Synthesis of 3,4-dihydropyrano[3,2-c]chromene using Fe3O4 nanoparticles-supported β-cyclodextrin-guanidine as an efficient and recycable heterogeneous catalyst

Dihydropyrano[3,2-c]chromene nucleus is a source of many biological properties and its derivatives show anti-microbial, anti-fungal, analgesic, anti-cytotoxic, anti-tuberculosis [1] and AChE inhibitory [2] activities. Therefore, the development of efficient methods for synthesis of these important heterocycles has attracted researchers’ attention. Cyclodextrins show ability to encapsulate variety of guest molecules such as aliphatic and aromatic hydrocarbons, acids, amines, alcohols and small inorganic anions through host-guest interactions [3]. Immobilization of homogeneous organic catalysts on various support materials is sustainable method to recover and recycle catalysts. Owning unique structures and properties, magnetic nanoparticles can be serve as a highly efficient catalyst supports. Herein, considering the importance of chromenes and with a purpose of developing an efficient, reusable, heterogeneous, cost-effective and environment-friendly catalyst for synthesis of these compounds, amino-functionalized β-CD was prepared and grafted on Fe3O4 nanoparticles via the chemical co-precipitation approach. The prepared catalyst’s efficiency was explored in synthesis of dihydropyrano[3,2-c]chromenes.