A supramolecular magnetic and multifunctional Titriplex V-grafted chitosan organocatalyst for the synthesis of acridine-1,8-diones and 2-amino-3-cyano-4<i>H</i>-pyran derivatives

In this research, a new supramolecular magnetic modified chitosan, namely, Fe₃O₄@CS-TDI-Titriplex V, was designed and prepared conveniently by grafting diethylenetriaminepentaacetic acid (Titriplex V) onto a biopolymeric chitosan backbone having urethane, urea, ester and amide functional groups. The obtained magnetic biopolymeric nanomaterial was properly characterized by different spectroscopic, microscopic or analytical methods including FTIR spectroscopy, EDX spectroscopy, XRD, FESEM, TG-DTA and VSM. The application of the supramolecular Fe₃O₄@CS-TDI-Titriplex V nanocomposite as a heterogeneous solid acidic organocatalyst was investigated to promote the three-component synthesis of both acridinediones and 2-amino-3-cyano-4<i>H</i>-pyran derivatives as important pharmaceutical scaffolds under green conditions. The obtained nanomaterial exhibited proper catalytic activity in the above mentioned transformations through multicomponent reaction (MCR) strategies. The reactions proceeded very well in the presence of the Fe₃O₄@CS-TDI-Titriplex V solid acid nanomaterial in EtOH to afford the corresponding acridinediones and 2-amino-3-cyano-4<i>H</i>-pyran derivatives in high to excellent yields. The key advantages of the present protocol include the use of a renewable, biopolymeric and biodegradable solid acid as well as a simple procedure for the preparation of the hybrid material. Furthermore, the Fe₃O₄@CS-TDI-Titriplex V nanomaterial was used four times with a slight decrease in its catalytic activity.