Successful Application of Cu(II) Complex of 3-Hydroxy-2-naphtoic Acid (Cu-HNA) as a Reusable Heterogeneous Catalyst for One-Pot Synthesis of Benzoxanthene Derivatives

In this work, a new application of Cu(II) complex with 3-hydroxy-2-naphtoic acid (Cu-HNA) as a reusable heterogeneous catalyst in the synthesis of tetrahydrobenzo[a]xanthene-11-ones via a one-pot three-component condensation of aryl aldehydes, 2-naphthol, and dimedone in solvent-free condition was reported. At the end of the reaction, with a simple filtration, the catalyst was easily recovered and reused at least five times with no significant loss of its catalytic activity. Appropriate activity and efficient of the catalyst, very good yields, short reaction time, mild and simple work-up, and no use of organic solvents are other benefits of this proposed methodology.