Temperature effects on the stereospecificity of nucleophilic fluorination: formation of trans-[18F]4-fluoro-l-proline during the synthesis of cis-[18F]4-fluoro-l-proline
作者:Babak Behnam Azad、Rezwan Ashique、N. Renée Labiris、Raman Chirakal
DOI:10.1002/jlcr.1947
日期:2012.1
110°C) to produce diastereomerically pure cis-[18F]4-FPro in 38% radiochemical yield at the end of a 90-min synthesis. Investigation of the effect of temperature on the stereospecificity of nucleophilic fluorination showed that diasteriomerically pure cis-[18F]4-FPro or trans-[18F]4-FPro was produced at lower temperatures (85°C–110°C) during the fluorination of (2S,4R) or (2S,4S) precursors, respectively
据报道,氟 18 标记的 (2S,4S)-4-氟-l-脯氨酸 (cis-[18F]4-FPro) 是一种潜在的正电子发射断层扫描示踪剂,可用于研究肺纤维化、骨肉瘤、乳腺癌和结肠癌。在本文中,我们报告了 (2S,4R)-N-叔丁氧基羰基-4-(对甲苯磺酰氧基)脯氨酸甲酯(在 110°C 下)的立体定向放射性氟化,以生产非对映异构纯的顺式-[18F]4-FPro在 90 分钟合成结束时,放射化学产率为 38%。温度对亲核氟化立体专一性影响的研究表明,在氟化过程中,在较低温度(85°C–110°C)下产生了非对映异构纯的顺式-[18F]4-FPro 或反式-[18F]4-FPro (2S,4R) 或 (2S,4S) 前体的分别。然而,在较高温度(130°C–145°C)下,(2S,4R) 前体的氟化产生顺式-[18F]4-FPro 和反式-[18F]4-FPro 非对映异构体的混合物,其中顺式-[18F]4-FPro