PREPARATION OF CARRIER-FREE ~(18)F-FLUORIDE USING A SERIES OF LITHIUM CROWN COMPLEXES AS A TARGET FOR RAPID LABELLING OF HALOGENATED HYDROCARBONS

A new method is described for the preparation of reactor-produced carrier-free 18F using Li2CO3 complexed with benzo-12-crown-4, 15-crown-5, 18-crown-6, dibenzo-24-crown-8 as a target for subsequent synthesis of labelled organic compounds. The relative yields of these targets are approximately 38% for benzo-12-crown-4, 53% for 15-crown-5, 55% for 18-crown-6 and 37% for dibenzo-24-crown-8 compared with the pure Li2CO3 target for the same quantity of lithium. After irradiation, this target was used as a solvent for synthesis of halogenated compounds. The labelling yields of CH2 18F (CH2)14CH3 typically reach 80±5% within 40 min at 60℃. The combination of preparation and labelling in one step makes this method very attractive for labelling of halogenated hydrocarbons with carrier-free 18F.