- N-Aroylbenzotriazoles as Efficient Reagents for o-Aroylation in Absence of Organic Solvent
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N-Aroylbenzotriazoles have been shown to be efficient reagents for esterification in the absence of organic solvent. Grinding of N-aroylbenzoytiazoles with twofold excess of alcohols for a couple of hours at room temperature gave corresponding esters in high percentage of yields.
- Hahnvajanawong, Viwat,Phungpis, Baramee
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p. 2671 - 2674
(2021/10/25)
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- Iodine-catalyzed synthesis of β-uramino crotonic esters as well as oxidative esterification of carboxylic acids in choline chloride/urea: a desirable alternative to organic solvents
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Abstract: Iodine-mediated selective synthesis of β-uramino crotonic esters was achieved via the reaction of β-dicarbonyls and urea at room temperature. Choline chloride/urea mixture, as an eco-friendly, cheap, non-toxic, and recyclable deep eutectic solvent (DES), was employed as sustainable media as well as reagent at the same time in these transformations. Some derivatives of β-uramino crotonic esters were synthesized with good to high yields without a tedious work-up. The process could be done to synthesize the above-mentioned compounds in gram scale. Moreover, oxidative cross-esterification of carboxylic acids with alkyl benzenes was carried out in the above-mentioned DES by the employment of tetrabutylammonium iodide (TBAI) as the catalyst and tert-butyl hydroperoxide (TBHP) as the oxidant at 80?°C. DES/TBAI system was reused up to five consecutive times. Graphic abstract: Iodine-catalyzed C–N and C–O bond formation in choline chloride/urea as a green solvent under the mild reaction conditions. Providing the clean procedure toward synthesis of β-uramino crotonic esters and benzylic esters.[Figure not available: see fulltext.].
- Moayyed, Mohammadesmaeil,Saberi, Dariush
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p. 445 - 455
(2020/09/07)
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- A metal-free iodine-mediated conversion of hydroxamates to esters
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A metal-, oxidant-, and additive-free conversion of hydroxamates to esters have been achieved using molecular iodine as the reagent using a novel but not-so-explored heron-type rearrangement. The reaction proceeds with almost equal facility with substrates having either electron-donating or electron-withdrawing substituent. Similarly, α,?-unsaturated, and sterically hindered ortho-substituted hydroxamates also undergo the desired transformation smoothly.
- Ghosh, Subhankar,Banerjee, Jeet,Ghosh, Rajat,Chattopadhyay, Shital K.
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p. 1353 - 1360
(2020/03/30)
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- Mechanochemical Palladium-Catalyzed Carbonylative Reactions Using Mo(CO)6
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Esters and amides were mechanochemically prepared by palladium-catalyzed carbonylative reactions of aryl iodides by using molybdenum hexacarbonyl as a convenient solid carbonyl source and avoiding a direct handling of gaseous carbon monoxide. Real-time monitoring of the mechanochemical reaction by in situ pressure sensing revealed that CO is rapidly transferred from Mo(CO)6 to the active catalytic system without significant release of molecular carbon monoxide.
- van Bonn, Pit,Bolm, Carsten,Hernández, José G.
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p. 2576 - 2580
(2020/02/20)
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- Bu 4 NI-Catalyzed C-C Bond Cleavage and Oxidative Esteri??cation of Allyl Alcohols with Toluene Derivatives
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A novel oxidative esterification of 1-arylprop-2-en-1-ols with toluene derivatives catalyzed by tetrabutylammonium iodide (TBAI) is reported. The optimization of the reaction conditions illustrates that each of experiment parameters including the catalyst, solvent, and oxidant is significant for present oxidative functionalization. This metal-free protocol has a broad substrate scope including the halogen groups for further functionalization and enriches the reactivity profile of allyl alcohol and toluene derivatives. In addition, this protocol represents a new transformation of allyl alcohol involving C-C bond cleavage and C-O bond forming.
