Synthesis of 18F labelled fluoro-m-tyrosine, fluoro-m-tyramine and fluoro-3-hydroxyphenylacetic acid

Direct fluorination of m-tyrosine, m-tyramine and 3-hydroxyphenyl acetic acid with [18F]F2 in anhydrous hydrogen fluoride produced in each case a mixture of 2- and 6-fluoro derivatives as the major products. The radiochemical yields with respect to [18F]F2 of each reaction was 43, 30 and 37%, respectively. The radiofluorination of m-tyrosine in HF was more efficient than in CH3CN/BF3, TFA or HF/BF3. From 100 mCi of [18F]F2, 16 mCi of a mixture of 2- and 6-fluoro-L-m-tyrosine (specific activity 200 mCi/mmol) was produced at the end of 150 min of synthesis time.