Hayes_2018_J.Labelled.Comp.Radiopharm_61_1089

O-(1-Fluoropropan-2-yl)-O-(4-nitrophenyl) methylphosphonate is a reactive organophosphate ester (OP) developed as a surrogate of the chemical warfare agent sarin that forms a similar covalent adduct at the active site serine of acetylcholinesterase. The radiolabeled O-(1-[(18) F]fluoropropan-2-yl)-O-(4-nitrophenyl) methylphosphonate ([(18) F] fluorosarin surrogate) has not been previously prepared. In this paper, we report the first radiosynthesis of this tracer from the reaction of bis-(4-nitrophenyl) methylphosphonate with 1-[(18) F]fluoro-2-propanol in the presence of DBU. The 1-[(18) F]fluoro-2-propanol was prepared by reaction of propylene sulfite with Kryptofix 2.2.2 and [(18) F] fluoride ion. The desired tracer O-(1-[(18) F]fluoropropan-2-yl)-O-(4-nitrophenyl) methylphosphonate was obtained in a >98% radiochemical purity with a 2.4% +/- 0.6% yield (n = 5, 65 minutes from start of synthesis) based on starting [(18) F] fluoride ion and a molar activity of 49.9 GBq/mumol (1.349 +/- 0.329 Ci/mumol, n = 3). This new facile radiosynthesis routinely affords sufficient quantities of [(18) F] fluorosarin surrogate in high radiochemical purity, which will further enable the tracer development as a novel radiolabeled OP acetylcholinesterase inhibitor for assessment of OP modes of action with PET imaging in vivo.