Regioselective Synthesis of 4,5-Diaryl-1-methyl-1<i>H</i>-imidazoles Including Highly Cytotoxic Derivatives by Pd-Catalyzed Direct C-5 Arylation of 1-Methyl-1<i>H</i>-imidazole with Aryl Bromides
作者:Fabio Bellina、Silvia Cauteruccio、Annarita Di Fiore、Renzo Rossi
DOI:10.1002/ejoc.200800738
日期:2008.11
A general and efficient three-step procedure for the highly regioselective synthesis of 1-methyl-1H-imidazoles possessing electron-rich, electron-neutral, and/or electron-deficient aryl moieties at their 4- and 5-positions is described. The first step involves the Pd-catalyzed direct C-5 arylation of commercially available 1-methyl-1H-imidazole with aryl bromides, and the second and third steps of
描述了在 4 位和 5 位具有富电子、电子中性和/或缺电子芳基部分的 1-甲基-1H-咪唑的高度区域选择性合成的通用和有效的三步法。第一步涉及 Pd 催化的市售 1-甲基-1H-咪唑与芳基溴化物的直接 C-5 芳基化,该序列的第二步和第三步涉及所得 5-芳基的选择性 C-4 溴化。 1-甲基-1H-咪唑与NBS,然后是PdCl2(dppf)-催化的5-芳基-4-溴-1-甲基-1H-咪唑和芳基硼酸在相转移条件下的铃木型反应。如此制备的两种 4,5-二芳基-1-甲基-1H-咪唑,可被视为天然存在的考布他汀 A-4 (CA-4) 的 Z 限制类似物,已证明对多种人类肿瘤细胞系具有高度细胞毒性,并且这些衍生物之一已被证明比 CA-4 和迄今为止文献中研究的所有咪唑衍生物更具细胞毒性。(© Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany