Synthesis of biscoumarin derivatives by the reaction of aldehydes and 4-hydroxycoumarin using ruthenium(III) chloride hydrate as a versatile homogeneous catalyst

Abstract

The one-pot domino Knoevenagel-type condensation/Michael reaction of aromatic, heteroaromatic and aliphatic aldehydes with 4-hydroxycoumarin in aqueous media in the presence of ruthenium salt as homogeneous catalyst was investigated. It was found that 5 mol % of RuCl 3·nH 2O catalyzes biscoumarin synthesis in high yields (70-95 %) under optimized, mild, green and environmentally benign reaction conditions in short times (25-35min). © 2012 Copyright (CC) SCS.