Synthesis of biscoumarin derivatives by the reaction of aldehydes and 4-hydroxycoumarin using ruthenium (III) chloride hydrate as a versatile homogeneous catalyst
Vitamins and antivitamins K: tautomerism of dicoumarol
作者:I. Chmielewska、J. Cieślak
DOI:10.1016/0040-4020(58)88012-6
日期:1958.1
Two isomeric dimethyl ethers of dicoumarol and derivatives substituted in the methylene group [formulae (XX) and (XXI)] were obtained. This result proves the tautomerism of dicoumarol and suggests for it the coumarin-chromone structure (XXIIa).
Studies on 4-Hydroxycoumarins. IV. Esters of the 4-Hydroxycoumarins<sup>1</sup>
作者:Mark A. Stahmann、Lloyd H. Graf、Charles F. Huebner、Saul Roseman、Karl Paul Link
DOI:10.1021/ja01234a018
日期:1944.6
Sulfated titania catalyzed water mediated efficient synthesis of dicoumarols—a green approach
作者:Bikash Karmakar、Anupam Nayak、Julie Banerji
DOI:10.1016/j.tetlet.2012.06.024
日期:2012.8
An efficient, mild, and environmental friendly method has been developed for the synthesis of dicoumarols in water over Lewis and Bronsted acid catalyst sulfated titania (TiO2/SO42-). The method involves the condensation of various aromatic and aliphatic aldehydes with 4-hydroxycoumarin. It affords the corresponding product in high yield with short reaction times employing a very low loading of catalyst. The catalyst was reused several times without significant change in activity. Crown Copyright (C) 2012 Published by Elsevier Ltd. All rights reserved.
Efficient synthesis of bis-(4-hydroxycoumarin) using sulfanilic acid as recyclable catalyst in water
A catalytic reaction between aromatic aldehydes and 4-hydroxycoumarin has been developed to form a decent range of functionalized biscoumarin skeletons in excellent yields using sulfanilic acid as reusable catalyst in aqueous media. The catalytic reaction shows good generality and was compatible with aldehydes bearing electron-withdrawing and electron-releasing substituents. This method avoids the use of tedious work-up and column chromatographic purification of products, making the method expedient and superior. The efficient and cost-effective catalyst could be recovered and reused several times.