One Pot, Three-Component Synthesis of 2-Amino-4H-Chromenes Catalyzed Using NCTDSS in Water

New derivatives of 2-amino-4H-chromenes were prepared using nano-TiO2 on dodecyl-sulfated silica support (NCTDSS) as a new heterogeneous catalyst in water. The NTDSS catalyst was characterized using different techniques such as TEM, SEM, XRD, ICP, and FT-IR. The catalyst was successfully used for the synthesis of 2-amino-4H-chromenes condensation in water as a green solvent. The high catalytic activity of this catalyst in aqueous medium can be due to the formation of colloidal particles on the surface of the NTDSS catalyst due to the DS parts bonded to the silica surface which acts as a surfactant. In this study, it seems that accelerating the reaction rate in aqueous media is effective due to the production of emulsion droplets containing nano TiO2 on the surface of the catalyst as a reaction reactor. The catalyst was produced by the reaction between sodium dodecyl sulfate (SDS) and silica chloride (SC) and then the addition of TiCl4 .