Efficient synthesis of supported proline catalysts for asymmetric aldol reactions

Elmekawy, Ahmed; Sweeney, Joseph; Brown, David R.

doi:10.1039/c4cy00970c

Cited by 28 publications

(24 citation statements)

References 34 publications

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“…37 In continuation, the OH groups on the titanium coating magnetic nanoparticles (Fe 3 O 4 @ TiO 2 ) can be functionalized with 3-chloropropyltriethoxysilan molecule. 38 Next, the new catalyst 1 was obtained by replacing chloride group using molybdic acid. The structure of the nanocatalyst 1 was studied and fully characterized using SEM, EDX, VSM, XRD, and FT-IR.…”

Section: Resultsmentioning

confidence: 99%

Molybdic Acid-Functionalized Nano-Fe3O4@TiO2 as a Novel and Magnetically Separable Catalyst for the Synthesis of Coumarin-Containing Sulfonamide Derivatives

Farahi

Karami

Abdollahi

2020

ACSi

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Supported molybdic acid on nano-Fe 3 O 4 @TiO 2 (Fe 3 O 4 @TiO 2 @(CH 2) 3 OMoO 3 H) has been successfully prepared, characterized and applied as a catalyst for the synthesis of sulfonamide containing coumarin moieties. The prepared Fe 3 O 4 nanoparticles by coprecipitation of Fe 2+ and Fe 3+ ions were treated with tetraethyl orthotitanate to obtain Fe 3 O 4 @TiO 2. By anchoring 3-chloropropyltriethoxysilan on Fe 3 O 4 @TiO 2 followed by reacting with molybdic acid, the desired catalyst was produced. The synthesized catalyst was characterized using XRD, SEM, EDS, FT-IR and VSM analysis. Fe 3 O 4 @TiO 2 @ (CH 2) 3 OMoO 3 H was used as a catalyst for the synthesis of sulfonamide containing coumarin moieties via a three-component reaction of aryl aldehydes, para-toluenesulfonamide and 4-hydroxycoumarin or 5,7-dihydroxy-4-methylcoumarin. The catalyst recovery test showed the catalyst is highly reusable without losing its activity.

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Section: Resultsmentioning

confidence: 99%

Molybdic Acid-Functionalized Nano-Fe3O4@TiO2 as a Novel and Magnetically Separable Catalyst for the Synthesis of Coumarin-Containing Sulfonamide Derivatives

Farahi

Karami

Abdollahi

2020

ACSi

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“…The investigated optical nanosensors, NPAN‐SBA‐15, NPAN‐SBA‐16 and NPAN‐MCM‐41, Scheme , were synthesized as follows: 1.0 g of chloro‐functionalized SBA‐15 or SBA‐16 or MCM‐41 was suspended in 20 ml xylene at 140 °C and stirred for 1 h, then 2 mmol (0.26 g) from the synthesized azo dye was added with constant stirring at the same temperature. After 12 h, the solid product was filtered.…”

Section: Methodsmentioning

confidence: 99%

Development of nanomaterial chemosensors for toxic metal ions sensing

Fayed

El‐Nahass

El‐Daly

et al. 2019

Applied Organom Chemis

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Heavy metal ions are harmful to aquatic life and humans owing to their high toxicity and non-biodegradability, so their removal from wastewater is an important task. Therefore, this work focuses on designing suitable, simple and economical nanosensors to detect and remove these metal ions with high selectivity and sensitivity. Based on this idea, different types of mesoporous materials such as hexagonal SBA-15, cubic SBA-16 and spherical MCM-41, their chloro-functionalized derivatives, as well as 4-(4-nitro-phenylazo)naphthalen-1-ol (NPAN) azo dye have been synthesized, with the aim of designing some optical nanosensors for metal ions sensing applications. The mentioned azo dye has been anchored into the chloro-functionalized mesoporous materials. The designed nanosensors were characterized using scanning and transmission electron microscopy as well as Fourier transform infrared and UV-visible spectral analysis, nitrogen adsorption-desorption isotherms, low-angle X-ray diffraction and thermogravimetric analyses. Their optical sensing to various toxic metal ions such as Cd (II), Hg (II), Mn (II), Fe (II), Zn (II) and Pb (II) at different values of pH (1.1, 4.9, 7 and 12) was investigated. The optimization of experimental conditions, including the effect of pH and metal ion concentration, was examined. The experimental results showed that the solution pH had a major impact on metal ion detection. The optical nanosensors respond well to the tested metal ions, as reflected by the enhancement in both absorption and emission spectra upon adding different concentrations of the metal salts and were fully reversible on adding ethylene diamine tetra acetic acid or citric acid to the formed complexes. High values of the binding constants for the designed nanosensors were observed at pHs 7 and 12, confirming the strong chelation of different metals to the nanosensor at these pHs. Also, high binding constants and sensitivity were observed for NPAN-MCM-41 as a nanosensor to detect the different metal ions. From the obtained results, we succeeded in transforming the harmful azo dye into an environmentally friendly form via designing of the optical nanosensors used to detect toxic metal ions in wastewater with high sensitivity.

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“…6 As such, there have been ongoing efforts to find means of efficiently producing single enantiomers. 7 Pure enantiomers can often be obtained from asymmetric syntheses using various chiral catalysts, including organometallics, enzymes, and organocatalysts. Unlike chiral organometallic catalysts, chiral organocatalysts [8][9][10][11][12][13][14][15][16][17][18][19][20] do not incorporate metals, and so reduce the risk of metal contamination in the product as well as the potential for environmental effects.…”

Section: Introductionmentioning

confidence: 99%

Synthesis of polymer microsphere‐supported chiral pyrrolidine catalysts by precipitation polymerization and their application to asymmetric Michael addition reactions

Debnath

Oyama

Ono

et al. 2021

Journal of Polymer Science

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Polymer microsphere-supported chiral pyrrolidine catalysts were successfully synthesized by a precipitation polymerization incorporating a methacrylate monomer bearing chiral N-Boc-pyrrolidine moiety, followed by removal of the N-Boc groups. The resulting polymeric catalysts were applied to the asymmetric Michael addition reactions of aldehydes with alkyl vinyl ketones. The effects of the comonomer, the molar ratios within the catalyst, the catalyst loading, the temperature, and the solvent on the catalytic performance were investigated in detail. The reactions were found to proceed smoothly in the absence of a solvent. A hydrophobic polystyrene-based chiral pyrrolidine catalyst exhibited high reactivity (up to 97% yield) and enantioselectivity (up to 95% ee) during these reactions. The catalyst could also be recovered and reused up to five times without significant loss of activity.

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Efficient synthesis of supported proline catalysts for asymmetric aldol reactions

Abstract: l-Proline is grafted onto silica (MCM-41) in a single step and shows high activity and enantioselectivity in an aldol reaction.

Cited by 28 publications

References 34 publications

Molybdic Acid-Functionalized Nano-Fe3O4@TiO2 as a Novel and Magnetically Separable Catalyst for the Synthesis of Coumarin-Containing Sulfonamide Derivatives

Molybdic Acid-Functionalized Nano-Fe3O4@TiO2 as a Novel and Magnetically Separable Catalyst for the Synthesis of Coumarin-Containing Sulfonamide Derivatives

Development of nanomaterial chemosensors for toxic metal ions sensing

Synthesis of polymer microsphere‐supported chiral pyrrolidine catalysts by precipitation polymerization and their application to asymmetric Michael addition reactions

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