- Chen, Yaoyao,Cui, Yongmei,Jia, Xueshun,Li, Chengliang,Li, Jian,Sun, Mingming
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p. 3667 - 3674
(2019/09/30)
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- Palladium-Catalyzed Carbonylative Synthesis of Benzyl Benzoates Employing Benzyl Formates as Both CO Surrogates and Benzyl Alcohol Sources
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An efficient and convenient palladium-catalyzed carbonylation reaction for the synthesis of benzyl benzoates from aryl bromides has been developed. Benzyl formates have been explored as a new type of efficient and useful CO sources and also reaction partners. A wide range of benzyl benzoates was obtained in good to excellent yields.
- Lai, Ming,Qi, Xinxin,Wu, Xiao-Feng
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supporting information
p. 3776 - 3778
(2019/06/24)
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- Palladium-Catalyzed Alkoxycarbonylation of Arylsulfoniums
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Alkoxycarbonylation of arylsulfoniums has been developed with the aid of a catalytic amount of a palladium-Xantphos complex under an atmospheric pressure of CO gas. Various functional groups such as carbonyl, cyano, halo, and sulfonyl groups were well tolerated under the present catalysis. Since aryldimethylsulfoniums were readily prepared from the corresponding aryl methyl sulfides and methyl triflate, one-pot alkoxycarbonylation of aryl methyl sulfides could be accomplished.
- Minami, Hiroko,Nogi, Keisuke,Yorimitsu, Hideki
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supporting information
p. 2518 - 2522
(2019/04/17)
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- Versatile Heterogeneous Palladium Catalysts for Diverse Carbonylation Reactions under Atmospheric Carbon Monoxide Pressure
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Herein, we report a versatile carbonylation protocol using heterogeneous Pd0 nanoparticles supported on the metal–organic frameworks (MOFs) MIL-88B-NH2 (Fe/Cr). The synthesis of a vast array of carbonyls, which includes amides, esters, carboxylic acids, and α-ketoamides, was achieved through mono- and dicarbonylation reactions. The selectivity could be controlled simply by tuning the reaction conditions. Superior activity and selectivity were recorded in some cases compared to that achieved with commercial Pd/C. However, the utility of an elaborate catalyst support is questionable and important reactivity and recyclability issues are discussed.
- Vico Solano, Marta,González Miera, Greco,Pascanu, Vlad,Inge, A. Ken,Martín-Matute, Belén
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p. 1089 - 1095
(2018/02/06)
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- Aerobic oxidative esterification and thioesterification of aldehydes using dibromoisocyanuric acid under mild conditions: No metal catalysts required
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A practical direct method for the direct preparation of esters and thioesters from aldehydes is described. Esters and thioesters were synthesized by oxidative esterification and thioesterification via in situ generated acyl bromide intermediates, which were used to react with various alcohols and thiols. The esterification and thioesterification were readily performed in the presence of dibromoisocyanuric acid in dichloromethane, without any metal catalysts and under mild conditions. By using this reaction protocol, various esters and thioesters were prepared in high yields. This effective method offers a promising approach for the facile esterification and thioesterification of aldehydes.
- Kwon, Young-Do,La, Minh Thanh,Kim, Hee-Kwon
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p. 10833 - 10841
(2018/07/05)
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- N-Methylpyrrolidin-2-one-Promoted Formation of Functional Esters through C–O Bond Cleavage
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Trifluoromethanesulfonic acid catalyzed C–O bond cleavage leading to the preparation of functional esters in the presence of N-methylpyrrolidin-2-one (NMP) was accomplished. Various substrates were well tolerated, and a gram-scale experiment was successfully realized. DFT calculations indicated that NMP plays a decisive role in accelerating nucleophilic attack of the functional acid to generate the functional esters in chlorobenzene.
