Synthesis and11C-labelling of (E,E)-1-(3?,4?-dihydroxystyryl)-4-(3?-methoxy-4?-hydroxystyryl) benzene for PET imaging of amyloid deposits?
作者:Yanming Wang、Chester A. Mathis、Guo-feng Huang、Daniel P. Holt、Manik L. Debnath、William E. Klunk
DOI:10.1002/jlcr.585
日期:2002.7
Carboxylic acid derivatives of the amyloid-binding dye Congo red do not enter the brain well and are thus unable to serve as in vivo amyloid-imaging agents. A neutral amyloid probe, (E,E)-1-(3′,4′-dihydroxystyryl)-4-(3′-methoxy-4′-hydroxystyryl)benzene (3), devoid of any carboxylate groups has been designed and synthesized via a 12-step reaction sequence with a total yield of 30%. The unsymmetric compound 3 has also been labelled with C-11 via [11C]methyl iodide ([11C]CH3I) methylation of a symmetric 4,4′-dimesyl protected precursor followed by deprotection. Preliminary evaluation indicated that compound 3 selectively stained plaques and neurofibrillary tangles in post-mortem AD brain, and exhibited good binding affinity (Ki=38±8 nM) for Aβ(1–40) fibrils in vitro. In vivo pharmacokinetic studies indicated that [11C]3 exhibited higher brain uptake than its carboxylic acid analogs and good clearance from normal control mouse brain. [11C]3 also exhibited specific in vivo binding to pancreatic amyloid deposits in the NOR-beta transgenic mouse model. These results justify further investigation of 3 and similar derivatives as surrogate markers for in vivo quantitation of amyloid deposits. Copyright © 2002 John Wiley & Sons, Ltd.
淀粉样蛋白结合染料刚果红的羧酸衍生物不能很好地进入大脑,因此不能作为体内淀粉样蛋白成像剂。我们设计出了一种中性淀粉样蛋白探针--(E,E)-1-(3′,4′-二羟基苯乙烯基)-4-(3′-甲氧基-4′-羟基苯乙烯基)苯(3),这种探针不含任何羧酸基,通过 12 步反应顺序合成,总产率为 30%。通过对对称的 4,4′-二甲酰基保护前体进行[11C]甲基碘([11C]CH3I)甲基化,然后进行脱保护,非对称化合物 3 也被标记为 C-11。初步评估表明,化合物 3 可选择性地染色死后 AD 大脑中的斑块和神经纤维缠结,并在体外对 Aβ(1-40)纤维表现出良好的结合亲和力(Ki=38±8 nM)。体内药代动力学研究表明,[11C]3 比其羧酸类似物具有更高的脑摄取率,并能很好地从正常对照小鼠脑中清除。在 NOR-beta 转基因小鼠模型中,[11C]3 也表现出与胰腺淀粉样蛋白沉积物的特异性体内结合。这些结果证明有理由进一步研究 3 和类似衍生物作为体内淀粉样蛋白沉积定量的替代标记物。Copyright © 2002 John Wiley & Sons, Ltd. All Rights Reserved.