- Green synthesis of gold nanoparticles (Au NPs) using Tribulus terrestris extract: Investigation of its catalytic activity in the oxidation of sulfides to sulfoxides and study of its anti-acute leukemia activity
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With regards to applied, facile, green chemical research, a bio-inspired approach is being reported for the synthesis of Au NPs by using Tribulus terrestris extract. The innate oxygenated phytochemicals facilitated the green reduction of Au3+ ions to corresponding NPs and also stabilized them by encapsulating them. This modification prevented the as-synthesized Au NPs towards agglomeration and tiny NPs were obtained in uniformly spherical in shape and in the range of 10–15 nm dimension. Physicochemical characteristics of the green synthesized Au NPs were evaluated by advanced physicochemical techniques like UV–Vis and FT-IR spectroscopy, SEM, TEM, EDX and XRD study. Catalytic performance of the biomolecule functionalized Au NPs was investigated in the controlled and selective oxidation of sulfides to sulfoxides using hydrogen peroxide as green oxidant at room temperature. Aromatic, aliphatic and heterocyclic sulfides were oxidized to their corresponding sulfoxides with high yields without formation of over oxidized sulfones. The catalyst was easily recovered and recycled for 8 successive times without noticeable decrease in catalytic activity. In addition, the biosynthesized Au NPs indicated suitable antioxidant and anti-acute leukemia properties against THP-1 cell line. Tribulus terrestris extract and the green synthesized Au NPs exhibited a maximum DPPH scavenging activity of 78% and 29.37%, respectively. Again, in the anticancer studies over THP-1 cell line following MTT assay, the Au NP exhibited gradual reduced % cell viability with increase in its concentration. At an Au NPs concentration of 2000 μg/mL, the % toxicity became maximum suggesting efficient inhibition of cancer invasion. Based on the above results, Au NPs-Tribulus could be administered as a potential anti-leukemia drug for the treatment of acute leukemia following the clinical trial studies in humans.
- Ahmed, Ahmed Ezzat,El-kott, Attalla,Khames, Ahmed,Zein, Mohamed Abdellatif,Zhao, Peng
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- CoFe2O4@SiO2-CPTES-Guanidine-Cu(II): A novel and reusable nanocatalyst for the synthesis of 2,3-dihydroquinazolin-4(1H)-ones and polyhydroquinolines and oxidation of sulfides
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CoFe2O4@SiO2-CPTES-Guanidine-Cu(II) magnetic nanoparticles were synthesized and used as a new, inexpensive and efficient heterogeneous catalyst for the synthesis of polyhydroquinolines and 2,3-dihydroquinazoline-4(1H)-ones and for the oxidation of sulfides. The structure of this nanocatalyst was characterized using Fourier transform infrared spectroscopy, scanning electron microscopy, energy-dispersive X-ray spectroscopy, vibrating sample magnetometry, thermogravimetric analysis, X-ray diffraction and inductively coupled plasma optical emission spectrometry. Simple preparation, high catalytic activity, simple operation, high yields, use of green solvents, easy magnetic separation and reusability of the catalyst are some of the advantages of this protocol.
- Heidari, Leili,Shiri, Lotfi
-
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- Applications of iron and nickel immobilized on hydroxyapatite-core-shell γ-Fe2O3 as a nanomagnetic catalyst for the chemoselective oxidation of sulfides to sulfoxides under solvent-free conditions
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In the present study, Fe2+ and Ni2+ immobilized on hydroxyapatite-core-shell γ-Fe2O3 (γ-Fe2O3@HAp-Fe2+ and γ-Fe2O3@HAp-Ni2+) with a high surface area has been synthesized and characterized by Fourier transform infrared (FTIR), X-ray diffraction (XRD), vibrating sample magnetometer (VSM), transmission electron microscopy (TEM), and scanning electron microscope (SEM) techniques. Then, γ-Fe2O3@HAp-Fe2+ and γ-Fe2O3@HAp-Ni2+ were used as a new and magnetically recoverable nano catalyst for the selective oxidation of sulfides to sulfoxides with 33% aqueous H2O2 (0.5 mL) as an oxidant at room temperature in good to excellent yields and short reaction time. Nontoxicity of reagent, mild reaction condition, inexpensive and high catalytic activity, simple experimental procedure, short period of conversion and excellent yields, and ease of recovery from the reaction mixture using an external magnet are the advantages of the present method.
