Biradicals from Thermolysis of <i>N</i>-[2-(1-Alkynyl)phenyl]-<i>N</i>‘-phenylcarbodiimides and Their Subsequent Transformations to 6<i>H</i>-Indolo[2,3-<i>b</i>]quinolines
作者:Chongsheng Shi、Quan Zhang、Kung K. Wang
DOI:10.1021/jo981845k
日期:1999.2.1
Thermolysis of the carbodiimide 9a in gamma-terpinene at 138 degrees C produced 2-(phenylamino)quinoline (11a, 49%) and the parent 6H-indolo[2,3-b]quinoline (14a, 16%). Apparently, 11a was produced via the biradical 10a followed by hydrogen-atom abstraction from gamma-terpinene. A two-step biradical pathway through 12a or a one-step intramolecular Diels-Alder reaction could furnish 13a, which then
碳二亚胺9a在138℃下在γ-萜品烯中的热解产生2-(苯氨基)喹啉(11a,49%)和母体6H-吲哚并[2,3-b]喹啉(14a,16%)。显然,通过双自由基10a生成11a,然后从γ-萜品烯中提取氢原子。通过12a的两步双自由基途径或一个分子内Diels-Alder反应一步可提供13a,然后将其进行互变异构化得到14a。对于在乙炔基末端具有三甲基甲硅烷基取代基的碳二亚胺9b,在138℃下在回流的对二甲苯中热解仅产生6H-吲哚并[2,3-b]喹啉14b(86%)。在回流的乙醇中用6 N NaOH处理14b,然后以92%的收率得到14a。类似地,通过碳二亚胺9c-f的热解获得6H-吲哚并[2,3-b]喹啉14c-f。通过使用4-甲氧基苯基异氰酸酯与亚氨基膦酸酯2d和2f之间的氮杂-维蒂希反应来产生相应的碳二亚胺,然后进行热分解,得到在C上具有甲氧基取代基的6H-吲哚并[2,3-b]喹啉16d和16f。