Novel Pyrazolo[1,5-a]pyrimidines as Translocator Protein 18 kDa (TSPO) Ligands: Synthesis, in Vitro Biological Evaluation, [18F]-Labeling, and in Vivo Neuroinflammation

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• 作者：Annelaure Damont ; Vincent M茅dran-Navarrete ; Fanny Cacheux ; Bertrand Kuhnast ; G茅raldine Pottier ; Nicholas Bernards ; Frank Marguet ; Fr茅d茅ric Puech ; Rapha毛l Boisgard ; Fr茅d茅ric Doll茅
• 刊名：Journal of Medicinal Chemistry
• 出版年：2015
• 出版时间：September 24, 2015
• 年：2015
• 卷：58
• 期：18
• 页码：7449-7464
• 全文大小：675K
• ISSN：1520-4804

文摘

A series of novel pyrazolo[1,5-a]pyrimidines, closely related to N,N-diethyl-2-(2-(4-(2-fluoroethoxy)phenyl)-5,7-dimethylpyrazolo[1,5-a]pyrimidin-3-yl)acetamide (2, DPA-714), were synthesized and biologically in vitro evaluated for their potential to bind the translocator protein 18 kDa (TSPO), a protein today recognized as an early biomarker of neuroinflammatory processes. This series is composed of fluoroalkyl- and fluoroalkynyl- analogues, prepared from a common iodinated intermediate via Sonogashira coupling reactions. All derivatives displayed subnanomolar affinity for the TSPO (0.37 to 0.86 nM), comparable to that of 2 (0.91 nM). Two of them were radiolabeled with fluorine-18, and their biodistribution was investigated by in vitro autoradiography and positron emission tomography (PET) imaging on a rodent model of neuroinflammation. Brain uptake and local accumulation of both compounds in the AMPA-mediated lesion confirm their potential as in vivo PET-radiotracers. In particular, [¹⁸F]23 exhibited a significantly higher ipsi- to contralateral ratio at 60 min than the parent molecule [¹⁸F]2 in vivo.