- Liu, Jianming,Wang, Yanyan,Yue, Yuanyuan,Liu, Na,Zhang, Jian,Zhao, Shufang,Tang, Qinghu,Zhuo, Kelei
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supporting information
p. 2641 - 2647
(2017/05/19)
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- Oxidation-Reduction Condensation of Diazaphosphites for Carbon-Heteroatom Bond Formation Based on Mitsunobu Mechanism
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An efficient oxidation-reduction condensation reaction of diazaphosphites with various nonacidic pronucleophiles in the presence of DIAD as a weak oxidant has been developed for carbon-heteroatom bond formation. This mild process affords structurally diverse tertiary amines, secondary amines, esters, ethers, and thioethers in moderate to excellent yields. The selective synthesis of secondary amines from primary amines has been achieved. Importantly, a practical application to the synthesis of antiparkinsonian agent piribedil has been demonstrated.
- Huang, Hai,Kang, Jun Yong
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supporting information
p. 544 - 547
(2017/02/10)
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- Esterification of the Primary Benzylic C-H Bonds with Carboxylic Acids Catalyzed by Ionic Iron(III) Complexes Containing an Imidazolinium Cation
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The first iron-catalyzed esterification of the primary benzylic C-H bonds with carboxylic acids using di-tert-butyl peroxide as an oxidant is achieved by novel ionic iron(III) complexes containing an imidazolinium cation. The use of well-defined, air-stable, and available iron(III) complex in a 5 mol % loading and readily available starting materials with a broad generality and outstanding sterically hindered tolerance renders this methodology a useful alternative to other protocols that are typically employed for the synthesis of benzyl esters.
- Lu, Bing,Zhu, Fan,Sun, Hong-Mei,Shen, Qi
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supporting information
p. 1132 - 1135
(2017/03/14)
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- Reusable ionic liquid-catalyzed oxidative esterification of carboxylic acids with benzylic hydrocarbons via benzylic Csp3-H bond activation under metal-free conditions
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A metal-free protocol for the direct oxidative esterification of the Csp3-H bond in benzylic hydrocarbons with carboxylic acids using heterocyclic ionic liquid as catalyst has been reported. The catalyst 1-butylpyridinium iodide could be easily recycled and reused for at least four cycles without obvious loss of catalytic activity.
- Mou, Fen,Sun, Yadong,Jin, Weiwei,Zhang, Yonghong,Wang, Bin,Liu, Zhiqing,Guo, Lei,Huang, Jianbin,Liu, Chenjiang
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p. 23041 - 23045
(2017/07/10)
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- Mitsunobu Reaction Using Basic Amines as Pronucleophiles
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A novel protocol for extending the scope of the Mitsunobu reaction to include amine nucleophiles to form C-N bonds through the utilization of N-heterocyclic phosphine-butane (NHP-butane) has been developed. Both aliphatic alcohols and benzyl alcohols are suitable substrates for C-N bond construction. Various acidic nucleophiles such as benzoic acids, phenols, thiophenol, and secondary sulfonamide also provide the desired products of esters, ethers, thioether, and tertiary sulfonamide with 43-93% yields. Importantly, C-N bond-containing pharmaceuticals, Piribedil and Cinnarizine, have been synthesized in one step from the commercial amines under this Mitsunobu reaction system.
- Huang, Hai,Kang, Jun Yong
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p. 6604 - 6614
(2017/07/15)
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- The invention relates to a raw material synthetic ester of carboxylic acid and alcohol method (by machine translation)
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The invention discloses a carboxylic acid and alcohol as the raw material ester method. The method uses three benzene oxygen phosphine/oxalyl system as carboxylic acid activator, to organic base as catalyst, carboxylic acid and alcohol in carboxylic acid activator and reacting under action of catalyst to generate ester. The present invention is carried out under inert atmosphere, the reaction temperature is 10 - 40 °C, the reaction time is 0.5 - 5 hours; the reaction triphenyl oxygen phosphorus, oxalyl, carboxylic acid and alcohol of the amount-of-substance ratio is (0.5 - 2): (0.6 - 2.3): 1: (0.6 - 2.3). The invention the reaction temperature is low, the reaction time is short, carboxylic acid activator are cheap and easily obtained, and can be recovered for reuse, of low cost; the reaction by-product only CO and CO2 , Has higher utilization rate of atom, is suitable for industrial application. (by machine translation)
- -
-
Paragraph 0027-0028
(2017/03/18)
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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; 68
(2017/01/02)
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- Catalytic Ester Metathesis Reaction and Its Application to Transfer Hydrogenation of Esters
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We report a Ru-complex-catalyzed ester metathesis reaction where an unsymmetrical ester such as ethyl hexanoate can be transformed to a mixture of starting material, hexyl ethanoate, ethyl acetate, and hexyl hexanoate in equal proportions, as expected from a classical metathesis reaction with 0.2 mol % catalyst. A 20× excess of low boiling alcohol, such as ethanol, allows for the transfer of an acyl moiety to the sacrificial low boiling ethyl acetate product, while significantly increasing the functional group tolerance and substrate scope; yields of alcohols can reach 90%, which represents an attractive alternative to current high H2 pressure hydrogenation protocols for Ru-based ester reduction chemistry. Both reactions have not been reported previously in the field of Ru-catalyzed transformations of the ester functionality.
