Synthesis of 14 (R,S)‐[¹⁸F]fluoro‐6‐thia‐heptadecanoic acid (FTHA)

No‐carrier‐added (n.c.a) 14(R,S)‐[¹⁸F]fluoro‐6‐thia‐heptadecanoic acid (FTHA) has been synthesized for evaluation as a PET tracer for myocardial long chain fatty acid utilization. The n.c.a. nucleophilic radiofluorination of benzyl 14(R,S)‐tosyloxy‐6‐thia‐heptadecanoate in acetonitrile utilized (cryptate 2.2.2/K)₂CO₃ for anion activation. The resulting [¹⁸F]fluoro‐ester was quantitatively hydrolyzed with addition of aqueous KOH and the product purified by reversed phase HPLC. The radiochemical yield of purified FTHA was 35–65% (n=5) with a synthesis time of 50 min. Radiochemical purity was >99%.