- Microwave-assisted NiCl2 promoted acylation of alcohols
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A microwave oven acylation of alcohols by carboxylic acid anhydrides has been developed. NiCl2 has been proven an efficient catalyst for the acylation of primary, secondary, and tertiary alcohols and phenols under microwave conditions.
- Constantinou-Kokotou, Violetta,Peristeraki, Anna
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- The Mechanism of Enzymatic and Biomimetic Oxidations of Aromatic Sulfides and Sulfoxides
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Biomimetic and enzymatic oxidations of benzyl sulfides and sulfoxides lead to products (sulfoxides or sulfones) different from those obtained with bona fide electron transfer oxidations (products of C-H and/or C-S bond cleavage), which suggests the operation of an oxygen transfer machanism.
- Baciocchi, Enrico,Lanzalunga, Osvaldo,Marconi, Francesco
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- Synthesis, Characterisation, and Determination of Physical Properties of New Two-Protonic Acid Ionic Liquid and its Catalytic Application in the Esterification
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A new ionic liquid was synthesised, and its chemical structure was elucidated by FT-IR, 1D NMR, 2D NMR, and mass analyses. Some physical properties, thermal behaviour, and thermal stability of this ionic liquid were investigated. The formation of a two-protonic acid salt namely 4,4′-trimethylene-N,N′-dipiperidinium sulfate instead of 4,4′-trimethylene-N,N′-dipiperidinium hydrogensulfate was evidenced by NMR analyses. The catalytic activity of this ionic liquid was demonstrated in the esterification reaction of n-butanol and glacial acetic acid under different conditions. The desired acetate was obtained in 62-88 % yield without using a Dean-Stark apparatus under optimal conditions of 10 mol-% of the ionic liquid, an alcohol to glacial acetic acid mole ratio of 1.3: 1.0, a temperature of 75-100°C, and a reaction time of 4 h. α-Tocopherol (α-TCP), a highly efficient form of vitamin E, was also treated with glacial acetic acid in the presence of the ionic liquid, and O-acetyl-α-tocopherol (Ac-TCP) was obtained in 88.4 % yield. The separation of esters was conducted during workup without the utilisation of high-cost column chromatography. The residue and ionic liquid were used in subsequent runs after the extraction of desired products. The ionic liquid exhibited high catalytic activity even after five runs with no significant change in its chemical structure and catalytic efficiency.
- Shahnavaz, Zohreh,Zaharani, Lia,Khaligh, Nader Ghaffari,Mihankhah, Taraneh,Johan, Mohd Rafie
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- Acetylation of alcohols and phenols under solvent-free conditions using copper zirconium phosphate
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Copper zirconium phosphate nanoparticles have been used as an efficient catalyst for the acetylation of a wide range of alcohols and phenols with acetic anhydride in good to excellent yields under solvent-free conditions. The steric and electronic properties of the different substrates had a significant influence on the reaction conditions required to achieve the acetylation. The catalyst used in the current study was characterized by inductively-coupled plasma optical emission spectroscopy, energy dispersive spectroscopy, X-ray diffraction, N2 adsorption-desorption, scanning electron microscopy, and transmission electron microscopy. These analyses revealed that the interlayer distance in the catalyst increased from 7.5 to 8.0 ? when Cu2+ was intercalated between the layers, whereas the crystallinity of the material was reduced. This nanocatalyst could also be recovered and reused at least six times without any discernible decrease in its catalytic activity. This new method for the acetylation of alcohols and phenols has several key advantages, including mild and environmentally friendly reaction conditions, as well as good to excellent yields and a facile work-up.
- Hajipour, Abdol R.,Karimi, Hirbod
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- Synthesis and characterization of MCM-41@XA@Ni(II) as versatile and heterogeneous catalyst for efficient oxidation of sulfides and acetylation of alcohols under solvent-free conditions
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Herein, Ni(II) immobilized on modified mesoporous silica MCM-41 was designed and synthesized via a facile sequential strategy. The structure of the catalyst was characterized by X-ray diffraction. The thermal property of the as-synthesized materials was studied using thermogravimetric-differential thermal analysis. The average particles size and morphology of MCM-41@XA@Ni(II) were investigated using scanning electron microscopy and transmission electron microscopy. This nanostructure catalyst was effective for the selective oxidation of sulfides and acetylation of alcohols in solvent-free conditions. The easy recyclability of the catalyst and their complete chemoselectivity toward the sulfur group of substrates in the oxidation of sulfides are important “green” attributes of this catalyst.
- Nazarzadeh, Somayeh,Ghorbani-Choghamarani, Arash,Tahanpesar, Elham
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- Side-Chain Oxidation of α-Substituted 4-Methoxytoluenes by Potassium 12-Tungstocobalt(III)ate. The Effect of α-Substituents on the Formation and Deprotonation of the Intermediate Cation Radicals
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A kinetic study of the side-chain oxidation of α-substituted 4-methoxytoluenes (4-MeOPhCH2R, R = H, Me, OH, OMe, OAc, CN) by K5Co(III)W12O40*11H2O (Co(III)W) in AcOH/H2O (55:45) has been carried out.The reactions follow complex kinetics, suggesting that both the electron transfer and the radical cation deprotonation steps influence the reaction rate.A careful kinetic analysis has allowed the determination of the values of k1, the rate constant for the electron transfer step, and of k-1/k2, the ratio between the rate constant of the back electron transfer and the one of the deprotonation of the cation radical.A satisfactory Marcus correlation between k1 and the free energy changes for the electron-transfer step is obtained, affording a value of 41 kcal mol-1 for the intrinsic barrier of the process.Therefrom a value of 57 kcal mol-1 for the reorganization energy pertaining to the conversion of 4-MeOPhCH2R into 4-MeOPhCH2R(1+) can be calculated.By assuming that k-1 is constant (the back electron transfer should be diffusion controlled for all substrates), the relative rate constants for the deprotonation of the radical cations, k2(R)/k2(H), can be obtained by the (k-1/k2)H/(k-1/k2)R ratios.It has been observed that k2(R)/k2(H) increases by increasing the oxidation potential of the substrate, whereas the reverse occurs with k1.The effect on k1 is, however, much larger than on k2(R)/k2(H), which allows us to conclude that α-substituents influence the oxidation rate of 4-methoxytoluene mainly through the effect exerted on the rate of the electron-transfer step.
- Baciocchi, Enrico,Bietti, Massimo,Mattioli, Mario
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- CuSO4 as a mild, green, and efficient catalyst for the one-pot conversion of THP ethers to acetates
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An efficient direct conversion of THP ethers into the corresponding acetates was achieved with acetic anhydride in the presence of CuSO4 ? 5H2O as an available and green catalyst in high yields.
- Asadolah, Karim,Heravi, Majid M.
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- Molecular iodine in ionic liquid: A green catalytic system for esterification and transesterification
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Esterification of carboxylic acids and transesterification of-ketoesters with alcohols have been developed using a catalytic amount of iodine in polyethylene glycol (PEG) ionic liquid (IL 1000) to afford the corresponding esters in good yields. By simple separation of the ionic-liquid phase containing the iodine, the system of I2/IL 1000 can be reused several times. Copyright
- Ren, Yiming,Cai, Chun
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- Photoredox-Catalyzed Benzylic Esterification via Radical-Polar Crossover
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Photoredox-catalyzed C-O bond formation reactions are reported. The decarboxylative esterification reaction allows the conversion of a variety of arylacetic acids into the corresponding benzyl carboxylates. Furthermore, the use of (diacetoxyiodo)benzene allows the conversion of the benzylic C-H bond through hydrogen atom transfer. The reactions were applied to the divergent transformation of pharmaceuticals via decarboxylative or C-H esterification reactions.
