- STRUCTURE-REACTIVITY CORRELATION IN THE PYRIDINOLYSIS OF SUBSTITUTED PHENYL ACETATES
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The pyridinolysis of substituted phenyl acetates in acetonitrile was investigated with an electric conductivity method.The rates of these reactions were increased with electron-donating group in pyridine and electron-withdrawing group in phenyl acetate. ρX (X;substituents in phenyl ring) values increase gradually according to the electron-donating ability in pyridine substituents, but the /ρY/ (Y;substituents in pyridine ring) values decrease with that of substituents.The β values increase with increasing electron-withdrawing ability of the substituents in the phenyl ring, it can be inferred that N---C bond formation increases progressively p-methyl to p-nitrophenyl acetates.This is in agreement with prediction of substituent effects for a simple SN2 displacement reaction.The sensitivity parameters, β and ρ, are inter-related and are themselves sensitive to the reactivity of the system.All above results are interpreted in terms of a dissociative SN2 mechanism involving a metastable tetrahedral intermediate.
- Yoh, Soo-Dong,Kang, Joong-Kyu,Kim, Sung-Hong
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- Steric effect of NHC ligands in Pd(II)–NHC-catalyzed non-directed C–H acetoxylation of simple arenes
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Although there has been a lot of progress in oxidative arene C–H functionalization reactions catalyzed by Pd(II/IV) system, the non-directed, site-selective functionalization of arene molecules is still challenging. It has been established that ligands play a pivotal role in controlling rate- as well as selectivity-determining step in a catalytic cycle involving well-defined metal-ligand bonding. N-heterocyclic carbene (NHC) ligands have had a tremendous contribution in the recent extraordinary success of achieving high reactivity and excellent selectivity in many catalytic processes including cross-coupling and olefin-metathesis reactions. However, the immense potential of these NHC ligands in improving site-selectivity of non-directed catalytic C–H functionalization reactions of simple arenes is yet to be realized, where overriding the electronic bias on deciding selectivity is a burdensome task. The presented work demonstrated an initiative step in this regard. Herein, a series of well-defined discrete [Pd(NHCR′R)(py)I2] complexes with systematically varied degree of spatial congestion at the Pd centre, exerted through the R and R’ substituents on the NHC ligand, were explored in controlling the activity as well as the site-selectivity of non-directed acetoxylation of representative monosubstituted and disubstituted simple arenes (such as toluene, iodobenzene and bromobenzene, naphthalene and 1,2-dichlorobenzene). The resulting best yields were found to be 75% for toluene and 65% for bromobenzene with [Pd(NHCMePh)(py)I2], 75% for iodobenzene and 79% for naphthalene with [Pd(NHCMeMe)(py)I2], and 41% for 1,2-dichlorobenzene with [Pd(NHCCyCy)(py)I2]. Most importantly, with increasing the bulkiness of the NHC ligand in the complexes, the selectivity of the distal C-acetoxylated products in comparison to the proximal ones, was enhanced to a great extent in all cases. Considering the vast library of NHC ligands, this study underscores the future opportunity to develop more strategies to improve the activity and the crucial site-selectivity of C–H functionalization reactions in simple as well as complex organic molecules.
- Mandal, Tanmoy,Yadav, Sudha,Choudhury, Joyanta
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- P2O5/SiO2 as an efficient reagent for esterification of phenols in dry media
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A simple and efficient method for esterification of carboxylic acid with phenols using P2O5/SiO2 reagent in dry media is reported.
- Eshghi,Rafei,Karimi
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- Palladium-Catalyzed Desilylative Acyloxylation of Silicon-Carbon Bonds on (Trimethylsilyl)arenes: Synthesis of Phenol Derivatives from Trimethylsilylarenes
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A strategy for desilylative acetoxylation of (trimethylsilyl)arenes has been developed in which (trimethylsilyl)arenes are converted into acetoxyarenes. The direct acetoxylation is performed in the presence of 5 mol % of Pd(OAc)2 and PhI(OCOCF3)2 (1.5 equiv) in AcOH at 80°C for 17 h. The acetoxyarenes are obtained in good to high yields (67-98%). The synthetic utility is demonstrated with a one-pot transformation of (trimethylsilyl)arenes to phenols by successive acetoxylation and hydrolysis. Furthermore, desilylative acyloxylation of 2-(trimethylsilyl)naphthalene using several carboxylic acids has been conducted.
- Gondo, Keisuke,Oyamada, Juzo,Kitamura, Tsugio
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- Nucleophilicity of Phenolates in the Reaction with p-Nitrophenyl Acetate in Ethanol
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The rate of release of p-nitrophenol in the reaction of nine substituted phenolates with p-nitrophenyl acetate has been determined by spectrophotometric measurements in absolute ethanol at 22 deg C.The phenolate anion is the reactive species and competes with ethoxide anion, arising from solvolysis of the phenolate, for nucleophilic attack on the ester carbonyl carbon atoms.From the observed reaction rates the solvolysis constants and the pKa values of the phenols were obtained.The second-order rate constants for phenoxide anions were correlated with the pKa values of the corresponding phenols giving a Broensted β value of 0.57.A comparison with the nucleophilic reactivity of arenethiolates towards the same substrate in ethanol has been made.The rate-determining step is probably the expulsion of the leaving group in the raection of arenethiolates, whereas it is the nucleophile attack in the reaction of phenoxides.
