Fe(HSO4)3/SiO2: An efficient and heterogeneous catalyst for cyclization of 2-aminochalcones to 2-aryl-2,3-dihydroquinolin-4(1H)-ones

Silica ferric hydrogensulfate is an efficient heterogeneous catalyst for the cyclization of 2- aminochalcones to the corresponding 2,3-dihydroquinolin- 4(1H)-ones. This intramolecular aza Michael reaction was carried out in high yields using chalcones bearing of electron donating and electron withdrawing groups. The catalyst is reusable without significant decreases in its activity after four times recycling.