Efficient preparation of 1,8-dioxo-octahydroxanthene derivatives by recyclable cobalt-incorporated sulfated zirconia (ZrO2/SO42−/Co) nanoparticles

Abstract

This study presents one-pot multicomponent preparation of 1,8-dioxo-octahydroxanthene derivatives under very mild conditions using cobalt-incorporated sulfated zirconia (ZrO2/SO42−/Co) as an efficient heterogeneous recyclable multifunctional nanocatalyst. The nanocatalyst was successfully characterized by FTIR, XRD, TGA, FE-SEM, TEM, ICP, and EDX analyses. The nanoparticles have a mean size of 13 nm, with a combination of the monoclinic-tetragonal crystal structure. A wide scope of aldehydes bearing different functional groups was condensed with dimedone and/or 1,3-cyclohexadione in water at room temperature with good-to-high yields at short reaction times. The catalyst can be efficiently recovered and reused several times without much loss of its activity. Besides, hot filtration test gives more insight into the heterogeneous nature of the catalyst. Finally, a plausible mechanism for this transformation was proposed.