A new synthetic route to norlichexanthone (1,3,6-trihydroxy-8-methyl- 9H-xanthen-9-one) derivatives has been developed by using a Smiles rearrangement of an appropriately substituted depside in the key step. 2,4,7-Trichloronorlichexanthone (22) and 4,5,7- trichloronorlichexanthone (29) have been prepared by this method. The former xanthone (22) was shown to be a constituent of the lichens Lecanora sulphurata and L. flavo-pallescens and the latter (29) a constituent of Micarea austroternaria var. isabellina.
在关键步骤中,通过对适当取代的副酮进行斯迈尔斯重排,开发出了一种新的去甲黄酮(1,3,6-三羟基-8-甲基-9H-氧杂蒽-9-酮)衍生物的合成路线。用这种方法制备了 2,4,7-三氯orlichexanthone(22)和 4,5,7-三氯orlichexanthone(29)。前一种氧杂蒽酮(22)被证明是地衣 Lecanora sulphurata 和 L. flavo-pallescens 的一种成分,而后一种氧杂蒽酮(29)则是 Micarea austroternaria var.