- Guanti, Giuseppe,Cevasco, Giorgio,Thea, Sergio,Dell'Erba, Carlo,Petrillo, Giovanni
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- PtII and PdII complexes with a trans-chelating bis(pyridyl) ligand
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An atropisomeric bis(pyridyl) chelate ligand bis{3,3'-[N-Ph-2-(2'-py) indolyl]} (bpib) has been found to readily form trans-chelating PdII and PtII complexes. Two such complexes, Pt(bpib)Cl2 and Pd(bpib)Cl2 have
- Wang, Nan,McCormick, Theresa M.,Ko, Soo-Byung,Wang, Suning
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- Liquid-phase reactions of isomeric methylphenols with ozone
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Ozonation of isomeric methylphenols in acetic anhydride was studied. Here, acetic anhydride acts simultaneously as solvent and acylating agent. In the presence of a mineral acid methylphenols were converted into methylphenyl acetates during preparation of solutions for ozonation. The major products in the oxidation of isomeric methylphenyl acetates with ozone were aliphatic peroxides (80-90%); oxidation of the methyl group gave rise to the corresponding acetoxybenzyl acetates (7-14%) and acetoxybenzylidene diacetates (3-6%). A probable scheme for the liquid-phase oxidation of methylphenyl acetates with ozone in acetic anhydride was proposed.
- Galstyan
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- Palladium(II) acetate catalyzed aromatic substitution reaction
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Relative rate measurements indicate that the palladation reaction, although nonselective, adheres to the selectivity relationship for electrophilic aromatic substitution. Kinetic isotope effects and the dependence of the rate on oxidant concentration implicate arylpalladium(II) and arylpalladium(IV) compounds as intermediates in the reactions leading to biaryls and aryl acetates.
- Stock, Leon M.,Tse, Kwok-Tuen,Vorvick, Linda J.,Walstrum, Steven A.
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- A PdII Carbene Complex with Anthracene Side-Arms for π-Stacking on Reduced Graphene Oxide (rGO): Activity towards Undirected C–H Oxygenation of Arenes
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An N-heterocyclic carbene palladium(II) complex containing two anthracene side arms was immobilized on the surface of reduced graphene oxide (rGO) by π-stacking. The activity of the homogeneous analogue and the supported complex in undirected C–H acetoxylation reaction of arenes was studied. The results show that the catalytic efficiency in acetoxylation of benzene is improved in the immobilized materials compared to the homogeneous analogue. According to XPS analysis, the immobilized catalyst maintains the original oxidation state of PdII after the catalytic reaction.
- Majeed, Maitham H.,Shayesteh, Payam,Persson, Axel R.,Wallenberg, L. Reine,Schnadt, Joachim,Wendt, Ola F.
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- Method for promoting acylation of amine or alcohol by carbon dioxide
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The invention relates to a method for promoting acylation of amine or alcohol by carbon dioxide, which comprises the following steps of: mixing an amine compound, carboxylate or thiocarboxylate compound and a reaction solvent under the action of carbon dioxide, and reacting to obtain an amide compound, or under the action of carbon dioxide, mixing the alcohol compound, the thiocarboxylate compound and the reaction solvent [gamma]-valerolactone, and reacting to obtain the ester compound. According to the invention, under the promotion action of carbon dioxide, carboxylate or thiocarboxylate is used as an acylation reagent, and amine and alcohol are converted into amide and ester compounds in the absence of a transition metal catalyst, so that acylation reagents such as acyl chloride or anhydride with irritation and corrosivity are avoided; and the method has the advantages of simple operation, mild reaction conditions, high tolerance of substrate functional groups, strong applicability and high yield, and provides an efficient, reliable and economical preparation method for synthesis of amide and ester compounds.
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Paragraph 0034-0035
(2021/05/29)
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- An efficient method to prepare aryl acetates by the carbonylation of aryl methyl ethers or phenols
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Synthesis of valuable chemicals from lignin based compounds is critical for the application of biomass. Here, we develop a method of preparing aryl acetates by the carbonylation of aryl methyl ethers or phenols under low CO pressure. Good to excellent yields of aryl acetates were obtained using different substrates, and a possible reaction mechanism was proposed by conducting a series of control experiments. This method may provide a potential way for the utilization of lignin.
- Zhang, Dejin,Yang, Guoqiang,Xiong, Junping,Liu, Jia,Hu, Xingbang,Zhang, Zhibing
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p. 2683 - 2687
(2021/02/16)
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- Unprecedented acetylation of phenols using a catalytic amount of magnesium powder
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The acetylation of phenols with acetic anhydride was achieved using a catalytic amount of magnesium metal powder under air and solvent-free conditions to afford corresponding phenyl acetates in excellent yield (up to 98%).
- Bajracharya, Gan B.,Shrestha, Suryaman Sama
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supporting information
p. 1688 - 1693
(2018/06/15)
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- Synthesizing method of 4-(4-bromo-3-aldehyde-phenoxyl)-benzonitrile
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The invention provides a synthesizing method of 4-(4-bromo-3-aldehyde-phenoxyl)-benzonitrile. The synthesizing method comprises the following steps of using 3-methylphenol as the starting raw material, and reacting with acid anhydride to prepare 3-methyl-benzene ester; enabling the 3-methyl-benzene ester and sulfonyl chloride to react, so as to prepare a mixture of 3-chloromethyl-benzene ester and3-dichloromethyl-benzene ester; adding ulotropine, and hydrolyzing, so as to obtain 3-hydroxyl-benzaldehyde; performing brominating reaction, so as to obtain 4-bromo-3-hydroxyl-benzaldehyde; adding 4-fluorobenzonitrile, and performing condensation reaction, so as to obtain the 4-(4-bromo-3-aldehyde-phenoxyl)-benzonitrile. The synthesizing method has the advantages that the prices of the reactionraw materials are low, the obtaining is easy, the reaction steps are fewer, the production cost is low, the technology is simple, the product purity is high and reaches 99.0% or above, and the synthesizing method is suitable for industrialized production.
