Cellulose@Fe2O3-SO3H: A Novel Magnetic Composite Nanomaterial for the Synthesis of Chromene Derivatives

Magnetic nanocomposites are one of the best catalysts for organic reaction beacause of their simple recoverable features. We can simply recover these catalysts from reaction pot with one external magnetic field. A possible method simple separation and recycling of the catalysts is immobilizing catalytically active species in the surface of magnetic particles which can be separated from the reaction system by applying an appropriate magnetic field. Cellulose, as an important and naturally abundant biopolymer, can be easily functionalized with various organic groups for desired purposes like applications as a support for heterogeneous catalysis, composites matrixes and immobilization processes. In this study, we have prepared a biopolymer-based magnetic nanocomposite via in situ synthesis of maghemite (gamma-Fe2O3) on cellulose and then its sulfonation. It has been proven that sulfonated catalyst shows very good activities for one-pot three-component synthesis of chromenes under mild reaction conditions. In general this catalyst is recoverable, green, easy separation because of its magnetic feature, environmentally friendly properties and good yield and low reaction time for this multicomponent reaction as a very good strategy for the synthesis of medicinal and pharmaceutical compounds.