TiO2/nanoclinoptilolite, a recyclable and high efficient heterogeneous nanocatalyst, for the synthesis of 2-amino-4H-chromene derivatives

The synthesis of pharmaceutically and biologically active 2-amino-4H-chromenes was described using TiO2/nanoclinoptilolite (TiO2/NCP) as an efficient nanocatalyst under solvent-free condition. The TiO2/NCP was fabricated through modification of NCP with HDTMA, then the surface modified NCP was impregnated with titanium tetrachloride solution. Finally, the material incorporated with titanium was calcinated at 500 ºC and was characterized by FT-IR, ICP-OES, SEM, and XRD. The experimental conditions have been completely optimized and established, providing an increase in the rate and high yields. This procedure provides several merits such as a simple workup, economical, environmentally benign, short reaction time and excellent yields. Moreover, the prepared nanocomposite showed very high stability and reusability in the synthetic method under solvent-free and mild conditions.