Abstract:

2,4,6-Triarylpyrylium salts were synthesized with aromatic aldehydes and aromatic ketones as starting materials. We succeeded in the conversion of these salts with hydroxylamine hydrochloride in water and synthesized the 3, 5-diarylisoxazole derivatives under microwave irradiation. In comparison with literature method, the microwave approach shows the salient features of rapid reaction rates and significant energy saving, clean reaction conditions, enhancement in chemical yield, and nonuse of perchloric acid(70%), which will result in cost saving and minimize safety concerns in the organic laboratory. In addition, the use of aqueous reaction conditions results in simple, environmentally friendly procedures. This rapid and easy technique coupled with water medium may contribute to the dream of Green Technology. The optimum reaction conditions were selected(P=600 W, time=8 min, yield 83%) and twelve compounds were synthesized via this procedure. The structures of the products were confirmed by elemental analysis, MS and 1H NMR spectroscopy.

Key words: Microwave Irradiation, water, triarylpyrylium salts, hydroxylamine hydro- chloride, diarylisoxazoles