Versatile Synthesis of Dihydroquinolines and Quinoline Quinones Using Cyclobutenediones. Construction of the Pyridoacridine Ring System
作者:Dawei Zhang、Isidro Llorente、Lanny S. Liebeskind
DOI:10.1021/jo970039v
日期:1997.6.1
1-BOC-2-lithio-1,4-dihydropyridines were condensed with 3,4-disubstituted cyclobutenediones to produce 1,2-adducts. Neat thermolysis under oxygen-free conditions produced substituted 1,4-dihydroquinoline hydroquinones in which the tert-butoxy residue of the BOC group was displaced by a phenolic residue, generating an oxazolone ring that functioned to protect both rings of the dihydroquinoline hydroquinone
将1-BOC-2-硫代-1,4-二氢吡啶与3,4-二取代的环丁二烯键缩合以生成1,2-加合物。在无氧条件下进行的纯热解生成了取代的1,4-二氢喹啉对苯二酚,其中BOC基团的叔丁氧基残基被酚基残基取代,生成了恶唑酮环,该环起保护二氢喹啉对苯二酚的两个环免遭不当氧化的作用。使用在乙酸中的2当量邻氯苯醌可实现氧化芳构化并伴有恶唑酮环的损失,并以高收率提供了取代的喹啉醌。通过使用这种策略,可以实现吡啶ring环系统的简明合成。