Fluorination of aromatic compounds from 1-aryl-3,3-dimethyltriazenes and fluoride anions in acidic medium: 2. Synthesis of (S)-[18F]-3-fluoro-α-methylphenylalanine

We propose here a new methodology to prepare 3-fluoro-α-methylphenylalanine in which fluorine is introduced at the end of the synthesis, on an elaborated substrate bearing a triazeno substituent which is decomposed by triflic acid in the presence of fluoride anions (yield=31% versus 19F−). As 18F− cannot be available free of other basic anions, this technique has been modified and adapted with some success to the radiosynthesis of [18F]-3-fluoro-α-methylphenylalanine.