Facile and Green One-Pot Synthesis of Fluorophore Chromeno[4,3-b]quinolin-6-one Derivatives Catalyzed by Halloysite Nanoclay under Solvent-free Conditions

摘要

In this study,we demonstrated a straightforward method for the easy access of chromeno[4,3-b]quinolin-6-ones via a onepot three-component reaction of 4-hydroxycoumarin,aldehydes and aryl amines in the presence of halloysite nanoclay as an eco-friendly,inexpensive and green heterogeneous catalyst under solvent-free conditions.Moreover,symmetric and unsymmetric bis-chromeno[4,3-b]quinolin-6-ones were obtained from dialdehyde or diamines in good yields by this method.To date,this is the first report on the synthesis of symmetric and unsymmetric bis-chromeno[4,3-b]quinolin-6-ones via such a one-pot,multicomponent reaction.Some prepared chromeno [4,3-b]quinolin-6-ones displayed as interesting fluorophore compounds,hereupon their fluorescence properties were considered.Good to excellent yields,short reaction times and avoidance of toxic solvents are the significant features of this green procedure.