Ferric Hydrogensulfate-Catalyzed One-Pot Synthesis of Indeno[1,2-b]quinoline-7-ones

Ferric hydrogensulfate was found to be an efficient catalyst for the three-component synthesis of indeno[1,2-b]quinoline-7-one derivatives through one-pot condensation of 1-naphthylamine or 1-antharacylamine, aromatic aldehydes, and 1,3-indandione. The catalyst could be recovered conveniently and reused at least four times without any loss of activity. The efficient method has the advantages of inexpensiveness of the catalyst, short reaction times, simplicity, easy workup, and good to excellent yields.