A convenient approach to 2,2′-(1,4-phenylene)bis[1-acetyl-1,2-dihydro-4H-3,1-benzoxazin-4-one] derivatives 4 was explored employing the one-pot condensation of anthranilic acids (=2-aminobenzoic acids) 1 with terephthalaldehyde (=benzene-1,4-dicarboxaldehyde; 2) under ultrasound-irradiation conditions (Scheme 1). The reactions proceeded smoothly in the presence of excess Ac2O in the absence of any other catalyst and solvent to afford the respective products in high yields.

Ultrasound-promoted catalyst-free synthesis of 2,2′-(1,4-phenylene)bis[1-acetyl-1,2-dihydro-4H-3,1-benzoxazin-4-one] derivatives in high yields without other catalysts or solvents.

Paper

Ultrasound‐Promoted Catalyst‐Free Synthesis of 2,2′‐(1,4‐Phenylene)bis[1‐acetyl‐1,2‐dihydro‐4H‐3,1‐benzoxazin‐4‐one] Derivatives

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