Enantiomeric radiochemical synthesis of R and S (1-(6-amino-9H-purin-9-yl)-3-fluoropropan-2-yloxy)methylphosphonic acid (FPMPA)
作者:Dale O. Kiesewetter、Kathleen Knudson、Matt Collins、Sharat Srinivasula、Esther Lim、Michele Di Mascio
DOI:10.1002/jlcr.1505
日期:2008.3.30
Therapy for human immunodeficiency virus (HIV)-infected patients requires chronic multidrug administration. The eventual failure of therapy in some patients has brought into question the tissue concentration of the drugs. With an appropriately radiolabeled compound, we could utilize positron emission tomography to provide quantitative time–activity curves for various tissues. We have developed a fluorine-18 labeled analog of Tenofovir, the active metabolite of Tenofovir DF, a commonly prescribed component of multidrug therapy. Because (1-(6-amino-9H-purin-9-yl)-3-fluoropropan-2-yloxy)methylphosphonic acid (FPMPA) has a chiral center, we prepared both enantiomers and confirmed that the S-isomer exhibited significantly higher antiviral activity than the R-isomer. In viral replication inhibition assays in human MT4 cells infected with SHIVDH12R, S-FPMPA had an IC50 of 1.85 µM (95% CI; 0.8–5.53), while the R-isomer was inactive. An appropriate chiral precursor was prepared to allow the incorporation of fluorine-18. The [18F]FPMPA in racemic, R, or S form was prepared in a 50 min synthesis in 38±5% yield (n=23, corrected for decay). The product was of high radiochemical and enantiomeric purity. The specific activity of the final product was 4.0±1.8 Ci/µmol at EOB (end of bombardment). This product may provide information about drug tissue distribution in animal models under chronic drug treatment. Copyright © 2008 John Wiley & Sons, Ltd.
针对感染人类免疫缺陷病毒(HIV)患者的治疗需要长期多药物联合管理。一些患者治疗最终失败的问题引发了人们对药物在组织中的浓度的质疑。通过合适的放射性标记化合物,我们可以利用正电子发射断层扫描(PET)为各种组织提供定量的时间—活动曲线。我们开发了一种氟-18标记的替诺福韦类似物,该类是替诺福韦DF的活性代谢物,替诺福韦DF是一种常用的多药物治疗成分。由于(1-(6-氨基-9H-嘌呤-9-基)-3-氟丙基-2-氧甲基)磷酸(FPMPA)具有手性中心,我们制备了两种对映异构体,并确认S-异构体的抗病毒活性显著高于R-异构体。在用SHIVDH12R感染的人MT4细胞的病毒复制抑制实验中,S-FPMPA的IC50为1.85 µM(95% CI;0.8–5.53),而R-异构体则无活性。我们制备了合适的手性前体,以便于氟-18的引入。[18F]FPMPA的外消旋体、R或S形式在38±5%的产率下进行了50分钟的合成(n=23,考虑衰变后修正)。该产品具有高放化学纯度和对映体纯度。最终产品的特定活性在轰击结束时为4.0±1.8 Ci/µmol。该产品可能为动物模型中的药物组织分布提供信息,尤其是在慢性药物治疗下。版权 © 2008 John Wiley & Sons, Ltd.