Synthesis of 3-[(2S)-azetidin-2-ylmethoxy]-5-[<sup>11</sup>C]-methylpyridine, an analogue of A-85380, via a Stille coupling
作者:Farhad Karimi、Bengt Långström
DOI:10.1002/jlcr.569
日期:2002.4
3-[(2S)-azetidin-2-ylmethoxy]-5-[11C]-methylpyridine (5d), which might be a novel ligand for nicotinic receptors, was synthesized via coupling [11C]iodomethane with tert-butyl (2S)-2-([5-(trimethylstannyl)pyridin-3-yl]oxy}methyl) azetidine-1-carboxylate (4) at 80°C for 5 min with tri-o-tolylphosphine-bound, unsaturated palladium(0), followed by deprotection using trifluoroacetic acid (TFA). The previous problem (solid-phase extraction before injection on semi-preparative LC) with automation of Stille coupling reactions has been overcome. In a typical experiment, 0.46 GBq of 5d was obtained from 5.2 GBq of [11C]iodomethane. The decay-corrected radiochemical yield was 39% (based on the quantity [11C]iodomethane trapped). The synthesis time was 43 min from end of radionuclide production. During a production condition using 36 μAh of proton beam irradiation, a specific radioactivity of 50 GBq/μmol of the final product was obtained in biological buffer. Copyright © 2002 John Wiley & Sons, Ltd.
3-[(2S)-吖丁啶-2-基甲氧基]-5-[11C]-甲基吡啶(5d),可能是一种新型的烟碱受体配体,通过[11C]碘甲烷与叔丁基(2S)-2-([5-(三甲基锡烷基)吡啶-3-基]氧}甲基)吖丁啶-1-羧酸酯(4)在80°C下5分钟内进行偶联反应,使用三邻甲苯基膦结合的、不饱和的钯(0),随后使用三氟乙酸(TFA)进行脱保护合成得到。先前的问题(在半制备LC注射前进行固相萃取)已经通过自动化Stille偶联反应得到解决。在一个典型实验中,从5.2 GBq的[11C]碘甲烷中获得了0.46 GBq的5d。衰变校正后的放射化学产率为39%(基于捕获的[11C]碘甲烷量计算)。合成时间为从放射性核素生产结束后的43分钟。在生产条件下,使用36 μAh的质子束辐照,最终产品在生物缓冲液中的比活度为50 GBq/μmol。版权所有 © 2002 John Wiley & Sons, Ltd.