Guanidinylated SBA-15/Fe3O4 mesoporous nanocomposite as an efficient catalyst for the synthesis of pyranopyrazole derivatives

Abstract

In this study, a novel mesoporous nanocomposite was fabricated in several steps. In this regard, SBA-15 was prepared by the hydrothermal method, next it was magnetized by in-situ preparation of Fe3O4 MNPs. After that, the as-prepared SBA-15/Fe3O4 functionalized with 3-minopropyltriethoxysilane (APTES) via post-synthesis approach. Then, the guanidinylated SBA-15/Fe3O4 was obtained by nucleophilic addition of APTES@SBA-15/Fe3O4 to cyanimide. The prepared nanocomposite exhibited excellent catalytic activity in the synthesis of dihydropyrano[2,3-c]pyrazole derivatives which can be related to its physicochemical features such as strong basic sites (presented in guanidine group), Lewis acid site (presented in Fe3O4), high porous structure, and high surface area. The characterization of the prepared mesoporous nanocomposite was well accomplished by different techniques such as FT-IR, EDX, FESEM, TEM, VSM, TGA, XRD and BET. Furthermore, the magnetic catalyst was reused at least six consequent runs without considerable reduction in its catalytic activity.

Facile and General Electrochemical Diselenylation of Terminal Alkynes

“…In recent years, electrochemistry has emerged as a potent platform for the production of a diverse spectrum of organic compounds, enabling the development of more sustainable and greener catalytic techniques. , Recently, a nanocatalyst is also a new, green, and sustainable redox method. − Direct synthesis of trisubstituted alkenes by difunctionalization of terminal alkynes through an eco-friendly electrochemical radical strategy is an ideal approach. Organoselenium compounds represent a valuable class of compounds, being ubiquitous in functional materials, pharmaceuticals, agrochemicals, and natural products. − Chemical synthesis of these materials has long been the focus of research. − Electrochemically driven diselenylation of terminal alkynes has proven elusive.…”

Palladium Nanoparticles on Chitosan-Coated Superparamagnetic Manganese Ferrite: A Biocompatible Heterogeneous Catalyst for Nitroarene Reduction and Allyl Carbamate Deprotection

“…These nanoparticles are efficient catalysts with high magnetic properties and excellent reusability [ 23 ]. Moreover, F. H. Afruzi introduced a novel mesoporous nanocomposite that was magnetized by magnetite nanoparticles (APTES@SBA-15/Fe 3 O 4 ), which exhibited excellent catalytic activity [ 24 ]. A wide range of magnetic catalysts are used for industrial purposes.…”

Highly Active and Efficient Cu@SiO2 Catalyst: Enabled Nucleophilic and Electrophilic Activation of Active Methylene Compounds

“…Another method of enantioselective production of GB is via Michael addition of branched aldehydes with β-nitroacrylates. [14][15][16][17][18][19][20][21][22][23][24][25] Organometallic catalytic systems are widely used to synthesize those crucial molecules. The advantages of the organometallic catalytic system include its high reactivity and selectivity, however nonrecyclable and expensive.…”

“…For instance, our group reported the synthesis of flavouring molecules using AMC and sub‐benzylic alcohols via alkylation‐decarboxylation. Only a few other synthetic methods appeared to facilitate the conversion of AMCs into highly important molecules, such as fructone, coumarin, immine, Gabapentin, and fused acetals Scheme 1 [11–15] …”

“…Notably, GB can be synthesized using multistep chemical and enzymatic routes by adding nitrilase‐mediated hydrolysis with reduction by the Raney nickel catalyst. Another method of enantioselective production of GB is via Michael addition of branched aldehydes with β ‐nitroacrylates [14–25] . Organometallic catalytic systems are widely used to synthesize those crucial molecules.…”