Green synthesis of benzimidazole derivatives using copper(II)-supported on alginate hydrogel beads

Abstract

The study addresses the challenge of developing sustainable and efficient catalytic systems for the synthesis of benzimidazole derivatives, which are of significant importance in the field of medicinal chemistry due to their diverse biological activities. The objective is to develop a recyclable and environmentally friendly catalyst utilizing copper(II)-loaded alginate hydrogel beads, which can facilitate the synthesis of these compounds while minimizing environmental impact. The preparation process entails crosslinking sodium alginate with copper(II) ions to form hydrogel beads, which are then washed and characterized through techniques such as scanning electron microscopy (SEM), Energy dispersive X-ray spectroscopy (EDX), Fourier Transform Infrared Spectroscopy (FTIR), X-ray diffraction (XRD), Inductively coupled plasma (ICP), and Zeta potential to analyses the morphology, composition and porosity of the beads. The catalytic performance is evaluated through recycling tests, which demonstrate the catalyst's ability to maintain selectivity and activity over multiple reaction cycles. The Cu(II)-Alg hydrogel beads were used for synthesizing substituted benzimidazole derivatives in a water-ethanol solvent at room temperature. This method offers significant advantages, including extremely mild reaction conditions, short reaction times (<1 h), high yields (70–94 %), and ease of processing. The most significant results indicate that the Cu(II)-alginate catalyst exhibits a high loading capacity and retains its catalytic efficiency for at least 3 cycles, thereby highlighting its potential for sustainable applications in organic synthesis.