芳基取代香豆素合成方法的研究进展

Current Developments in Synthetic Methods for Arylcoumarins

本文综述了在香豆素母体环上具有不同取代基的3-位和4-位芳基取代化合物的合成进展。其中Perkin反应以水杨醛和芳基乙酸为原料,在有机碱和醋酸酐存在下反应,而对于有N,N-二乙氨基取代的香豆素则需要用Knoevenagal反应在催化量的有机碱存在下由N,N-二乙氨基取代的水杨醛与芳基乙腈反应制得。由于一些取代水杨醛的合成比较困难,这时可利用Pechmann反应在路易斯酸催化下由取代酚直接反应制备香豆素化合物。以上这三种制备芳基取代香豆素的方法一般收率都较高,可应用于工业化生产。另外,在Vilsmeier-Haack反应中可用Vilsmeier试剂来制备芳基香豆素化合物,该反应副产物很少,条件比较温和。利用钯金属等催化合成的4-芳基香豆素化合物反应中,避免了常用的Pechmann反应中使用等当量的矿物酸或路易斯酸,可减少对环境带来的污染。

Current developments in synthesizing 3- and 4-arylcoumarins with diversified groups on the coumarin skeleton were discussed. By the Perkin reaction, coumarins can be prepared from salicylaldehyde and aryl acetic acid in the presence of an organic base and acetic anhydride; by the Knoevenagal reaction, the N,N-diethylamino substituted coumarins can be obtained from N,N-diethylamino substituted salicylaldehyde and benzylacetonitrile with a catalytic organic base in. The Pechmann reaction directly produces arylcoumarins from substituted phenol, avoiding the use of substituted salicylaldehyde, which is not readily prepared. The three reactions mentioned above can be applied to industrial purposes with satisfactory yields. Alternatively, these coumarins can also be synthesized by the Vilsmeier-Haack reaction at low temperature with excellent yields. The Pd-catalyzed reactions decrease environmental contamination by omitting the use of equivalent mineral acid or Lewis acid in the reaction.