Probing Solid‐Supported Alkali and Alkaline Earth Metal Salts‐Based Catalysts in the Multicomponent Synthesis of Acridine‐1,8‐diones: Box–Behnken and Density Functional Theory (DFT) Study

Solid support catalysts and their applications in synthetic chemistry provide advantages, including significant catalytic efficiency and reduced environmental impact. Alkali and alkaline earth metals have received attention owing to their benign, cost‐effective nature, as well as being eco‐friendly and free from heavy metal disposal concerns. Compared to transition metal salts, such factors make alkali and alkaline earth metals an attractive alternative for catalytic applications. Based on these factors, herein, the solid‐supported catalysts were prepared by adsorbing alkali and alkaline earth metal (Na, K, Mg, Ca, and Ba) salts on silica gel, molecular sieves, and activated charcoal. The catalyst's efficacy was explored by employing it in the synthesis of N ‐heterocyclic acridine‐1,8‐diones ( 4a–d ) through multicomponent reaction. Optimization studies were carried out and further demonstrated via Box–Behnken design (BBD). The effects of three variables, including catalyst loading, temperature, and reaction time, were studied. The response surface and contour plots were developed to demonstrate optimal conditions in the preparation of acridine‐1,8‐diones. The BBD predicted and actual yields, determined by the optimal amount of catalyst, temperature, and reaction time, validate the significance of the study. Structure optimization as well as molecular electrostatics potential (MEP) of acridine‐1,8‐diones ( 4a–d) were also performed via density functional theory (DFT) analysis.