Synthesis and preliminaryin vivo evaluation of 4-[18F]fluoro-N-{2-[4-(6-trifluoromethylpyridin-2-yl)piperazin-1-yl]ethyl}benzamide, a potential PET radioligand for the 5-HT1A receptor
作者:M. Vandecapelle、F. Dumont、F. De Vos、K. Strijckmans、D. Leysen、K. Audenaert、R. A. Dierckx、G. Slegers
DOI:10.1002/jlcr.837
日期:2004.8
4-Fluoro-N-2-[4-(6-trifluoromethylpyridin-2-yl)piperazin-1-yl]ethyl}benzamide is a full 5-HT1A agonist with high affinity (pKi=9.3), selectivity and a c log P of 3.045. The corresponding PET radioligand 4-[18F]fluoro-N-2-[4-(6-trifluoromethylpyridin-2-yl)piperazin-1-yl]ethyl}benzamide was synthesized by nucleophilic aromatic substitution on the nitro precursor. The fluorinating agent K[18F]F/Kryptofix 2.2.2 was both dried (9 min, 700 W) and incorporated in the precursor (5 min, 700 W) using a commercially available microwave oven. In a total synthesis time of 60 min, an overall radiochemical yield of 18% (SD=5, n=7, EOS) was obtained. Radiochemical purity was always higher than 99% and specific activity always higher than 81.4 GBq/µmol (2.2 Ci/µmol). Initial brain uptake in mice was 2.19% ID (5.47% ID/g, 2 min) but decreased rapidly (0.17% ID, 0.45% ID/g (60 min)). During the first 20 min p.i., radioactivity concentration of the brain was significantly higher than that of blood demonstrating good brain entry of the tracer. Copyright © 2004 John Wiley & Sons, Ltd.
4-氟-N-2-[4-(6-三氟甲基吡啶-2-基)哌嗪-1-基]乙基}苯甲酰胺是一种完全5-HT1A激动剂,具有高亲和性(pKi=9.3)、选择性和c log P为3.045。相应的PET放射性配体4-[18F]氟-N-2-[4-(6-三氟甲基吡啶-2-基)哌嗪-1-基]乙基}苯甲酰胺是通过在硝基前体上进行亲核芳香族取代合成的。使用市售的微波炉,将氟化剂K[18F]F/Kryptofix 2.2.2干燥(9分钟,700 W)并掺入前体(5分钟,700 W)。在总共60分钟的合成时间内,获得了18%的总体放射化学收率(SD=5,n=7,EOS)。放射化学纯度始终高于99%,比活度始终高于81.4 GBq/µmol(2.2 Ci/µmol)。小鼠的初始脑摄取率为2.19% ID(5.47% ID/g,2分钟),但迅速下降(0.17% ID,0.