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Silica Sulfuric Acid Catalyzed Synthesis of Benzoxazoles, Benzimidazoles and Oxazolo[4,5-b]pyridines Under Heterogeneous and Solvent-Free Conditions

Mohammadpoor-Baltork نويسنده , Moghadam M. نويسنده , Tangestaninejad S. نويسنده , Mirkhani V. نويسنده , Zolfigol M.A. نويسنده , Hojati S.F. نويسنده

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This paper is dedicated to Professor H. Firouzabadi for his great contribution to the development of organic chemistry in the country in the occasion of his 65th birthday and also his retirement. A simple, rapid and efficient method for the preparation of benzoxazoles, benzimidazoles and oxazolo[4,5-b]pyridines from the reaction of orthoesters with o-aminophenols, o-phenylenediamine and 2-amino-3-hydroxypyridine in the presence of silica sulfuric acid under heterogeneous and solvent-free conditions is reported. The significant features of this method are short reaction times, high yields of the products, mild reaction conditions, solvent free reaction, cheapness, non-toxicity and reusability of the catalyst.

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