Synthesis of two optically active calcium channel antagonists labelled with carbon-11 for in vivo cardiac PET imaging
作者:Frédéric Dollé、Françoise Hinnen、Héric Valette、Chantal Fuseau、Raphaël Duval、Jean-Louis Péglion、Christian Crouzel
DOI:10.1016/s0968-0896(97)00024-2
日期:1997.4
(+/-)-S11568 (1, 3-ethyl-5-methyl-(+/-)-2-[(2-(2-aminoethoxy)methyl]-4-(2,3-dichlorophenyl)-6-methyl-1, 4-dihydropyridine -3,5-dicarboxylate), has an in vitro profile of high potency and of high selectivity for the low-voltage dependent L-type calcium channel. In in vitro binding studies, it displaced specifically bound (-)-[H-3]PN 200-110 (isradipine (2), the reference molecule for in vitro studies) from cardiac and vascular smooth muscle preparations with potencies of 5.6 and 51 nM, respectively. It also appears as a pure pharmacological antagonist acting at a single channel L-type and free of any interaction at the benzothiazepine binding site such as amlodipine (3). Both enantiomers of S11568 have in vitro activities, the dextro isomer S12967 ((+)-1) being 6 to 18-fold less potent than the levo one S12968 ((-)-1). Two couples of optically active labelling precursors of S11568, ((-)-10/(+)-10 and (-)-14/(+)-14) have been synthesized using a modified Hantzsch's dihydropyridine synthesis. In both cases, the enantiomers were separated by preparative chiral HPLC. They both have been independently labelled with carbon-ii, using [C-11]diazomethane or [C-11]iodomethane to give multimilliCurie quantities of (-)-1 (S12968) and (+)-1 (S12967) with high specific activities (500-1000 mCi/mu mol, 18.5-37.0 GBq/mu mol). Both enantiomers appear suitable for PET experiments: their myocardial concentration increases after a bolus injection to reach a maximum in 2 min and then remains on a plateau with a slight downslope while the blood concentration falls rapidly. Myocardial uptake was threefold higher than lung uptake, leading to a good contrast on PET images. The present preliminary biological results obtained in Beagle dogs showed that both enantiomers have similar myocardial kinetics and in vivo affinity for the left ventricular myocardium. (C) 1997 Elsevier Science Ltd.
化合物(+/-)-S11568(1,3-乙基-5-甲基-(+/-)-2-[(2-(2-氨基乙氧基)甲基]-4-(2,3-二氯苯基)-6-甲基-1,4-二氢吡啶-3,5-二羧酸盐)在体外显示出高活性和高选择性,针对依赖低电压的L型钙通道。在体外结合研究中,它分别以5.6 nM和51 nM的效力特异性地从心脏和血管平滑肌准备中取代了(-)-[H-3]PN 200-110(异搏定(2),用于体外研究的参考分子)。它还表现为一个纯粹的药理拮抗剂,作用于单通道L型钙通道,且不与苯并噻嗪结合位点(如氨氯地平(3))发生相互作用。S11568的两个对映体都具有体外活性,右旋异构体S12967((+)-1)的效力比左旋异构体S12968((-)-1)低6到18倍。使用改进的Hantzsch二氢吡啶合成法,合成了S11568的两对光学活性标记前体(((-)-10/(+)-10和(-)-14/(+)-14)。在这两种情况下,对映体均通过制备型手性HPLC分离。两者均独立地使用[C-11]二偶氮甲烷或[C-11]碘甲烷标记,得到了高比活度(500-1000 mCi/μmol,18.5-37.0 GBq/μmol)的(-)-1(S12968)和(+)-1(S12967),数量为多毫居里。两个对映体均适用于正电子发射断层扫描(PET)实验:在静脉注射后,心肌浓度迅速上升,2分钟达到峰值,然后维持在稳定水平略有下降,而血液浓度迅速下降。心肌摄取量是肺摄取量的三倍,导致PET图像的良好对比度。目前在比格犬中获得的初步生物结果显示,两个对映体在心肌动力学和对左室心肌的体内亲和力方面相似。© 1997 Elsevier Science Ltd.