- Sajjadifar, Sami,Rezayati, Sobhan,Arzehgar, Zeinab,Abbaspour, Sima,Torabi Jafroudi, Mogharab
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p. 960 - 969
(2018/03/29)
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- Synthesis and characterization of oxo-vanadium complex anchored onto SBA-15 as a green, novel and reusable nanocatalyst for the oxidation of sulfides and oxidative coupling of thiols
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Abstract: The present work describes the synthesis of a new oxo-vanadium complex immobilized on SBA-15 nanostructure as an efficient catalyst for oxidation of sulfides and oxidative coupling of thiols. Characterization of the resultant AMPD@SBA-15 nanostructure was performed by various physico-chemical techniques such as Fourier transform infrared spectroscopy, transmission and scanning electron microscopies, energy-dispersive X-ray spectroscopy, inductively coupled plasma optical emission spectroscopy, X-ray diffraction, thermal gravimetric analysis, and N2 adsorption and desorption. The results of the developed procedure bring several benefits such as the use of commercially available, ecologically benign, operational simplicity, and cheap and chemically inert reagents. It shows good reaction times, practicability and high efficiency, and is easily recovered from the reaction mixture by simple filtration and reused for several consecutive cycles without noticeable change in its catalytic activity. More importantly, high efficiency, simple and an inexpensive procedure, commercially available materials, easy separation, and an eco-friendly procedure are the several advantages of the currently employed heterogeneous catalytic system.
- Tamoradi, Taiebeh,Ghadermazi, Mohammad,Ghorbani-Choghamarani, Arash,Molaei, Somayeh
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p. 4259 - 4276
(2018/03/21)
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- Laccase-TEMPO as an efficient catalyst system for metal- and halogen-free aerobic oxidation of thioethers to sulfoxides in aqueous media at ambient conditions
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We present for the first time an eco-friendly procedure for the aerobic oxidation of thioethers to sulfoxides using laccase-TEMPO catalyst system. This catalyst system allows for simpler (easy work-up) and greener methodologies (room temperature, phosphate buffer) while keeping high reaction yields and selectivity. This work is superior to others due to free from any transition metal and halide co-catalysts.
- Rostami, Amin,Mohammadi, Behnaz,Shokri, Zahra,Saadati, Shaghayegh
-
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- Nickel Schiff base complex anchored on Fe3O4@MCM-41 as a novel and reusable magnetic nanocatalyst and its application in the oxidation of sulfides and oxidative coupling of thiols using H2O2
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A novel and reusable nanocatalyst was synthesized by anchoring a nickel Schiff base complex onto Fe3O4@MCM-41 (Fe3O4@MCM-41@Ni-P2C) and characterization was accomplished with Fourier transform infrared spectroscopy (FT-IR), thermogravimetric analysis (TGA), powder X-ray diffraction (XRD), vibrating sample magnetometry (VSM), transmission electron microscopy (TEM), scanning electron microscopy (SEM) and atomic absorption spectroscopy (AAS) techniques. This catalytic system was efficiently used for oxidation of sulfides to sulfoxides and oxidative coupling of thiols to corresponding disulfides using H2O2 as green oxidant at room temperature. These reactions were carried out in a green solvent (ethanol) and/or under solvent-free conditions with short reaction time, complete selectivity and very high conversion under mild reaction conditions. More importantly, separation and recycling of this magnetic catalyst can be easily done through a simple and low cost magnetic separation process.
- Nikoorazm, Mohsen,Ghorbani, Farshid,Ghorbani-Choghamarani, Arash,Erfani, Zahra
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p. 552 - 561
(2018/04/26)
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- Zeolite nanoparticles (H-ZSM5) as a highly efficient, green, and reusable heterogeneous catalyst for selective oxidation of sulfides to sulfoxides under mild conditions
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H-ZSM5 is applied as an efficient, highly reusable, and heterogeneous catalyst for the oxidation of sulfides to sulfoxides using 30% H2O2 under solvent-free conditions at room temperature. A variety of aromatic and aliphatic sulfides with different functional groups were successfully oxidized with good to excellent yields in short reaction times. The catalyst can be easily recovered by simple filtration and recycled for several consecutive runs without any significant loss of its catalytic activity.
