- A facile and versatile electro-reductive system for hydrodefunctionalization under ambient conditions
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A general electrochemical system for reductive hydrodefunctionalization is described, employing the inexpensive and easily available triethylamine (Et3N) as a sacrificial reductant. This protocol is characterized by facile operation, sustainable conditions, and exceptionally wide substrate scope covering the cleavage of C-halogen, N-S, N-C, O-S, O-C, C-C and C-N bonds. Notably, the selectivity and capability of reduction can be conveniently switched by simple incorporation or removal of an alcohol as a co-solvent.
- Huang, Binbin,Guo, Lin,Xia, Wujiong
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supporting information
p. 2095 - 2103
(2021/03/26)
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- LiHMDS: Facile, highly efficient and metal-free transesterification under solvent-free condition
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Transesterification is one of the important organic reactions employed in numerous industrial as well as laboratory applications for the synthesis of various esters. Herein, we report a rapid, highly efficient, and transition metal-free transesterification reaction in the presence of LiHMDS under solvent-free conditions. The transesterification reaction was carried out with three different benzoate esters and a wide range of primary and secondary alcohols (from C3-C18) in good to excellent yields (45 examples). By considering the commercial role of esters, this method will be promising for the facile synthesis of esters in industry-relevant applications.
- Gore, Kiran R.,Mittapelli, Lavanya L.
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- Hydrogen-bond-assisted transition-metal-free catalytic transformation of amides to esters
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The amide C-N cleavage has drawn a broad interest in synthetic chemistry, biological process and pharmaceutical industry. Transition-metal, luxury ligand or excess base were always vital to the transformation. Here, we developed a transition-metal-free hydrogen-bond-assisted esterification of amides with only catalytic amount of base. The proposed crucial role of hydrogen bonding for assisting esterification was supported by control experiments, density functional theory (DFT) calculations and kinetic studies. Besides broad substrate scopes and excellent functional groups tolerance, this base-catalyzed protocol complements the conventional transition-metal-catalyzed esterification of amides and provides a new pathway to catalytic cleavage of amide C-N bonds for organic synthesis and pharmaceutical industry. [Figure not available: see fulltext.]
- Huang, Changyu,Li, Jinpeng,Wang, Jiaquan,Zheng, Qingshu,Li, Zhenhua,Tu, Tao
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- Electrochemical esterification via oxidative coupling of aldehydes and alcohols
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An electrolytic method for the direct oxidative coupling of aldehydes with alcohols to produce esters is described. Our method involves anodic oxidation in presence of TBAF as supporting electrolyte in an undivided electrochemical cell equipped with graphite electrodes. This method successfully couples a wide range of alcohols to benzaldehydes with yields ranging from 70 to 90%. The protocol is easy to perform at a constant voltage conditions and offers a sustainable alternative over conventional methods.
- Smeyne, Dylan,Verboom, Katherine,Bryan, Maria,LoBue, James,Shaikh, Abid
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supporting information
(2021/03/26)
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- Cesium Carbonate Catalyzed Esterification of N-Benzyl- N-Boc-amides under Ambient Conditions
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We report a general activated amide to ester transformation catalyzed by Cs2CO3. Using this approach, esterification proceeds under relatively mild conditions and without the need for a transition metal catalyst. This method exhibits broad substrate scope and represents a practical alternative to existing esterification strategies. The synthetic utility of this protocol is demonstrated via the facile synthesis of crown ether derivatives and the late-stage modification of a representative natural product and several sugars in reasonable yields.
- Ye, Danfeng,Liu, Zhiyuan,Chen, Hao,Sessler, Jonathan L.,Lei, Chuanhu
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supporting information
p. 6888 - 6892
(2019/09/07)
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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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- Silver-mediated oxidative functionalization of alkylsilanes
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A general approach to the functionalization of aliphatic C-Si bonds in the presence of silver salts and oxidants has been reported. This strategy encompasses a range of valuable C-Si transformations, including the direct conversions of a C-Si bond to C-OCF3, C-OBz, C-OCOCF3, C-SCF3, C-SCN, and C-N3 bonds. Among them, trifluoromethoxylation of alkylsilanes is reported for the first time. In addition, mechanistic studies indicate that this reaction may proceed through a radical mechanism.
