Alkanedisulfamic acid-functionalized silica-coated magnetic nanoparticles (ADSA-MNPs) were prepared by a simple method and evaluated as efficient catalysts for the preparation of mono-, bis-, and tris[bis(4-hydroxycoumarinyl)methanes] through condensation of 4-hydroxy-2H-coumarin-2-one with mono-, di-, or trialdehydes, respectively. The heterogeneous nanocatalyst was readily recovered from the reaction mixture by using external magnet and was reused five times without significant loss of catalytic activity.
