Ultrasonic‐Assisted Synthesis of Isoxazolo‐Fused‐Indenopyridine: A Simple and Chemoselective Approach

Herein, we present a novel and efficient one‐pot synthesis method utilizing ultrasonic assistance for the preparation of 5‐oxo‐3‐aryl‐5 H ‐indeno[1,2‐ b ]isoxazolo[4,5‐ e ]pyridine‐4‐carbonitrile by the three‐component reaction of ninhydrin, malononitrile, and 5‐amino‐isoxazoles in ethanol. This method's advantages are environmentally friendly, short reaction time, easy purification process, and formation of three new bonds (two C–C and one C–N) in one‐pot regioselective and chemoselective reaction. We confirmed the structures of the target compounds via X‐ray diffraction studies.