Syntheses of [18F]5-fluoro-3-nitro-L-tyrosine

The detection of 3-nitro-L-tyrosine has been used as a biomarker of "reactive nitrogen species" in biological matrices and has been an ongoing challenge in analytical chemistry. In this work, fluorine-18 labelled 5-fluoro-3-nitro-L-tyrosine (FNT) was synthesized as a potential radiotracer to probe the biological fate of 3-nitro-L-tyrosine. The synthesis of [F-18]FNT was carried out by reaction of [F-18]3-fluoro-L-tyrosine with NaNO3 in TFA solvent for 5 min at 4 degreesC. The radiochemical yield (RCY) of [18F]FNT was 96 +/- 2% and [F-18]3-fluoro-L-tyrosine, was 29 +/- 1%, relative to [F-18]3-fluoro-L-tyrosine and [F-18]F-2, respectively. The syntheses of [F-18]FNT were also accomplished by direct fluorination of 3-nitro-L-tyrosine with [F-18]F-2 and by nitration Of L-tyrosine with NaNO3, followed by fluorination, in TFA (4 degreesC) or anhydrous HF (-65 degreesC) solvent. The latter two synthetic routes produced [F-18]FNT in 13.5 +/- 1.5% RCY, within I h. Products were characterized by use of H-1, C-13 and F-19 NMR spectroscopy and mass spectrometry. (C) 2002 Published by Elsevier Science B.V.