An Efficient, High Yielding Protocol for the Synthesis of Functionalized Quinolines via the Tandem ddition/Annulation Reaction of O-Aminoaryl Ketones with α-Methylene Ketones

Quinolines are well known for a wide range of medicinal properties being used as antimalarial,antiasthmatic, antihypertensive, antibacterial and tyrosine kinase inhibiting agents [1].They are also applied for the preparation of nano and meso structures having enhanced electronicand photonic properties [2]. Thus, the synthesis of quinolines is an important and usefultask in organic chemistry. The Friedlander annulation is a straight forward synthesis of thesecompounds [3]. This method involves the acid or base catalyzed or thermal condensation betweenα-2-aminoaryl ketone and another carbonyl compound possessing a reactive α-methylene group followed by cyclodehydration.We recently observed that CaFe2O4@SiO2@SO3H catalyzes the synthesis of quinolines undermild conditions (Fig. 1). Initial research was focused on the reaction between α-2-aminoarylketone and another carbonyl compound possessing a reactive α-methylene group followed bycyclodehydration and different solvents and different amounts of the catalyst were tested tofind the optimized conditions. The easy removal of the catalyst makes this method a suitablechoice for the synthesis of new biologically active compounds. A simple process, short reactiontime, green condition, availability and use of inexpensive reagents make the procedurenovel and unique. High yields (75-96%) are other advantages of our method.