- Maeda, Bumpei,Sakakibara, Yota,Murakami, Kei,Itami, Kenichiro
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- Transprotection of silyl ethers of nucleosides in FeCl3 based ionic liquids
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Ionic liquid mediated deprotection of tert-butyldimethyl silyl (TBDMS) ethers derived from various primary and secondary alcohols have been studied and the reaction conditions optimized. Deprotection of the silyl ethers in FeCl3 based ionic liquids in presence of acetic anhydride yielded the acetate esters of the corresponding alcohols in good yields. The transprotection methodology was extended to the silyl ethers of nucleosides to yield the corresponding acetylated products. Copyright Taylor & Francis, Inc.
- Harjani, Jitendra R.,Nara, Susheel J.,Salunkhe, Manikrao M.,Sanghvi, Yogesh S.
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- Iodine as an extremely powerful catalyst for the acetylation of alcohols under solvent-free conditions
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Iodine was found to promote quantitative acetylation of alcohols in a very short time with an equimolar amount of acetic anhydride under solvent-free conditions at room temperature.
- Phukan, Prodeep
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- Vitamin B1 supported on silica-encapsulated γ-Fe 2O3 nanoparticles: Design, characterization and application as a greener biocatalyst for highly efficient acylation
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A new magnetic catalyst was synthesized by the immobilization of vitamin B1 (thiamine hydrochloride) on the surface of silica-encapsulated γ-Fe2O3 nanoparticles. Its capability was evaluated in the acylation of alcohols and phenols with acetic anhydride under solvent-free conditions and afforded the desired products in high yield. This novel magnetic organocatalyst could be separated from the reaction vessel by use of an external magnet and recovered 5 times without a significant loss of its activity. The amount of loaded vitamin B1 on the silica-encapsulated γ-Fe2O3 was assigned by TGA and confirmed by back titration. Availability, cheapness and low toxicity are reasons associated with the utilization of vitamin B1 as a catalyst. The catalyst has been characterized by FT-IR, XRD, SEM, VSM and TG/DTA. The Royal Society of Chemistry.
- Azizi, Kobra,Heydari, Akbar
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- An approach to heterodiarylmethanes via sp2-sp3 Suzuki-Miyaura cross-coupling
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The synthesis of a range of structurally diverse diarylmethanes via the Suzuki-Miyaura cross-coupling of aryl methane acetates and arylboronic acids is reported, including several challenging examples containing nitrogen, oxygen and sulfur heteroatoms in one or both coupling partners. A single set of optimized conditions was used to generate the diarylmethanes in 52-91% yield.
- Stewart, Gavin W.,Maligres, Peter E.,Baxter, Carl A.,Junker, Ellyn M.,Krska, Shane W.,Scott, Jeremy P.
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- Green bioprocesses in sponge-like ionic liquids
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Abstract Ionic liquids (ILs) are a new class of liquid solvent, whose use has led to a green chemical revolution because of their unique array of physico-chemical properties, headed by their negligible vapour pressure and their exceptional ability to stabilize biocatalysts. Hydrophobic ILs based on cations with long alkyl side-chains, e.g. N,N,N,N-hexadecyltrimethylammonium bis(trifluoromethylsulfonyl)imide ([C16tma][NTf2]), are temperature switchable ionic liquid/solid phases that behave as sponge-like systems (sponge-like ionic liquid, SLILs). Based on this new property, SLILs have been used to develop straightforward and clean approaches for producing nearly pure synthetic compounds with added value (e.g. geranyl acetate, anisyl acetate, methyl oleate, etc.) in two steps: an enzymatic synthetic step as liquid phase, and then a product separation step involving simple centrifugation as a solid phase.
- Lozano, Pedro,Bernal, Juana M.,Gómez, Celia,García-Verdugo, Eduardo,Isabel Burguete,Sánchez, Gregorio,Vaultier, Michel,Luis, Santiago V.
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- Acetylation of alcohols and phenols under solvent-free conditions using iron zirconium phosphate
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Iron zirconium phosphate (ZPFe) nanoparticles were found to function as an efficient catalyst for the acetylation of a wide range of alcohols and phenols using acetic anhydride, generating good to excellent yields under solvent-free conditions. The steric and electronic properties of various substrates had a significant influence on the reaction conditions required to achieve the acetylation. The catalyst used in the current study was characterized by inductively coupled plasma-optical emission spectrometry, X-ray diffraction, N2 adsorption-desorption, scanning electron microscopy, and transmission electron microscopy. These analyses revealed that the interlayer distance in the catalyst increased from 7.5 to 9.3 ? when Fe3+ was intercalated between the layers, whereas the crystallinity of the material was reduced. This nanocatalyst could also be recovered and reused at least six times without any discernible decrease in its catalytic activity. This new method for the acetylation of alcohols and phenols has several important advantages, including mild and environmentally friendly reaction conditions, as well as good to excellent yields and a facile work-up.
- Hajipour, Abdol R.,Karimi, Hirbod,Masti, Amir
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- Potassium fluoride assisted selective acetylation of alcohols with acetic acid
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Potassium fluoride promotes the acetylation of primary and secondary alcohols with acetic acid in excellent yield. Phenols are not affected under this reaction conditions. The groups like double bond, chloro, methoxy, benzyloxy, thiol, and nitro remain unaffected.
- Bosco, J. W. John,Raju, B. Rama,Saikia, Anil K.
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- Molecular iodine catalyzed selective acetylation of alcohols with vinyl acetate
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Molecular iodine is found to catalyze the acetylation of alcohols efficiently with vinyl acetate. The reaction is mild and selective with good to high yields. Molecular iodine displays significant functional group tolerance, being compatible with methoxy, double bonds, spiroketals, ketals and phenolic hydroxyl functions.
- Bosco, J.W. John,Agrahari, Aditya,Saikia, Anil K.
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- Hierarchically porous Br?nsted acidic ionic liquid functionalized nitrogen-doped carbons for pyrolysis biofuel upgrading via esterification of acetic acid with high boiling point alcohols
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Br?nsted acidic ionic liquid (BAIL) functionalized hierarchically porous nitrogen-doped carbons (NHPCs) with interesting 3D interconnected macro-meso-microporous structure are successfully prepared by chemical bonding ?[C3][SO3CF3?] (C3 = PrSO3H) groups throughout the NHPC supports that are obtained via a single step CaCO3 nanoparticle-directed nanocasting approach combined with K2C2O4 chemical activation and urea/melamine self-activation during the process of carbonization of glucose and urea/melamine. By changing initial urea-to-glucose weight ratio in the preparation systems, the macro/meso/micropore proportion of the resulting GU?[C3N][SO3CF3] catalysts are well-adjusted. The morphological characteristics, porosity properties and chemical structure of the prepared catalysts are well-characterized so that the contribution of the synergistic effect of CaCO3 nanoparticle and K2C2O4 to the formation of hierarchically porous structure is revealed. Owing to super strong Br?nsted acidity and unique hierarchically porous structure of the catalysts, they exhibit excellent heterogeneous acid catalytic activity in raw pyrolysis biofuel upgrading via esterification of acetic acid with high boiling point benzyl alcohol or 4-methoxybenzyl alcohol in toluene media, and therefore high acetic acid removal efficiency and efficient production of value-added benzyl acetate or 4-methoxybenzyl acetate are obtained simultaneously. The catalysts also show good reusability in target reactions, attributing to chemical interactions between BAILs and NHPC supports.
