Recent Advances in the Synthesis of Coumarin Derivatives via Knoevenagel Condensation: A Review

Vekariya, Rajesh H.

doi:10.1080/00397911.2014.926374

Cited by 209 publications

(99 citation statements)

References 117 publications

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“…Compared to previous reports [25,[42][43][44][45][46][52][53][54][55][56][57][58], this study also demonstrated that the surface area of the catalytic systems can be manipulated by the synthetic methodology. As can be observed from the obtained data, the acidic SiO 2 catalyst varies in the surface area in comparison to the one prepared from TEOS and displays more activity towards the Pechmann reaction.…”

Section: Methodsmentioning

confidence: 80%

“…For that matter, many researchers continue to aim their attention towards the development of simple, cheap, retrieved and/or recyclable catalysts for synthesizing coumarins. For instance, Sripathi and Logeeswari [42] used ultrasound in obtaining coumarin derivatives through the reaction of phenyl acetyl chloride and salicylaldehyde. Meanwhile, Zareyee and Serehneh [43] employed CMK-5 adapted by sulfonic acid as a catalyst to synthesize coumarin from substituted phenols and ethylacetoacetate.…”

Section: Introductionmentioning

confidence: 99%

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Catalytic Activity of Sulfated and Phosphated Catalysts towards the Synthesis of Substituted Coumarin

et al. 2018

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New modified acidic catalysts were prepared from the treatment of silica, titania and silica prepared from hydrolyzed tetraethyl orthosilicate (TEOS) with sulfuric and phosphoric acid. The sulfated and phosphated silica synthesized from TEOS were calcined at 450 and 650 • C. These catalysts were characterized by X-ray diffraction (XRD), Fourier-transform infrared spectroscopy (FTIR), transmission electron microscope (TEM), and scanning electron microscope (SEM). The surface areas, total pore volume, and mean pore radius of the acidic catalysts were investigated, while the pore size distribution was determined by the Barrett, Joyner and Halenda (BJH) method. The catalytic activity of the sulfated and phosphated silica and/or titania were examined with the Pechmann condensation reaction, in which different phenols reacted with ethyl acetoacetate as a neat reaction to obtain the corresponding coumarin derivatives. The results indicated that the treatment of the catalysts with sulfuric or phosphoric acid led to a decrease in the phases' crystallinity to a certain degree. The morphology and the structure of the acidified catalysts were examined and their particle size was calculated. Furthermore, the amount of the used catalysts played a vital role in controlling the formation of the products as well as their performance was manipulated by the number and nature of the active acidic sites on their surfaces. The obtained results suggested that the highest catalytic conversion of the reaction was attained at 20 wt % of the catalyst and no further increase in the product yield was detected when the amount of catalyst exceeded this value. Meanwhile the phenol molecules were a key feature in obtaining the final product.

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Section: Methodsmentioning

confidence: 80%

Section: Introductionmentioning

confidence: 99%

Catalytic Activity of Sulfated and Phosphated Catalysts towards the Synthesis of Substituted Coumarin

et al. 2018

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“…The simplicity and versatility of the coumarin molecule makes it an interesting starting point for a wide range of applications (Matos et al 2015). They are used as technological potential in pharmaceutical, agrochemical, fragrance industries, food, cosmetic industry, and in color technology as optical brightening agents or laser dyes (Daru and Stirling 2011;Santos et al 2013;Venugopala et al 2013;Vekariya and Patel 2014). Coumarins constitute the largest class of fluorescent dyes (Martins et al 2012).…”

Section: Introductionmentioning

confidence: 99%

Fungi as a source of natural coumarins production

Costa

Tavares

Oliveira

2016

Appl Microbiol Biotechnol

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Natural coumarins and derivatives are compounds that occur naturally in several organisms (plant, bacteria, and fungi) consisting of fused benzene and α-pyrone rings. These compounds show high technological potential applications in agrochemical, food, pharmaceuticals, and cosmetics industries. Therefore, the need for bulk production of coumarins and the advancement of the chemical and pharmaceutical industries led to the development of synthetic coumarin. However, biotransformation process, synthetic bioengineering, metabolic engineering, and bioinformatics have proven effective in the production of natural products. Today, these biological systems are recognized as green chemistry innovation and business strategy. This review article aims to report the potential of fungi for synthesis of coumarin. These microorganisms are described as a source of natural products capable of synthesizing many bioactive metabolites. The features, classification, properties, and industrial applications of natural coumarins as well as new molecules obtained by basidiomycetes and ascomycetes fungi are reported in order to explore a topic not yet discussed in the scientific literature.

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“…The Knoevenagel condensation belongs to the important carbon-carbon bond forming reactions in organic synthesis. 39,40 We have adapted Scheme 1, since the Knoevenagel condensation has proven as adequate test reaction for heterogeneous base catalysis over the last decades and is therefore excessively used to evaluate basic catalysts, typically in batch mode. 41 Although heterogeneous organocatalysis in continuous-flow mode (also with silica supports) receives increased attention, [42][43][44] reports on the Knoevenagel reaction with fixed catalyst supports (porous-layer open-tubular design, monoliths, particulate beds) are relatively scarce.…”

Section: Heterogeneously Catalyzed Reactionmentioning

confidence: 99%

High-performance monoliths in heterogeneous catalysis with single-phase liquid flow

et al. 2017

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Hierarchical, macro-mesoporous silica monoliths with domain sizes (sum of mean macropore size and skeleton thickness) of ∼1 μm are highly efficient supports in heterogeneous catalysis with single-phase liquid flow. Their unprecedented performance regarding low backmixing, the elimination of internal and external diffusive transport limitations, as well as the simultaneous realization of a large (internal and external) surface area of the monolith skeleton allow reactor operation under exclusive reaction control. For experimental characterization, the Knoevenagel condensation was employed with an aminopropylated silica monolith integrated into an on-line coupled, high-pressure reaction-analysis system. It allows precise, fully automated adjustment and control of all relevant reaction parameters and promises a boost in the rapid, reproducible determination of the intrinsic reaction kinetics, in general. Hydrodynamic and reaction kinetic parameters identify extreme plug-flow conditions with this high-surface-area, compact type of microreactor and quasi-homogeneous operation in continuous-flow mode.

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Recent Advances in the Synthesis of Coumarin Derivatives via Knoevenagel Condensation: A Review

Cited by 209 publications

References 117 publications

Catalytic Activity of Sulfated and Phosphated Catalysts towards the Synthesis of Substituted Coumarin

Catalytic Activity of Sulfated and Phosphated Catalysts towards the Synthesis of Substituted Coumarin

Fungi as a source of natural coumarins production

High-performance monoliths in heterogeneous catalysis with single-phase liquid flow

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