Ipso Substitution as a Route to Benzo[<i>c</i>]quinolizines and 4-Hydroxycoumarins
作者:Yannan Liu、Mark J. Kurth
DOI:10.1021/jo0161126
日期:2002.4.1
A convenient ipso substitution method for the preparation of benzo[c]quinolizine (2) and 4-hydroxy-3-(2'-pyridyl)coumarin (3) has been developed. The intramolecular nucleophilic substitution reaction of 3-oxo-2-(2'-pyridyl)-(2-halophenyl)propanoate (1) in refluxing xylenes gives initially benzo[c]quinolizine, while further heating results in the formation of 4-hydroxycoumarin. A mechanism has been
开发了一种方便的ipso取代方法,用于制备苯并[c]喹啉嗪(2)和4-羟基-3-(2'-吡啶基)香豆素(3)。3-氧代-2-(2'-吡啶基)-(2-卤代苯基)丙酸酯(1)在回流二甲苯中的分子内亲核取代反应最初产生苯并[c]喹啉嗪,而进一步加热导致形成4-羟基香豆素。已经提出了一种机制来合理化两个竞争性反应途径,并讨论了HCl的作用。在最佳条件下,以中等至良好的产率制备了七个苯并[c]喹啉嗪和五个香豆素。