- Zhang, Qingqing,Zhang, Chaoyue,Sun, Yingnan,Guo, Yihang,Song, Daiyu
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- Trimethylsilylation of alcohols and phenols, and direct acetylation of silyl ethers catalyzed by Fe(ClO4)3.6H2O
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In this article, a mild and efficient protocol for the trimethylsilylation of various aliphatic and benzylic alcohols and phenols with trimethylsilyl chloride using a catalytic amount of ferric perchlorate at room temperature and relatively short reaction times in good to excellent yields is reported. Direct acetylation of trimethylsilyl ethers catalyzed with Fe(ClO4)3.6H2O(0.02 mmol)/Fe(ClO4)3SiO2(0.2 g) using acetic anhydride at ambient temperature is also reported.
- Oskooie, Hossein A.,Heravi, Majid M.,Tehrani, Maryam H.,Behbahani, Farahnaz K.,Heravi, Omid M.
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- Mesoporous sulfonic acid silicas for pyrolysis bio-oil upgrading via acetic acid esterification
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Propylsulfonic acid derivatised SBA-15 catalysts have been prepared by post modification of SBA-15 with mercaptopropyltrimethoxysilane (MPTMS) for the upgrading of a model pyrolysis bio-oil via acetic acid esterification with benzyl alcohol in toluene. Acetic acid conversion and the rate of benzyl acetate production was proportional to the PrSO3H surface coverage, reaching a maximum for a saturation adlayer. Turnover frequencies for esterification increase with sulfonic acid surface density, suggesting a cooperative effect of adjacent PrSO3H groups. Maximal acetic acid conversion was attained under acid-rich conditions with aromatic alcohols, outperforming Amberlyst or USY zeolites, with additional excellent water tolerance.
- Manayil, Jinesh C.,Inocencio, Carlos V. M.,Lee, Adam F.,Wilson, Karen
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- Selective acetylation of alcohols and amines with ethyl acetate in the presence of H6[PMo9V3O40] as the catalyst
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Acetylation of various alcohols and benzyl amine was tested in the presence of H6[PMo9V3O40], a mixed addenda heteropolyacid, in ethyl acetate under reflux condition. Phenols and anilines are not affected under the reaction conditions. Selective transestrification of alcohols can be achieved in the presence of phenol and aniline derivatives using this method. Springer-Verlag 2007.
- Heravi, Majid M.,Bakhtiari, Khadijeh,Javadi, Negar M.,Oskooie, Hossein A.,Bamoharram, Fatemeh F.
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- ZWITTERIONIC CATALYSTS FOR (TRANS)ESTERIFICATION: APPLICATION IN FLUOROINDOLE-DERIVATIVES AND BIODIESEL SYNTHESIS
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An amide/iminium zwitterion catalyst has a catalyst pocket size that promotes transesterification and dehydrative esterification. The amide/iminium zwitterions are easily prepared by reacting aziridines with aminopyridines. The reaction can be applied a wide variety of esterification processes including the large-scale synthesis of biodiesel. The amide/iminium zwitterions allow the avoidance of strongly basic or acidic condition and avoidance of metal contamination in the products. Reactions are carried out at ambient or only modestly elevated temperatures. The amide/iminium zwitterion catalyst is easily recycled and reactions proceed in high to quantitative yields.
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Paragraph 0013; 0028
(2021/01/29)
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- Proton-exchanged montmorillonite-mediated reactions of hetero-benzyl acetates: Application to the synthesis of Zafirlukast
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Proton-exchanged montmorillonite (H-mont) with outstanding surface characteristics can provide abundant acidic sites in the mesopores, and serve as an efficient heterogeneous catalyst for the synthesis of heterocycle-containing diarylmethanes via Friedel-Crafts-like alkylation of (hetero)arenes by heterobenzyl acetates under mild reaction conditions without requiring any additives or an inert atmosphere. Using this strategy, the gram-scale synthesis of indole-containing diarylmethane 13 has been accomplished in good yield for the preparation of Zafirlukast. In addition, H-mont can be applied to the nucleophilic substitution reactions of heterobenzyl acetate 5p with a variety of alcohols and 1,3-dicarbonyl compounds.
- Yang, Lei,Chen, Xuan,Ni, Kaidong,Li, Yuansheng,Wu, Jianhong,Chen, Weilin,Ji, Yin,Feng, Lili,Li, Fei,Chen, Dongyin
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supporting information
(2020/06/28)
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- Synthesis of task-specific imidazolium ionic liquid as an efficient catalyst in acetylation of alcohols, phenols, and amines
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Herein, we report the synthesis of task-specific amino-functionalized imidazolium ionic liquid, acetate1-(2-tert-butoxycarbonylamino-ethyl)-3-methyl-3H-imidazol-1-ium; (Boc-NH-EMIM.OAc), as an efficient catalyst for the acetylation of alcohols, phenols, and amines in the presence of acetic anhydride (acetylating reagent). Remarkably, acetic anhydride in the presence of 10?molpercent of catalyst (Boc-NH-EMIM.OAc) under solvent-free conditions showed excellent acetylation activity in shorter duration of time. On the basis of this, a general procedure for acetylation of alcohols, phenols, and amines has been developed. The ionic liquid (Boc-NH-EMIM.OAc) can be readily recovered and reused successfully up to four consecutive cycles without any significant loss of its catalytic activity. We have been able to show that this acetylating method has many advantages. It gives high yields, takes shorter time, and develops the possibility of benign environmental-friendly process.
- Chaubey, Snehkrishn A.,Mishra, Roli
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p. 3259 - 3268
(2020/04/17)
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- KMnO4-catalyzed chemoselective deprotection of acetate and controllable deacetylation-oxidation in one pot
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A novel and efficient protocol for chemoselective deacetylation under ambient conditions was developed using catalytic KMnO4. The stoichiometric use of KMnO4 highlighted the dual role of a heterogeneous oxidant enabling direct access to aromatic aldehydes in one-pot sequential deacetylation-oxidation. The reaction employed an alternative solvent system and allowed the clean transformation of benzyl acetate to sensitive aldehyde in a single step while preventing over-oxidation to acids. Use of inexpensive and readily accessible KMnO4 as an environmentally benign reagent and the ease of the reaction operation were particularly attractive, and enabled the controlled oxidation and facile cleavage of acetate in a preceding step. This journal is
- Gurawa, Aakanksha,Kumar, Manoj,Rao, Dodla S.,Kashyap, Sudhir
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supporting information
p. 16702 - 16707
(2020/10/27)
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- Gold(i)-NHC-catalysed synthesis of benzofurans: Via migratory cyclization of 2-alkynylaryl ethers
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Homogeneous cationic gold(i) catalysis emerged as a preferred avenue for the activation of alkenes and alkynes towards reactions with weak nucleophiles, especially in cyclization reactions. Here we report an intramolecular carboalkoxylation reaction of electron-rich benzyl ethers of 2-ethynylaryl phenols catalysed by a digold(i)-NHC complex. The reaction proceeds efficiently with low catalyst loading and the resulting 2,3-disubstituted benzofurans form in moderate to good yields. Based on the results of a cross-over experiment, spectroscopic data, and DFT calculations, we propose a mechanism that accounts for the observed chemo- and regioselectivity.
