Synthesis of f‐18 labelled fluoro‐melatonins and 5‐hydroxy‐fluoro‐tryptophans

Abstract Reaction of dilute [F‐18]fluorine gas with either melatonin or 5‐hydroxy‐tryptophan in hydrogen fluoride at −70°C gives 6‐fluoro‐melatonin or 4‐ and 6‐fluoro‐5‐hydroxytryptophan. They are of potential use in Positron Emission Tomography to image the binding sites for melatonin and to study the metabolism of serotonin.