Synthesis of indeno and acenaphtho cores containing dihydroxy indolone, pyrrole, coumarin and uracil fused heterocyclic motifs under sustainable conditions exploring the catalytic role of the SnO2 quantum dot

Abstract

A tin oxide (SnO₂) quantum dot (QD) catalyzed approach for the synthesis of indeno and acenaphtho cores containing dihydroxy indolone, pyrrole, coumarin and uracil fused derivatives was achieved via a multicomponent one-pot approach in aqueous medium. A variety of functional groups were compatible with the reaction conditions. This synthesis was established to follow the group-assistant-purification chemistry process, thus avoiding the use of traditional chromatography. An SnO₂ QD was prepared using a simple solvothermal method and characterized using X-ray diffraction and transmission electron spectroscopy images. The easy recovery of the catalyst and high yield of the products make the protocol attractive, sustainable and economic. The catalyst was reused for seven cycles with almost unaltered catalytic activity. The low cost, ease of handling and the simplicity of this catalytic system make the method competitive with other strong mineral acid-catalysed multicomponent protocols.