- Dubey, Abhishek,Khaskin, Eugene
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p. 3998 - 4002
(2016/07/06)
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- Design, synthesis and structure-activity relationship of new HSL inhibitors guided by pharmacophore models
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Hormone-sensitive lipase (HSL) is a critical enzyme involved in the hormonally regulated release of fatty acids and glycerol from adipocyte lipid stores. Its inhibition may improve insulin sensitivity and blood glucose handling in type 2 diabetes. Accordingly, many small-molecule HSL inhibitors have recently been identified. In continuation of our efforts for discovery of new HSL inhibitors, we prepared a variety of esters, amides, sulfonamides and sulfonate esters capable of fitting two pharmacophore models that we developed and published earlier. The tested compounds were synthesized via coupling reactions of aroyl chlorides or sulfonyl chlorides with phenols, amines and related derivatives. Our efforts led to the identification of interesting compounds of low micromolar anti-HSL bioactivities, which have potential to be developed into effective antidiabetic agents.
- Al-Shawabkeh, Jumana D.,Al-Nadaf, Afaf H.,Dahabiyeh, Lina A.,Taha, Mutasem O.
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p. 127 - 145
(2014/03/21)
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- Montmorillonite K10 and KSF clays as acidic and green catalysts for effective esterification of phenols and alcohols under MWI
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Montmorillonite K-10 and KSF clays catalyze esterification of phenols and alcohols under microwave irradiation and solvent-free conditions in high yields within seconds.
- Marvi,Fekri,Takhti
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p. 1837 - 1840
(2015/01/09)
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- Efficient palladium-catalyzed aminocarbonylation of aryl iodides using palladium nanoparticles dispersed on siliceous mesocellular foam
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A highly dispersed nanopalladium catalyst supported on mesocellular foam (MCF), was successfully used in the heterogeneous catalysis of aminocarbonylation reactions. During the preliminary evaluation of this catalyst it was discovered that the supported palladium nanoparticles exhibited a "release and catch" effect, meaning that a minor amount of the heterogeneous palladium became soluble and catalyzed the reaction, after which it re-deposited onto the support. It's catchy! An efficient palladium-catalyzed protocol for the aminocarbonylation of aryl iodides is reported in which the palladium immobilized on the amino-functionalized mesocellular foam (MCF) was found to operate through a "release and catch" mechanism (see scheme). A very low content of palladium was found in solution upon completion of the reaction and a variety of different aryl iodides were converted to the corresponding amides under mild conditions.
- Tinnis, Fredrik,Verho, Oscar,Gustafson, Karl P. J.,Tai, Cheuk-Wai,Baeckvall, Jan-E.,Adolfsson, Hans
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supporting information
p. 5885 - 5889
(2014/05/20)
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- Versatile and sustainable alcoholysis of amides by a reusable CeO 2 catalyst
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CeO2 catalyzed the esterification between an equivalent molar ratio of primary amides and alcohols under neutral conditions, which provides the first versatile reusable catalytic system for direct alcoholysis of amides to esters with wider scope and 67 times higher turnover number (TON) than previous catalytic systems.