- Closser, Kristina D.,Dillon, Christopher C.,Le, Quang,Lichtenstein, Dana A.,Muchalski, Hubert,Pisor, Jeremy W.
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supporting information
p. 8186 - 8191
(2020/11/03)
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- Application of Yttrium Iron Garnet as a Powerful and Recyclable Nanocatalyst for One-Pot Synthesis of Pyrano[2,3-c]pyrazole Derivatives under Solvent-Free Conditions
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The application of yttrium iron garnet (YIG) superparamagnetic nanoparticles as a new recyclable and highly efficient heterogeneous magnetic catalyst for one-pot synthesis of pyrano[2,3-c]pyrazole derivatives under solvent-free conditions, as well as etherification and esterification reactions are described. The advantages of the proposed method include the lack of organic solvents, clean reaction, rapid removal of the catalyst, short reaction times, excellent yields, and recyclability of the catalyst.
- Sedighinia,Badri,Kiasat
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p. 1755 - 1763
(2020/01/11)
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- Cycloaddition of CO2 with epoxides and esterification reactions using the porous redox catalyst Co-POM@MIL-101(Cr)
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The catalytic activity of the recently reported Co-POM@MIL-101(Cr) composite, synthesized from K5[CoW12O40] (Co-POM) and chromium(iii) terephthalate (MIL-101), was studied in the solvent-free cycloaddition of CO2 with epoxides and esterification of acetic acid with various alcohols. The materials containing varying amounts of Co-POM were synthesized using a one-pot HF-free method in a "bottle around ship" strategy. The material was thoroughly characterized using several methods such as powder X-ray diffraction (PXRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), X-ray photoelectron spectroscopy (XPS), and electron paramagnetic resonance spectroscopy (EPR). Temperature programmed desorption (TPD) of NH3 and CO2, and the CO2 adsorption capacity (adsorption isotherms) were used to study the acid-base properties of the materials. The combination of the electron-transfer character of Co(iii)-POM and ordered mesopores in MIL-101(Cr) creates an efficient catalytic system with mild conditions (90 °C and 20 bar CO2 pressure) for solvent-free cycloaddition of CO2 to various epoxides. Esterification of acetic acid with alcohols was also carried out using the Co-POM@MIL-101 catalysts and high yields were achieved for different alcohols. The catalysis experiments also clearly show that the active site in this heterogeneous catalyst is the Co(iii) center in the Keggin anion structure. It presumably conducts both the cycloaddition of CO2 to epoxides and the esterification reaction via an outer-sphere electron transfer mechanism using the Co(iii)/Co(ii) redox pair. The heterogeneous Co-POM@MIL-101 catalysts were separated by simple filtration and reused five times in the cycloaddition of CO2 with styrene epoxide and seven times for the esterification of acetic acid with benzyl alcohol with negligible leaching of Co-POM and no considerable loss of activity.
- Marandi, Afsaneh,Bahadori, Mehrnaz,Tangestaninejad, Shahram,Moghadam, Majid,Mirkhani, Valiollah,Mohammadpoor-Baltork, Iraj,Frohnhoven, Robert,Mathur, Sanjay,Sandleben, Aaron,Klein, Axel
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p. 15585 - 15595
(2019/10/19)
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- Bu 4 NI-Catalyzed C-C Bond Cleavage and Oxidative Esteri??cation of Allyl Alcohols with Toluene Derivatives
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A novel oxidative esterification of 1-arylprop-2-en-1-ols with toluene derivatives catalyzed by tetrabutylammonium iodide (TBAI) is reported. The optimization of the reaction conditions illustrates that each of experiment parameters including the catalyst, solvent, and oxidant is significant for present oxidative functionalization. This metal-free protocol has a broad substrate scope including the halogen groups for further functionalization and enriches the reactivity profile of allyl alcohol and toluene derivatives. In addition, this protocol represents a new transformation of allyl alcohol involving C-C bond cleavage and C-O bond forming.
- Chen, Yaoyao,Cui, Yongmei,Jia, Xueshun,Li, Chengliang,Li, Jian,Sun, Mingming
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p. 3667 - 3674
(2019/09/30)
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- 4-Imidazol-1-yl-butane-1-sulfonic acid ionic liquid: Synthesis, structural analysis, physical properties and catalytic application as dual solvent-catalyst
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4-Imidazol-1-yl-butane-1-sulfonic acid (ImBu-SO3H) has been successfully synthetized and fully characterized by FT-IR and high-resolution NMR spectroscopy (1H, 13C). The “plausible” alternative structures of ImBu-SO3H were discussed on the basis of its NMR data. The ionic liquid showed interesting dual solvent-catalyst property, which was studied experimentally for the acetylation of a variety of functionalized alcohols, phenols, thiols, amines and α-tocopherol (α-CTP) as the most active form of vitamin E with acetic anhydride and which provided good yields within a short reaction time. ImBu-SO3H was successfully recycled by product extraction with an average recovered yield of 82% for 5 subsequent runs. The catalytic activity of the recycled ImBu-SO3H showed almost no loss even after five consecutive runs.
- Khaligh, Nader Ghaffari,Mihankhah, Taraneh,Johan, Mohd Rafie,Juan, Joon Ching
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p. 866 - 878
(2019/07/12)
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- Coating of polydopamine on polyurethane open cell foams to design soft structured supports for molecular catalysts
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Polydopamine-coated polyurethane open cell foams are used as structured supports for molecular catalysts through the covalent anchoring of alkoxysilyl arms by the catechol groups of the mussel-inspired layer. This strong bonding prevents their leaching. No alteration of the mechanical properties of the flexible support is observed after repeated uses of the catalytic materials.
- Ait Khouya, Ahmed,Mendez Martinez, Miguel L.,Bertani, Philippe,Romero, Thierry,Favier, Damien,Roland, Thierry,Guidal, Valentin,Bellière-Baca, Virginie,Edouard, David,Jierry, Lo?c,Ritleng, Vincent
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supporting information
p. 11960 - 11963
(2019/10/11)
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- Amide/Iminium Zwitterionic Catalysts for (Trans)esterification: Application in Biodiesel Synthesis
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A class of zwitterionic organocatalysts based on an amide anion/iminium cation charge pair has been developed. The zwitterions are easily prepared by reacting aziridines with aminopyridines. They are catalytically applicable to transesterifications and dehydrative esterifications. Mechanistic studies reveal that the amide anion and iminium cation work synergistically in activating the reaction partners, with the iminium cationic moiety interacting with the carbonyl substrates through nonclassical hydrogen bonding. The reaction can be applied to large-scale synthesis of biodiesel under mild conditions.
