synthesis of 2-amino-4h-pyran derivatives in aqueous media with nano-sno2 as recyclable catalyst

A nanosno2 catalyzed environmentally benign strategy for the synthesis of 2amino4hpyran derivatives via the multicomponent reaction between aryl aldehydes, βdicarbonyl compounds and malononitrile in aqueous media under reflux conditions in excellent yields is established. the structures of the synthesized compounds were confirmed using ir, 1hnmr. the elemental analysis and morphology of the catalyst was characterized using scanning electron microscopy (sem) and transmission electron microscopy (tem). this onepot three component protocol provides an efficient improved pathway for the synthesis of pyrans in the terms of short reaction times, simple working up procedure and recyclability of catalyst.