sulfonated chitosan encapsulated magnetically fe3o4 nanoparticles as effective and reusable catalyst for ultrasound-promoted rapid, three-component synthesis of spiro-4h-pyrans

A facile one-pot protocol for synthesis of spiro-4h-pyrans using sulfonated chitosan-coated fe3o4 nanoparticles (fe3o4@cs-so3h nps) as an efficient catalyst under ultrasonic condition has been developed. first, the fe3o4@cs nps were prepared from the reaction of chitosan with fe3o4 nps. then, the treatment of fe3o4@cs nps with chlorosulfonic acid leads to the formation of fe3o4@cs-so3h nps which exerts excellent catalytic activity toward one-pot, three-component synthesis of spiro-4h-pyran derivatives. the core–shell structure and the composition of produced magnetic nanocatalyst were characterized by ft-ir, xrd, vsm, sem and edx techniques.