- Lam, Ying-Pong,Ng, Wing-Hin,Tan, Fei,Tse, Ying-Lung Steve,Wang, Xinyan,Yeung, Ying-Yeung
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p. 8083 - 8092
(2019/08/26)
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- Decarboxylative Acetoxylation of Aliphatic Carboxylic Acids
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Organic molecules bearing acetoxy moieties are important functionalities in natural products, drugs, and agricultural chemicals. Synthesis of such molecules via transition metal-catalyzed C-O bond formation can be achieved in the presence of a carefully chosen directing group to alleviate the challenges associated with regioselectivity. An alternative approach is to use ubiquitous carboxylic acids as starting materials and perform a decarboxylative coupling. Herein, we report conditions for a photocatalytic decarboxylative C-O bond formation reaction that provides rapid and facile access to the corresponding acetoxylated products. Mechanistic investigations suggest that the reaction operates via oxidation of the carboxylate followed by rapid decarboxylation and oxidation by Cu(OAc)2
- Senaweera, Sameera,Cartwright, Kaitie C.,Tunge, Jon A.
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p. 12553 - 12561
(2019/10/14)
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- Biogenic CuFe2O4 magnetic nanoparticles as a green, reusable and excellent nanocatalyst for acetylation reactions under solvent-free conditions
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A convenient green method has been developed for the synthesis of biogenic CuFe2O4 magnetic nanoparticles using tea extracts within a very short reaction time. The prepared nanoparticles with an average size of 8.78 nm have been used as an effective catalyst for the acetylation of various alcohols, phenols and amines in good to excellent yields under solvent-free conditions. The catalyst was characterized by XRD, XPS, VSM, SEM and TEM study. A magnetic study of the fresh and recycled catalyst after the fourth cycle was performed by VSM measurement. The main advantages of this protocol are simple biogenic synthesis of the catalyst, a reusable and heterogeneous catalytic system, and short reaction times with excellent yields.
- Chutia, Rituparna,Chetia, Bolin
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p. 15200 - 15206
(2018/09/29)
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- Enzymatic chemical transformations of aldehydes, ketones, esters and alcohols using plant fragments as the only biocatalyst: Ximenia americana grains
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The present study demonstrated the ability of Ximenia american as a biocatalyst in reduction, hydrolysis and esterification reactions. The reduction reactions of aldehydes and ketones, ester hydrolysis and esterification of alcohols were carried out with interesting results. Reduction of ketones afforded yields of 6–60% with ee in the range of 35–>99% and that of aldehydes in yields of 51–99%. On the other hand, ester hydrolysis afforded yields of 58–98% with ee in the range 34–87%, while esterification of alcohols in 18–99% yields. Experimental conditions for all reactions have been defined using standard substrates as indicated in results and discussion. Some of the products are the potential building blocks for the synthesis of molecules which are of pharmaceutical and agrochemical importance.
- da Silva, Romézio Alves Carvalho,de Mesquita, Bruna Marques,de Farias, Iolanda Frota,do Nascimento, Patrícia Georgiana Garcia,de Lemos, Telma Leda Gomes,Queiroz Monte, Francisco José
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p. 187 - 194
(2018/01/05)
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- Lipase-mediated selective acetylation of primary alcohols in ethyl acetate
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An environmental friendly process to selectively acetylate primary alcohols was demonstrated. The esterification process consists of treatment of a primary alcohol in the presence of immobilized C. antarctica lipase (Novozyme-435) in ethyl acetate at room temperature. Primary alcohols were acetylated in the presence of secondary alcohols and phenols.
- de Souza, Ernane C.,Romero-Ortega, Moises,Olivo, Horacio F.
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supporting information
p. 287 - 290
(2017/12/29)
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- A General Catalytic Method for Highly Cost- and Atom-Efficient Nucleophilic Substitutions
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A general formamide-catalyzed protocol for the efficient transformation of alcohols into alkyl chlorides, which is promoted by substoichiometric amounts (down to 34 mol %) of inexpensive trichlorotriazine (TCT), is introduced. This is the first example of a TCT-mediated dihydroxychlorination of an OH-containing substrate (e.g., alcohols and carboxylic acids) in which all three chlorine atoms of TCT are transferred to the starting material. The consequently enhanced atom economy facilitates a significantly improved waste balance (E-factors down to 4), cost efficiency, and scalability (>50 g). Furthermore, the current procedure is distinguished by high levels of functional-group compatibility and stereoselectivity, as only weakly acidic cyanuric acid is released as exclusive byproduct. Finally, a one-pot protocol for the preparation of amines, azides, ethers, and sulfides enabled the synthesis of the drug rivastigmine with twofold SN2 inversion, which demonstrates the high practical value of the presented method.
- Huy, Peter H.,Filbrich, Isabel
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supporting information
p. 7410 - 7416
(2018/04/30)
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- Nucleophilic Substitutions of Alcohols in High Levels of Catalytic Efficiency
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A practical method for the nucleophilic substitution (SN) of alcohols furnishing alkyl chlorides, bromides, and iodides under stereochemical inversion in high catalytic efficacy is introduced. The fusion of diethylcyclopropenone as a simple Lewis base organocatalyst and benzoyl chloride as a reagent allows notable turnover numbers up to 100. Moreover, the use of plain acetyl chloride as a stoichiometric promotor in an invertive SN-type transformation is demonstrated for the first time. The operationally straightforward protocol exhibits high levels of stereoselectivity and scalability and tolerates a variety of functional groups.
- Stach, Tanja,Dr?ger, Julia,Huy, Peter H.
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supporting information
p. 2980 - 2983
(2018/05/28)
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- Zn-Catalyzed tert-Butyl Nicotinate-Directed Amide Cleavage as a Biomimic of Metallo-Exopeptidase Activity
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A two-step catalytic amide-to-ester transformation of primary amides under mild reaction conditions has been developed. A tert-butyl nicotinate (tBu nic) directing group is easily introduced onto primary amides via Pd-catalyzed amidation with tert-butyl 2-chloronicotinate. A weak base (Cs2CO3 or K2CO3) at 40-50 °C can be used provided that 1,1′-bis(dicyclohexylphosphino)ferrocene is selected as ligand. The tBu nic activated amides subsequently allow Zn(OAc)2-catalyzed nonsolvolytic alcoholysis in tBuOAc at 40-60 °C under neutral reaction conditions. The activation mechanism is biomimetic: the C3-ester substituent of the pyridine in the directing group populates the trans-conformer suitable for Zn-chelation, C=Oamide-Zn-Ndirecting group, and Zn-coordinated alcohol is additionally activated as a nucleophile by hydrogen bonding with the acetate ligand of the catalyst. Additionally, the acetate ligand assists in intramolecular O-to-N proton transfer. The chemoselectivity versus other functional groups and compatibility with challenging reaction partners, such as peptides, sugars, and sterols, illustrates the synthetic applicability of this two-step amide cleavage method. The tBu nic amides do not require purification before cleavage. Preliminary experiments also indicate that other weak nucleophiles can be used such as (hetero)arylamines (transamidation) as exemplified by 8-aminoquinoline.
- Wybon, Clarence C. D.,Mensch, Carl,Hollanders, Charlie,Gadais, Charlène,Herrebout, Wouter A.,Ballet, Steven,Maes, Bert U. W.