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Paragraph 0024; 0034; 0036-0039; 0082; 0084-0087
(2019/01/14)
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- Na 2 CO 3-Catalyzed O-Acylation of Phenols for the Synthesis of Aryl Carboxylates with Use of Alkenyl Carboxylates
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Inorganic base-catalyzed O-acylation of phenol and its derivatives has been developed. The procedure provides an efficient catalysis system for the preparation of aryl carboxylates with alkenyl carboxylates as acyl reagents. The reaction proceeded smoothly by using ?-Na 2 CO 3 as the catalyst in MeCN to produce the corresponding aryl carboxylates in good to excellent yields.
- Zhou, Xiao-Yu,Chen, Xia
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supporting information
p. 2321 - 2325
(2018/10/20)
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- Technological method for preparing m-aminophenol
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The invention relates to a technological method for preparing m-aminophenol, belongs to the technical field of chemical material preparation and solves the technical problem of limit caused by utilizing phenyl acetate as a preparation raw material. The technological method disclosed by the invention has the advantages of simpleness in operation, high product yield, reaction easy to control and thelike. The technological method is characterized by comprising the steps: preparing 3-carboxyphenyl phenyl acetate after preparing m-cresyl acetate and utilizing the prepared 3-carboxyphenyl phenyl acetate to prepare the m-aminophenol. The technological method comprises the steps: a, taking a C9H8O4 solvent, adding into an ethyl acetate solution, fully stirring until complete dissolution, dropwiseadding thionyl chloride into a system under the ice water bath condition, thermally insulating 1+/-0.5 hours, warming to 60 DEG C and refluxing; b, under the ice water bath condition, adding triethylamine and hydroxylamine hydrochloride into the system, thermally insulating for 2 hours and warming to a room temperature; c, spin drying the solvent on a rotary evaporator, then adding water and potassium carbonate, warming to 60 to 70 DEG C and hydrolyzing; d, utilizing ethyl acetate to extract the solution, utilizing a thin-layer chromatography to determine whether extraction is complete and obtaining the finished product of the m-aminophenol after the extraction is finished.
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Paragraph 0031-0037; 0061; 0085
(2018/04/01)
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- Technological method for preparing carboxylic phenyl acetate
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The invention relates to a technological method for preparing carboxylic phenyl acetate, and belongs to the technical field of chemical material preparation, solving the technical problem of limitation of raw materials for preparing phenyl acetate in the prior art. The technological method has the advantages of simplicity in operation, high product yield, easiness in reaction control and the like.The technological method includes preparing cresyl acetate, and preparing the carboxylic phenyl acetate from the obtained cresyl acetate; putting the obtained cresyl acetate in a triangular flask, adding water, fully stirring the water, adding glacial acetic acid, and increasing the system to 60-80 DEG C; weighing potassium permanganate, slowly adding the potassium permanganate into the system insmall quantity repeatedly, and keeping the temperature of the system at 50-80 DEG C for 8-10 hours of reaction after the potassium permanganate is added completely; after purple fades in the system completely, increasing the temperature of the system to 90-110 DEG C, and immediately filtering the generated solution after reaction; c, adjusting the pH of the obtained filtrate to not more than 1 byhydrochloric acid, performing extraction by ethyl acetate, and removing extraction agents in the mixture to obtain a solid carboxylic phenyl acetate product.
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Paragraph 0025; 0026; 0027; 0028; 0042; 0056
(2018/04/02)
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- Highly Active Manganese-Mediated Acylation of Alcohols with Acid Chlorides or Anhydrides
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To explore further the practical uses of highly active manganese (Mn?), a variety of alcohols were treated with Mn?, and the resulting complexes were coupled with acid chlorides and/or acetic anhydride in the absence of any extra catalyst. The subsequent reactions took place smoothly under mild conditions, providing the corresponding O-acylation products in good to excellent isolated yields.
- Joo, Seong-Ryu,Youn, Young-Jin,Hwang, Young-Ran,Kim, Seung-Hoi
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p. 2665 - 2669
(2017/10/07)
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- Copper-Catalyzed C-S Bond Formation via the Cleavage of C-O Bonds in the Presence of S8 as the Sulfur Source
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Useful and applicable methods for one-pot and odorless synthesis of unsymmetrical and symmetrical diaryl sulfides via C-O bond activation are presented. First, a new efficient procedure for the synthesis of unsymmetrical sulfides using the cross-coupling reaction of phenolic esters such as acetates, tosylates, and triflates and with arylboronic acid or triphenyltin chloride as the coupling partners is reported. Depending on the reaction, S 8 /KF or S 8 /NaO t -Bu system is found to be an effective source of sulfur in the presence of copper salts and in poly(ethylene glycol) as a green solvent. Then, the synthesis of symmetrical diaryl sulfides from phenolic compounds by using S 8 as the sulfur source and NaO t -Bu in anhydrous DMF at 120 °C under N 2 is described. By these protocols, the synthesis of a variety of unsymmetrical and symmetrical sulfides become easier than the available protocols in which thiols and aryl halides are directly used for the preparation of the sulfides.
