Polymer-Shell-Encapsulated Magnetite Nanoparticles Bearing Hexamethylenetetramine for Catalysing Aza-Michael Addition Reactions

Polymer-encapsulated magnetite nanoparticles bearing Hexamethylenetetramine (Fe3O4@HMTA) have been developed for catalysing the aza-Michael addition to form beta-amino compounds. The effects of solvent, amount and reuse on catalytic activity of the Fe3O4@HMTA have been studied. The catalytic activity of the Fe3O4@HMTA has not deteriorated during successive recycling. Eight different substrates have been subjected to aza-Michael additions, and yields of the products in the range of 50-90 % have been observed in the presence of catalyst depending upon the substituent groups in the reactants. The formation of a single chiral adduct by reacting a acrylamide derivative of l-proline benzyl ester with morpholine seems to suggest that the reaction conditions preclude the racemization of products.