- Rostami, Amin,Saedmocheshi, Noosheen,Shirvandi, Zeinab
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p. 835 - 839
(2018/06/20)
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- Synthesis and characterization of sulfamic acid supported on Fe3O4 nanoparticles: A green, versatile and magnetically separable acidic catalyst for oxidation reactions and Knoevenagel condensation
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Sulfamic acid immobilized on diethylenetriamine functionalized Fe3O4 nanoparticles (SA-DETA-Fe3O4) was successfully prepared and characterized by X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FT-IR), vibrating sample magnetometer (VSM), thermo gravimetric analysis (TGA), X-Ray diffraction (XRD) and scanning electron microscopy (SEM). The sulfamic acid was found as a magnetically separable and highly active catalyst for the oxidative coupling thiols, oxidation of sulfides. Furthermore, the SA-DETA-Fe3O4 showed the high catalytic activity in Knoevenagel condensation of aromatic aldehydes with active methylene compounds (malononitrile and ethyl cynoacetate). The nanosolid catalyst could be easily recovered by a simple magnetic separation and reused for many cycles without deterioration in catalytic activity.
- Shiri, Lotfi,Narimani, Hojatollah,Kazemi, Mosstafa
-
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- Synthesis and characterization of tribenzyl ammonium-tribromide supported on magnetic Fe3O4 nanoparticles: a robust magnetically recoverable catalyst for the oxidative coupling of thiols and oxidation of sulfides
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Abstract: Taking into account the principles of green chemistry, magnetic nanoparticles, especially Fe3O4 nanoparticles, open up a new chapter in modern organic synthesis to inset a fascinating, stupendous and efficient catalytic strategy for facilitating catalyst recovery in various chemical reactions. Inspired by this topic, tribenzyl ammonium-tribromide immobilized on magnetic nanoparticles (Fe3O4–TBA-Br3) as a bromine source was successfully synthesized and its catalytic activity in the oxidative coupling of thiols and oxidation of sulfides was investigated. It is the first report on the use of the immobilized bromine source on Fe3O4 nanoparticles as a nanomagnetic recyclable catalyst for the oxidative coupling of thiols. The nanosolid catalyst could be easily recovered by a simple magnetic separation and reused for several cycles without significant degradation in catalytic activity. Graphical Abstract: [Figure not available: see fulltext.]
- Shiri, Lotfi,Ghorbani-Choghamarani, Arash,Kazemi, Mosstafa
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p. 2707 - 2724
(2017/04/18)
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- Synthesis and characterization of Co (II) and Fe (III) Schiff base complexes grafted onto mesoporous MCM-41: A heterogeneous and recyclable nanocatalysts for the selective oxidation of sulfides and oxidative coupling of thiols
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Novel organic–inorganic hybrid heterogeneous catalysts containing cobalt(II) and iron(III) Schiff base complexes, grafted on the internal surface of MCM-41 pores were prepared by introducing a metal salt into a mesoporous silica functionalized with a Schiff base ligand. The chemical and physical properties of the catalysts were investigated by BET, TGA, XRD, FT-IR, and TEM techniques. These complexes were found to be efficient, selective catalysts for the oxidation of various sulfides to sulfoxides and oxidative coupling of thiols to their corresponding disulfides with urea hydrogen peroxide in excellent yield at room temperature. The designed catalytic system prevents effectively the overoxidation of sulfides and thiols to sulfoxides and sulfones, respectively. Also the heterogeneous catalysts can be recovered easily and reused many times without significant loss of activity and selectivity.
