A novel, efficient, and recyclable biocatalyst for Michael addition reactions and its iron(iii) complex as promoter for alkyl oxidation reactions

Abstract

Chitosan-g-poly(2-cyano-1-(pyridin-3-yl)allyl acrylate) (Cs-g-PCPA), having a grafting percentage G% of 64%, was prepared and was then subjected to complexation with iron (III) (Cs-g-PCPA/Fe(III)). The results of catalytic studies demonstrated that Cs-g-PCPA serves as an efficient, recyclable and eco-friendly, basic catalyst for Michael additions, which produce adducts in high yields under mild conditions. Moreover, Cs-g-PCPA supported Iron (III) complex was prepared and was then characterized by using FESEM, XRD, TGA, and XPS. In addition, EDS plot of the Fe(III)-chelate, confirms the presence of a relatively high amount (13%) of Fe(III). Cs-g-PCPA (G% = 64) supported Iron (III) complex (Cs-g-PCPA/Fe(III)) in presence of H2O2 can be used to oxidize methyl pyridazinyl carbonitriles to form the corresponding fused furan derivatives efficiently. These polymeric catalysts are stable so that they can be recycled and reused more than five times without losing their catalytic activity.

Synthesis, Characterization of Chitosan-Aluminum Oxide Nanocomposite for Green Synthesis of Annulated Imidazopyrazol Thione Derivatives

“…FTIR spectrum of pure CS revealed a broad O–H stretching band at υ = 3419 cm −1 , caused by intermolecular H– bonding, that is overlapped with an N–H stretching band in the same region. The characteristic bands for amide groups are found in this spectrum at υ = 3446, 1653, and 1609 cm −1 while the bands at 2918, 2875, 1425, and 1380 cm −1 in the spectrum assigned to the C–H bonds in CS chain [ 38 ]. In Figure 1 , the splitting of the broad band above υ = 3000 cm −1, and the appearance of two characteristic bands at 2151 and 2356 cm −1 is considered as evidence of the coordination between Al 2 O 3 and chitosan backbone.…”

Synthesis, structural, dielectric and optical properties of chitosan-MgO nanocomposite

“…It contains hydroxyl and amino functional groups which play an important role in the chemical adsorption of the metal ions [5]. CS and its derivatives, rather than any other polysaccharides, are considered as a powerful template for the preparation of metal oxide nanoparticles (NPs) owing to its unique ability to combine with metal ions via the hydroxyl and amino groups (Figure 1) [6][7][8][9][10].…”

Bringing Homogeneous Iron Catalysts on the Heterogeneous Side: Solutions for Immobilization

“…It is interesting to note how the same reaction was again the subject of another study a few years later [ 111 ]. Khalil et al carried out the same oxidation reaction using Fe 3+ ions immobilized in a chitosan biopolymer grafted with 2-cyano-1-(pyridine-3-yl)allyl acrylate (CPA) ( Figure 20 a).…”

“…The methods used for the synthesis of the biopolymer, for the transformation into spheres and for the complexation of iron were the same as previously reported [ 108 ]. The support, however, showed a greater ability to immobilize the iron cations (0.091 mmol of Fe 3+ /g of chitosan) and the catalyst, overall, led to a higher reaction yield [ 111 ]. The authors also proposed a reaction mechanism consisting of four steps ( Figure 20 b).…”

“… ( a ) Chitosan polymeric chain grafted with 2-cyano-1-(pyridin-3-yl)allyl acrylate (CPA); ( b ) Proposed mechanism of the oxidation reaction of methylpyridazone using grafted chitosan with immobilized Fe 3+ ions (Cs–Fe 3+ ) as catalyst (Ar = phenyl, 4-chlorophenyl) [ 111 ]. …”