The synthesis of [11C]L-deprenyl-D2 for imaging of astrocytosis with positron emission tomography (PET) in neurodegenerative diseases has been previously reported. [11C]L-deprenyl-D2 radiosynthesis requires a precursor, L-nordeprenyl-D2, which has been previously synthesized from L-amphetamine as starting material with low overall yields. Here, we present an efficient synthesis of L-nordeprenyl-D2 organic precursor as free base and automated radiosynthesis of [11C]L-deprenyl-D2 for PET imaging of astrocytosis. The L-nordeprenyl-D2 precursor was synthesized from the easily commercial available and cheap reagent L-phenylalanine in five steps. Next, N-alkylation of L-nordeprenyl-D2 free base with [11C]MeOTf was optimized using the automated commercial platform GE TRACERlab® FX C Pro. A simple and efficient synthesis of L-nordeprenyl-D2 precursor of [11C]L-deprenyl-D2 as free base has been developed in five synthetic steps with an overall yield of 33%. The precursor as free base has been stable for 9 months stored at low temperature (−20 °C). The labelled product was obtained with 44 ± 13% (n = 12) (end of synthesis, decay corrected) radiochemical yield from [11C]MeI after 35 min synthesis time. The radiochemical purity was over 99% in all cases and specific activity was (170 ± 116) GBq/μmol. A high-yield synthesis of [11C]L-deprenyl-D2 has been achieved with high purity and specific activity. L-nordeprenyl-D2 precursor as free amine was applicable for automated production in a commercial synthesis module for preclinical and clinical application.

中文翻译：

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[11C]L-deprenyl-D2 标记前体的有效制备和自动放射合成。

[11C]L-deprenyl-D2 的合成用于在神经退行性疾病中使用正电子发射断层扫描 (PET) 对星形细胞增多症进行成像已有报道。[11C]L-deprenyl-D2 放射合成需要前体 L-nordeprenyl-D2，它以前是从 L-苯丙胺作为起始材料合成的，总收率低。在这里，我们提出了 L-去甲肾上腺素-D2 有机前体作为游离碱的有效合成和 [11C]L-去甲肾上腺素-D2 的自动放射合成，用于星形细胞增多症的 PET 成像。L-去甲肾上腺素-D2 前体是由易于商购且便宜的试剂 L-苯丙氨酸分五步合成的。接下来，使用自动化商业平台 GE TRACERlab® FX C Pro 优化 L-去甲肾上腺素-D2 游离碱与 [11C]MeOTf 的 N-烷基化。通过五个合成步骤开发了一种简单有效的 [11C]L-去甲肾上腺素-D2 前体作为游离碱的 L-去甲肾上腺素-D2 前体合成方法，总收率为 33%。作为游离碱的前体在低温 (-20 °C) 下可稳定储存 9 个月。合成时间 35 分钟后，从 [11C]MeI 获得的标记产物为 44 ± 13% (n = 12)（合成结束，衰变校正）放射化学产率。放射化学纯度均在99%以上，比活度为（170±116）GBq/μmol。[11C]L-deprenyl-D2 的高产率合成具有高纯度和比活性。作为游离胺的 L-去甲肾上腺素-D2 前体可用于商业合成模块中的自动化生产，用于临床前和临床应用。