Ultrasound promoted clay catalyzed efficient and one pot synthesis of substituted oxindoles

A simple facile, one-pot synthesis of oxindoles in reasonable purity is reported via intramolecular Friedal–Craft cyclization. Clay KSF is an inexpensive, efficient and mild catalyst for the synthesis of substituted oxindoles by the reaction of chloroacetyl chloride and various anilines under the influence of ultrasonic irradiation under solvent-free conditions. The remarkable advantages of this method are the simple experimental procedures, short reaction times, high yields of products, suitability for a wide variety of substituents, and the green aspects through the avoidance of toxic catalyst and solvents.