- Rostami, Abed,Rostami, Amin,Ghaderi, Arash,Gholinejad, Mohammad,Gheisarzadeh, Sajedeh
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p. 5025 - 5038
(2017/10/06)
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- Enhancing the Acylation Activity of Acetic Acid by Formation of an Intermediate Aromatic Ester
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Acylation is an effective C?C bond-forming reaction to condense acetic acid and lignin-derived aromatic compounds into acetophenones, valuable precursors to fuels and chemicals. However, acetic acid is intrinsically an ineffective acylating agent. Here, we report that its acylation activity can be greatly enhanced by forming intermediate aromatic esters directly derived from acetic acid and phenolic compounds. Additionally, the acylation reaction was studied in the liquid phase over acid zeolites and was found to happen in two steps: 1) formation of an acylium ion and 2) C?C bond formation between the acylium ion and the aromatic substrate. Each of these steps may be rate-limiting, depending on the type of acylating agent and the aromatic substrate. Oxygen-containing substituents, such as ?OH and ?OCH3, can activate aromatic substrates for step 2, with ?OH> ?OCH3, whereas alkyl substituent ?R cannot. At the same time, aromatic esters can rearrange to acetophenones by both an intramolecular pathway and, preferentially, an intermolecular one.
- Duong, Nhung N.,Wang, Bin,Sooknoi, Tawan,Crossley, Steven P.,Resasco, Daniel E.
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p. 2823 - 2832
(2017/07/13)
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- Polymer-Supported Palladium(II) Carbene Complexes: Catalytic Activity, Recyclability, and Selectivity in C?H Acetoxylation of Arenes
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Heterogeneous catalysts for selective oxidation of C?H bonds were synthesized by co-polymerization of new N-heterocyclic carbene-palladium(II) (NHC-PdII) monomers with divinylbenzene. The polymer-supported NHC-PdII-catalysed undirect
- Majeed, Maitham H.,Shayesteh, Payam,Wallenberg, L. Reine,Persson, Axel R.,Johansson, Niclas,Ye, Lei,Schnadt, Joachim,Wendt, Ola F.
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supporting information
p. 8457 - 8465
(2017/06/28)
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- Process method for preparing resorcinol
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The invention relates to a process method for preparing resorcinol and belongs to the technical field of preparation of chemical materials with an aim to solve the technical problem about limitation by taking phenylacetate as a preparation material. The technical scheme of the process method includes: sequentially preparing m-Tolyl acetate, m-carboxyl phenyl acetate and m-aminophenol, and then preparing the resorcinol with the prepared m-aminophenol in a manner of a, drying the obtained m-aminophenol prior to weighing, 1.09g of m-aminophenol, 50ml of water and 2.5ml of concentrated hydrochloric acid, mixing the reaction materials and heating the same to 35DEG C and fully stirring until a solution is clarified; b, weighing, by weight, 0.828g of solid sodium nitrite and solving the same in water; c, under the ice bath condition, dropwise adding a sodium nitrite solution to a system; d, under the ice bath condition, heating the system to 30-40DEG C after full stirring and performing continuous reaction; e, extracting the reacted solution with ethyl acetate, spin-drying a reactant fully extracted by the aid of a rotary evaporator to obtain resorcinol solids. The process method has the advantages of simpleness in operation, high production yield, easy reaction control and the like.
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Paragraph 0042-0048; 0078-0082; 0111-0116
(2018/01/14)
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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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p. 1387 - 1394
(2016/03/09)
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- Ligand-Promoted Palladium-Catalyzed C?H Acetoxylation of Simple Arenes
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The palladium-catalyzed C?H oxidation of simple arenes is an attractive strategy to obtain phenols, which have many applications in the fine chemicals industry. Although some advances have been made in this research area, low reactivity and selectivity are, in general, observed. This report describes a new catalytic system for the efficient C?H acetoxylation of simple arenes based on Pd(OAc)2 and a pyridinecarboxylic acid ligand.
- Valderas, Carolina,Naksomboon, Kananat,Fernández-Ibá?ez, M. ángeles
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p. 3213 - 3217
(2016/10/24)
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- Study on the aromatic transesterification reaction catalyzed by phosphotungstic acid
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A practical phosphotungstic acid-catalyzed aromatic transesterification reaction for the preparation of aryl benzoates has been developed. The transesterification method avoids the oxidation of the corresponding phenols to quinone compounds with easy operations, environmentally benign conditions and high yields of the products. It is noteworthy that in this process phosphotungstic acid can be reused and recycled.
- He, Hong-Qiang,Chang, Yu-Wei,Xu, Wei-Ming
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supporting information
p. 280 - 282
(2015/06/22)
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- Rh-Catalyzed Synthesis of Coumarin Derivatives from Phenolic Acetates and Acrylates via C-H Bond Activation
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An efficient annulation strategy involving the reaction of phenolic acetates with acrylates in the presence of [Rh2(OAc)4] as catalyst and formic acid as reducing agent, leading to the high yield synthesis of coumarin derivatives, has been developed. The addition of NaOAc as a base increased the yield of the products. The reaction is quite successful for both electron-rich as well as electron-deficient phenolic acetates, affording coumarins with excellent regioselectivity, and proceeds via C-H bond activation proven by deuterium incorporation studies.
