Green preparation of tetrahydrobenzimidazo[۲,۱-b]quinazolin-۱(۲H)-ones using γ-Fe_۲O_۳@KSF as novel and recyclable magnetic catalyst

The preparation of tetrahydrobenzimidazo[۲,۱-b]quinazolin-۱(۲H)-ones via a γ-Fe۲O۳@KSF-catalyzed multicomponent coupling reaction of ۲-aminobenzimidazole, benzaldehydes, and dimedone in solvent-free conditions is reported. γ-Fe۲O۳@KSF as a magnetic catalyst was prepared using the successive coating of a γ-Fe۲O۳ shell on a KSF core and was characterized by different methods including FT-IR, XRD, TGA and SEM techniques. The merits of this method include limited use of organic solvents, excellent purity of products, and an easy workup technique. The tetrahydrobenzimidazo[۲,۱-b]quinazolin-۱(۲H)-ones were prepared in yields of ۸۸-۹۴%. The catalyst was recovered through an external magnet and reused four times without any considerable loss of its activity.

Keywords:

Quinazolinone , γ-Fe۲O۳@KSF , multicomponent , Solvent-free , magnetic