- Wang, Feng,Xu, Peng,Cong, Fei,Tang, Pingping
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p. 8836 - 8841
(2019/01/03)
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- Systematic Evaluation of Sulfoxides as Catalysts in Nucleophilic Substitutions of Alcohols
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Herein, a method for the nucleophilic substitution (SN) of benzyl alcohols yielding chloro alkanes is introduced that relies on aromatic sulfoxides as Lewis base catalysts (down to 1.5 mol-%) and benzoyl chloride (BzCl) as reagent. A systematic screening of various sulfoxides and other sulfinyl containing Lewis bases afforded (2-methoxyphenyl)methyl sulfoxide as optimal catalyst. In contrast to reported formamide catalysts, sulfoxides also enable the application of plain acetyl chloride (AcCl) as reagent. In addition, it was demonstrated that weakly electrophilic carboxylic acid chlorides like BzCl promote Pummerer rearrangement of sulfoxides already at room temperature. This side-reaction also provided the explanation, why sulfoxide catalyzed SN-reactions of alcohols do not allow the effective production of aliphatic and electron deficient chloro alkanes. Comparison experiments provided further insight into the reaction mechanism.
- Motsch, Sebastian,Schütz, Christian,Huy, Peter H.
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supporting information
p. 4541 - 4547
(2018/09/13)
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- Integrative Photoreduction of CO2 with Subsequent Carbonylation: Photocatalysis for Reductive Functionalization of CO2
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Efficient conversion of CO2 into fuels and chemicals with solar energy would be promising, but also faces great challenge. In this context, we describe the photoreductive functionalization of CO2 to construct new C?C, C?N, and C?O bonds through the respective Pd-catalyzed Suzuki carbonylation, aminocarbonylation, and alkoxycarbonylation of aryl iodides with CO in situ generated through the photoreduction of CO2. This protocol opens up an alternative avenue for CO2 utilization by harnessing solar energy.
- He, Xing,Cao, Yu,Lang, Xian-Dong,Wang, Ning,He, Liang-Nian
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p. 3382 - 3387
(2018/09/14)
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- A solid acid catalysis of the preparation process of benzoic acid ester plasticizer (by machine translation)
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The present invention discloses a solid acidify catalytic benzoic acid ester plasticizer of the preparation process, the preparation method is: to benzoic acid and alcohol as the raw material, with agent and catalyst in direct reaction to produce benzoic acid ester compound; catalytic system of the invention compared with the sulfuric acid, toluene sulfonic acid and sulfuric acid to sodium has a better catalytic activity, so the catalyst less consumption, in addition, because of the use of the is supported on a solid acid catalyst, after the reaction directly filtering can realize the separation of the catalyst, and the catalyst can be reused, makes the production process more simple, and can be basically prevent the generation of waste water, makes the production process more green environmental protection. (by machine translation)
- -
-
Paragraph 0018; 0019
(2017/07/05)
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- Highly Efficient Carbon Monoxide Capture by Carbanion-Functionalized Ionic Liquids through C-Site Interactions
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A novel method for the highly efficient and reversible capture of CO in carbanion-functionalized ionic liquids (ILs) by a C-site interaction is reported. Because of its supernucleophilicity, the carbanion in ILs could absorb CO efficiently. As a result, a relatively high absorption capacity for CO (up to 0.046 mol mol?1) was achieved under ambient conditions, compared with CO solubility in a commonly used IL [Bmim][Tf2N] (2×10?3 mol mol?1). The results of quantum mechanical calculations and spectroscopic investigation confirmed that the chemical interaction between the C-site in the carbanion and CO resulted in the superior CO absorption capacities. Furthermore, the subsequent conversion of captured CO into valuable chemicals with good reactivity was also realized through the alkoxycarbonylation reaction under mild conditions. Highly efficient CO absorption by carbanion-functionalized ILs provides a new way of separating and converting CO.
- Tao, Duan-Jian,Chen, Feng-Feng,Tian, Zi-Qi,Huang, Kuan,Mahurin, Shannon M.,Jiang, De-En,Dai, Sheng
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supporting information
p. 6843 - 6847
(2017/06/06)
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- A microwave-assisted highly practical chemoselective esterification and amidation of carboxylic acids
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The ubiquitousness of esters and amide functionalities makes their coupling reaction one of the most sought-after organic transformations. Herein, we have described an efficient microwave-assisted synthesis of esters and amides. Soluble triphenylphosphine, in conjugation with molecular iodine, gave the desired products without the requirement for a base/catalyst. In addition, a solid-phase synthetic route is incorporated for the said conversion, which has added advantages over solution-phase pathways, such as low moisture sensitivity, easy handling, isolation of the product by simple filtration, and reusability. In short, our method is simple, mild, green, and highly chemoselective in nature.
