Synthesis ( IF 2.2 ) Pub Date : 2019-01-29 , DOI: 10.1055/s-0037-1611711 Didier Vargas , Enrique Larghi , Teodoro Kaufman 1
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Abstract
A straightforward approach toward a decorated cyclopenta[ij]isoquinoline embodying the ABC-ring system characteristic of the azafluoranthene (triclisine), tropoisoquinoline (pareitropone) and proaporphine (prodensiflorin B) alkaloids, is reported. The synthetic sequence entailed a novel 40% KF/Al2O3-mediated hydroacylation of a 2-allyl-benzaldehyde derivative, obtained in two steps from isovanillin, through O-allylation and Claisen rearrangement to assemble the AC-ring system. This was followed by an O-methylation and a reductive amination of the resulting indanone with aminoacetal. A modified Pomeranz–Fritsch cyclization was next implemented to install ring B, through sulfonamidation, followed by acid-promoted cyclization and final desulfonylation in situ.
A straightforward approach toward a decorated cyclopenta[ij]isoquinoline embodying the ABC-ring system characteristic of the azafluoranthene (triclisine), tropoisoquinoline (pareitropone) and proaporphine (prodensiflorin B) alkaloids, is reported. The synthetic sequence entailed a novel 40% KF/Al2O3-mediated hydroacylation of a 2-allyl-benzaldehyde derivative, obtained in two steps from isovanillin, through O-allylation and Claisen rearrangement to assemble the AC-ring system. This was followed by an O-methylation and a reductive amination of the resulting indanone with aminoacetal. A modified Pomeranz–Fritsch cyclization was next implemented to install ring B, through sulfonamidation, followed by acid-promoted cyclization and final desulfonylation in situ.
中文翻译：
氮杂荧蒽，对异喹啉和Proaporphine生物碱的ABC环系统的简明合成：烯烃加氢酰化/ Pomeranz-Fritsch环化方法
摘要
朝向装饰环戊二烯并[A直接的方法IJ ]异喹啉体现azafluoranthene（triclisine），tropoisoquinoline（pareitropone）和proaporphine（prodensiflorin B）生物碱的ABC-环系统特性报道。合成序列需要新型的40％KF / Al 2 O 3介导的2-烯丙基苯甲醛衍生物的加氢酰化作用，该步骤可从异香兰素分两步通过O-烯丙基化和Claisen重排组装成AC环系统。然后进行O-甲基化，并用氨基缩醛对所得的茚满酮进行还原胺化。接下来实施了改良的Pomeranz-Fritsch环化反应，以通过磺酰胺化安装B环，然后进行酸促进的环化反应和最后的脱磺酰化反应原地。
朝向装饰环戊二烯并[A直接的方法IJ ]异喹啉体现azafluoranthene（triclisine），tropoisoquinoline（pareitropone）和proaporphine（prodensiflorin B）生物碱的ABC-环系统特性报道。合成序列需要新型的40％KF / Al 2 O 3介导的2-烯丙基苯甲醛衍生物的加氢酰化作用，该步骤可从异香兰素分两步通过O-烯丙基化和Claisen重排组装成AC环系统。然后进行O-甲基化，并用氨基缩醛对所得的茚满酮进行还原胺化。接下来实施了改良的Pomeranz-Fritsch环化反应，以通过磺酰胺化安装B环，然后进行酸促进的环化反应和最后的脱磺酰化反应原地。
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