A green approach for the synthesis of 2-substituted benzoxazoles and benzothiazoles via coupling/cyclization reactions

We have developed the green method for the synthesis of benzoxazoles and benzothiazoles with moderate to good yields using imidazolium chlorozincate (II) ionic liquid supported into Fe₃O₄ nanoparticles (LAIL@MNP) under solvent-free sonication. The reaction was performed under mild conditions and only produced water as a sole byproduct. The reactions under solvent-free sonication showed advantages of faster reaction rate (30 min) and high yields of the products (up to 90%). Moreover, the LAIL@MNP material was easily separated from the reaction mixture and can be recycled for five consecutive runs with a slight decrease in its catalytic performance (from 82 to 73%).