DBU-functionalized MCM-41-coated nanosized hematite (DBU-F-MCM-41-CNSH): a new magnetically separable basic nanocatalyst for the diastereoselective one-pot four-component synthesis of 2-(N-carbamoylacetamide)-substituted 2,3-dihydrothiophenes†
DBU-functionalized MCM-41-coated nanosized hematite (DBU-F-MCM-41-CNSH) was prepared as a new magnetically separable mesoporous nanomaterial and was characterized by various techniques such as FT-IR, XRD, HR-TEM, FESEM, BET, VSM and elemental analyses (CHN and ICP). The synthesized magnetic mesoporous nanomaterial was applied successfully as a basic nanocatalyst for the diastereoselective synthesis of 2-(N-carbamoylacetamide)-substituted 2,3-dihydrothiophenes through a one-pot four-component reaction of aryl aldehydes, primary and secondary amines, 1,3-thiazolidinedione and malononiterile in a 1 : 2 v/v mixture of EtOH/H2O at 60 °C. Using this method, all desired products were obtained in good to excellent yields (83–94%) after short times (25–45 min). The chemical and physical stability of the catalyst was proved by studying its chemical structure using the same analyses after the 8th reuse.