Synthesis of densely functionalized chromenes using a magnetic recoverable ionic liquid as the catalyst

Abstract

In the present study, robust, versatile and straightforward strategy for the diversity-oriented convergent synthesis of a vast range of highly functionalized and biologically effective chromenes is introduced with the reaction of malononitrile, dimedone/cyclohexadione/4-hydroxycoumarin and benzaldehydes in the presence of [γ-Fe₂O₃@HAp-Si(CH₂)₃BF₄@DMIM] as the catalyst. The structures of all the newly synthesized products were characterized by spectroscopic (FT-IR, ¹H NMR, ¹³C NMR) and elemental analyses. This method benefits from several advantages such as using easily recoverable magnetic nanocatalyst, simple workup, short reaction time and excellent yields. The prepared nanoparticles were fully characterized by various spectroscopic, thermal and magnetic analyses. The catalyst exhibited good reusability feature and no loss of activity was observed even after 8 successive runs.