Photoactivated 1,3-dipolar cycloaddition for the rapid preparation of 18F labelled radiotracers

An 18F-labelled 2,5-diaryl tetrazole reagent has been prepared and reacted with substituted alkene dipolarophiles through a photoactivated 1,3-dipolar cycloaddition reaction. The radiobioconjugation reaction furnished the desired product in 5 min with radiochemical conversions of 85-95% at room temperature. Remarkably, for the activated dipolarophiles, these results were obtained in highly dilute solutions (10-100 μM).