Bentonite Catalyzed an Efficient and Green Synthesis of Arylidene Meldrum's Acid Derivatives in Aqueous Media

In the present paper, a simple, highly efficient, and environmentally friendly protocol was proposed for the Knoevenagel condensation reaction of aromatic aldehydes using Meldrum’s acid (2,2-dimethyl-4,6-dioxo-1,3-dioxane) with bentonite as an available non-toxic mineral catalyst exposed to aqueous media under green conditions. Together with the substitution protocol of electron-donating or -withdrawing groups, all reactions were finalized from 5 to 120 min in water at 90°C. With regard to such reactions, the purification of columns on products was not a requirement. Considering the environmental aspect, use of water as a green solvent, utilization of a reusable catalyst, simple work-up process and steps, as well as rapid reaction times were taken into account as some characteristics of these chemical reactions.