Rezayati S, Kalantari F, Ramazani A, Sajjadifar S, Aghahosseini H, Rezaei A. Magnetic Silica-Coated Picolylamine Copper Complex [Fe
3O
4@SiO
2@GP/Picolylamine-Cu(II)]-Catalyzed Biginelli Annulation Reaction.
Inorg Chem 2021;
61:992-1010. [PMID:
34962386 DOI:
10.1021/acs.inorgchem.1c03042]
[Citation(s) in RCA: 20] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Abstract
An efficient and heterogeneous novel magnetic silica-coated picolylaminecopper complex [Fe3O4@SiO2@GP/Picolylamine-Cu(II)] was synthesized, characterized, and employed as a magnetically recoverable nanocatalyst in Biginelli condensation for the preparation of biologically active 3,4-dihydropyrimidinones. Fe3O4@SiO2@GP/Picolylamine-Cu(II) was synthesized easily using chemical attachment of the picolylaminecompound on Fe3O4@SiO2@GP, followed by treatment with copper salt in ethanol under reflux conditions. Fe3O4@SiO2@GP/Picolylamine-Cu(II) was affirmed by various analyses such as Fourier transform infrared, thermogravimetric analysis, X-ray diffraction, vibrating-sample magnetometry, field-emission scanning electron microscopy, transmission electron microscopy, DLS, inductively coupled plasma, energy-dispersive X-ray spectrometry, X-ray photoelectron spectroscopy, and Brunauer-Emmett-Teller. The resulting catalyst system was successfully used in the Biginelli reaction through a variety of compounds such as aromatic aldehyde, urea, and ethyl acetoacetate under solvent-free conditions or ethylene glycol at 80 °C and yielded the desired products with high conversions with powerful reusability. The current approach was convenient and clean, and only 0.01 g of the catalyst could be used to perform the reaction. The easy work-up procedure, gram-scale synthesis, usage of nontoxic solvent, improved yield, short reaction times, and high durability of the catalyst are several remarkable advantages of the current approach. Also, the Fe3O4@SiO2@GP/Picolylamine-Cu(II) nanocatalyst could be recycled by an external magnet for eight runs with only a significant loss in the product yields.
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