- Noori, Nourolah,Nikoorazm, Mohsen,Ghorbani-Choghamarani, Arash
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p. 1388 - 1395
(2016/09/28)
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- Synthesis, characterization, and catalytic application of Cr and Mn Schiff base complexes immobilized on modified nanoporous MCM-41
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Immobilization of chromium and manganese Schiff base complexes by postgrafting of ligand then metal salts on the walls of mesoporous MCM-41 functionalized with (3-aminopropyl)triethoxysilane is described. Characterization of the resulting heterogeneous catalysts by Fourier-transform infrared (FT-IR) spectroscopy, thermogravimetric analysis (TGA), transmission electron microscopy (TEM), X-ray diffraction (XRD) analysis, and Brunauer–Emmett–Teller (BET) techniques indicated successful grafting of these two complexes inside the nanochannels of MCM-41. The complexes were found to be efficient, selective catalysts for oxidation of various sulfides to sulfoxides and oxidative coupling of thiols to corresponding disulfides using H2O2 as oxidant at room temperature. The recycling results of these heterogeneous catalysts showed good recyclability without significant loss of activity or selectivity in successive runs, indicating that the Cr and Mn Schiff base complexes supported on nanoporous MCM-41 remained intact and the coordination environments were not altered during the reaction.
- Nikoorazm, Mohsen,Ghorbani-Choghamarani, Arash,Noori, Nourolah
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p. 4621 - 4640
(2016/07/06)
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- Preparation of DSA@MNPs and application as heterogeneous and recyclable nanocatalyst for oxidation of sulfides and oxidative coupling of thiols
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Abstract: Dopamine sulfamic acid-functionalized magnetic Fe3O4 nanoparticles (DSA@MNPs) were prepared by a very simple and inexpensive procedure using commercial materials and characterized by X-ray diffraction (XRD) analysis, thermogravimetric analysis (TGA), Fourier-transform infrared (FT-IR) spectroscopy, scanning electron microscopy (SEM), transmission electron microscopy (TEM), and vibrating-sample magnetometry (VSM) techniques. They were employed as an efficient and recoverable catalyst in oxidation of sulfides to sulfoxides and oxidative coupling of thiols to disulfides using hydrogen peroxide as green oxidant at room temperature. This is the first report of application of DSA@MNPs in organic reactions. The supported magnetic nanoparticles could be easily recovered using an appropriate external magnet, minimizing catalyst loss during separation, and reused for several times without any loss of catalytic activity. Also, the amount of sulfamic acid function in the DSA@MNPs was calculated from ion-exchange pH analysis and back titration. Graphical abstract: [Figure not available: see fulltext.]
- Ghorbani-Choghamarani, Arash,Rabiei, Hossein,Tahmasbi, Bahman,Ghasemi, Banoo,Mardi, Farideh
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p. 5723 - 5737
(2016/06/01)
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- Synthesis and characterization of sulfamic acid-functionalized nanoparticles and study of its catalytic activity for the oxidation of sulfides to sulfoxides
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The synthesis, characterization and applications of sulfamic acid-functionalized magnetic nanoparticles as a magnetically separable nanocatalyst are described. The nanostructure of the catalyst was characterized by FT-IR spectroscopy, thermogravimetric (TGA) analysis, powder X-ray diffraction (XRD), scanning electron microscopy (SEM) and transmission electron microscope (TEM).
- Ghorbani-Choghamarani, Arash,Azadi, Gouhar
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- Boehmite silica sulfuric acid: as a new acidic material and reusable heterogeneous nanocatalyst for the various organic oxidation reactions
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In this research, project boehmite silica sulfuric acid (Boehmite-SSA) has been applied as new acidic porous catalyst for the selective oxidation of sulfides to sulfoxides and oxidative coupling of thiols to corresponding disulfides using hydrogen peroxide as oxidizing agent. The products have been obtained in short reaction times and high yields. Boehmite nanoparticles was prepared, coated by silica and then reacted with chlorosulfuric acid to obtain Boehmite-SSA. This catalyst was characterized by FT-IR, TGA/DTA, XRD, TEM, SEM, EDS and BET techniques. BET curve of boehmite nanoparticles identified as a typical type IV isotherm (definition by IUPAC), which are the characteristics of mesoporous material. Nitrogen adsorption/desorption measurement indicated that boehmite nanoparticles had BET surface area of about 122.8?m2/g. The catalyst was easily separated and reused for the several runs without significant loss of its catalytic efficiency.
