Background: Since introduction of chalcones in 1899, chalcones have been considered as precursors
of flavones in the biosynthesis of flavonoids. However, because the chalcones include multi-functional groups on
aromatic rings, developments of efficient synthetic methodologies as well as synthetic strategies involving protection/
deprotection should be considered.
Objective: The primary objective of this study was to describe chalcone synthesis under mild condition and its
Method: The chalcones synthesis is aldol condensation of acetophenones with aldehydes in the presence of catalytic
mount of copper(II) bromide at 70 °C.
Result: Proposed transformation of the chalcone synthesis is to proceed via catalytically generated abromocarbonyl
intermediate by copper(II) bromide, aldol condensation of a-bromocarbonyl intermediate is promoted
by HBr, while its byproducts, HOBr and HBr reconstitute the catalyst. Using this method, the natural
product echinatin (1) was conveniently synthesized in a single step with yield of 82%.
Conclusion: Cu(II) mediated aldol condensation via a-bromocarbonyl species involving Cu(II) catalyst reconstitution
were noted in this study. It was thought that it has the potential for application as a simple and quick synthesis
method for pharmaceutical ingredients.