Withdrawal Notice: MgAl2O4 Spinel-type as Highly Efficient Catalyst for One-pot Synthesis of 4H-pyrans

Abstract

Background: Pyran is an heterocyclic oxygen-containing compound that displays a wide range of therapeutic activities. Additionally, pyran is also one of the important structural subunits widely found in pharmaceuticals products. This makes it a recent focus for researchers from the industry and academic institutions. Herein, we reported an efficient and environmentally friendly one-pot strategy for the synthesis of bioactive 4H-pyran compounds via a multicomponent reaction of ethyl acetoacetate, malononitrile and substituted aromatic aldehydes in the presence of the heterogeneous spinel catalyst ( MgAl2O4 ) under mild conditions (room temperature and green solvents). The MgAl2O4 nanocatalyst was prepared from Mg/Al-LDH with a molar ratio 3 of Mg2+/Al3+ by heat treatment at 800°C. The samples were studied by a various characterization techniques such as XRD, TG-dTG, FT-IR and N2 adsorption-desorption. Good to excellent yields and facile separation of the catalyst from the reaction mixture are two of the most appealing features of this approach. Thus, bioactive molecules with pyran units may have fascinating biological properties. An efficient and green strategy for the one-pot synthesis of bioactive 4H-pyran compounds has been described. The pyrans heterocycles were produced by multicomponent reaction of ethyl acetoacetate, malononirile and substituted aromatic aldehydes in the presence of MgAl2O4 spinel nanocatalyst under mild conditions (room temperature and green solvents). MgAl2O4 nanocatalytst was prepared from Mg/Al-LDH with a molar ratio 3 of Mg2+/Al3+ by thermal treatment at 800°C. The samples were investigated by various characterization techniques such as XRD, TG-dTG, FT-IR and N2 adsorption-desorption. The following are the appealing qualities of this unique strategy including good to exceptional yields, and ease of separation of catalyst from the reaction mixture. Thus, the obtained bioactive compounds containing pyrans motif can be exhibiting interested biological activities. Methods: The substituted 4H-pyran compounds were carried out by condensation reaction of substituted aromatic aldehydes, ethyl ethyl acetoacetate and malononirile by using MgAl2O4 nanocatalyst under sustainable conditions. Objective: To develop an efficient methodology for synthesis of 4H-pyran heterocyclic molecules may have interesting applications in biology using a heterogeneous and easily synthesized catalyst. Results: This procedure outlines the synthesis of bioactive compounds in good yields and with ease of catalyst extraction from the reaction mixture under sustainable reaction conditions. Conclusion: In conclusion, it is important to reiterate that a spinel nanostucture has been successfully prepared and fully characterized using different physicochemical analysis methods. The catalytic activity of this heterogeneous catalyst was examined through the one-pot condensation of aryl benzaldehyde, malononitrile and ethyl acetoacetate. Therefore, we have developed a green method for the preparation of 4H-pyrans derivatives using MgAl2O4 as an efficient heterogeneous catalyst. The reactions were performed under green conditions, which have many benefits such as undergoing a simple procedure, good to excellent yields and easy to separate the catalyst.

Variation in Catalytic Efficacies of a 2D pH‐Stable MOF by Altering Activation Methods

“…The literature outlines an array of porous substrates as essential heterogeneous catalysts, attributable to their inherent multifunctional characteristics. Examples include spinel ferrites, meso/macroporous metal oxides, layered double hydroxides, (LDHs), zeolitic structures, and two‐dimensional graphene‐based materials [4–7] . On the other hand, several superior inherent properties of the Metal‐Organic Frameworks (MOFs) such as well‐ordered porous structures, [8–11] high surface areas, [12] functional organic linkers [13–14] and catalytically active sites [15–24] have been marked them out as prominent candidates for various application domains [8] such as gas storage [15,20,25–28] and separation, [10,15–17,20,27,29–35] catalysis, [15–24,36–42] sensing, [15,17,43–56] energy storage, [9,19,35,57–64] and drug delivery [20] and so on.…”

“…Examples include spinel ferrites, meso/macroporous metal oxides, layered double hydroxides, (LDHs), zeolitic structures, and two-dimensional graphenebased materials. [4][5][6][7] On the other hand, several superior inherent properties of the Metal-Organic Frameworks (MOFs) such as well-ordered porous structures, [8][9][10][11] high surface areas, [12] functional organic linkers [13][14] and catalytically active sites [15][16][17][18][19][20][21][22][23][24] have been marked them out as prominent candidates for various application domains [8] such as gas storage [15,20,[25][26][27][28] and separation, [10,[15][16][17]20,27,[29][30][31][32][33][34][35] catalysis, [15][16][17][18][19][20]…”

“…In view of the aforementioned discussions, using mixed ligand synthesis approach, we have strategically designed and developed a pH-stable, 2D Co-MOF, IITKGP-60, {[Co-(L)(PDAA)(H 2 O) 2 ] • 2H 2 O} n (where PDAA = 1,4-Phenylenediacetic acid, L = 1,4-bis(3-pyridyl)-2,3-diaza-1,3-butadiene) (Scheme 1), which exhibited excellent stability under a wide range of aqueous pH solutions (2)(3)(4)(5)(6)(7)(8)(9)(10)(11)(12). The developed MOF possessed abundant coordinated water molecules, which upon thermal activation generated the activated framework bearing ample number of OMSs.…”

“…(2)(3)(4)(5)(6)(7)(8)(9)(10)(11)(12) stable 2D MOF, IITKGP-60, efficient for heterogeneous catalysis reactions. The activated 2D framework features easily accessible open metal sites appropriate for interaction with the guest substrate molecules.…”