Alum (KAl(SO4)2·12H2O)-Catalyzed, Eco-Friendly, and Efficient One-Pot Synthesis of 2-Arylbenzothiazoles and 2-Arylbenzoxazole in Aqueous Medium

Alum (KAl(SO4)2·12H2O) performs as a novel catalyst for the synthesis of 2-arylbenzothiazoles and 2-arylbenzoxazole from o-aminothiophenol and o-aminophenol with various substituted aldehydes in good to excellent isolated yields (85–95%) using water as a solvent at ambient temperature. Several solvents were examined for this reaction; however, in terms of reaction yield and time, water was found to be the optimum solvent. The remarkable advantages offered by this method are an inexpensive and easily available catalyst, a simple procedure, mild conditions, much faster (60–90 min) reactions, and good to excellent yields of products.

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