- Gadakh, Sunita K.,Dey, Soumen,Sudalai, Arumugam
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p. 11544 - 11550
(2015/12/04)
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- Chelating Bis-N-heterocyclic Carbene-Palladium(II) Complexes for Oxidative Arene C-H Functionalization
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Bis-N-heterocyclic carbene (NHC)-chelated palladium(II) complexes have been synthesized, characterized fully including single-crystal X-ray structural analyses, and utilized for the first time toward catalytic oxidative C-H functionalization of arenes with PhI(OAc)2 and N-bromosuccinimide. (Figure Presented).
- Desai, Sai Puneet,Mondal, Moumita,Choudhury, Joyanta
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supporting information
p. 2731 - 2736
(2015/06/30)
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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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- A new ferrocene-based bulky pyridine as an efficient reusable homogeneous catalyst
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An effective approach to reusing a homogeneous catalyst has been demonstrated. A ferrocene-based bulky pyridine has been synthesized and utilized as a homogeneous catalyst for the synthesis of benzoylfumarates as well as for acetylation. After the reaction, the catalyst was separated by simple precipitation and reused without appreciable loss of activity. The Royal Society of Chemistry 2013.
- Kashyap, Bishwapran,Phukan, Prodeep
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p. 15327 - 15336
(2013/09/02)
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- Poly(N-vinylimidazole) as an efficient catalyst for acetylation of alcohols, phenols, thiols and amines under solvent-free conditions
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Poly(N-vinylimidazole) is able to promote instantaneous quantitative acetylation of a variety of functionalized alcohols, phenols, thiols and amines with acetic anhydride at room temperature under solvent-free conditions. This new method consistently has excellent yields and the catalyst can be reused and recovered several times. Furthermore, the reaction can even be carried out on a larger scale. The Royal Society of Chemistry.
- Khaligh, Nader Ghaffari
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- Palladium-catalyzed acetoxylation of arenes by novel sulfinyl n-heterocyclic carbene ligand complexes
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A series of novel ligands based on N-heterocyclic carbene and sulfoxide functionalities have been prepared and characterized. Pd(II) complexes have been synthesized by transmetalation from the corresponding NHC-Ag derivatives, and their behavior as catalysts has been studied in arene C-H bond oxidative activation. Studies conducted toward the elucidation of the reaction mechanism of the acetoxylation suggest a C-H activation step at Pd(IV) rather than Pd(II) intermediates.
- Tato, Francisco,Garcia-Dominguez, Andres,Cardenas, Diego J.
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supporting information
p. 7487 - 7494
(2014/04/03)
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- Polyvinylpolypyrrolidone-bound boron trifluoride: A highly efficient catalyst for acylation of alcohols, phenols and trimethylsilyl ethers by acetic anhydride
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A highly efficient method for the acylation of alcohols, phenols and trimethylsilyl ethers with acetic anhydride is described using polyvinylpolypyrrolidone-bound boron trifluoride (PVPP-BF3) under mild and heterogeneous conditions at room temperature in good to excellent yields. The polyvinylpolypyrrolidone-boron trifluoride complex shows more water tolerant, non-corrosive and stable solid catalyst elevated Lewis acid properties.
- Mokhtary, Masoud,Qandalee, Mohammad,Najafizadeh, Faranak
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experimental part
p. 389 - 393
(2012/08/28)
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- Convergent, fit-for-purpose, kilogram-scale synthesis of a 5-lipoxygenase inhibitor
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Process research and development of a synthetic route towards a novel 5-lipoxygenase inhibitor is described. The synthetic route provided 1 in 27% yield in nine steps (seven steps in the longest linear sequence) and was performed on kilogram scale. The synthesis began with the preparation of the coumarin core via an efficient von Pechmann condensation. The triazole fragment was obtained via a regioselective copper-catalyzed [3 + 2] cycloaddition between a chiral alkyne and the coumarin azide.
- Ouellet, Stephane G.,Gauvreau, Danny,Cameron, Mark,Dolman, Sarah,Campeau, Louis-Charles,Hughes, Gregory,O'Shea, Paul D.,Davies, Ian W.
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scheme or table
p. 214 - 219
(2012/06/05)
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- Novel double-SO3h functionalized ionic liquid for acetylation
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Novel double-SO3H functionalized ionic liquid (DFIL) was synthesized and its catalytic activities for acetylation studied. The result showed that the DFIL possess high acidity and was very efficient for the acetylation of alcohols, amines and phenols with good to excellent yields in short reaction times. Operational simplicity, stability to water and air, small amounts needed, low cost, high yields, high acidity, applicability to large-scale reactions and reusability are the key features of the DFIL, which indicated promising applications of DFIL in green chemical processes. Pleiades Publishing, Ltd., 2012.
- Zhu, Lili,Liang, Xuezheng
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p. 684 - 688
(2013/02/23)
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- Investigation on the substitution effects of the flavonoids as potent anticancer agents: A structure-activity relationships study
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Three series of flavonoid analogues substituted with different aminomethyl substitutions at C-6, C-7, and C-8 were designed and synthesized for the structure-activity relationship studies as potent anticancer agents. The prepared analogues were evaluated for their in vitro inhibitory activity against the growth of the hepatic cancer cell lines HepG2 and SMMC-7721. Structure-activity relationships indicated that not only the compounds with amino methyl groups were more active than those without the groups in the same series but also the compounds substituted by aminomethyl groups at position C-8 were more active than those at positions C-6 and C-7.
