Synthesis of a phenolic precursor and its efficient O‐[18F]fluoroethylation with purified no‐carrier‐added [18F]2‐fluoroethyl brosylate as the labeling agent

¹⁸F]2‐Fluoroethyl‐p‐toluenesulfonate also called ¹⁸F]2‐fluoroethyl tosylate has been widely used for labeling radioligands for positron emission tomography (PET). ¹⁸F]2‐Fluoroethyl‐4‐bromobenzenesulfonate, also called ¹⁸F]2‐fluoroethyl brosylate (¹⁸F]F(CH₂)₂OBs), was used as an alternative radiolabeling agent to prepare ¹⁸F]FEOHOMADAM, a fluoroethoxy derivative of HOMADAM, by O‐fluoroethylating the phenolic precursor. Purified by reverse‐phase HPLC, the no‐carrier‐added ¹⁸F]F(CH₂)₂OBs was obtained in an average radiochemical yield (RCY) of 35%. The reaction of the purified and dried ¹⁸F]F(CH₂)₂OBs with the phenolic precursor was performed by heating in DMF and successfully produced ¹⁸F]FEOHOMADAM, after HPLC purification, in RCY of 21%. Copyright © 2013 John Wiley & Sons, Ltd.