Efficient synthesis of the 18F-labelled 3-O-methyl-6-[18F]fluoro-L-DOPA.

The 18F-labelled amino acid derivative 3-O-methyl-6-[18F]fluoro-L-DOPA ([18F]OMFD) is a potential radiotracer for imaging tumour tissue using positron emission tomography. The precursor N-formyl-3-O-methyl-4-O-boc-6-trimethyl-stannyl-L-DOPA-ethyl ester enables direct electrophilic radiofluorination by stereoselective destannylation. After partial hydrolysis, optimized HPLC purification and sterile filtration, the [18F]OMFD obtained with high radiochemical purity and ready for use. The total synthesis time is about 50 min and the radiochemical yield achieved is 20-25% (decay corrected, related to [18F]F(2)). It was demonstrated that [18F]OMFD could be produced routinely and reliably for clinical use. [18F]FDOPA-preparation devices can be used with minor modifications.