Convenient Synthesis of a Simple Coumarin from Salicylaldehyde and Wittig Reagent. II : Synthesis ofBromo- and Methoxycarbonylcoumarins.
作者:Takashi HARAYAMA、Kazumitsu NAKATSUKA、Hiromi NISHIOKA、Kyoko MURAKAMI、Naomi HAYASHIDA、Hisashi ISHII
DOI:10.1248/cpb.42.2170
日期:——
Reaction of salicylaldehydes (1) with carbethoxymethylenetriphenylphosphorane in diethylaniline under reflux gave coumarins (3) in moderate to high yield except 3-methoxycarbonylsalicyladehyde (1e) as summarized in Table I. The substituent effects are discussed. A substituent at C6 on 1 usually facilitated the formation of the coumarin ring regardless of its electronic character.
在二乙基苯胺中,加热回流下香兰素(1)与碳乙氧基亚甲基三苯基磷烯反应,除了3-甲氧基羧基香兰素(1e)外,得到了中等到高产率的香豆素(3),具体结果总结在表I中。讨论了取代基的影响。在1的C6位的取代基通常促进香豆素环的形成,无论其电子特性如何。