Nanostructured coumarin-based cobalt complex as an efficient, heterogeneous and recyclable catalyst for the three-component synthesis of benzo[b]pyran and 3,4-dihydropyrano[c]chromene derivatives

Abstract

An improved one-pot three-component reaction of carbonyl compounds (dimedon, 4-hydroxy coumarin and 1,3-cyclohexadion) with malononitrile and aryl aldehydes in aqueous media (H2O:EtOH) as a solvent with short reaction time for the synthesis of benzo[b]pyran and 3,4- dihydropyrano[c]chromane derivatives by using nanostructured coumarin-based cobalt complex as an efficient heterogeneous catalyst. The salient features of this new protocol include simple procedure, high yields, easy isolation of products without need to column chromatography and short reaction times. Also, the nanocatalyst was recovered by adding EtOH and reused five times without significant loss of its catalytic activity. Biological impact assessments of the complex were conducted by DNA cleavage ability assay and eukaryotic cell toxicity measurement. Although the complex showed single-strand DNA breakage under oxidative conditions, its high polar nature revealed a marked decrease in cell toxicity data due to the restriction on cell entry.