First chemoenzymatic stereodivergent synthesis of both enantiomers of promethazine and ethopropazine
作者:Paweł Borowiecki、Daniel Paprocki、Maciej Dranka
DOI:10.3762/bjoc.10.322
日期:——
key-intermediates were further transformed into bromide derivatives by means of PBr3, and subsequently reacted with appropriate amine providing desired pharmacologically valuable (R)- and (S)-stereoisomers of title drugs in an ee range of 84-98%, respectively. The modular amination procedure is based on a solvent-dependent stereodivergent transformation of the bromo derivative, which conducted in toluene gives mainly
通过简单直接的四步化学酶法合成对映体富集的异丙嗪和乙丙嗪。中心手性结构单元 1-(10H-吩噻嗪-10-基)丙-2-醇是通过脂肪酶介导的动力学拆分方案获得的,该方案提供了两种对映体形式,具有极好的对映选择性(高达 E = 844) ,来自外消旋体。Novozym 435 和 Lipozyme TL IM 被发现是制备高度对映体富集的吩噻唑醇(高达 >99% ee)的理想生物催化剂,其绝对构型由 Mosher 方法确定,并通过 XRD 分析明确证实。由此获得的关键中间体进一步通过PBr3转化为溴化物衍生物,随后与适当的胺反应,得到标题药物所需的药理学价值的(R)-和(S)-立体异构体,ee范围分别为84-98% 。模块化胺化程序基于溴代衍生物的溶剂依赖性立体发散转化,在甲苯中进行主要产生单一转化的产物,而在甲醇中进行则仅提供净保留产物。通过使用手性柱的 HPLC 测量确定光学活性异丙嗪和乙丙嗪的对映体过量。