Cu(II)-Schiff base/SBA-15 as an efficient catalyst for synthesis of benzopyrano[3,2-c]chromene-6,8-dione derivatives

In this study, we synthesized the benzopyrano[3,2-c]chromene-6,8-dione derivatives by one-pot multi-component reaction of 1,3-cyclohexanedione, arylaldehydes, and 4-hydroxycoumarin under the solventless condition using Cu(II)-Schiff base/SBA-15 as a reusable heterogeneous catalyst in high yields. These kinds of catalysts are built from mesoporous silica SBA-15 which is covalently anchored with Cu(II)-Schiff base complex. The high yields, simple work-up procedure, reuseability of the catalyst, and environmentally friendly conditions are the main advantages of this method compared to the other techniques. The products were identified by using 1H NMR, mass and IR spectra, which were compared to those reported previously.