMR signals were dramatically reduced in mouse brain lysates. Our results indicate that the inhibitory effect of brain tissue on the 19F NMR signals from these probes can be attributed to the hydrophobicity of the tissue. These results highlight the importance of using hydrophilic 19F-MRI agents to avoid the inhibitory effects of brain tissues on 19F NMR signals.