Synthesis and biological evaluation of a lipophilic, fluorine-18-labeled 5-ethynyl-2′-deoxyuridine derivative
作者:Satish K. Chitneni、Tom De Ruymaeker、Jan Balzarini、Alfons M. Verbruggen、Guy M. Bormans
DOI:10.1002/jlcr.1312
日期:2007.6
The synthesis and preliminary biological evaluation of a lipophilic, fluorine-18-labeled 5-ethynyl-2′-deoxyuridine derivative [18F]-3 is described. Initially, 5-ethynyl-2′-deoxyuridine 5 was synthesized by coupling trimethylsilyl protected acetylene to 5-iodo-2′-deoxyuridine 4, followed by deprotection in alkaline conditions. Compound 5 was then reacted with 4-(4′-iodophenyl)phenol to give 5-[4(4′-hydroxyphenyl)phenyl]ethynyl-2′-deoxyuridine 6. Compound 6 was reacted with BrCH2CHF as alkylating agent to give stable or radiolabeled 3. The crude products were purified using reversed phase-high performance liquid chromatography to obtain compound 3 and [18F]-3 in 33 and 7.4% yield (decay corrected), respectively. The synthesis time to obtain pure [18F]-3 was about 60 min (starting from BrCH2CHF). The specific radioactivity of the tracer was between 74 and 222 GBq/µmol. The log P7.4 of [18F]-3 was found to be 2.4. However, biodistribution study in normal mice showed low uptake of the tracer in the brain. The affinity of compounds 6 and 3 for varicella-zoster virus thymidine kinase enzyme (VZV-TK) was examined in vitro and the results revealed that the fluorinated analog 3 has a poor affinity for the enzyme in contrast to the phenol precursor 6. Copyright © 2007 John Wiley & Sons, Ltd.
本文描述了一种亲脂性氟-18 标记的 5-乙炔基-2′-脱氧尿苷衍生物 [18F]-3 的合成和初步生物学评价。5- 乙炔基-2′-脱氧尿苷 5 最初是通过将三甲基硅烷保护的乙炔与 5- 碘-2′-脱氧尿苷 4 偶联,然后在碱性条件下脱保护而合成的。然后化合物 5 与 4-(4′-碘苯基)苯酚反应,得到 5-[4(4′-羟基苯基)苯基]乙炔基-2′-脱氧尿苷 6。化合物 6 与作为烷化剂的 BrCH2CHF 反应,得到稳定的或放射性标记的 3。使用反相高效液相色谱法纯化粗产物,得到化合物 3 和 [18F]-3,收率分别为 33% 和 7.4%(衰减校正)。获得纯[18F]-3 的合成时间约为 60 分钟(从 BrCH2CHF 开始)。示踪剂的比放射性介于 74 和 222 GBq/µmol 之间。研究发现,[18F]-3 的对数 P7.4 为 2.4。然而,在正常小鼠体内进行的生物分布研究表明,示踪剂在大脑中的吸收率较低。体外研究了化合物 6 和 3 对水痘-带状疱疹病毒胸苷激酶(VZV-TK)的亲和力,结果表明,与苯酚前体 6 相比,氟化类似物 3 对该酶的亲和力较差。Copyright © 2007 John Wiley & Sons, Ltd. All Rights Reserved.