- Pathak, Gunindra,Das, Diparjun,Rokhum, Lalthazuala
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p. 93729 - 93740
(2016/10/21)
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- By using low-temperature co- melt solvent a method of catalytic ester (by machine translation)
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The invention discloses a method of utilizing low-temperature co- melt solvent catalytic ester method, will be 0.05-0.5 mole of sharemelt solvent of low-temperature co-preprocessing, 1-5 mole of share alcohol and 1-10 mole of share of acid in the reaction vessel, stirring and heating, 25-200 ° C reaction under 2-96h, then the reaction fluid settlement , liquid, organic is accepted after passing an examination the level , get the esterification reaction products of the; reaction after the treatment and recovery of low-temperature co- melt solvent the preprocessing, can be reused. This invention utilizes the easy preparation of low-temperature co- melt solvent the preprocessing of catalytic esterification reaction, the reaction front is homogeneous, can be formed after the reaction of the two-phase reaction in the process of direct dehydration, without adding other dehydrating agent, has the advantages of simple operation, the reaction efficiency is high, corrosion of small equipment, less side reactions, the product quality is good, no pollution to the environment, and the like, it has broad application prospects. (by machine translation)
- -
-
Paragraph 0046; 0047
(2017/01/17)
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- Formamides as Lewis Base Catalysts in SNReactions—Efficient Transformation of Alcohols into Chlorides, Amines, and Ethers
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A simple formamide catalyst facilitates the efficient transformation of alcohols into alkyl chlorides with benzoyl chloride as the sole reagent. These nucleophilic substitutions proceed through iminium-activated alcohols as intermediates. The novel method, which can be even performed under solvent-free conditions, is distinguished by an excellent functional group tolerance, scalability (>100 g) and waste-balance (E-factor down to 2). Chiral substrates are converted with excellent levels of stereochemical inversion (99 %→≥95 % ee). In a practical one-pot procedure, the primary formed chlorides can be further transformed into amines, azides, ethers, sulfides, and nitriles. The value of the method was demonstrated in straightforward syntheses of the drugs rac-Clopidogrel and S-Fendiline.
- Huy, Peter H.,Motsch, Sebastian,Kappler, Sarah M.
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p. 10145 - 10149
(2016/08/16)
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- METHOD OF CONVERTING ALCOHOL TO HALIDE
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The present invention relates to a method of converting an alcohol into a corresponding halide. This method comprises reacting the alcohol with an optionally substituted aromatic carboxylic acid halide in presence of an N-substituted formamide to replace a hydroxyl group of the alcohol by a halogen atom. The present invention also relates to a method of converting an alcohol into a corresponding substitution product. The second method comprises: (a) performing the method of the invention of converting an alcohol into the corresponding halide; and (b) reacting the corresponding halide with a nucleophile to convert the halide into the nucleophilic substitution product.
- -
-
Page/Page column 50; 132; 133; 134
(2017/01/02)
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- Diacyl Disulfide: A Reagent for Chemoselective Acylation of Phenols Enabled by 4-(N,N-Dimethylamino)pyridine Catalysis
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A general and excellent acylation reagent, diacyl disulfide, was uncovered for efficient ester formation enabled by DMAP (4-(N,N-dimethylamino)pyridine) catalysis. This protocol offered a promising synthetic platform on site-selective acylation of phenolic and primary aliphatic hydroxyl groups, which greatly expanded the realm of protecting group chemistry. The importance of the reagent was also reflected by its excellent moisture tolerance, high efficiency, and potential in synthetic chemistry and biologically meaningful natural product modification.
- Liu, Hong-Xin,Dang, Ya-Qian,Yuan, Yun-Fei,Xu, Zhi-Fang,Qiu, Sheng-Xiang,Tan, Hai-Bo
-
supporting information
p. 5584 - 5587
(2016/11/17)
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- Nanocrystalline CeO2 as a Highly Active and Selective Catalyst for the Dehydration of Aldoximes to Nitriles and One-Pot Synthesis of Amides and Esters
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The dehydration of aldoximes into nitriles has been performed in the presence of various metal oxides with different acid-base properties (Al2O3, TiO2, CeO2, MgO). The results showed that a nanocrystalline CeO2 was the most active catalyst. An in situ IR spectroscopy study supports a polar elimination mechanism in the dehydration of aldoxime on metal oxide catalysts, in which Lewis acid sites and basic sites are involved. The Lewis acid sites intervene in the adsorption of the oxime on the catalyst surface while surface base sites are responsible for the C1-H bond cleavage. Thus, the acid-base properties of nanocrystalline CeO2 are responsible for the high catalytic activity and selectivity. A variety of aldoximes including alkyl and cycloalkyl aldoximes have been dehydrated into the corresponding nitriles in good yields (80-97%) using nanosized ceria which moreover resulted in a stable and reusable catalyst. Additionally, it has been showed that a variety of pharmacologically important products such as picolinamide and picolinic acid alkyl ester derivatives can be obtained in good yields from 2-pyridinaldoxime in a one-pot process using the nanoceria as catalyst.
