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.