One-Step Synthesis of N-Succinimidyl-4-[(18)F]Fluorobenzoate ([(18)F]SFB)

Herein, we present a one-step labeling procedure of N-succinimidyl-4-[(18)F]-fluorobenzoate ([(18)F]SFB) starting from spirocyclic iodonium ylide precursors. Precursor syntheses succeeded via a simple one-pot, two-step synthesis sequence, in yields of approximately 25%. Subsequent (18)F-nucleophilic aromatic labeling was performed, and radiochemical incorporations (RCCs) from 5–35% were observed. Purification could be carried out using HPLC and subsequent solid phase extraction. Radiochemical purity (RCP) of >95% was determined. The total synthesis time, including purification and formulation, was no longer than 60 min. In comparison to the established 3-step synthesis route of [(18)F]SFB, this one-step approach avoids formation of volatile radioactive side-products and simplifies automatization.