- Rapeyko, Anastasia,Climent, Maria J.,Corma, Avelino,Concepción, Patricia,Iborra, Sara
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p. 4564 - 4575
(2016/07/12)
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- Selective Monoesterification of Symmetrical Diols Using Resin-Bound Triphenylphosphine
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Coupling reactions to make esters and amides are among the most widely used organic transformations. We report efficient procedures for amide bond formation and for the monoesterification of symmetrical diols in excellent yields without any requirement for high dilution or slow addition using resin-bound triarylphosphonium iodide. Easy purification, low moisture sensitivity, and good to excellent yields of the products are the major advantages of this protocol.
- Pathak, Gunindra,Rokhum, Lalthazuala
-
supporting information
p. 483 - 487
(2015/09/22)
-
- Catalysis studies of macroreticular polystyrene cation-exchange resin with terminal perfluoroalkanesulfonic acids
-
Macroreticular p-(ω-sulfonic-perfluoroalkylated) polystyrene (FPS) resin with the advantages of both sulfonic polystyrene (such as macroreticular Amberlyst-15) and perfluoroalkanesulfonic resin (such as superacidic Nafion NR50) has exhibited excellent catalytic selectivity and activity in cyclization of pseudoionone and condensation of indole. In this paper, FPS was characterized by XPS, nitrogen sorption technique, FESEM and Hammett indicator method, and employed as the solid acid catalyst in the esterification, acylation and alkylation reactions. The FPS resin showed better activity than commercial solid acid catalysts (Amberlyst-15 and Nafion NR50) owing to its high surface area and strong acidity close to superacidity.
- Lin, Zhenghuan,Guan, Chuanjin,Huang, Limei,Wang, Wen,Ling, Qidan,Zhao, Chengxue
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p. 261 - 266
(2013/07/27)
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- Direct conversion of N -alkoxyamides to carboxylic esters through tandem nbs-mediated oxidative homocoupling and thermal denitrogenation
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Treatment of N-alkoxyamides with NBS in toluene was found to conveniently afford the corresponding carboxylic esters, including those bearing a bulky or long-chain substituent, in satisfactory to excellent yields. This approach not only represents a convenient and economic approach to a direct transformation of an alkoxyamide moiety into the carboxylic ester functional group, via oxidative homocoupling and the subsequent thermal denitrogenation, but also facilitates the synthesis of sterically hindered carboxylic esters.
- Zhang, Ningning,Yang, Rui,Zhang-Negrerie, Daisy,Du, Yunfei,Zhao, Kang
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p. 8705 - 8711
(2013/09/24)
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- The dual role of ionic liquid BmimBF4, precursor of N-heterocyclic carbene and solvent, in the oxidative esterification of aldehydes
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Room temperature ionic liquid BmimBF4 (1-butyl-3- methylimidazolium tetrafluoroborate) has been utilized in the N-heterocyclic carbene-catalyzed oxidation of aldehydes to yield esters. In the presence of MnO2 as oxidant and of DBU and caesium carbonate as bases, aromatic, heteroaromatic and aliphatic esters have been isolated in good to excellent yields. The recyclability of the used ionic liquid along with the excess of inorganic reagents has been proved. The simple and cheap BmimBF4 ionic liquid played the dual role of precatalyst and solvent. This is the first time that such a reaction has been carried out with an ionic liquid as solvent.
- Chiarotto, Isabella,Feroci, Marta,Sotgiu, Giovanni,Inesi, Achille
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p. 8088 - 8095
(2013/08/23)
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- Imidazolium ionic liquid-supported sulfonic acids: Efficient and recyclable catalysts for esterification of benzoic acid
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Several imidazolium ionic liquid (IL)-supported sulfonic acids with different anions, [C3SO3Hmim]HSO4, [C 3SO3Hmim]BF4, [C3SO 3Hmim]PF6, and [C3SO3Hmim]CF 3SO3, were synthesized and applied as catalysts for esterification reaction of benzoic acid. The experimental results indicate that imidazolium IL-supported sulfonic acid containing anion of HSO4 - shows the best catalytic activity. Only when less [C 3SO3Hmim]HSO4 (0.3 equiv.) applied, was the product obtained with high yield of 97%. Furthermore, the produced esters could be separated by decantation, and the catalyst could be reused after the removal of water.