- Ghorbani-Choghamarani, Arash,Hajjami, Maryam,Tahmasbi, Bahman,Noori, Nourolah
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p. 2193 - 2202
(2016/11/06)
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- CaF2 catalyzed chemoselective oxidation of sulfides to sulfoxides with hydrogen peroxide under solvent-free conditions
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Background: Sulfoxides are useful intermediates in organic synthesis. Furthermore, many biologically active compounds and drugs have sulfoxide moieties in their structures. The most popular approach for the preparation of sulfoxides involve selective oxidation of the corresponding sulfides. Although a wide variety of reagent systems have been traditionally used to accomplish this transform. However, many of these procedures utilize environmentally unfavorable reagents, solvents, and catalysts that highlight the matter of eco-efficiency in our environmentally conscious times. The use of 'green oxidants' such as molecular oxygen and hydrogen peroxide is attractive, since they are readily available, inexpensive, and environmentally benign, with formation of water as the only by-product. CaF2 is commercially available, environmentally compatible, cheap, easy to handle, and stable. It was recently shown to be a good substitute for conventional acidic catalytic materials. Methods: The sulfides (1 mmol) were oxidized to the corresponding sulfoxides using 30% H2O2 (3.6 mequiv.) in the presence of catalytic amount of CaF2 (0.25 mmol) under solvent-free conditions at room temperature. The purification was performed using short column chromatography with EtOAc/n-hexane (1/10). All the products are known and were characterized by IR and 1H-NMR and by melting point comparison with those of authentic samples. Results: The structurally diverse sulfides (including aryl, benzylic, heterocyclic, allylic and linear) were subjected to oxidation. The reactions proceeded well to produce the corresponding sulfoxides in good to high yields ranging from 80 to 97 % in short times. thiantrene and diphenyl sulfide, which are relatively unreactive substrates, were also converted to the corresponding sulfoxides to high yields, oxidation of them require higher temperature. Interestingly, the sulfur atom was chemoselectively oxidized in the sulfides compounds that containing oxidation-prone and acid-sensitive functional groups. Conclusion: This procedure offers several major advantages: (1) the use of a commercially available, cheap, and chemically stabile catalyst and oxidant; (2) highly efficient for the selective oxidation of structurally diverse sulfides in good to high yields; (3) excellent chemoselectivity; and (4) the method conforms to several of the guiding principles of green chemistry. We believe the present method to be an improvement with respect to other procedures.
- Rostami, Amin,Pourshiani, Omid,Gheisarzade, Sajede
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p. 201 - 205
(2016/02/26)
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- Immobilization of a vanadium complex onto functionalized nanoporous MCM-41 and its application as a catalyst for the solvent-free chemoselective oxidation of sulfide to sulfoxide
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A complex moiety containing VO(IV) was anchored covalently into organic-modified Si-MCM-41 to prepare a new catalyst. The prepared materials were characterized using various techniques. Several types of aromatic and aliphatic sulfides were successfully oxidized to the corresponding sulfoxides in good to excellent yields using H2O2 in the presence of a catalytic amount of the catalyst under solvent-free conditions. The results showed that the OH groups of the various compounds such as 2,2-(phenylthio)ethanol and 2-(methylthio)ethanol remained intact under similar conditions. Meanwhile the catalyst was stable in the reaction system, and could be reused at least four times without significant loss of its activity and chemoselectivity.
- Nikoorazm,Ghorbani-Choghamarani,Khanmoradi
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p. 236 - 241
(2016/04/05)
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- New metal complexes supported on Fe3O4 magnetic nanoparticles as recoverable catalysts for selective oxidation of sulfides to sulfoxides
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Fe3O4 nanoparticles were coated with aminopropyltriethoxysilane and subsequently reacted with isatin to obtain imine-bonded Fe3O4 nanoparticles. The addition of ZrOCl2·8H2O or CuCl2 led to the formation of complexes of Zr(IV)/isatin@Fe3O4 or Cu (II)/isatin@Fe3O4 as new magnetically separable catalysts. The synthesized catalysts were characterized using various techniques. These catalysts are shown to be efficient for chemo-selective oxidation of sulfides to sulfoxides using hydrogen peroxide as oxidative agent. This system has many advantages, such as excellent level of reusability of magnetic catalysts, high yields, simplicity of separation of catalysts using an external magnet, environmental benignity and ease of handling.
