[123I]tert-Butyl 8-iodo-5,6-dihydro-5-methyl-6-oxo-4H-imidazo [1,5-a][1,4]benzodiazepine 3-carboxylate ([123I]3), a high affinity and selective radioligand for the diazepam insensitive (DI) benzodiazepine receptor was synthesized in 2 steps from tert-butyl 8-bromo-5,6-dihydro-5-methyl-6-oxo-4H-imidazo[1,5-a][1,4]benzodiazepine 3-carboxylate (4). A key step in the synthesis of this potential SPECT imaging agent utilized (Ph3P)3Pd mediated stannylation of 4 with (Bu3Sn)2 to the corresponding 8-tributyltin derivative 5. Iododestannylation of 5 with no carrier added [123]NaI in aqueous ethanolic CH3CO3H furnished [123I]3 (85%) in greater than 98% radiochemical purity following TLC purification.
[123I]tert-Butyl 8-iodo-5,6-dihydro-5-methyl-6-oxo-4H-imidazo [1,5-a][1,4]benzodiazepine 3-carboxylate ([123I]3)是一种对
地西泮不敏感(DI)的苯二氮卓受体的高亲和力和选择性放射性
配体,它由tert-butyl 8-bromo-5,6-dihydro-5-methyl-6-oxo-4H-imidazo[1,5-a][1,4]benzodiazepine 3-carboxylate (4)通过两步合成而成。合成这种潜在的
SPECT成像剂的关键步骤是利用(Ph3P)3Pd将4与(Bu3Sn)2进行
锡化反应,得到相应的8-三
丁基锡衍
生物5。在
乙醇水溶液中,5与无载体添加的[123]NaI进行
碘代二
锡化反应,得到[123I]3(85%),经TLC纯化后,放射
化学纯度超过98%。