The catalytic activity of four heterogeneous solid acid catalysts with magnetic core and sulfonic acid groups is evaluated and compared using one-pot three component synthesis of phthalazine-trione derivatives under solvent-free condition. The NiFe 2 O 4 particles were selected as magnetic core, due to their enhanced chemical and magnetic stability. Furthermore, the desired products were obtained in excellent yields at short reaction times and environmentally friendly condition using the novel and reusable sulfonic acid grafted onto TiO 2 -coated nickel ferrite nanoparticles. This protocol avoids the use of expensive catalysts, toxic solvents and harsh reaction conditions.