- Wang, Xiao-Bing,Yang, Lei,Kong, Ling-Yi,Liu, Wei,Guo, Qing-Long
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p. 1833 - 1849,17
(2020/07/30)
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- O-acylation of substituted phenols with various alkanoyl chlorides under phase-transfer catalyst conditions
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Esterification of several types of mono-and disubstituted phenols with various mono-and dialkanoyl chlorides was performed in phase-transfer catalysis conditions, using tetrabutylammonium chloride in a mixture of aqueous NaOH and dichloromethane. The process is particularly efficient (almost quantitative yields) as well as rapid (only 5 min reaction time, at a temperature of0°C). Taylor & Francis Group, LLC.
- Simion, Alina Marieta,Hashimoto, Iwao,Mitoma, Yoshiharu,Egashira, Naoyoshi,Simion, Cristian
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experimental part
p. 921 - 931
(2012/02/01)
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- Electron-deficient [TiIV(salophen)(OTf)2]: A new and highly efficient catalyst for the acetylation of alcohols and phenols with acetic anhydride
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In the present work, a highly efficient method for acetylation of alcohols and phenols with acetic anhydride catalyzed by high-valent [Ti IV(salophen)(OTf)2] is reported. Under these conditions, primary, secondary and tertiary alcohols as well as phenols were acetylated with short reaction times and high yields. The catalyst was reused several times without loss of its catalytic activity.
- Yadegari, Maryam,Moghadam, Majid,Tangestaninejad, Shahram,Mirkhani, Valiollah,Mohammadpoor-Baltork, Iraj
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experimental part
p. 2237 - 2243
(2011/10/03)
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- Iron (III) phosphate as a green and reusable catalyst promoted chemo selective acetylation of alcohols and phenols with acetic anhydride under solvent free conditions at room temperature
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Iron (III) phosphate was employed as an efficient catalyst for the chemo selective acetylation of alcohols and phenols under solvent free condition at room temperature and with high yields. Iron (III) phosphate is also a potential green catalyst due to solid intrinsically, reusable and with high catalytic activity.
- Behbahani,Farahani,Oskooie
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experimental part
p. 633 - 637
(2011/10/08)
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- Investigation of catalytic activity of high-valent vanadium(IV) tetraphenylporphyrin: A new, highly efficient and reusable catalyst for acetylation of alcohols and phenols with acetic anhydride
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In the present work, the catalytic activity of high-valent tetraphenylporphyrinatovanadium(IV) trifluoromethanesulfonate, [V IV(TPP)(OTf)2], in the acetylation of alcohols and phenols with Ac2O is reported. This new V(IV) catalyst was used as an efficient catalyst for not only primary alcohols (benzylic and aliphatic) but also sterically-hindered secondary and tertiary alcohols with acetic anhydride and the corresponding acetates were obtained in 85-99% yield and 0.5-15 min. Acetylation of phenols with acetic anhydride was also performed to afford the desired acetates in 88-99% and 1.5-20 min. This catalyst can be reused several times without loss of its catalytic activity.
- Taghavi, S. Abdolmanaf,Moghadam, Majid,Mohammadpoor-Baltork, Iraj,Tangestaninejad, Shahram,Mirkhani, Valiollah,Khosropour, Ahmad Reza
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experimental part
p. 159 - 164
(2011/12/16)
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- Comparisons of O-acylation and Friedel-Crafts acylation of phenols and acyl chlorides and Fries rearrangement of phenyl esters in trifluoromethanesulfonic acid: Effective synthesis of optically active homotyrosines
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Reactions involving phenol derivatives and acyl chlorides have to be controlled for competitive O-acylations and C-acylations (Friedel-Crafts acylations and Fries rearrangements) in acidic condition. The extent for these reactions in trifluoromethanesulfonic acid (TfOH), which is used as catalyst and solvent, is examined. Although diluted TfOH was needed for effective O-acylation, concentrated TfOH was required for effective C-acylations in mild condition. These results have been applied to the novel synthesis of homotyrosine derivatives. Both Fries rearrangement of N-TFA-Asp(OBn)-OMe and Friedel-Crafts acylation of phenol with N-TFA-Asp(Cl)-OMe in TfOH afforded the homotyrosine skeleton, followed by reduction and deprotection afforded homotyrosines maintaining stereochemistry of Asp as an optically pure form.
- Murashige, Ryo,Hayashi, Yuka,Ohmori, Syo,Torii, Ayuko,Aizu, Yoko,Muto, Yasuyuki,Murai, Yuta,Oda, Yuji,Hashimoto, Makoto
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experimental part
p. 641 - 649
(2011/03/19)
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- Iron-doped single-walled carbon nanotubes as new heterogeneous and highly efficient catalyst for acylation of alcohols, phenols, carboxylic acids and amines under solvent-free conditions
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Iron-doped single-walled carbon nanotubes (Fe/SWCNTs) represent an efficient and new heterogeneous reusable catalyst for the acylation of a variety of alcohols, phenols, carboxylic acids and amines with acid chlorides or acid anhydrides under solvent-free conditions. The reactions of various primary, secondary, tertiary, and benzylic alcohols, diols, phenols, as well as aromatic and aliphatic amines give acylated adducts in good to excellent yields.
