申请人:Thomas C. Elder, Inc.
公开号:US04235781A1
公开(公告)日:1980-11-25
.alpha.-Loweralkylfurocoumarins are produced by forming a .beta.-haloalk-2-enyl, e.g., .beta.-haloallyl, ether of a hydroxycoumarin having an active hydrogen in the position ortho to the hydroxy group, and heating the formed ether, preferably in dimethylaniline or like basic amine solvent. An abnormal Claisen rearrangement produces a novel o-hydroxy-(.beta.-haloalk-2-enyl) coumarin intermediate which can be dehydrohalogenated directly without isolation to the desired .alpha.-loweralkylfurocoumarin, e.g., .alpha.-methylfurocoumarin.
.alpha.-低烷基呋喃香豆素是通过形成一个.beta.-卤代烷基,例如.beta.-卤代丙烯基,与一个在羟基位置邻近具有活性氢的羟基香豆素的醚,并在二甲基苯胺或类似的碱性胺溶剂中加热所形成的醚而制得的。一种异常的克莱森重排反应产生了一种新的o-羟基-(.beta.-卤代烯基)香豆素中间体,该中间体可以直接去卤化脱去卤素而不需要分离,从而得到所需的.alpha.-低烷基呋喃香豆素,例如.alpha.-甲基呋喃香豆素。