- Hajjami, Maryam,Kolivand, Somaye
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p. 282 - 288
(2016/05/02)
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- Preparation and characterization of organically modified MCM-48 as heterogonous catalyst for oxidation of sulfides and thiols
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MCM-48 mesoporous synthesized and grafted with aminopropyl triethoxysilane (APTES) and subsequently reacted by isatin to obtain the imine of MCM-48. Addition of ZrOCl2.8H2O, leading to form the complex of Zr(IV)/isatin-MCM-48 as new Schiff base complex of zirconium(IV)-modified-MCM-48. The synthesized catalyst was characterized by XRD, TGA, FT-IR and BET. The resulting catalyst was efficient for selective oxidation of sulfides to sulfoxides and oxidation of thiols to disulfides with hydrogen peroxide. In this method isolation and reusability of catalyst have been investigated.
- Hajjami, Maryam,Yousofvand, Zakieh
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p. 1733 - 1740
(2019/11/28)
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- Schiff base complex coated Fe3O4 nanoparticles: A highly reusable nanocatalyst for the selective oxidation of sulfides and oxidative coupling of thiols
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In this work, a new nanomagnetic complex of Cu(II) has been synthesized. The prepared catalyst was characterized by TG/DTG, FT-IR, TEM, VSM, ICP, AAS, XRD, EDS and SEM analyses. It was found to be an efficient catalyst for the oxidation of sulfides and oxidative coupling of thiols. High catalytic activity, ease of recovery from the reaction mixture using an external magnet, and several reuse times without significant losses in performance are additional eco-friendly attributes of this catalytic system.
- Ghorbani-Choghamarani, Arash,Ghasemi, Banoo,Safari, Zohre,Azadi, Gouhar
-
-
- Oxo-vanadium(IV) Schiff base complex supported on modified MCM-41: A reusable and efficient catalyst for the oxidation of sulfides and oxidative S-S coupling of thiols
-
Oxo-vanadium(IV) Schiff base complex supported on MCM-41 as an organic-inorganic hybrid heterogeneous catalyst was synthesized with post-grafting of MCM-41 with 3-aminoropropyltrimethoxysilane and subsequent reaction with 3,4-dihydroxybenzaldehyde and then complexation with oxo-vanadium acetylacetonate salt. The catalyst was analysed using a series of characterization techniques such as Fourier transform infrared spectroscopy, small-angle X-ray diffraction, nitrogen absorption isotherm, transmission electron microscopy and thermogravimetric analysis. The data collected provided evidence that the vanadium complex was anchored onto MCM-41. High catalytic activity of this catalyst was observed in the oxidation of various sulfides and thiols (into sulfoxides and disulfides, respectively) with urea hydrogen peroxide as oxidant in high to excellent yields and selectivity under mild conditions. The heterogeneous catalyst could be recovered easily and reused several times without significant loss in catalytic activity and selectivity.
- Nikoorazm, Mohsen,Ghorbani-Choghamarani, Arash,Noori, Nourolah
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p. 328 - 333
(2015/04/27)
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- Magnetic nanoparticle immobilized N-propylsulfamic acid: The chemoselective, efficient, green and reusable nanocatalyst for oxidation of sulfides to sulfoxides using H2O2 under solvent-free conditions
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An efficient and eco-friendly method is reported for the chemoselective oxidation of sulfides to sulfoxides in good to high yields using 30% H 2O2 in the presence of catalytic amounts of N-Propylsulfamic acid supported onto magnetic Fe3O4 nanoparticles (MNPs-PSA) under solvent-free conditions at room temperature. Various types of aromatic and aliphatic sulfides possessing functional groups such as alcohol, ester, and aldehyde are successfully and selectively oxidized without affecting sensitive functionalities. The magnetic nanocatalyst can be readily recovered easily by applying an external magnet device and reused for at least 10 reaction runs without considerable loss of reactivity.
