Production of 6-<span style="font-variant: small-caps">l</span>-[¹⁸F]Fluoro-<i>m</i>-tyrosine in an Automated Synthesis Module for ¹¹C-Labeling

• Main Authors: Viktoriya V. Orlovskaya, Austin S. Craig, Olga S. Fedorova, Olga F. Kuznetsova, Bernd Neumaier, Raisa N. Krasikova, Boris D. Zlatopolskiy
• Format: Article
• Language: English
• Published: MDPI AG 2021-09-01
• Series: Molecules
• Subjects: fluorine-18; radiofluorination; Cu-mediated; alcohol-enhanced; 6-<span style="font-variant: small-caps">l</span>-[¹⁸F]fluoro-<i>m</i>-tyrosine; automated synthesis
• Online Access: https://www.mdpi.com/1420-3049/26/18/5550

6-<span style="font-variant: small-caps;">l</span>-[¹⁸F]Fluoro-<i>m</i>-tyrosine (6-<span style="font-variant: small-caps;">l</span>-[¹⁸F]FMT) represents a valuable alternative to 6-<span style="font-variant: small-caps;">l</span>-[¹⁸F]FDOPA which is conventionally used for the diagnosis and staging of Parkinson’s disease. However, clinical applications of 6-<span style="font-variant: small-caps;">l</span>-[¹⁸F]FMT have been limited by the paucity of practical production methods for its automated production. Herein we describe the practical preparation of 6-<span style="font-variant: small-caps;">l</span>-[¹⁸F]FMT using alcohol-enhanced Cu-mediated radiofluorination of Bpin-substituted chiral Ni(II) complex in the presence of non-basic Bu₄ONTf using a volatile <i>i</i>PrOH/MeCN mixture as reaction solvent. A simple and fast radiolabeling procedure afforded the tracer in 20.0 ± 3.0% activity yield within 70 min. The developed method was directly implemented onto a modified TracerLab FX C Pro platform originally designed for ¹¹C-labeling. This method enables an uncomplicated switch between ¹¹C- and ¹⁸F-labeling. The simplicity of the developed procedure enables its easy adaptation to other commercially available remote-controlled synthesis units and paves the way for a widespread application of 6-<span style="font-variant: small-caps;">l</span>-[¹⁸F]FMT in the clinic.