A highly efficient eco-friendly AFO reaction using grinding technique: synthesis of 3-hydroxy-2-phenyl-4H-chromen-4-ones

2′-Hydroxychalcones, on reaction with urea-hydrogen peroxide complex (UHP) and potassium hydroxide moist with ethanol, under grinding conditions, provided 3-hydroxy-2-phenyl-4H-chromen-4-ones (3-hydroxyflavones or flavonols) in excellent yields. Epoxidation followed by oxidative cyclization takes place simultaneously in a single pot reaction