Zn(OAc)₂ · 2H₂O-Catalyzed, Simple, and Clean Procedure for the Synthesis of 2-Substituted Benzoxazoles Using a Grindstone Method

Abstract

Zn(OAc)₂ · 2H₂O efficiently catalyzes the condensation reaction between 2-aminophenol and various araldehydes to afford the 2-substituted benzoxazoles in good to excellent yields. The remarkable features of this protocol are simple and mild reaction conditions, use of readily available catalyst, and shorter reaction time, and in addition the reaction proceeds just by grinding the substrates and catalyst without any solvent and hence matches the green chemistry protocols.

Keywords:

• 2-Aminophenol
• araldehydes
• benzoxazoles
• grindstone method
• solvent-free condition
• Zn(OAc)₂ · 2 H₂O

Notes

^a Reaction condition: Aldehyde (1 mmol), 2-aminophenol (1 mmol), and Zn(OAc)₂ · 2H₂O (0.5 mmol) were ground using a pestle and mortar at rt until the overall mixture turned into a solid.

^b Yields refer to pure isolated products.