Intramolecular Inverse-Electron-Demand Diels−Alder Reactions of Imidazoles with 1,2,4-Triazines: A New Route to 1,2,3,4-Tetrahydro-1,5-naphthyridines and Related Heterocycles
作者:Brian R. Lahue、Sie-Mun Lo、Zhao-Kui Wan、Grace H. C. Woo、John K. Snyder
DOI:10.1021/jo040193z
日期:2004.10.1
The intramolecular inverse-electron-demand Diels−Alder reaction between imidazoles and 1,2,4-triazines linked by a trimethylene tether from the imidazole N1 position to the triazine C3 proceed in excellent yields to produce 1,2,3,4-tetrahydro-1,5-naphthyridines. The reaction proceeds by a cycloaddition with subsequent loss of nitrogen, followed by a presumed stepwise loss of a nitrile. The analogous
咪唑和1,2,4-三嗪之间的分子内逆电子需求的Diels-Alder反应由三亚甲基系链从咪唑N1位置连接到三嗪C3,从而以极好的收率进行生产1,2,3,4-四氢-1,5-萘啶。该反应通过环加成反应进行,随后损失氮气,然后逐步损失腈。使用四亚甲基系链的类似分子内环加成反应也以可接受的收率得到了2,3,4,5-四氢-1 H-吡啶并[3,2- b ]氮杂。微波辐射也可以促进产生四氢-1,5-萘啶的反应。