Facile Metal-Free Synthesis of 3-Aryl-4-Substituted Coumarins from<i>O</i>-Hydroxy Carbonyl Compounds
作者:Kiran Taksande、D. S. Borse、Pradeep Lokhande
DOI:10.1080/00397910903222082
日期:2010.7.12
The intramolecular cyclization of the esters of salicylaldehyde, O-hydroxyacetophenones, methyl salicylate, and 2′-hydroxy chalcones by potassium hydroxide in pyridine leads to a short and convenient synthesis of 3,4-disubstituted coumarins. Twenty 3-phenyl coumarins were synthesized in 80–90% yields. No other by-product, such as 2-benzylchromone or β-diketones, was observed the reactions. The mild
氢氧化钾在吡啶中对水杨醛、O-羟基苯乙酮、水杨酸甲酯和 2'-羟基查耳酮的酯进行分子内环化,可快速方便地合成 3,4-二取代香豆素。以 80-90% 的产率合成了 20 种 3-苯基香豆素。在反应中没有观察到其他副产物,例如 2-苄基色酮或 β-二酮。温和的反应条件包括去除更多酸性的苄质质子,这导致了一种相对便宜、无毒、无金属的合成 3-芳基-4-取代香豆素的方法。