Synthesis of a Histamine H<sub>3</sub> Receptor Antagonist—Manipulation of Hydroxyproline Stereochemistry, Desymmetrization of Homopiperazine, and Nonextractive Sodium Triacetoxyborohydride Reaction Workup
作者:Daniel J. Pippel、Lana K. Young、Michael A. Letavic、Kiev S. Ly、Bita Naderi、Aki Soyode-Johnson、Emily M. Stocking、Nicholas I. Carruthers、Neelakandha S. Mani
DOI:10.1021/jo100629z
日期:2010.7.2
We have recently completed the synthesis of 1-[2-(4-cyclobutyl-[1,4]diazepane-1-carbonyl)-4-(3-fluoro-phenoxy)-pyrrolidin-1-yl]-ethanone, a hydroxyproline-based H3 receptor antagonist, on 100 g scale. The synthesis proceeds through four steps and route selection was driven by a desire to minimize the cost-of-goods. Naturally occurring trans-4-hydroxy-L-proline was chosen as the precursor to the target’s
我们最近完成了羟基脯氨酸1- [2-(4-环丁基-[1,4]二氮杂-1-羰基)-4-(3-氟-苯氧基)-吡咯烷-1-基]-乙酮的合成的H 3受体拮抗剂,量为100 g。合成过程通过四个步骤进行,并且路线选择是由将商品成本降至最低的愿望所驱动的。选择天然存在的反式-4-羟基-L-脯氨酸作为靶标核心的前体,这需要在两个立体发生中心进行反转。通过策略性使用La Rosa的内酯和后期的Mitsunobu反应来完成反演。使用N的第一代合成-Boc-高哌嗪在第二代方法中得到了改进,其中高哌嗪直接去对称。最后,关键中间体的水溶性使得必须开发用于三乙酰氧基硼氢化钠还原的非萃取性后处理。