Re-evaluation of 3-bromopropyl triflate as the percursor in the preparation of 3-[18F]fluoropropyl bromide

We re-evaluated 3-bromo-1-trifluoromethanesulfonyloxypropane (3-bromopropyl triflate, 1) as the precursor for the preparation of the fluorine-18 labeled compound 2 by reoptimizing fluorine-18 incorporation reaction conditions (120°C) and developing a method to inactivate the unreacted triflate precursor (water treatment). This new reaction condition enabled us to prepare 3-[18F]fluoropropyl bromide (2) in high yield. It was used for the synthesis of a N-fluoropropyl derivative such as N-(3-[18F]fluoropropyl)spiperone ([18F]FPSP, 3) with high chemical purity.