Synthesis of Coumarins, 4-Hydroxycoumarins, and 4-Hydroxyquinolinones by Tellurium-Triggered Cyclizations<sup>1</sup>
作者:Donald C. Dittmer、Qun Li、Dimitry V. Avilov
DOI:10.1021/jo050070u
日期:2005.6.1
can be conveniently prepared by treatment of α-halocarboxylic acid esters of salicylaldehyde, o-hydroxyacetophenone, methyl salicylate, and methyl N-methyl- or N-phenylanthranilates with sodium or lithium telluride. Phenylketene formation competes with cyclization of the α-chlorophenylacetate ester of methyl salicylate as demonstrated by a trapping experiment with benzylamine. Elemental tellurium
可通过处理水杨醛的α-卤代羧酸酯,邻羟基苯乙酮,水杨酸甲酯和N-甲基或N-苯基邻氨基苯甲酸甲酯来方便地制备香豆素,4-羟基香豆素和4-羟基喹啉-2(1 H)-酮。钠或碲化锂。苯酮的形成与水杨酸甲酯的α-氯苯基乙酸酯的环化竞争,如苄胺的捕获实验所证明的。元素碲可以回收再利用。