An expeditious, efficient and green synthesis of some 2-arylbenzoxazoles catalyzed by PTSA under solvent-free condition

A simple, efficient and rapid procedure for the preparation of various 2-substituted benzoxazoles (3) has been developed. The reaction of o -aminophenol with various substituted aromatic aldehydes proceeds smoothly in the presence of p- toulene sulfonic acid (PTSA) as a solid catalyst at room temperature. The products were obtained in excellent yield in very short time. Mild reaction conditions, clean reaction media, simple workup and easy purification are advantages of this methodology.