Magnetic nanoparticles-supported tungstosilicic acid: as an efficient magnetically separable solid acid for the synthesis of benzoazoles in water

Khalafi-Nezhad, Ali; Panahi, Farhad; Yousefi, Reza; Sarrafi, Sina; Gholamalipour, Yasaman

doi:10.1007/s13738-013-0400-8

Cited by 18 publications

(8 citation statements)

References 60 publications

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“…The retention of Keggin unit after coating is confirmed by the presence of characteristic peaks of H 4 [SiW 12 O 40 ] at 800, 897, 952, 1116 cm −1 which are due to W─O─W, W═O and Si─O vibrations . A broad band at around 3300–3450 cm −1 is due to absorption of OH bonds on the surface of all materials synthesized …”

Section: Resultsmentioning

confidence: 84%

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Amelioration of H₄[W₁₂SiO₄₀] by nanomagnetic heterogenization: For the synthesis of 1H–pyrazolo[1,2‐b]phthalazinedione derivatives

Arora

Rajput

2017

Applied Organom Chemis

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We conveniently coated silicotungstic acid (STA, H4[W12SiO40]) on amino‐functionalized Si–magnetite nanoparticles, as surface functionalization of magnetic nanoparticles is an excellent way for green and efficient catalysis. The nanoparticles were structurally characterized using various techniques. The catalytic activity and recyclability of the STA–amine–Si–magnetite nanoparticles were probed through synthesis of 1H–pyrazolo[1,2‐b]phthalazinedione derivatives. The reaction proceeds smoothly to provide products in excellent yields and short reaction times. The catalyst could be readily recovered using a simple external magnet and reused several times without any significant loss in activity. Herein, we report a comparison of the activity of H4[W12SiO40] as a homogeneous and heterogeneous catalyst, the latter being found to be more efficient. The findings offer effective methods for environmentally friendly synthesis of pyrazolo[1,2‐b]phthalazinedione derivatives.

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Section: Resultsmentioning

confidence: 84%

“…[25,26] A broad band at around 3300-3450 cm −1 is due to absorption of OH bonds on the surface of all materials synthesized. [27] The diffractograms of magnetite, Si-Magnetite, Amine-Si-Magnetite and STA-Amine-Si-Magnetite are shown in Figure 2. All the peaks for magnetite were consistent with JCPDS card no.…”

Section: Characterization Of Catalystmentioning

confidence: 99%

Amelioration of H₄[W₁₂SiO₄₀] by nanomagnetic heterogenization: For the synthesis of 1H–pyrazolo[1,2‐b]phthalazinedione derivatives

Arora

Rajput

2017

Applied Organom Chemis

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“…In the structure of this catalyst, system l-cysteine moieties were chemically grafted to the surface of magnetic nanoparticles, creating efficient amino acid-based catalytic sites to be used in organic reactions. In this study and in continuation of over previous works on magnetic nanoparticle-based catalyst systems [47][48][49][50][51][52][53][54], we would like to show the catalytic applicability of this LCMNP in another MCR for efficient synthesis of a class of xanthene derivatives.…”

Section: Introductionmentioning

confidence: 85%

l-Cysteine-functionalized magnetic nanoparticles (LCMNP): as a magnetic reusable organocatalyst for one-pot synthesis of 9-(1H-indol-3-yl) xanthen-4-(9H)-ones

et al. 2016

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“…A strong absorption band in the range of 586 cm −1 is observable which this main peak has been attributed to Fe-O/Fe-O-Fe bindings of magnetite. 53 The mentioned peaks appeared in the FT-IR of MNP-TSA catalyst. 53 The mentioned peaks appeared in the FT-IR of MNP-TSA catalyst.…”

Section: Scheme 1 Synthetic Route For the Preparation Of Mnp-ta Catalystmentioning

confidence: 98%

Magnetic nanoparticles-supported tungstic acid (MNP-TA): an efficient magnetic recyclable catalyst for the one-pot synthesis of spirooxindoles in water

2015

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This paper reports the preparation, characterization and catalytic application of a novel magnetically separable catalyst consisting of tungstic acid supported on silica coated magnetic nanoparticles. To obtain this new catalyst system, first, (3-chloropropyl)triethoxysilane was reacted with silica coted magnetic nanoparticles to generate a 3-chloropropyl magnetic nanoparticle (3-CPMNP) substrate. 10 Subsequently, the addition of sodium tungstate to 3-CPMNP resulted in the stabilization of tungstic acid species on the surface of magnetic nanoparticles (MNP-TA). The synthesized catalyst was characterized using some different microscopic and spectroscopic techniques such as X-ray powder diffraction (XRD), transmission electron microscopy (TEM), scanning electron microscopy (SEM), and FT-IR spectroscopy. The catalyst nanoparticles were obtained with near spherical morphology and average size 15 of ~45 nm. The W content of the catalyst was determined by ICP analysis to be 82.5 ppm (82.5 mg/L), which was equal to 8.25% w/w (0.45 mmol/g). The catalyst was successfully used for the one-pot synthesis of spirooxindoles via multicomponent reaction of isatins and dicarbonyl compounds in water as a green solvent. The results revealed that, this new catalyst showed high catalytic activity in this protocol and it can be reused at least 6 times without any treatment in its catalytic activity.

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Magnetic nanoparticles-supported tungstosilicic acid: as an efficient magnetically separable solid acid for the synthesis of benzoazoles in water

Cited by 18 publications

References 60 publications

Amelioration of H₄[W₁₂SiO₄₀] by nanomagnetic heterogenization: For the synthesis of 1H–pyrazolo[1,2‐b]phthalazinedione derivatives

Amelioration of H₄[W₁₂SiO₄₀] by nanomagnetic heterogenization: For the synthesis of 1H–pyrazolo[1,2‐b]phthalazinedione derivatives

l-Cysteine-functionalized magnetic nanoparticles (LCMNP): as a magnetic reusable organocatalyst for one-pot synthesis of 9-(1H-indol-3-yl) xanthen-4-(9H)-ones

Magnetic nanoparticles-supported tungstic acid (MNP-TA): an efficient magnetic recyclable catalyst for the one-pot synthesis of spirooxindoles in water

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Magnetic nanoparticles-supported tungstosilicic acid: as an efficient magnetically separable solid acid for the synthesis of benzoazoles in water

Cited by 18 publications

References 60 publications

Amelioration of H4[W12SiO40] by nanomagnetic heterogenization: For the synthesis of 1H–pyrazolo[1,2‐b]phthalazinedione derivatives

Amelioration of H4[W12SiO40] by nanomagnetic heterogenization: For the synthesis of 1H–pyrazolo[1,2‐b]phthalazinedione derivatives

l-Cysteine-functionalized magnetic nanoparticles (LCMNP): as a magnetic reusable organocatalyst for one-pot synthesis of 9-(1H-indol-3-yl) xanthen-4-(9H)-ones

Magnetic nanoparticles-supported tungstic acid (MNP-TA): an efficient magnetic recyclable catalyst for the one-pot synthesis of spirooxindoles in water

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Amelioration of H₄[W₁₂SiO₄₀] by nanomagnetic heterogenization: For the synthesis of 1H–pyrazolo[1,2‐b]phthalazinedione derivatives

Amelioration of H₄[W₁₂SiO₄₀] by nanomagnetic heterogenization: For the synthesis of 1H–pyrazolo[1,2‐b]phthalazinedione derivatives