- Sharghi, Hashem,Jokar, Mahboubeh,Doroodmand, Mohammad Mahdi
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experimental part
p. 426 - 442
(2011/04/15)
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- Synthesis, structure-activity relationship of novel substituted 4H-chromen-1,2,3,4-tetrahydropyrimidine-5-carboxylates as potential anti-mycobacterial and anticancer agents
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Series of 4H-chromen-1,2,3,4-tetrahydropyrimidine-5-carboxylate derivatives 7a-7zb, 8a-8d and 9a-9d were synthesized and screened for their in vitro anti-mycobacterial activity against Mycobacterium tuberculosis H37Rv (MTB) and cytotoxicity against three human cancer cell lines including A549, SK-N-SH and HeLa. The results indicate that six compounds are more potent and 7za is most effective anti-mycobacterial derivative compared to the standard drugs Ethambutol and Ciprofloxacin. However, 12 compounds exhibited cytotoxicity against human neuroblastoma cell line; amongst them the compound 7v is most effective compared to the standard drug Doxorubicin. This is the first report assigning in vitro anti-mycobacterial, anticancer and structure-activity relationship for this new class of 4H-chromen-1,2,3,4-tetrahydropyrimidine-5- carboxylates.
- China Raju,Nageswara Rao,Suman,Yogeeswari,Sriram,Shaik, Thokhir Basha,Kalivendi, Shasi Vardhan
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scheme or table
p. 2855 - 2859
(2011/06/24)
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- Acetylation of alcohols and phenols with acetic anhydride under solvent-free conditions using an ionic liquid based on morpholine as a recoverable and reusable catalyst
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Rapid and efficient acetylation of alcohols and phenols with acetic anhydride is performed in the presence of economical Bronsted acidic ionic liquids that bear a propanesulfonic acid group on a morpholinium cation as catalysts under solvent-free conditions. [MMPPA][HSO4] (N-methylmorpholinium propanesulfonic acid ammonium hydrogensulfate) was proven to be the most active catalyst, and after removal of water, it could be recycled and reused for up to four times without a noticeable decrease in catalytic activity. Springer-Verlag 2010.
- Yue, Caibo,Liu, Qingqing,Yi, Tingfeng,Chen, Yun
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experimental part
p. 975 - 978
(2011/09/30)
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- Promotive effect of the platinum moiety on the DNA cleavage activity of copper-based artificial nucleases
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Copper-based artificial metallonucleases are likely to satisfy more biomedical requirements if their DNA cleavage efficiency and selectivity could be further improved. In this study, two copper(II) complexes, [CuL 1CI2 (1) and [CuL2CI2] (2), and two copper(II)-platinum(II) heteronuclear complexes, [CuRL1 (DMSO)CI 4] (3) and [CuPtL2DMSO)CI4] (4), were synthesized using two afunctional ligands, N-[4-(2-pyridylmethoxy)benzyl]-N,N- bis(2-pyridylmethyl)amine (L1) and N-[3-(2pyridylmethoxy)benzyl]-N, Nbls(2-pyridylmethyl)amine (L2). These complexes have been characterized by elemental analysis, electrospray ionization mass spectrometry, IR spectroscopy, and UV-vis spectroscopy. The DNA binding ability of these complexes follows an order of 1 2 3 4, as revealed by the results of spectroscopy and agarose gel electrophoresis studies. Their cleavage activity toward supercoiled pUC19 plasmid DNA is prominent at micromolar concentration levels in the presence of ascorbic acid. The introduction of a platinum(II) center to the copper(II) complexes induces a significant enhancement in cleavage activity as compared with copper(II) complexes alone. These results show that the presence of a platinum(II) center in copper(II) complexes strengthens both their DNA binding ability and DNA cleavage efficiency.
- Dong, Xindian,Wang, Xiaoyong,Lin, Miaoxin,Sun, Hui,Yang, Xiaoliang,Guo, Zijian
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experimental part
p. 2541 - 2549
(2010/05/14)
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- Pd(II)-catalyzed C-H activation/aryl-aryl coupling of phenol esters
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(Chemical Equation Presented) Although nitrogen-containing group-directed cyclopalladation reactions have been well-known, Pd(II) insertion into C-H bonds promoted by coordination of an oxygen-only group to the palladium remains rather rare. In the present study, the first cyclopalladation complex formed from a simple phenol ester was characterized by X-ray crystallography. A promising protocol for the ortho C-H activation/aryl-aryl coupling of phenol esters that was not sensitive to moisture or air was then established. The utility of the reaction was demonstrated for the synthesis of useful phenol derivatives. Copyright
- Xiao, Bin,Fu, Yao,Xu, Jun,Gong, Tian-Jun,Dai, Jian-Jun,Yi, Jun,Liu, Lei
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supporting information; experimental part
p. 468 - 469
(2010/03/25)
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- One-pot synthesis of 1,2,3-triols from allylic hydroperoxides and a catalytic amount of OsO4 in aqueous acetone
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Allylic hydroperoxides were converted into the corresponding triols in the presence of a catalytic amount of OsO4. The present reaction involves regeneration of active osmium species by the hydroperoxide functionality and occurs in a diastereoselective manner to form triols in high yields. A plausible mechanism for the formation of 1,2,3-triols from allylic hydroperoxide is presented.
- Alp, Cemalettin,Atmaca, Ufuk,?elik, Murat,Gültekin, Mehmet Serdar
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body text
p. 2765 - 2768
(2010/02/28)
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- Counterattack mode differential acetylative deprotection of phenylmethyl ethers: Applications to solid phase organic reactions
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A counterattack protocol for differential acetylative cleavage of phenylmethyl ether has been developed. The phenylmethyl moiety is liberated as benzyl bromide that is isolated and reused providing advantages in terms of waste minimization/utilization and atom economy. The applicability of this methodology has been extended for solid phase organic reactions with the feasibility of reuse of the solid support.
- Chakraborti, Asit K.,Chankeshwara, Sunay V.
