The cavities of SBA mesoporous silica materials can be used as nanoreactors for embedding catalytic species such as nanoparticles, complexes and heteropolyacids etc. The encapsulated catalysts are renowned as superior catalytic systems regarding their catalytic activity, selectivity and reusability as well as suppressed leaching. An efficient method to improve the encapsulation of these catalysts, is in creating anchors for capturing catalytic species. It has been performed by functionalization of the surface of SBA mesoporous silica materials with various groups including sulfur, phosphorus and amine-based functional groups. The aim of this article is to review the recent advances (2014–2017) in the field of the utility of functionalized SBA for developing encapsulated catalysts. In most cases the reusability of the catalyst and the leaching of the catalytic active species were discussed to disclose the role of functionalized SBA in heterogenizing and suppressing the leaching. Moreover, to show the superiority of these developed encapsulated catalysts, with a couple of examples we compared their catalytic activities with those of the conventional ones.

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Current advances in the utility of functionalized SBA mesoporous silica for developing encapsulated nanocatalysts: state of the art

A retrievable nanostructure heterogeneous catalyst, based on lipase (lipase from the fungus Aspergillus niger), namely Fe3O4-bonded lipase (Fe3O4 NPs@ lipase) was prepared in nano size and fully characterized by several techniques such as Fourier transform infrared spectroscopy, X-ray diffraction, Scanning electron microscopy, Transmission electron microscopy and Vibrating sample magnetometer. The retrievable nanostructure catalyst was asserted to be an efficient catalyst in the synthesis of benzothiazepine and spirobenzothiazine chroman derivatives through three-component reaction of coumarine-3-carboxylic acid derivatives, 2-aminothiophenol, and alkyl isocyanides at room temperature under mild conditions. .

Synthesis and Characterization of Immobilized Lipase on Fe 3 O 4 Nanoparticles as Nano biocatalyst for the Synthesis of Benzothiazepine and Spirobenzothiazine Chroman Derivatives

In recent years, spiro compounds have attracted significant interest in medicinal chemistry due to their numerous biological activities attributed primarily to their versatility and structural similarity to important pharmacophore centers. Currently, the development of drugs with potential antioxidant activities is of great importance since numerous investigations have shown that oxidative stress is involved in the development and progression of numerous diseases such as cancer, senile cataracts, kidney failure, diabetes, high blood pressure, cirrhosis, and neurodegenerative diseases, among others. This article provides an overview of the synthesis and various antioxidant activities found in naturally occurring and synthetic spiro compounds. Among the antioxidant activities reviewed are DPPH, ABTS, FRAP, anti-LPO, superoxide, xanthine oxidase, peroxide, hydroxyl, and nitric oxide tests, among others. Molecules that presented best results for these tests were spiro compounds G14, C12, D41, C18, C15, D5, D11, E1, and C14. In general, most active compounds are characterized for having at least one oxygen atom; an important number of them (around 35%) are phenolic compounds, and in molecules where this functional group was absent, aryl ethers and nitrogen-containing functional groups such as amine and amides could be found. Recent advances in the antioxidant activity profiles of spiro compounds have shown that they have a significant position in discovering drugs with potential antioxidant activities.

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Spirocyclic derivatives as antioxidants: a review

Incorporating sulfanilic acid as a hydrophobic Bronsted acid inside the nanospaces of SBA-15 led to a water-tolerant solid acid catalyst, SBA-15-PhSO3H, which showed excellent catalytic performance in synthesis of uracil-fused spirooxindoles in aqueous ethanol. The synthesized compounds were evaluated for their antioxidant activity by 1,1-diphenyl-2-picrylhydrazyl (DPPH) radical-scavenging assay.

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Sulfanilic acid functionalized mesoporous SBA-15: A water-tolerant solid acid catalyst for the synthesis of uracil fused spirooxindoles as antioxidant agents

Among isatin-based heterocyclic, spirooxindoles are interesting synthetic molecules because of their variety of pharmacological activities. There is a wide range of multi-component reactions that cover this topic. This review covers the different synthesis methods of spirooxindoles reported by Iranian researchers in the last 15 years.

Recent investigations in the synthesis of spirooxindole derivatives by Iranian researchers

A series of spiro-pyranoxindole derivatives were prepared in good yields via a three-component reaction of isatins with activated methylene reagents and kojic acid using 1,4-diazabicyclo[2.2.2]octa...

BaharfarRobabeh

Papers

DABCO-functionalized mesoporous SBA-15: an efficient and recyclable catalyst for the synthesis of spiro-pyranoxindoles as antioxidant agents