N-(3,4-Dimethylisoxazol-5-yl)piperazine-4-[4-(2-fluoro-4-[¹¹C]methylphenyl)thiazol-2-yl]-1-carboxamide: A promising positron emission tomography ligand for fatty acid amide hydrolase

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• 作者：Yoko Shimoda^a ; ^&dagger ; ; Masayuki Fujinaga^a ; ^&dagger ; ; Akiko Hatori^a ; Joji Yui^a ; Yiding Zhang^a ; Nobuki Nengaki^a ; ^b ; Yusuke Kurihara^a ; ^b ; Tomoteru Yamasaki^a ; Lin Xie^a ; Katsushi Kumata^a ; Hideki Ishii^a ; Ming-Rong Zhang^a ; ^{zhang@nirs.go.jp" class="auth_mail" title="E-mail the corresponding author}
• 关键词：PET ; Fatty acid amide hydrolase ; [11C]methyl iodide ; Irreversible specific binding
• 刊名：Bioorganic & Medicinal Chemistry
• 出版年：2016
• 出版时间：15 February 2016
• 年：2016
• 卷：24
• 期：4
• 页码：627-634
• 全文大小：1046 K

文摘

To visualize fatty acid amide hydrolase (FAAH) in brain in vivo, we developed a novel positron emission tomography (PET) ligand N-(3,4-dimethylisoxazol-5-yl)piperazine-4-[4-(2-fluoro-4-[¹¹C]methylphenyl)thiazol-2-yl]-1-carboxamide ([¹¹C]DFMC, [¹¹C]1). DFMC (1) was shown to have high binding affinity (IC₅₀: 6.1 nM) for FAAH. [¹¹C]1 was synthesized by C–¹¹C coupling reaction of arylboronic ester 2 with [¹¹C]methyl iodide in the presence of Pd catalyst. At the end of synthesis, [¹¹C]1 was obtained with a radiochemical yield of 20 ± 10% (based on [¹¹C]CO₂, decay-corrected, n = 5) and specific activity of 48–166 GBq/μmol. After the injection of [¹¹C]1 in mice, high uptake of radioactivity (>2% ID/g) was distributed in the lung, liver, kidney, and brain, organs with high FAAH expression. PET images of rat brains for [¹¹C]1 revealed high uptakes in the cerebellar nucleus (SUV = 2.4) and frontal cortex (SUV = 2.0), two known brain regions with high FAAH expression. Pretreatment with the FAAH-selective inhibitor URB597 reduced the brain uptake. Higher than 90% of the total radioactivity in the rat brain was irreversible at 30 min after the radioligand injection. The present results indicate that [¹¹C]1 is a promising PET ligand for imaging of FAAH in living brain.