Synthesis and characterization of 4,6-dichloroindole-based radioligands for imaging the glycine site of the NMDA ion channel
作者:R. N. Waterhouse、A. Sultana、N. Guo、Bora Lee、N. Simpson、Lee Collier、M. Laruelle
DOI:10.1002/jlcr.528
日期:2002.2
To provide effective PET or SPECT ligands for the glycine binding site of the NMDA ion channel, we have synthesized and characterized in vitro four substituted derivatives of the potent glycine site antagonist 3-[2-[(phenylamino)carbonyl]ethenyl]-4,6-dichloroindole-2-carboxylic acid (Ki=3.0 nM). These new ligands contain groups amenable to labeling with C-11 for PET, or I-123 for SPECT. In vitro analysis of these compounds revealed that placement of a methoxy group at either the ortho or para position of the phenylaminocarbonyl group significantly reduced receptor affinity (Ki=74.0±8.1 and 26.5±4.9 nM, respectively), as did placement of an iodine at the para position (Ki=60.4±8.2 nM). However, the meta-methoxy derivative (4b) maintained high affinity (Ki=4.8±0.9 nM) for the glycine site and was therefore labeled with carbon-11 by reacting the corresponding desmethyl derivative with [11C]methyl iodide. Radiochemical yields of 14±10% (EOS), and high specific activity (1.2±0.5 Ci/μmol (EOS, n=7)) were realized, and the product was prepared in a sterile saline solution suitable for in vivo use. Copyright © 2002 John Wiley & Sons, Ltd.
为了提供有效的正电子发射断层扫描(PET)或单光子发射计算机断层扫描(SPECT)配体,针对NMDA离子通道的甘氨酸结合位点,我们合成并在体外表征了四种强效甘氨酸位点拮抗剂3-[2-[(苯胺基)羧酰乙烯基]-4,6-二氯吲哚-2-羧酸的取代衍生物(Ki=3.0 nM)。这些新配体包含可用于用C-11进行PET标记或I-123进行SPECT标记的基团。对这些化合物的体外分析显示,在苯胺羧酰基的邻位或对位放置甲氧基会显著降低受体亲和力(Ki分别为74.0±8.1 nM和26.5±4.9 nM),在对位放置碘亦会导致亲和力下降(Ki=60.4±8.2 nM)。然而,邻位甲氧基衍生物(4b)对甘氨酸位点保持了高亲和力(Ki=4.8±0.9 nM),因此通过将相应的脱甲基衍生物与[11C]碘甲烷反应进行C-11标记。最终获得的放射化学产率为14±10%(EOS),且高特异活性为1.2±0.5 Ci/μmol(EOS,n=7),所制备的产物使用适合体内使用的无菌生理盐水溶液。版权 © 2002 John Wiley & Sons, Ltd.