Semi-automated Synthesis of 1-¹⁸Ffluoroethyl-L-tryptophan

A novel ¹⁸Ffluoro amnio acid analogue 1-¹⁸Ffluoroethyl -L- tryptophan (1-¹⁸FFETrp) was designed and synthesized. The cold standard 1-¹⁹FFETrp was synthesized by sevenstep reactions, starting from tryptophan. Then fluoromultifunctional chemistry process control unit (CPCU) was used to synthesize 1-¹⁹FFETrp by nucleophilic fluorination. 1-¹⁸FFETrp was synthesized in a twostep semiautomated procedure. The no decay corrected radiochemica1 yield of 1-¹⁸FFETrp was 1.5％ within 50 min total reaction time. Further experimental work is needed to improve the radiochemical yield, with the hope of attaining a satisfacting new PET imaging agent for differentiating the tumors and inflammation.