Convenient and Robust Metal-Free Synthesis of Benzazole-2-Ones Through the Reaction of Aniline Derivatives and Sodium Cyanate in Aqueous Medium

Benzazole-2-ones (benzimidazolones, benzothiazolones, benzoxazolones) are important derivatives of benzazole compounds that exist widely in many biologically and pharmaceutically active molecules. Furthermore, benzazole-2-one derivatives also have many applications in agrochemical and material science. Herein, a novel, practical and green synthesis of titled compounds by the reaction of aniline derivatives with inexpensive and easily accessible sodium cyanate has been reported. Good to excellent yields of products have been obtained under catalyst- and ligand-free conditions in water as solvent. This procedure avoids the use of time-consuming and tedious column chromatography and the products were easily isolated by simple extraction followed by washing with dichloromethane.