- Siddiki, S. M. A. Hakim,Touchy, Abeda Sultana,Tamura, Masazumi,Shimizu, Ken-Ichi
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p. 35803 - 35807
(2014/11/07)
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- Direct, rapid and convenient synthesis of esters and thioesters using PPh3/N-chlorobenzotriazole system
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We have developed an efficient method for esterification and thioesterification of various carboxylic acids with different alcohols and thiols using PPh3/N-chlorobenzotriazole mixed reagent in CH2Cl2 at room temperature.
- Rouhi-Saadabad, Hamed,Akhlaghinia, Batool
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p. 253 - 263
(2014/02/14)
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- Transition-metal-free transformation of aryl bromides into aromatic esters and amides via aryl trichloromethyl ketones
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A variety of aryl bromides have been treated with Mg and then chloral, followed by tBuOCl and subsequently alcohols or amines to produce the corresponding aromatic esters or amides in good yields via the formation of aryl trichloromethyl ketones as intermediates. These reactions are examples of a transition-metal-free one-pot preparation of aromatic esters and amides from aryl bromides. Aryl bromides have been treated with Mg and then chloral, followed by tBuOCl or tBuOCl with I2 as an additive, and subsequently alcohols or amines to form the corresponding aromatic esters and aromatic amides via aryl trichloromethyl ketones as intermediates. Copyright
- Dohi, Souya,Moriyama, Katsuhiko,Togo, Hideo
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p. 7815 - 7822
(2013/12/04)
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- Transition metal free oxidative esterification of alcohols with toluene
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Using Bu4NI as the catalyst and tert-butyl hydroperoxide as the oxidant, direct esterification of alcohols with toluene derivatives was achieved. Mechanistic investigations indicate that the alcohols are sequentially oxidized to aldehydes, carboxylic acids, and then to benzyl esters. Bu 4N+ functions as a phasetransfer reagent and iodide catalyzes the reaction.
- Liu, Lianghui,Yun, Lin,Wang, Zikuan,Fu, Xuefeng,Yan, Chun-Hua
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supporting information
p. 5383 - 5386
(2013/09/12)
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- Palladium-catalyzed benzylation of carboxylic acids with toluene via benzylic C-H activation
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Direct benzylation of carboxylic acids with toluene has been developed via palladium-catalyzed C-H acyloxylation under 1 atm of oxygen. This reaction demonstrates good functional group tolerance and high yields, providing a facile, atom-economic, and efficient method for the synthesis of benzyl esters.
- Liu, Hongqiang,Shi, Guangfa,Pan, Shulei,Jiang, Yuyu,Zhang, Yanghui
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supporting information
p. 4098 - 4101
(2013/09/12)
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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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- Cooperative N-Heterocyclic Carbene (NHC) and Ruthenium Redox Catalysis: Oxidative Esterification of Aldehydes with Air as the Terminal Oxidant
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The paper describes a cooperative NHC (N-heterocyclic carbene) and ruthenium-based redox catalysis for the mild aerobic oxidative esterification of various aromatic and heteroaromatic aldehydes. The ruthenium(II) complex Ru(bpz)3(PF6)2 (bpz=2,2′-bipyrazine) as catalyst is shown to be compatible with free NHCs. The NHC is used in these cascade reactions for the umpolung of the aldehyde to form the corresponding Breslow intermediate which in turn gets oxidized to an acylazolium ion by the ruthenium redox catalyst. Air is used as a terminal oxidant for oxidation (regeneration) of the ruthenium catalyst. In addition, we will show that in the absence of the ruthenium redox catalyst and alcohol, NHC-catalyzed aerobic oxidation of aldehydes delivers the corresponding acids in good to excellent yields. Mechanistic studies and DFT calculations supporting our suggested mechanisms are provided. Copyright
- Zhao, Junfeng,Mueck-Lichtenfeld, Christian,Studer, Armido
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supporting information
p. 1098 - 1106
(2013/05/21)
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- Phosphorus oxychloride as an efficient coupling reagent for the synthesis of esters, amides and peptides under mild conditions
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A mild method is described for the conversion of carboxylic acids into esters, amides, as well as peptides without racemization through carboxyl activation by the reagent combination of POCl3 and DMAP. Long chain alcohols could be converted to the corresponding ester in good yields. 31P NMR spectrum was used to detect phosphorus-containing intermediates in ongoing reactions directly, and a possible mechanism has been proposed based on these results. The Royal Society of Chemistry 2013.
