104-21-2Relevant articles and documents
Dessau,Heiba
, p. 3647 (1975)
-
Cavill,Solomon
, p. 3943,3946 (1954)
-
The Mechanism of Enzymatic and Biomimetic Oxidations of Aromatic Sulfides and Sulfoxides
Baciocchi, Enrico,Lanzalunga, Osvaldo,Marconi, Francesco
, p. 9771 - 9774 (1994)
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.
Acetylation of alcohols and phenols under solvent-free conditions using copper zirconium phosphate
Hajipour, Abdol R.,Karimi, Hirbod
, p. 1982 - 1989 (2014)
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.
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
Baciocchi, Enrico,Bietti, Massimo,Mattioli, Mario
, p. 7106 - 7110 (1993)
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.
AUTOCATALYTIC SOLVOLITIC DEMERCURATION OF 4-METHOXYBENZYLMERCURIC CHLORIDE
Butin, K. P.,Magdesieva, T. V.,Voskoboinikov, A. Z.,Reutov, O. A.
, (1987)
-
Photoredox-Catalyzed Benzylic Esterification via Radical-Polar Crossover
Maeda, Bumpei,Sakakibara, Yota,Murakami, Kei,Itami, Kenichiro
, p. 5113 - 5117 (2021)
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.
Benzyl Acetates by Acetoxylation of Methylbenzenes using Peroxydisulfate as Oxidizing Agent
Belli, Aldo,Giordano, Claudio,Citterio, Attilio
, p. 477 - 479 (1980)
-
Vitamin B1 supported on silica-encapsulated γ-Fe 2O3 nanoparticles: Design, characterization and application as a greener biocatalyst for highly efficient acylation
Azizi, Kobra,Heydari, Akbar
, p. 8812 - 8816 (2014)
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.
Green bioprocesses in sponge-like ionic liquids
Lozano, Pedro,Bernal, Juana M.,Gómez, Celia,García-Verdugo, Eduardo,Isabel Burguete,Sánchez, Gregorio,Vaultier, Michel,Luis, Santiago V.
, p. 54 - 59 (2015)
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.
Potassium fluoride assisted selective acetylation of alcohols with acetic acid
Bosco, J. W. John,Raju, B. Rama,Saikia, Anil K.
, p. 2849 - 2855 (2004)
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.
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
Zhang, Qingqing,Zhang, Chaoyue,Sun, Yingnan,Guo, Yihang,Song, Daiyu
, p. 10 - 24 (2019)
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.
Mesoporous sulfonic acid silicas for pyrolysis bio-oil upgrading via acetic acid esterification
Manayil, Jinesh C.,Inocencio, Carlos V. M.,Lee, Adam F.,Wilson, Karen
, p. 1387 - 1394 (2016)
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.
ZWITTERIONIC CATALYSTS FOR (TRANS)ESTERIFICATION: APPLICATION IN FLUOROINDOLE-DERIVATIVES AND BIODIESEL SYNTHESIS
-
Paragraph 0013; 0028, (2021/01/29)
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.
KMnO4-catalyzed chemoselective deprotection of acetate and controllable deacetylation-oxidation in one pot
Gurawa, Aakanksha,Kumar, Manoj,Rao, Dodla S.,Kashyap, Sudhir
supporting information, p. 16702 - 16707 (2020/10/27)
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