- Rostami, Amin,Tahmasbi, Bahman,Abedi, Fatemeh,Shokri, Zahra
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p. 200 - 205
(2013/08/23)
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- Selective oxidation of sulfides to sulfoxides using H 2O 2 catalyzed by p-toluenesulfonic acid (p-TsOH) under solvent-free conditions
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An efficient, chemoselective, and environmental friendly procedure for the oxidation of sulfides to sulfoxides is described. Various types of aromatic and aliphatic sulfides are selectively oxidized to sulfoxides in good to excellent yields using 30% H2O2 in the presence of catalytic amounts of a p-TsOH under solvent-free conditions at room temperature.
- Rostami, Amin,Hassanian, Fatemeh,Ghorbani-Choghamarani, Arash,Saadati, Shaghayegh
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p. 833 - 838
(2013/08/23)
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- Silica-supported molybdenum complex: A novel, selective and reusable organic-inorganic hybrid catalyst for eco-friendly oxidation of sulfides and olefins
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A novel, highly efficient and reusable molybdenum based catalyst has been synthesized by covalent grafting of 2,6-diacetylpyridine-monosalicyloylhydrazone onto functionalized silica followed by complexation with MoO 2(acac)2, and the resulting organic-inorganic hybrid material was found to be highly effective catalyst for oxidation of various sulfides and olefins to their corresponding sulfoxides/sulfones and epoxides, respectively. The catalyst was characterized by elemental analysis (CHN), diffuse reflectance UV-Vis, 13C CPMAS NMR spectroscopy, X-ray diffraction (XRD), scanning electron microscopy (SEM) and BET surface area analysis, energy dispersive X-ray fluorescence (ED-XRF), Fourier-transform infrared (FT-IR) and atomic absorption spectroscopy (AAS). Mild reaction conditions, high turnover frequency, high selectivity, easy recovery and reusability of the catalyst render the present protocol very useful to address the industrial needs and environmental concerns.
- Sharma,Pandey, Amit,Gulati, Shikha
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- Ammonium bromide as an effective and viable catalyst in the oxidation of sulfides using nitro urea and silica sulfuric acid
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A new catalytic method for the chemoselective oxidation of sulfides to the sulfoxides has been studied. A variety of dialkyl, alkylaryl and diaryl sulfides were subjected to the oxidation reaction by a mixture of nitro urea, derived from urea nitrate, silica sulfuric acid (SiO2-OSO3H) and catalytic amounts of ammonium bromide in CH2Cl2 at room temperature.
- Ghorbani-Choghamarani,Zamani
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experimental part
p. 142 - 148
(2012/01/03)
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- Polyvinylpolypyrrolidone-supported hydrogen peroxide (PVP-H 2O2), silica sulfuric acid and catalytic amounts of ammonium bromide as green, mild and metal-free oxidizing media for the efficient oxidation of alcohols and sulfides
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Polyvinylpolypyrrolidone-supported hydrogen peroxide (PVP-H 2O2), silica sulfuric acid (SiO2OSO 3H) and catalytic amounts of ammonium bromide (NH4Br) are introduced as green media for the in situ generation of bromoniume ion (Br +), which was applied for the selective oxidation of sulfides and alcohols into sulfoxides and carbonyl compounds, respectively. The oxidation reactions were carried out heterogeneously in acetonitrile, as solvent, at room temperature (oxidation of sulfides) and/or 60 °C (oxidation of alcohols).
- Ghorbani-Choghamarani,Azadi
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experimental part
p. 1082 - 1090
(2012/02/15)
-
- Trimethylphenylammonium tribromide as a new and efficient oxidizing agent for the oxidative coupling of thiols into disulfides and chemoselective oxidation of sulfides into sulfoxides
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Trimethylphenylammonium tribromide has been introduced as a versatile and new oxidizing agent for the preparation of disulfides and sulfoxides from thiols and sulfides, respectively. The reaction progress is simple, and proceeds under mild and homogenous conditions in ambient temperature. Supplemental materials are available for this article. Go to the publisher's online edition of Phosphorus, Sulfur, and Silicon and the Related Elements to view the free supplemental file. Copyright Taylor &Francis Group, LLC.
