A new precursor for the preparation of 6-[18F]Fluoro-L -m-tyrosine ([18F]FMT): efficient synthesis and comparison of radiolabeling

For the electrophilic preparation of 6-[18F]fluoro- -m-tyrosine ([18F]FMT), a PET tracer for measuring changes in dopaminergic function in movement disorders, a novel precursor, N-(tert-butoxycarbonyl)-3-(tert-butoxycarbonyloxy)-6-trimethylstannnyl- -phenylalanine ethyl ester, was synthesized in four steps and 26% yield starting from -m-tyrosine. [18F]FMT produced by two methods at two institutions was comparable in both radiochemical yield, 25–26%, and quality (chemical, enantiomeric, and radiochemical purity and specific activity) as that obtained with the original N-trifluoroacetyl-3-acetyl-6-trimethylstannyl- -m-tyrosine ethyl ester [18F]FMT precursor.