A novel superparamagnetic powerful guanidine-functionalized γ-Fe2O3 based sulfonic acid recyclable and efficient heterogeneous catalyst for microwave-assisted rapid synthesis of quinazolin-4(3H)-one derivatives in Green media.

The novel organic-inorganic nanohybrid superparamagnetic (γ-Fe2O3@CPTMS-guanidine@SO3H) nanocatalyst modified with sulfonic acid represents an efficient and green catalyst for the one-pot synthesis of quinazolin-4(3H)-one derivatives via three-component condensation reaction between anthranilic acid, acetic anhydride and different amines under microwave irradiation and solvent-free conditions (4a-q). XRD, FT-IR, FE-SEM, TGA, VSM and EDX were used to characterize this new magnetic organocatalyst. Outstanding performance, short response time (15-30 min), simple operation, easy work-up procedure, and avoidance of toxic catalysts can be regarded as its significant advantages. Moreover, it can be easily separated from the reaction solution through magnetic decantation using an external magnet, and recycled at least six times without notable reduction in its activity.