- Ghorbani-Choghamarani, Arash,Soleiman-Beigi, Mohammad,Noormohammadi, Farid
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scheme or table
p. 1665 - 1672
(2011/10/05)
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- Catalytic oxidation of sulfides to sulfoxides by poly(4-vinyl pyridinium nitrate), silica sulfuric acid and ammonium bromide as a catalyst
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A new catalytic procedure for the chemoselective oxidation of sulfides to sulfoxides was studied. A variety of aliphatic and aromatic sulfides were subjected to sulfoxidation by combining poly(4-vinyl pyridinium nitrate), silica sulfuric acid (SiO2-OSO3H), and catalytic amounts of ammonium bromide in CH2Cl2 in the presence of a few drops of water at room temperature. Excellent yields were obtained.
- Ghorbani-Choghamarani, Arash,Sardari, Sara
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experimental part
p. 1347 - 1350
(2011/09/19)
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- Aqueous sodium hypochlorite mediated chemoselective oxidation of chalcogenides to monoxides and dioxides by microwave exposure
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A solvent-free, rapid, and highly selective oxidation of sulfides, selenides, and tellurides (chalcogenides) to the corresponding monoxides (sulfoxides, selenoxides, and telluroxides) or the corresponding dioxides (sulfones, selenones, and tellurones) has been developed using aqueous sodium hypochlorite on solid supports by exposure to microwave. Chemoselectivity and quantitative yields have been attained in most cases.
- Khurana, Jitender,Nand, Bhaskara
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experimental part
p. 906 - 909
(2011/01/08)
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- Electrophilic aromatic selenylation: New OPRT inhibitors
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2-Ethoxyethaneseleninic acid reacts with electron-rich aromatic substrates to deliver, by way of the selenoxides, the (2-ethoxyethyl)seleno ethers, which can in turn be transformed into a diverse set of aryl-selenylated products. Among these, a family of 5-uridinyl derivatives shows submicromolar inhibition of human and malarial orotate phosphoribosyltransferase.
- Abdo, Mohannad,Zhang, Yong,Schramm, Vern L.,Knapp, Spencer
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supporting information; experimental part
p. 2982 - 2985
(2010/11/19)
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- Lewis acid-promoted electron transfer deoxygenation of epoxides, sulfoxides, and amine N-oxides: the role of low-valent niobium complexes from NbCl5 and Zn
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A mild and operationally simple deoxygenation of epoxides, sulfoxides, and amine N-oxides is described using a sub-stoichiometric amount of low-valent niobium complexes generated in situ from commercially available NbCl5 and zinc dust. The deoxygenation proceeds by a reductive cleavage of polarized O-C/O-N/O-S bonds through a single electron transfer from zinc metal to the niobium-substrate complex due to the high oxophilic nature of the niobium species. The presence of adjacent radical-stabilizing groups is beneficial to epoxide substrates; however the similar prerequisite does not apply to sulfoxides and amine N-oxides, where a broad range of substrates are efficiently deoxygenated in excellent yields.
- Oh, Kyungsoo,Knabe, William Eric
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supporting information; experimental part
p. 2966 - 2974
(2009/05/30)
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- Copper catalyzed oxidation of sulfides to sulfoxides with aqueous hydrogen peroxide
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Copper(II) complex 1 catalyzes the oxidation of sulfides to sulfoxides with 30% H2O2 in high yields. Addition of a catalytic amount of TEMPO to the reaction mixture enhances the conversion and selectivity. Complex 1 can be recycled without loss of activity.
- Velusamy, Subbarayan,Kumar, Akkilagunta V.,Saini, Rakesh,Punniyamurthy
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p. 3819 - 3822
(2007/10/03)
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- Bis(p-methoxyphenyl) Selenoxide as a Mild and Selective Oxidizing Agent
-
The title compound oxidized thiolsto disulfides, sulfides to sulfoxides, hydroquinone or catechol to benzoquinones, and phosphine to phosphine oxide in high yields under very mild conditions.In addition, it functioned as a useful reagent for the syntheses of 1,2,4-thiadiazole derivatives from thioureas or thioamides.
- Ogura, Fumio,Yamaguchi, Hachiro,Otsubo, Tetsuo,Tanaka, Hiroyuki
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p. 641 - 642
(2007/10/02)
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