- Cai, Yue Qin,Yu, Guo Qiang,Liu, Chuan Duo,Xu, Yuan Yuan,Wang, Wei
-
experimental part
p. 1 - 4
(2012/03/27)
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- Bis(cyclopentadienyldicarbonyliron) as a convenient carbon monoxide source in palladium-catalyzed carbonylative coupling of aryl iodides with amines, alcohols, and thiols
-
Bis(cyclopentadienyldicarbonyliron) ([CpFe(CO)2]2) serves as a carbon monoxide source in carbonylative coupling reactions. Treatment of aryl iodides with primary amines in the presence of DBU and [CpFe(CO)2]2 under palladium catalysis provides the corresponding benzamides in good yields. Similar reactions with phenols and thiols provide the corresponding benzoate esters and thioesters, respectively. A catalytic amount of DMAP as an additive promoted the carbonylative coupling reactions with primary alcohol and secondary amine.
- Nakaya, Ryotaro,Yorimitsu, Hideki,Oshima, Koichiro
-
experimental part
p. 904 - 906
(2011/12/05)
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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
-
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
-
experimental part
p. 426 - 442
(2011/04/15)
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- Palladium-catalyzed aerobic oxidative direct esterification of alcohols
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One step from alcohol to ester: A palladium-catalyzed oxidative esterification of various benzylic alcohols with methanol and long-chain aliphatic alcohols was carried out in the presence of molecular oxygen as the oxidant (see scheme). By considering the effects of substitution and potential mechanistic pathways, the applicability of this method to a range of different substrates was shown. Copyright
- Liu, Chao,Wang, Jing,Meng, Lingkui,Deng, Yi,Li, Yao,Lei, Aiwen
-
supporting information; experimental part
p. 5144 - 5148
(2011/06/26)
-
- An improved greener esterification of fatty alcohols using a renewable acid-ionic liquid couple as catalyst-solvent
-
We have developed a simple and efficient method for the esterification of various organic acids with C4-C18 alcohols using the 1-octyl-3-methyl- imidazolium tetrafluoroborate-para-toluenesulphonic acid (OMIM/BF 4-PTSA) couple, without organic solvent, either by classic heating or by microwave irradiation. The utilisation of the OMIM/BF4-PTSA couple presents considerable advantages: high yield, low temperature, short reaction time, isolation of the ester by simple decantation, easy reuse of the catalyst couple.
- Nguyen, Hoang-Phuong,Znifeche, Samira,Baboulene, Michel
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p. 2085 - 2093
(2007/10/03)
-
- Non-antibiotic antibacterial activity of dodecyl gallate
-
Dodecyl (C12) gallate (3,4,5-trihydroxybenzoate) (1) was found to possess antibacterial activity specifically against Gram-positive bacteria, in addition to its potent antioxidant activity. The time-kill curve study indicates that this amphipathic gallate exhibits bactericidal activity against methicillin resistant Staphylococcus aureus (MRSA) strains. Dodecyl (lauryl) gallate inhibited oxygen consumption in whole cells and oxidation of NADH in membrane preparation. The antibacterial activity of this gallate comes in part from its ability to inhibit the membrane respiratory chain. As far as alkyl gallates are concerned, their antimicrobial spectra and potency depend in part on the hydrophobic portion of the molecule.
- Kubo, Isao,Fujita, Ken-ichi,Nihei, Ken-ichi,Masuoka, Noriyoshi
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p. 573 - 580
(2007/10/03)
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- One-pot preparation of esters from carboxylic acids using the PPh3-CCl3CN system
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A convenient one-pot process for preparing various esters from carboxylic acids using the Ph3P-CCl3CN has been developed. Racemic α-tocopherol, clofibrate and flavoxate were prepared in high yields using this method.
- Jang, Doo Ok,Cho, Dae Hyan,Kim, Joong-Gon
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p. 2885 - 2890
(2007/10/03)
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- ALKYLATION DES IONS CARBOXYLATES PAR LES SELS DE SULFONIUM: INFLUENCE DES SELS DE CUIVRE
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Sulfonium salts are extremely powerful alkylating agents, particularly in the two-phase technique both solid-liquid and liquid-liquid.Alkylation of carboxylate salts by sulfonium salts does not show very large dependence on ratio of reactivities of various groups attached to the sulfur and mixtures of esters are often obtained.In the presence of copper(I) salts, there is a strong acceleration of the reaction of allylic sulfonium salts and it becomes very selective in favour of the unsaturated residues.Prenyl sulfonium salts, which react very eficiently through the α-position in the absence of copper salts, give exclusively tertiary esters when a catalytic amount of copper bromide is present.
- Badet, B.,Julia, M.,Ramirez-Munoz, M.,Sarrazin, C. A.
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p. 3111 - 3126
(2007/10/02)
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