Synthesis of α-carbolines and β-carbolinones via intramolecular Diels-Alder reactions of 2(1H)-pyrazinones
作者:Abdellah Tahri、Kris J. Buysens、Erik V. Van der Eycken、Didier M. Vandenberghe、Georges J. Hoornaert
DOI:10.1016/s0040-4020(98)00802-3
日期:1998.10
2(1H)-Pyrazinones bearing a X-(o-C6H4)CC-R moiety (X=NH, NAc) are shown to undergo an intramolecular cycloaddition-elimination reaction on thermolysis in refluxing bromobenzene yielding α-carbolines or β-carbolinones. The product distribution depends strongly on the substitution pattern of the pyrazinone precursors and the solvent used for thermolysis. A high yield and selective formation of β-carbolinones
显示带有X-(o -C 6 H 4)CCR部分(X = NH,NAc)的2(1 H)-吡嗪酮在回流过程中发生热分解过程中发生分子内环加成消除反应,从而生成溴代溴苯或β-咔啉酮。产物分布在很大程度上取决于吡嗪酮前体的取代方式和用于热解的溶剂。当在四氢萘中回流加热时,可以高收率和选择性形成β-咔啉酮。使用乙酸酐作为溶剂促进了反应,并且使得通过在前述溶剂中热解无法获得的咔啉成为可能。