Recyclable Keggin Heteropolyacids as an Environmentally Benign Catalyst for the Synthesis of New 2-Benzoylamino-N-phenyl-benzamide Derivatives under Microwave Irradiations at Solvent-Free Conditions and the Evaluation of Biological Activity

2-Benzoylamino-N-phenyl-benzamide derivatives (5a–h) were prepared from 2-phenyl-3,1-(4H)-benzoxazin-4-one 3 and substituted anilines 4a–h in the presence of a Keggin-type heteropolyacids series (H3PW12O40·13H2O; H4SiW12O40·13H2O; H4SiMo12O40·13H2O; and H3PMo12O40·13H2O) as catalysts without solvent and under microwave irradiation. We found that the use of H3PW12O40·13H2O acid coupled to microwave irradiation allowed obtaining a high-yielding reaction with a short time. The compound structures were established by 1H-NMR and 13C-NMR. The antibacterial and antifungal activities of the synthesized compounds exhibited an inhibition of the growth of bacteria and fungi.