investigated. Though the lactone rings in coumarin dimers are very susceptible to nucleophilic ring-opening, heating these derivatives reformed six-membered lactone rings except for certain imide and diamide derivatives. The large neiboring group effect allowed the relactonization by the attack of hydroxyphenyl group to carbonyl carbon in preference to the scission of cyclobutane ring.
研究了头对头
香豆素二聚体和十二个内酯开环衍
生物的热行为。尽管
香豆素二聚体中的内酯环对亲核开环非常敏感,但加热这些衍
生物会重新形成六元内酯环,但某些
酰亚胺和二酰胺衍
生物除外。大的邻基效应允许通过羟基苯基攻击羰基碳而不是
环丁烷环的断裂进行再内酯化。