Expansion of the aromatic part of Cinchona alkaloids. Annulation of quinolines with phenoxazine motifs
作者:Małgorzata Wąsińska-Kałwa、Mirosław Giurg、Przemysław J. Boratyński、Jacek Skarżewski
DOI:10.1016/j.tet.2017.11.072
日期:2018.1
An oxidative cross-coupling strategy for quinoline ring annulation in Cinchona alkaloids has been developed. Key-reaction optimization by changing oxidants and adjusting the nucleophilicity of the 2-aminophenols led to cupreine and cupreidine expanded with the phenoxazinone unit in 56–75% yield. The stereochemical integrity of the obtained alkaloid structures was confirmed by combined experimental
已经开发了金鸡纳生物碱中喹啉环环化的氧化交叉偶联策略。通过改变氧化剂和调节2-氨基苯酚的亲核性来优化键反应,从而使铜嘌呤和铜吡啶与苯恶嗪酮单元一起以56%至75%的收率扩大。通过结合实验和计算的CD和NMR数据确认了所获得生物碱结构的立体化学完整性。构象研究揭示了三个构象体的快速平衡,其吡啶并[ a -3,2]吩恶嗪部分的取向不同。