Green chemistry approach to the synthesis of 2-aryl/heteroaryl substituted 2,3-dihydroquinazolin-4(1H)-ones using lemon juice under concentrated solar radiations as a renewable source†

This study explores a novel and eco-friendly synthesis of 22 derivatives of 2-aryl/heteroaryl substituted 2,3-dihydroquinazolin-4(1H)-ones, compounds with significant medicinal potential, using concentrated solar radiation (CSR) and lemon juice as a natural catalyst. Traditional methods for synthesizing these compounds often involve complex, energy-intensive processes and toxic reagents. In contrast, the method presented here utilizes solar energy and a biodegradable, non-toxic catalyst, aligning with the principles of green chemistry. The reaction, involving 2-aminobenzamide and various aromatic and heteroaromatic aldehydes, was optimized by varying temperature, catalyst concentration, and solvent. Through optimization, a combination of 0.3 mL of lemon juice and CSR achieved a 97% product yield in 10 minutes. A wide range of aromatic and heteroaromatic aldehydes were tested, all of which produced excellent yields, confirming the method's broad applicability. The substrate scope was explored with different aldehydes, containing groups/structures like chloro, bromo, nitro, methyl, methoxy, fluoro, hydroxy, imidazole, thiazole, chromone, pyrrole, and 1,4-dioxane, yielding up to 97%. Comparative studies with other catalysts and solvents confirmed the superior efficiency of lemon juice. This study not only demonstrates a sustainable approach to synthesizing 2,3-dihydroquinazolin-4(1H)-ones but also highlights the potential of solar energy in organic synthesis, offering a viable alternative to conventional methods. This environmentally benign method offers an efficient and sustainable route for synthesizing 2,3-dihydroquinazolin-4(1H)-one derivatives.