- Chen, Hu,Xu, Xunfu,Liu, Liu,Tang, Guo,Zhao, Yufen
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p. 16247 - 16250
(2013/09/23)
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- Covalently bound benzyl ligand promotes selective palladium-catalyzed oxidative esterification of aldehydes with alcohols
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It's a benzyl kind of magic: In the title reaction proceeding with benzyl chloride as the oxidant, the benzyl group serves as a carbon ligand, thus having an 3-coordination effect on palladium (see scheme). A variety of aldehydes and alcohols were selectively converted into the corresponding esters in good to excellent yields. Copyright
- Liu, Chao,Tang, Shan,Zheng, Liwei,Liu, Dong,Zhang, Heng,Lei, Aiwen
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supporting information; experimental part
p. 5662 - 5666
(2012/07/01)
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- Organocatalyzed anodic oxidation of aldehydes
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A method for the catalytic formation of electroauxiliaries and subsequent anodic oxidation has been developed. The process interfaces N-heterocyclic carbene-based organocatalysis with electro-organic synthesis to achieve direct oxidation of catalytically generated electroactive intermediates. We demonstrate the applicability of this method as a one-pot conversion of aldehydes to esters for a broad range of aldehyde and alcohol substrates. Furthermore, the anodic oxidation reactions are very clean, producing only H2 gas as a result of cathodic reduction.
- Finney, Eric E.,Ogawa, Kelli A.,Boydston, Andrew J.
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supporting information; experimental part
p. 12374 - 12377
(2012/09/05)
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- NHCs-mediated benzoates formation directly from aromatic aldehydes and alkyl halides
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A NHCs-mediated benzoates formation was developed by treatment of aromatic aldehydes with alkyl halides in the presence of oxygen. Corresponding benzoate derivatives were obtained in high yields up to 99%. The reaction mechanism was also discussed and a NHCs-mediated O-alkylation and subsequent oxidation process was proposed.
- Li, Yi,Du, Wenting,Deng, Wei-Ping
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experimental part
p. 3611 - 3615
(2012/06/15)
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- Novel and efficient method for esterification catalyzed by 1-glycyl-3-methyl imidazolium chloride-iron (III) complex
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1-Glycyl-3-methyl imidazolium chloride-iron (III) complex [[Gmim]Cl-Fe(III)] was found to be a heterogeneous catalyst for an efficient and greener solvent free synthesis of esters by the condensation of carboxylic acids and alcohols with excellent yield at ambient temperature. This operation formulates very interesting, ecological perspective due to simple reaction condition, isolation, and purification of products. In addition, this method features reusability of catalyst, reduced waste, thus making new protocol more environmentally suitable whilst no catalyst leaching was observed. Iranian Chemical Society 2012.
- Karthikeyan, Parasuraman,Bhagat, Pundlik Rambhau,Kumar, Sellappan Senthil,Muskawar, Prashant Narayan,Aswar, Sachin Arunrao
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p. 983 - 990
(2013/02/23)
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- Reactivity of N-nitrosoamides in confined spaces
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The thermal rearrangement of several N-nitrosoamides was studied by 1H NMR in the context of reversible encapsulation. The N-nitrosoamide guests were isolated from the bulk solvent in a hydrogen-bonded dimeric host capsule which prevented their rearrangement. The guests appear to be preserved in their ground state conformations by the pressure exerted by the host. The conformations of the free and bound N-nitrosoamides are of comparable relative energies as determined by DFT calculations.