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p. 203 - 218
(2018/01/17)
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- Reusable and efficient polyvinylpolypyrrolidone-supported triflic acid catalyst for acylation of alcohols, phenols, amines, and thiols under solvent-free conditions
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Abstract: A triflic acid-functionalized polyvinylpolypyrrolidone was prepared and fully characterized by FT-IR, TGA, and SEM. This super acidic solid catalyst shows high catalytic activity for selective acylation of alcohols, phenols, amines, and thiols with anhydrides under solvent-free conditions at room temperature. In addition, this method features an easy to handle solid super acid catalyst and an operationally simple procedure, affording the desired acylated products in excellent yields. Graphical abstract: [Figure not available: see fulltext.].
- Tajbakhsh, Mahgol,Tajbakhsh, Mahmoud,Khaksar, Samad,Gazvini, Helia Janatian,Heidary, Marzieh
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p. 1117 - 1122
(2017/05/10)
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- Supported palladium nanoparticles as switchable catalyst for aldehyde conjugate/s and acetate ester syntheses from alcohols
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Polymer-supported Pd(0) (Pd@PS) nanoparticles (NPs) were explored as a switchable catalyst for oxidative aldehyde conjugate/s (AC/s) and acetate esters (AEs) syntheses from alcohols. Using the same substrates, the catalyst in the presence of oxygen and K2CO3 participated in AC/s synthesis, and in the presence of traces of air and NaOtBu, unusual AEs products were obtained.
- Kumar, Sandeep,Chaudhary, Abha,Bandna,Bhattacherjee, Dhananjay,Thakur, Vandna,Das, Pralay
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supporting information
p. 3242 - 3245
(2017/07/12)
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- Doping of copper (I) oxide onto a solid support as a recyclable catalyst for acetylation of amines/alcohols/phenols and synthesis of trisubstituted imidazole
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A study of copper-mediated C-heteroatom especially C-N and C-O bond formations using simpler methodologies has been carried out. In the present work, acetylation of various substrates such as amines, phenols and alcohols; synthesis of 2,4,5-trisubstituted imidazole is done using simple and easily available starting materials. Copper (I) oxide was synthesized in situ by the reduction of Fehling's solution with glucose followed by its anchoring onto different supports like silica, HAP, basic alumina and cellulose. Comparison and contrasts between the reactivity of copper (I) oxide supported onto different supports for these reactions are made. The reactivity of copper (I) oxide seems to be largely dependent on the nature of support and the most active catalyst for a particular reaction was further characterized by different spectroscopic techniques such as FTIR, XRD, TGA, XPS, SEM, TEM and AAS. The catalysts were found to be stable, easily recyclable without any significant loss in activity. Graphical abstract: Applications of solid supported copper (I) oxides (where solid support is silica, HAP, cellulose and basic alumina) are studied for various organic transformations with special emphasis on C-N and C-O bond formation reactions.[Figure not available: see fulltext.]
- Gupta, Manjulla,Gupta, Monika
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p. 231 - 241
(2016/01/09)
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- Preparation, characterization and application of RHA/TiO2 nanocomposites in the acetylation of alcohols, phenols and amines
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In this work, anatase-phase nano-titania was prepared by embedding in rice husk ash, and identified using a variety of techniques. The obtained nanocomposite (RHA/TiO2) was used as a green and inexpensive catalyst for the promotion of the acetylation of alcohols, phenols and amines with Ac2O at room temperature under solvent free conditions. The procedure gave the products in excellent yields during all reaction times. Also this catalyst can be reused for several times without loss of its catalytic activity.
- Seddighi, Mohadeseh,Shirini, Farhad,Goli-Jolodar, Omid
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p. 1003 - 1010
(2016/08/08)
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- Highly efficient and recyclable acetylation of phenols and alcohols by nickel zirconium phosphate under solvent-free conditions
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Nickel zirconium phosphate nanoparticles have been used as an efficient catalyst for the acetylation of a wide range of alcohols and phenols with acetic anhydride in good to excellent yields under solvent-free conditions. The steric and electronic properties of the different substrates had a significant influence on the reaction conditions required to achieve the acetylation. The catalyst used in the current study was characterized by inductively coupled plasma optical emission spectroscopy, X-ray diffraction, N2 adsorption-desorption, scanning electron microscopy, and transmission electron microscopy. This nanocatalyst could also be recovered and reused at least six times without any discernible decrease in its catalytic activity.
- Hajipour, Abdol Reza,Karimi, Hirbod,Kohi, Afshin
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- P4VPy–CuO nanoparticles as a novel and reusable catalyst: application at the protection of alcohols, phenols and amines
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P4VPy–CuO nanoparticles were synthesized using ultrasound irradiations. Relevant properties of the synthesized nanoparticles were investigated by X-ray diffraction, scanning electron microscopy, transmission electron microscopy and Fourier transform infrared spectroscopy. After identification, the prepared reagent was used for the promotion of different types of protection reactions of alcohols, phenols and amines. Easy workup, short reaction times, excellent yields, relatively low cost and reusability of the catalyst are the striking features of the reported methods.
- Shirini, Farhad,Fallah-Shojaei, Abdollah,Abedini, Masoumeh,Samavi, Laleh
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p. 1699 - 1712
(2016/07/27)
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- Selective acetylation of primary alcohols by ethyl acetate
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A KOtBu and ethyl acetate mediated efficient methodology has been developed for the acetylation of primary and secondary alcohols where ethyl acetate is the source of acetyl group. The reaction is fast, mild, efficient, and highly selective towards the primary alcohols.
- Singha, Raju,Ray, Jayanta K.
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supporting information
p. 5395 - 5398
(2016/11/11)
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- Oxidative "reverse-esterification" of ethanol with benzyl/alkyl alcohols or aldehydes catalyzed by supported rhodium nanoparticles
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A very unusual role of polystyrene stabilized rhodium (Rh@PS) nanoparticles as a supported catalyst is described for "reverse-esterification" of ethanol with benzyl/alkyl alcohols or aldehydes. Faster and selective oxidation of ethanol to acetaldehyde and H2 under Rh@PS catalyzed conditions which restricted further oxidation of benzyl/alkyl alcohols and their in situ reaction gave the corresponding acetate esters following the dehydrogenative-coupling approach. A hitherto redox dehydrogenative-coupling of ethanol and aldehydes has also been explored for the same acetate ester synthesis under Rh@PS catalyzed conditions.
- Guha, Nitul Ranjan,Sharma, Saurabh,Bhattacherjee, Dhananjay,Thakur, Vandna,Bharti, Richa,Reddy, C. Bal,Das, Pralay
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p. 1206 - 1211
(2016/03/09)
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- Synthesis and characterization of ionic liquid immobilized on magnetic nanoparticles: A recyclable heterogeneous organocatalyst for the acetylation of alcohols
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Herein, we describe a simple and efficient procedure for the preparation of 3-((3-(trisilyloxy)propyl)propionamide)-1-methylimidazolium chloride ionic liquid supported on magnetic nanoparticle (TPPA-IL-Fe3O4). The structure of this magnetic ionic liquid is fully characterized by FT-IR, TGA, XRD, VSM, SEM, EDX and DLS techniques. TPPA-IL-Fe3O4 is employed as a catalyst for the acetylation of alcohols with acetic anhydride under mild and heterogeneous conditions at room temperature with good to excellent yields. The magnetic catalyst could be readily separate from the reaction media by simple magnetic decantation, and reused several times without significant loss of its catalytic activity.
