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

Abstract

2-Benzoylamino-<i>N</i>-phenyl-benzamide derivatives (<b>5a</b>-<b>h</b>) were prepared from 2-phenyl-3,1-(4<i>H</i>)-benzoxazin-4-one <b>3</b> and substituted anilines <b>4a</b>-<b>h</b> 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.