- Sather, Aaron C.,Berryman, Orion B.,Ajami, Dariush,Rebek Jr., Julius
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p. 2100 - 2103
(2011/05/09)
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- Organoactinides promote the dimerization of aldehydes: Scope, kinetics, thermodynamics, and calculation studies
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Surprising catalytic activities have been found for the actinide complexes Cp*2ThMe2 (1), Th(NEtMe)4 (2), and Me2SiCp″2Th(C4H9) 2(3) toward oxygenated substrates. During the catalytic dimerization of benzaldehydes to their corresponding esters, complexes 1 and 2 gave 65 and 85% yield in 48 h, respectively, while the geometry-constrained complex 3 gave 96% yield in 24 h. Exploring the effect of substituents on benzaldehyde, it has been found that, in general, electron-withdrawing groups facilitate the reaction. Kinetic study with complexes 1 and 3 reveals that the rate of the reaction is first order in catalyst and substrate, which suggests the rate equation "rate = k[catalyst]1[aldehyde]1". The activation energy of the reaction was found to be 7.16 ± 0.40 and 3.47 ± 0.40 kcal/mol for complexes 1 and 3 respectively, which clearly indicates the advantage of the geometry-constrained complex. Astonishing are the reactivity of the organoactinide complexes with oxygen-containing substrates, and especially the reactivity of complex 3, toward the dimerization of substrates like p-methoxybenzaldehyde, m/p-nitrobenzaldehyde, and furanaldehyde and the reactivity toward the polymerization of terephthalaldehyde. Density functional theory mechanistic study reveals that the catalytic cycle proceeds via an initially four-centered transition state (+6 kcal/mol), followed by the rate-determining six-centered transition state (+13.5 kcal/mol), to yield thermodynamically stable products.
- Sharma, Manab,Andrea, Tamer,Brookes, Nigel J.,Yates, Brian F.,Eisen, Moris S.
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experimental part
p. 1341 - 1356
(2011/04/16)
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- A simple and convenient method for preparation of carboxylic acid alkyl esters, phenolic and thioesters using chlorodiphenylphosphine/I2 and imidazole reagent system
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Condensation of carboxylic acids with alcohols, phenols and thiols proceeded smoothly to afford carboxylic acid alkyl esters, phenolic esters and thioesters by using the combination of chlorodiphenylphosphine, imidazole and molecular iodine in refluxing acetonitrile. Esterification with this mixed reagent system gave the corresponding products in excellent yields. The phosphorus-containing byproduct was simply removed from the organic phase by basic aqueous workup without the need for chromatography purification.
- Nowrouzi, Najmeh,Mehranpour, Abdol Mohammad,Rad, Javad Ameri
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experimental part
p. 9596 - 9601
(2011/01/03)
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- 5,5′-Dimethyl-3,3′-azoisoxazole as a new heterogeneous azo reagent for esterification of phenols and selective esterification of benzylic alcohols under Mitsunobu conditions
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5,5′-Dimethyl-3,3′-azoisoxazole is used as a new efficient heterogeneous azo reagent for the highly selective esterification of primary and secondary benzylic alcohols and phenols with aliphatic and aromatic carboxylic acids via Mitsunobu protocols. The reaction is highly selective for primary benzylic alcohols versus secondary ones, aliphatic alcohols and also phenols. The isoxazole hydrazine byproduct can be simply isolated by filtration and recycled to its azoisoxazole by oxidation.
- Iranpoor, Nasser,Firouzabadi, Habib,Khalili, Dariush
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supporting information; experimental part
p. 4436 - 4443
(2010/11/05)
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- Microwave-promoted aminocarbonylation of aryl triflates using Mo(CO)6 as a solid CO source
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Palladium-catalyzed carbonylations of aryl triflates with a range of nucleophiles using Mo(CO)6 as a solid CO source were explored. The reactions proceeded smoothly providing moderate to good yields of the corresponding aryl amides, esters, or acylsulfonamides after only 20 min of microwave irradiation. The acyl transfer reagent 4-dimethylaminopyridine was found to promote some of the more difficult transformations.
