Regiospecific and Highly Flexible Synthesis of 1,4,5-Trisubstituted 2-Sulfanylimidazoles from Structurally Diverse Ethanone Precursors
作者:Stefan Laufer、Dominik Hauser、Andy Liedtke
DOI:10.1055/s-2007-1000852
日期:2008.1
Imidazoles represent important bioactive scaffolds in medicinal chemistry. More than 2,500 structures are listed in drug discovery databases and over 3,000 patents have been claimed for imidazole-based structures. Recent imidazole pharmacophores have targeted various MAP kinases. p38 Mitogen-activated protein (MAP) kinase plays a central role in the signaling network responsible for the upregulation of proinflammatory cytokines like IL-1β and TNFα and offers, therefore, a valid target for small molecule anti-inflammatory drugs. 2-Sulfanylimidazole derivatives offer some advantages over prototype inhibitors (SB203580), e.g. lower cytochrom P450 interactions and better kinetic properties. We report here three novel regioselective and, at the same time, highly flexible synthetic approaches towards 1,4,5-trisubstituted 2-sulfanylimidazoles starting from different ethanone regioisomers allowing maximum variability of all substituents introduced. As a result, a variety of selective and highly potent p38 MAPK inhibitors were prepared and selected for further preclinical development. Synthesis of structurally diverse inhibitor candidates, p38 inhibition data, and selectivity profiling of some selected compounds are specified. Furthermore, the benefits of the useful, brief synthetic sequences are outlined and contrasted with already published multistep routes.
咪唑类是药物化学中重要的生物活性骨架。药物发现数据库中列出了超过2,500种结构,并且已有超过3,000项专利针对咪唑类结构提出申请。最近的咪唑类药效团主要针对各种MAP激酶。p38丝裂原活化蛋白(MAP)激酶在信号网络中起着核心作用,该网络负责上调如IL-1β和TNFα等促炎细胞因子,因此,它为小分子抗炎药物提供了有效的靶点。2-巯基咪唑衍生物相较于原型抑制剂(如SB203580)具有一些优势,例如较低的细胞色素P450相互作用和更好的动力学特性。我们在此报告了三种新颖的区域选择性且高度灵活的合成方法,这些方法从不同的乙酮区域异构体出发,实现了对所有引入取代基的最大可变性,从而合成了1,4,5-三取代的2-巯基咪唑。由此,制备并筛选出一系列选择性强且高效的p38 MAPK抑制剂,用于进一步的临床前开发。详细描述了结构多样化的抑制剂候选物的合成、p38抑制数据以及部分精选化合物的选择性分析。此外,还概述了简短合成序列的优点,并与已发表的多步骤路线进行了对比。