Poly(4-vinylpyridine) is reported as a green, commercial available and efficient basic recyclable catalyst for the synthesis of chromene derivatives. This catalyst can be easily recovered by simple filtration and recycled up to 5 consecutive runs without any loss of its efficiency.
Novel metal oxide of CuO-ZnO nanocatalyst was prepared by a coprecipitation method and characterized by x-ray diffusion, Brunauer-Emmett-Teller surface area, scanning electron microscopy, transmission electron microscopy, and energy dispersive spectroscopy (EDS) analysis. The catalyst is efficient for the synthesis of 2-amino-4H-chromenes by one-pot condensation of aromatic aldehydes, hydroxynaphthalene derivatives, and malononitrile in water at reflux conditions. Moreover, CuO-ZnO nanocatalyst can be recycled up six times without any significant loss of its catalytic activity.