Fe3O4@SiO2-NH2 Nanocomposite as a Robust and Effective Catalyst for the One-pot Synthesis of Polysubstituted Dihydropyridines

Abstract

A practical, simple and efficient method for the synthesis of polysubstituted dihydropyridines was described via multicomponent reactions of aldehydes, arylamines, dimethyl acetylenedicarboxylate and malononitrile/ethyl acetoacetate in the presence of Fe 3 O 4 @SiO 2 -NH 2 nanocomposites. The present methodology provides a novel and efficient method for the synthesis of dihydropyridine derivatives with some advantages, such as excellent yields, short reaction times, recoverability and low catalyst loading. The nanomagnetic catalyst could be readily recovered using an external magnet and reused several times without any significant loss in activity. The catalyst was fully characterized by FT-IR, SEM, XRD, EDX and VSM analysis.

An Efficient One-Pot Synthesis of Benzimidazoles Using Magnetically Recoverable Catalyst Chromium Doped Nickel Copper Zinc Spinel Ferrite

“…After completion of reaction (monitored by TLC), catalyst recycling was achieved by fixing the catalyst magnetically at the bottom of the flask with a strong magnet, after which the solution was taken off, the solid catalyst washed twice with acetone, dried at room temperature and the fresh substrate was introduced into the flask, allowing the reaction to proceed for the next run. The catalyst was consecutively reused five times widths light loss of its catalytic activity 9 (Cycle number and yield of 3a: 1, 97 %; 2, 97 %; 3, 96 %; 4, 96 %; 5, 95 %), may be due to negligible leaching out of metals from ferrite system. 30 These catalysts are highly magnetic therefore; they could be easily and almost completely separated by an external magnet which is of a great advantage for a heterogeneous catalyst.…”

“…Especially the ferro-spinels have been shown to be selective and active catalysts 4 and exhibit extra stability under various reaction conditions. 5 Now a days, functionalized magnetic nanoparticles used as effective catalyst in different chemical reactions including synthesis of 1,1 diacetates 6 , diazepine derivatives 7 , α-amino acids 8 , 1,4-dihydropyridines 9 , etc. For these applications of metal oxides as heterogeneous catalysts, high surface area and accessible porosity are relevant properties.…”

Ultrasound Assisted 1,4-diazabicyclo[2.2.2] Octaniumdiacetate Multicomponent Synthesis of Benzodiazepines: A Novel, Highly Efficient and Green Protocol

“…[16][17][18] Multicomponent reactions (MCRs) are efficient tools in modern synthetic organic chemistry because they are fast, simple, offer high-atomic efficiency, are environ-mentally friendly and save time and energy. [19][20][21][22][23] On the other hand, ionic liquids are suitable compounds because they are non-flammable, non-volatile, soluble, exhibit polarity and are highly thermal and chemically stable. 24 MCRs combined with ionic liquid can assist in the synthesis of the benzodiazepines to reduce the cost of starting materials and decrease the generation of undesirable by-products.…”

Preparation and catalytic study on a novel amino-functionalized silica-coated cobalt oxide nanocomposite for the synthesis of some indazoles

“…[11][12][13] This led to the idea of preparing an active catalyst, Co 3 O 4 @SiO 2 @NH 2 , through morphology-controlled synthesis which ensure that faces which are active specifically are exposed predominantly at the surface. As well as, to the best of our knowledge, no attempt has been made to synthesis of Co 3 In continuing our efforts towards the development of efficient and environmentally benign heterogeneous catalysts, [14][15][16][17][18] herein, Co 3 O 4 @SiO 2 @NH 2 nanocomposite was prepared as a highly efficient magnetic catalyst by a simple method. The main goal of this catalytic synthesis was to introduce a novel and effective magnetic nanocomposite to expand the use of these types of composites for organic reactions.…”