Synthesis of 1,4-dihydropyrimidines with immobilized urease: effect of method immobilization on magnetic supports

Vargas, Annie Y.; Rojas, Hugo; Romanelli, Gustavo Pablo; Martínez, José Javier Pérez-Fadón

doi:10.1515/gps-2016-0143

Cited by 8 publications

(6 citation statements)

References 34 publications

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“…Brønsted acids or Lewis acids, such as HBF 4 [23], H 3 PW 12 O 40 [24], InBr 3 [25], ZrCl 4 [26], Fe(OTs) 3 •6H 2 O [27], and Ce(NO 3 ) 3 •6H 2 O [28], have been traditionally used as catalysts. In recent years, some novel catalysts, including organocatalysts [29,30], biocatalysts [31], immobilized urease [32], PS-PEG-SO 3 H [33], Ti-graftedpolyamidoamine dendritic silica hybrid catalyst [34], halogenated macroporous sulfonic resins [35], polyaniline-supported FeCl 3 [36], cobalt supported on alumina catalyst [37], and ionic liquid [38][39][40][41] have attracted great attention for use in the Biginelli reaction. These catalysts, for their uses in accomplishing the Biginelli reaction, have produced varying degrees of success.…”

Section: Introductionmentioning

confidence: 99%

Deep eutectic solvents (DESs) as powerful and recyclable catalysts and solvents for the synthesis of 3,4-dihydropyrimidin-2(1H)-ones/thiones

Cui

Bao

2019

Green Processing and Synthesis

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Deep eutectic solvents (DESs) are successfully used as powerful and recyclable catalysts and solvents for the synthesis of 3,4-dihydropyrimidin-2(1H)-ones/thiones (DHPMs). The acidity of DESs is the main factor that determines catalytic activity. DESs, based on p-toluene sulfonic acid (PTSA) and choline chloride (ChCl), exhibits the highest catalytic activity. ChCl/2PTSA is suitable for a vast variety of aromatic aldehydes with electron-donating and electron-withdrawing groups, different β-diketonates, and urea or thiourea to obtain the corresponding DHPMs. Furthermore, DESs can be recycled easily after synthesis. The reused DESs achieve catalytic efficiency six times without significant changes. This study will provide a new green catalyst and efficient process for the synthesis of DHPMs.

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Section: Introductionmentioning

confidence: 99%

Deep eutectic solvents (DESs) as powerful and recyclable catalysts and solvents for the synthesis of 3,4-dihydropyrimidin-2(1H)-ones/thiones

Cui

Bao

2019

Green Processing and Synthesis

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“…The use of magnetic composites has been previously studied by our research group, demonstrating that the iron oxide particles can be completely coated in the cross‐linking process with glutaraldehyde and polyethyleneimine. This was demonstrated by XPS analysis, where the absence of the signal associated with Fe 2p 3/2 and 2p 1/2 suggests that the Fe 3 O 4 particles were totally covered …”

Section: Resultsmentioning

confidence: 91%

Etherification of Hydroxymethylfurfural with Preyssler Heteropolyacids Immobilized on Magnetic Composites

et al. 2018

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A thermodynamic study about the stability of intermediates in the reaction of 5-hydroxymethylfurfural (HMF) over Preyssler heteropolyacids (HPA-Preyssler) was performed to explain the self-etherification or oxidation of HMF. Although the product of etherification forms in higher proportion when a heteropolyacid is used, other oxidation products are also observed. The availability of HPA-Preyssler protons is essential to conduct the self-etherification; however, this is not favored when the heteropolyacid is immobilized on metallic oxides and besides, the reusability of the supported heteropolyacid is low. In this study, magnetic composites were used to incorporate the HPA-Preyssler to prevent the formation of by-products and to facilitate the separation from the reaction medium. The results of catalytic tests and acidity analysis demonstrated a better proton availability, and the recovery of glutaraldehyde of the heteropolyacid decreases the leaching of immobilized HPA-Preyssler when the composite is reused. The reaction was optimized obtaining a maximum yield to OBMF near 70% in 5 h.[a] Dr.

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“…Fe 3 O 4 covered by SiO 2 prevents the loss of the magnetic properties and increase the amount of immobilized enzyme [18]. Previous results reported by our group using X-ray photoelectron spectra demonstrated the absence of signals associated with Fe 2 p 3/2 and p 1/2 [19]. This suggested that the Fe 3 O 4 particles were totally covered when the particles were previously covered with SiO 2 and again treated with polyethyleneimine (PEI) and glutaraldehyde.…”

Section: Introductionmentioning

confidence: 72%

Nanopartículas magnéticas funcionalizadas y modificadas con entrecruzamiento para mejorar la inmovilización de la invertasa

2021

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Se han desarrollado procedimientos de inmovilización con invertasa utilizando diferentes soportes. Sin embargo, las desventajas como el uso de partículas pequeñas para inmovilizaciones de invertasa en reactores de lecho compacto se están resolviendo utilizando partículas magnéticas. En este estudio, los compuestos que contienen Fe3O4 se prepararon mediante la incorporación de una capa de polisiloxano necesaria para la adsorción física de la invertasa. Además, la magnetita funcionalizada se activó con glutaraldehído y polietilenimina (PEI) con el objetivo de realizar una inmovilización covalente. Se analizó el efecto de diferentes condiciones como la relación enzima: soporte, pH y temperatura en la conservación de la invertasa. Los resultados demostraron que la relación enzima: soporte óptima es mayor para la unión covalente que para la adsorción física. El pH ideal para la enzima inmovilizada es 5,0 y la actividad enzimática se mantiene hasta 70 ° C. Los valores de km son similares en ambos métodos de inmovilización. El análisis del efecto del pH y la termoestabilidad mostró que la actividad catalítica de la invertasa no se ve afectada en comparación con la enzima libre. La inmovilización covalente muestra una mayor eficacia en el proceso de inmovilización (Fε), menos inhibición y el doble de estabilidad. Las enzimas inmovilizadas por métodos físicos y covalentes se pueden reutilizar hasta por cuatro ciclos y se pueden eliminar del medio de reacción aplicando un campo magnético externo.

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Synthesis of 1,4-dihydropyrimidines with immobilized urease: effect of method immobilization on magnetic supports

Abstract: The effect of the urease immobilization method was studied on magnetic supports for the Biginelli/Hantzsch reaction. For this purpose, Fe

Cited by 8 publications

References 34 publications

Deep eutectic solvents (DESs) as powerful and recyclable catalysts and solvents for the synthesis of 3,4-dihydropyrimidin-2(1H)-ones/thiones

Deep eutectic solvents (DESs) as powerful and recyclable catalysts and solvents for the synthesis of 3,4-dihydropyrimidin-2(1H)-ones/thiones

Etherification of Hydroxymethylfurfural with Preyssler Heteropolyacids Immobilized on Magnetic Composites

Nanopartículas magnéticas funcionalizadas y modificadas con entrecruzamiento para mejorar la inmovilización de la invertasa

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