Synthesis of (R)-(-)-2-Fluoronorapomorphine — A Precursor for the Synthesis of (R)-(-)-2-Fluoro-N-[11C]propylnorapomorphine for Evaluation as a Dopamine D2 Agonist Ligand for PET Investigations
作者:Kåre Søndergaard、Jesper Langgaard Kristensen、Nic Gillings、Mikael Begtrup
DOI:10.1002/ejoc.200500295
日期:2005.10
Subsequent acid-catalysed rearrangement afforded N-benzylnormorphothebaine which was selectively triflylated at the 2-position and pivaloylated at the 11-position. The triflate underwent palladium-catalysed amination with benzophenone imine. Amination conditions required sequential base addition to give substantial conversion of the triflate to the corresponding N-substituted benzophenone imine. After
2-氟代诺帕吗啡是 2-氟-N-[11C] 丙基去甲吗啡的 PET 标记前体,通过 13 个步骤从可待因中制备,总产率为 10%。可待因分四步转化为 N-苄基去甲可待因,然后使用 Swern 协议将其氧化。随后的酸催化重排得到 N-苄基去甲吗啡肽,其在 2 位选择性地三氟甲磺酸酯化并在 11 位进行新戊酰化。三氟甲磺酸酯与二苯甲酮亚胺进行钯催化胺化。胺化条件需要连续添加碱以使三氟甲磺酸酯显着转化为相应的 N-取代二苯甲酮亚胺。酸水解后,所得苯胺通过 Balz-Schiemann 反应转化为 2-氟化合物。N-苄基的氢解,然后使用 BBr3 对儿茶酚部分进行脱保护,提供 2-氟去甲吗啡。(© Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2005)