Cu(OTf)2 loaded protonated trititanate nanotubes catalyzed reaction: a facile method for the synthesis of furo[2,3-b]quinoxalines†
Abstract
An efficient method is developed for the synthesis of furo[2,3-b]quinoxalines using novel Cu(OTf)2 loaded protonated trititanate nanotube catalysts via A3-coupling followed by 5-endo-dig cyclization from o-phenylenediamines, ethylglyoxalate and phenylacetylenes. This method is beneficial and advantageous as it facilitates high yield in conventional heating and a short reaction time besides offering reusable heterogeneous catalysts. These catalysts can be recovered by centrifugation and their activity remain largely unchanged for five successive runs. On the other side, these catalysts are prepared using simple hydrothermal and wet-impregnation methods and are characterized using XRD, HR-TEM and N2-adsorption–desorption techniques.