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experimental part
p. 1367 - 1370
(2009/07/04)
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- Polymer-supported gadolinium triflate as a convenient and efficient Lewis acid catalyst for acetylation of alcohols and phenols
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A polymer-supported gadolinium triflate (CMPS-IM-Gd) catalyst was prepared from chloromethyl polystyrene (CMPS) resin using a simple and convenient procedure. This polymeric catalyst was used as an efficient Lewis acid catalyst for the acetylation of various alcohols and phenols with acetic anhydride, affording high yields under mild conditions. The reaction was completed in a short period of time with small amounts of the catalyst. The catalyst was reused over 10 times without any significant loss of its catalytic activity.
- Yoon, Hyo-Jin,Lee, Sang-Myung,Kim, Jong-Ho,Cho, Hong-Jun,Choi, Jung-Woo,Lee, Sang-Hyeup,Lee, Yoon-Sik
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p. 3165 - 3171
(2008/09/20)
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- TiO2: A simple and an efficient catalyst for esterification of phenols under solvent-free condition
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In the presence of catalytic amount of titanium oxide (TiO2), without any additional solvent at 25°C, phenols are conveniently acylated by acid chlorides to get phenolic esters in excellent yields. The TiO2 powder can be reused three times after simple washing with CH2Cl 2.
- Pasha, Mohamed Afzal,Manjula, Krishnappa
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p. 597 - 600
(2008/09/19)
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- Rapid and efficient method for acetylation of alcohols and phenols with acetic anhydride catalyzed by silica sulfate
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A rapid and efficient method is described for acetylation of a series of alcohols and phenols with acetic anhydride catalyzed by silica sulfate solid acid at room temperature or at refluxing temperature in excellent yield. Copyright Taylor & Francis Group, LLC.
- Jin, Tong-Shou,Zhao, Ying,Liu, Li-Bin,Chen, Zhuo,Li, Tong-Shuang
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p. 1221 - 1227
(2007/10/03)
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- Novel synthesis, reactivity, and stereochemistry of substituted 3-trifluoromethyl- and 3-perfluoroalkyl-3-phenoxyprop-2-enal
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Substituted 3-phenoxy-3-perfluoroalkylprop-2-enals 3a-s are synthesized in high yields starting from a gem-iodoacetoxy derivative 1 and phenoxides 2. Then efficient syntheses of push-pull derivatives 4, 5, 8a,b, and nonconjugated analogues 6 and 7 illustrate the synthetic potentialities of 3. Stereochemical studies of these perfluoroalkyl-containing trisubstituted olefinic derivatives 3-8b revealed that the 4JCF coupling constant observed in the 13C NMR spectra was crucial in the determination of their configurations and conformations in solution. The solvent polarity effect on the stereochemistry of push-pull compounds 3-5 and 8a,b was studied. Unusual significant medium polarity effect on the stereochemistry of imino enol ether derivative 4 was observed.
- El Kharrat, Salem,Laurent, Philippe,Blancou, Hubert
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p. 6742 - 6752
(2007/10/03)
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- Phytotoxins from Hofmeisteria schaffneri: Isolation and synthesis of 2′-(2″-hydroxy-4″-methylphenyl)-2′-oxoethyl acetate
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Activity-directed fractionation of a CH2Cl2-MeOH (1:1) extract of Hofmeisteria schaffneri led to the isolation of a new phytotoxin characterized as 2′-(2″-hydroxy-4″-methylphenyl)- 2′-oxoethyl acetate and designated the trivial name of hofmeisterin (1). In addition, the known compounds β-carotene, euparin, and 3′,4′,4a′,9a′-tetrahydro-6,7′- dimethylspiro[benzofuran-3(2H),2′-pyrano[2,3-b]benzofuran]-2, 4a′-diol (2) were obtained. The identification of the isolates was accomplished by spectroscopic methods. The structure of 1 was unequivocally confirmed by synthesis. The methyl derivative 1a was also synthesized following the same strategy. Compounds 1 and 2 inhibited radicle growth of Amaranthus hypochondriacus (IC50 = 3.2 × 10-4 and 1.2 × 10-5 M, respectively) and significantly inhibited activation of the calmodulin (CaM)-dependent enzyme cAMP phosphodiesterase (PDE) with IC 50 values of 4.4 and 4.22 μM, respectively.
- Perez-Vasquez, Araceli,Reyes, Adelfo,Linares, Edelmira,Bye, Robert,Mata, Rachel
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p. 959 - 962
(2008/12/22)
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- Facile catalyzed acylation of alcohols, phenols, amines and thiols based on ZrOCl2·8H2O and acetyl chloride in solution and in solvent-free conditions
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Acylation of heteroatoms (O, N and S) with acetyl chloride based on the use of a catalytic amount of the moisture stable, inexpensive ZrOCl 2?8H2O, proceeds efficiently producing the corresponding acylated products in excellent yields.
- Ghosh, Rina,Maiti, Swarupananda,Chakraborty, Arijit
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p. 147 - 151
(2007/10/03)
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- P2O5 / SiO2 as a mild and efficient reagent for acylation of alcohols, phenols and amines under solvent-free conditions
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P2O5 / SiO2 is a highly efficient reagent for the acetylations of a variety of alcohols, phenols and amines with acetic anhydride under solvent-free conditions. Primary, secondary, allylic and benzylic alcohols, diols and phenols with electron-donating or withdrawing substituents can be easily acetylated in good to excellent yield.
- Eshghi, Hossein,Shafieyoon, Parvaneh
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p. 802 - 805
(2007/10/03)
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