- Ghorbani-Choghamarani, Arash,Norouzi, Masoomeh
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p. 832 - 840
(2015/11/16)
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- Tetraethylammonium hydrogen carbonate: A cheap, efficient, and recyclable catalyst for transesterification reactions under solvent-free conditions
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Tetraethylammonium hydrogen carbonate (TEAHC) was proven to be an efficient catalyst for transesterification reactions in the absence of solvent. The reaction between isopropenyl or ethyl acetate and an alcohol (not efficient in the absence of catalyst) was induced by the presence of TEAHC, which seems to assist the proton transfer from the alcohol to the ester, yielding the corresponding acetate in very good yields in the absence of any solvent. Moreover, the TEAHC can be recycled several times without significant loss in activity.
- Chiarotto, Isabella
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supporting information
p. 1840 - 1847
(2016/11/18)
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- Microwave-Assisted Catalytic Acetylation of Alcohols by Gold-Nanoparticle-Supported Gadolinium Complex
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A gold nanoparticle (AuNP)-supported gadolinium complex (RS-Au-L-Gd) catalyst was prepared through simple chelation of GdCl3 to the surface-bound spacer, 1,4,7-tris(carboxymethyl)-10-(11-mercaptoundecyl)-1,4,7,10-tetraazacyclododecane (HSDO3A). This AuNP-supported Gd complex was found to be a highly effective catalyst for the acetylation of various alcohols and phenol in the presence of acetic anhydride. With a loading of 0.4 mol% of RS-Au-L-Gd, the almost complete transformation can be achieved in 60 s under microwave irradiation conditions. This hybrid catalyst was air stable, water soluble, dissolvable in many organic media, and precipitable. It can be readily recycled more than eight times without any significant loss of its catalytic activity. GRAPHICAL ABSTRACT.
- Chang, Tsao-Ching,Yu, Shuchun Joyce
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p. 661 - 672
(2015/10/29)
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- Efficient approach for the chemoselective acetylation of alcohols catalyzed by a novel metal oxide nanocatalyst CuO-ZnO
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A new method has been developed for the chemoselective acetylation of alcohols with acetic anhydride in the presence of phenols using a novel, recyclable CuO-ZnO nanocatalyst. The catalyst was synthesized using the co-precipitation method and characterized by N2 adsorption-desorption, X-ray diffraction, scanning electron microscopy, transmission electron microscopy and energy dispersion scanning analyses. Furthermore, this catalyst could be recycled up to six times without significant loss in its activity.
- Albadi, Jalal,Alihosseinzadeh, Amir,Mardani, Mehdi
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p. 308 - 313
(2015/09/28)
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- A general Pd-catalyzed α- And γ-benzylation of aldehydes for the formation of quaternary centers
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A palladium-catalyzed benzylation of α-branched aldehydes has been developed using benzyl methyl carbonates. The method gives access to congested quaternary centers in the vicinity of one of the most sensitive carbonyl functionalities and displays unprecedented generality with respect to both coupling partners. Evidence for the direct involvement of a Pd-η3-benzyl intermediate is provided. Extension of this strategy to the γ-benzylation of α,β-unsaturated aldehydes is further demonstrated.
- Franzoni, Ivan,Guénée, Laure,Mazet, Clément
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supporting information
p. 6338 - 6343
(2015/06/08)
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- Synthesis of lipase nano-bio-conjugates as an efficient biocatalyst: Characterization and activity-stability studies with potential biocatalytic applications
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In the present study, we have synthesized lipase-nano-bio-conjugates via immobilization of various lipases on multiwall carbon nano-tubes (MCNT), in order to construct an efficient and recyclable biocatalytic system. In a screening study lipase Pseudomonas fluorescens (PFL) acted as an efficient biocatalyst (lipase-nano-bio-conjugates) which showed higher retention of lipase activity and protein loading. Consequently the immobilization support : lipase (MCNT : PFL) composition was screened in which MCNT : PFL (2 : 1) was calculated as a robust biocatalyst composition which showed higher activity retention and protein loading. This nano-bio-conjugate was then characterized in detail with physical and biochemical techniques using SEM, TEM, FTIR, Km, Vmax, catalytic efficiency and (%) water content analysis. This developed biocatalyst was further used for practical biocatalytic applications such as O-acylation reactions. Various reaction parameters were optimized in detail like reactant molar ratio (2 : 3.5), solvent, MCNT : PFL biocatalyst amount (36 mg), temperature (50°C) etc. The developed biocatalytic protocol was then extended to synthesize several (twenty-two) industrially important acylated moieties with an excellent yield, these products are well characterized by 1HNMR, 13CNMR and GCMS analysis. Moreover in the present study, we have reviewed the potential industrial applications of various synthesized compounds. Also, we have studied the thermodynamic aspect which demonstrated more feasibility of use of immobilized MCNT : PFL lipase over free lipase. Interestingly, immobilized MCNT : PFL lipase showed 2.3 fold higher catalytic activity than free PFL. Besides this, the biocatalyst was efficiently recycled for up to five cycles. Thus the present protocol demonstrated, (i) synthesis of nano-bio-conjugates as a bio-catalyst, (ii) detailed physical-biochemical characterization of nano-bio-conjugates, (iii) optimization of the biocatalytic protocol (iv) practical biocatalytic applications along with a mechanistic study (v) a thermodynamic feasibility study and (vi) recyclability study. 2015
- Badgujar, Kirtikumar Chandulal,Sasaki, Takehiko,Bhanage, Bhalchandra Mahadeo
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p. 55238 - 55251
(2015/07/07)
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- Polystyrene trimethyl ammonium chloride impregnated Rh(0) (Rh@PMe3NCl) as a catalyst and methylating agent for esterification of alcohols through selective oxidation of methanol
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Rhodium(0) nanoparticle (NP)-impregnated polystyrene trimethyl ammonium chloride (PMe3NCl) resin (Rh@PMe3NCl) under basic conditions acts as a cross-dehydrogenative coupling-methylating (CDCM) agent for the selective oxidation of methanol and its in situ reaction with benzyl/alkyl alcohols allowing methyl group transfer for acetate ester synthesis in a tandem approach. The redox property of methanol which restricts the oxidation of benzyl/alkyl alcohols for product formation is critically investigated.
- Guha, Nitul Ranjan,Bhattacherjee, Dhananjay,Das, Pralay
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p. 2575 - 2580
(2015/06/30)
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- Synthesis of 5-aryl-3-C-glycosyl- and unsymmetrical 3,5-diaryl-1,2,4-triazoles from alkylidene-amidrazones
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Among 1,2,4-triazole derivatives with versatile biological activities 3-C-glucopyranosyl-5-substituted-1,2,4-triazoles belong to the most efficient inhibitors of glycogen phosphorylase, and are thus potential antidiabetic agents. In seeking new synthetic methods for this class of compounds oxidative ring closures of N1-alkylidene carboxamidrazones were studied. O-Peracylated N1-(β-d-glycopyranosylmethylidene)-arenecarboxamidrazones were prepared from the corresponding glycosyl cyanides and amidrazones by Raney-Ni reduction in the presence of NaH2PO2. Bromination of the so obtained compounds by NBS gave hydrazonoyl bromide type derivatives which were ring closed to 3-C-glycosyl-5-substituted-1,2,4-triazoles in pyridine or by NH4OAc in AcOH. Under the same conditions O-perbenzoylated N1-arylidene-C-(β-d-glucopyranosyl)-formamidrazones gave the expected 1,2,4-triazoles as minor products only. N1-Arylidene-arenecarboxamidrazones were also transformed into 3,5-diaryl-1,2,4-triazoles with NBS/NH4OAc in AcOH indicating high functional group tolerance and general applicability of the method.
