Ultrasound-assisted synthesis of β-amino ketones via a Mannich reaction catalyzed by Fe3O4 magnetite nanoparticles as an efficient, recyclable and heterogeneous catalyst

In this study, magnetite nanoparticles (Fe3O4 MNPs) were introduced as a heterogeneous novel catalyst for ultrasound-assisted stereoselective synthesis of beta-amino carbonyl during Mannich reaction. For this propose, MNPs with particle size lower than 40 nm were synthesized via a chemical precipitation method. The prepared MNPs were characterized by IR, XRD and SEM and the applicability of the synthesized MNPs for catalysis of Mannich reaction was investigated. An orthogonal array design (OAD) was employed to study the effects of various parameters on the reaction conditions. In order to have the highest reaction yield, the effects of various experimental parameters (four parameters at four levels) including the type of solvent, temperature, amount of catalyst (MNPs) and reaction time were studied with the orthogonal array design method and optimized. The present methodology offers several advantages, such as good yields, short reaction times and a recyclable catalyst with a very easy work up. In addition, the obtained results indicated that MNPs can be used as an effective and inexpensive catalyst for stereoselective synthesis of beta-amino carbonyl by a one-pot three component condensation of aldehydes, ketones and amines. (C) 2012 Production and hosting by Elsevier B.V. on behalf of King Saud University.