The synergic effect of the chitosan biomacromolecule support has been demonstrated for catalyzing of Hantzsch esters by CuSO₄.

The desired products were simply prepared from different aldehydes, β-dicarbonyls and ammonium acetate in the presence of a low loading of chitosan supported copper(II) sulfate (CSCS) in EtOH under reflux conditions.

The biodegradable CSCS catalyst was characterized by field emission scanning electron microscopy (FESEM) and energy-dispersive X-ray spectroscopy analysis (EDX) methods as well as coupled plasma-atomic emission (ICP-AE) and FT-IR spectroscopy.

The CSCS catalyst is recyclable and reused four times without significant loss of its activity.