Carbodiimide-Mediated Preparation of the Tricyclic Pyrido[3‘,2‘:4,5]pyrrolo[1,2-<i>c</i>]pyrimidine Ring System and Its Application to the Synthesis of the Potent Antitumoral Marine Alkaloid Variolin B and Analog
作者:Pedro Molina、Pilar M. Fresneda、Santiago Delgado
DOI:10.1021/jo026508x
日期:2003.1.1
pyrido[3',2':4,5]pyrrolo[1,2-c]pyrimidine ring system, and finally installation of the 2-aminopyrimidine ring at C5. The required 7-azaindole ring appropriately substituted is formed by a modified indole synthesis involving a nitrene insertion process (two steps). Formation of the annelated pyrimidine ring is achieved by two routes both involving a carbodiimide-mediated cyclization process, which allow
海洋生物碱variolin B的总合成已通过13个步骤完成,由3-甲酰基-4-甲氧基吡啶的总收率为6.5%。我们的方法是基于依次形成7-氮杂吲哚环,三环吡啶并[3',2':4,5]吡咯并[1,2-c]嘧啶环体系,最后安装2-氨基嘧啶环在C5。所需的被适当取代的7-氮杂吲哚环是通过涉及腈插入过程的改性吲哚合成(两个步骤)形成的。退火的嘧啶环的形成通过两个途径完成,这两个途径均涉及碳二亚胺介导的环化过程,这允许在核心三环的C9处引入胺官能团(六个步骤)。使用Bredereck规程(三个步骤)在C5处安装东北2-氨基嘧啶环。最终的,