- Szcs, Béla,Bokor, éva,Szabó, Katalin E.,Kiss-Szikszai, Attila,Tóth, Marietta,Somsák, László
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p. 43620 - 43629
(2015/06/02)
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- Synthesis of sulfonic acid containing ionic-liquid-based periodic mesoporous organosilica and study of its catalytic performance in the esterification of carboxylic acids
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A new sulfonic acid containing ionic-liquid-based periodic mesoporous organosilica (PMO-IL-SO3H) material was prepared and its catalytic application was investigated in the esterification of carboxylic acids with alcohols. The PMO-IL-SO3H nanocatalyst was first characterized with diffuse reflectance infrared Fourier transform (DRIFT) spectroscopy, transmission electron microscopy (TEM), thermogravimetric analysis (TGA), and nitrogen sorption analysis. Then, the catalytic performance of this material was studied in the esterification of carboxylic acids with short- and long-chain aliphatic alcohols, cyclic alcohols, and benzylic alcohols under solvent-free conditions. The results showed that the catalyst has superior activity for the conversion of several alcohols to afford the corresponding ester products in excellent yields and high purity. Moreover, the catalyst could be recovered and reused several times without a significant decrease in activity and product selectivity. Copyright
- Elhamifar, Dawood,Karimi, Babak,Moradi, Abbas,Rastegar, Javad
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p. 1147 - 1152
(2014/10/16)
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- A simple acetylation of alcohols using ZnO nanopowder synthesized by microwave irradiation
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An efficient and selective method for acetylation of alcohols using ZnO nanopowder is described. In this method, alcohols are refluxed with a mixture of CH3COOH in the presence of catalytic amounts of ZnO nanopowder to afford their corresponding esters in good yields. This methodology is highly efficient for various structurally different alcohols: 1°, 2°, 3°. The prepared nano zinc oxide used in acetylation of alcohols which in comparison to ordinary ZnO has apparent advantages in promoting the yields of product formation.
- Javaherian, Mohammad,Sabzi, Hashem Eskandari
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p. 631 - 634
(2014/06/23)
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- A novel silver nanoparticle embedded mesoporous polyaniline (mPANI/Ag) nanocomposite as a recyclable catalyst in the acylation of amines and alcohols under solvent free conditions
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A mesoporous polyaniline/silver (mPANI/Ag) nanocomposite has been prepared using mesoporous organic polymer polyaniline with silver nitrate via radical polymerization of aniline monomer in the presence of hydrochloric acid. The mPANI/Ag nanocomposite has been characterized by powder X-ray diffraction (XRD), transmission electron microscopy (TEM), energy-dispersive X-ray spectra (EDX), Fourier transform infrared spectroscopy (FT-IR), and ultraviolet-visible absorption spectra (UV-vis). The XRD patterns indicated that the crystalline phase of Ag is cubic. TEM images show that the Ag nanoparticles are well dispersed in the mesoporous polyaniline matrix. The mPANI/Ag acts as an efficient heterogeneous nanocatalyst in the acylation of substituted amines and alcohols using acetic acid. The catalyst is air-stable, inexpensive, easy to prepare and can be reused several times without a significant decrease in activity and selectivity. This journal is
- Mandi, Usha,Roy, Anupam Singha,Banerjee, Biplab,Islam, Sk. Manirul
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p. 42670 - 42681
(2015/02/19)
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- Acetylation of alcohols and phenols by zinc zirconium phosphate as an efficient heterogeneous catalyst under solvent-free conditions
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An efficient method for the acetylation of a wide range of alcohols as well as phenols with acetic anhydride in good to excellent yields under solvent-free conditions, using zinc zirconium phosphate as the catalyst was investigated. The catalyst was characterized by XRD, inductivity coupled plasma-optical emission spectroscopy, and scanning electron microscope. Products are easily isolated and the protocol is mild and green, compared to the existing methods. Graphical abstract: [Figure not available: see fulltext.]
- Hajipour, Abdol Reza,Karimi, Hirbod,Karimzadeh, Morteza
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p. 1461 - 1472
(2014/09/30)
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- Preparation and characterization of multi-walled carbon nanotubes (MWCNTs), functionalized with phosphonic acid (MWCNTs-C-PO3H2) and its application as a novel, efficient, heterogeneous, highly selective and reusable catalyst for acetylation of alcohols, phenols, aromatic amines, and thiols
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A novel, efficient, heterogeneous, and reusable multi-walled carbon nanotubes (MWCNTs), functionalized with phosphonic acid (MWCNTs-C-PO 3H2) has been synthesized. The synthesized CNTs were characterized using some electron microscopic techniques such as scanning electron microscopy (SEM), atomic force microscopy (AFM), Energy dispersive X-ray spectroscopy (EDAX), and also some thermal and spectroscopic methods such as thermogravimetry (TG). The nitrogen adsorption behavior of the MWCNTs-C-PO3H2 catalyst was evaluated using the TG instrumentation system at 25°C. The catalyst was applied successfully for highly efficient and selective acetylation of alcohols, phenols, thiols and aromatic amines with acetic anhydride at room temperature under solvent-free conditions. The reusability of the catalyst was checked and the recovered catalyst was reused for five runs without significant loss in activity.
- Dehghani, Farzaneh,Sardarian, Ali Reza,Doroodmand, Mohammad Mehdi
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p. 673 - 684
(2014/05/20)
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- Sol-gel derived LaFeO3/SiO2 nanocomposite: Synthesis, characterization and its application as a new, green and recoverable heterogeneous catalyst for the efficient acetylation of amines, alcohols and phenols
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LaFeO3/SiO2 nanocomposite was synthesized by the sol-gel process from metal nitrates and tetraethyl orthosilicate (TEOS) as the SiO2 source. The nanocomposite product was characterized by XRD, FT-IR, SEM, and surface area measurements and was used as a heterogeneous catalyst for the efficient acetylation of amines, alcohols and phenols to the corresponding acetates using acetic anhydride under solvent-free conditions. Among the various substrates, acetylation of amines was preceded rapidly, so that an amine group could be selectively acetylated in the presence of alcoholic or phenolic hydroxyl groups by the appropriate choice of reaction time. The catalyst can also be reused several times without the loss of activity. In addition, the catalytic activity of the LaFeO3/SiO2 nanocomposite was higher than that of the pure LaFeO3 nanoparticles. The method is high yielding, clean, cost effective, compatible with the substrates having other functional groups and very suitable for the practical organic synthesis.
- Farhadi, Saeed,Jahanara, Kosar,Sepahdar, Asma
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p. 1103 - 1112
(2014/08/05)
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