- Odell, Luke R.,S?vmarker, Jonas,Larhed, Mats
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scheme or table
p. 6115 - 6118
(2009/04/04)
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- Organoactinides promote the Tishchenko reaction: The myth of inactive actinide-alkoxo complexes
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For many decades, compounds containing oxygen atoms were excluded from the actinide-catalysis field because of the high oxophilic nature of these complexes. Pursuing the conceptual question about the potential activity of actinide-oxo bonds we were surprised to find that the coupling of aromatic aldehydes catalyzed by Cp*2ThMe2 and Th(NEtMe)4 via thorium-alkoxide intermediates takes place in high yields to produce the corresponding esters. In this paper we present our breakthrough results including comprehensive mechanistic, deuterium labeling, kinetic, and thermodynamic studies. A plausible mechanism is presented taking into account as well the thermochemistry of the process. Copyright
- Andrea, Tamer,Barnea, Eyal,Eisen, Moris S.
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p. 2454 - 2455
(2008/09/18)
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- Easily prepared azopyridines as potent and recyclable reagents for facile esterification reactions. An efficient modified mitsunobu reaction
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(Chemical Equation Presented) The 2,2′-, 3,3′-, and 4,4′-azopyridines (azpy) and their alkyl pyridinium ionic liquids were studied as a new class of electron-deficient reagents for Mitsunobu esterification reactions. Among these compounds, 4,4′-azopyridine was found to be the most suitable one for esterification and thioesterification reactions. This new reagent promises to provide general and complementary solutions for separation problems in Mitsunobu reactions without restricting the reaction scope and facilitates the isolation of its hydrazine byproduct. The pyridine hydrazine byproduct can be simply recycled to its azopyridine by an oxidation reaction.
- Iranpoor, Nasser,Firouzabadi, Habib,Khalili, Dariush,Motevalli, Somayeh
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p. 4882 - 4887
(2008/09/21)
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- Surfactant-mediated solvent-free dealkylative cleavage of ethers and esters and trans-alkylation under neutral conditions
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A simple, surfactant-mediated, one-pot, solvent-free dealkylative cleavage of aryl ethers and esters followed by subsequent optional trans-alkylation under essentially neutral conditions has been developed.
- Bhattacharya, Apurba,Patel, Nitin C.,Vasques, Tomas,Tichkule, Ritesh,Parmar, Gaurang,Wu, Jiejun
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p. 565 - 567
(2007/10/03)
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- A fast and simple method for the acylation of alcohols with acid chlorides promoted by metallic samarium
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Acylation of primary, secondary, allyl and benzyl alcohols with acid chlorides promoted by samarium metal under neutral condition gave carboxylic acid esters in good to excellent yields. Acylation of a tertiary alcohol did not occur under the same reaction conditions.
- Jia, Xue-Shun,Wang, Hai-Long,Huang, Qing,Kong, Ling-Long,Zhang, Wei-He
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p. 135 - 138
(2007/10/03)
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- Efficient method for the preparation of carboxylic acid alkyl esters or alkyl phenyl ethers by a new-type of oxidation-reduction condensation using 2,6-dimethyl-1,4-benzoquinone and alkoxydiphenylphosphines
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A new-type of oxidation-reduction condensation proceeded smoothly to afford carboxylic acid alkyl esters or alkyl phenyl ethers in good to high yields by combined use of alkoxydiphenylphosphines (1) having primary, bulky secondary or tertiary alkoxy groups, a mild quinone-type oxidant such as 2,6-dimethyl-1,4-benzoquinone (DMBQ) and carboxylic acids or phenols. Generally, alkoxydiphenylphosphines were prepared easily from chlorodiphenylphosphine (2) and alcohols in the presence of pyridine, and were isolated by distillation. On the other hand, the phosphines 1 were also prepared in situ from N,N-dimethylaminodiphenylphosphine (3a) and primary or secondary alcohols while primary, bulky secondary or tertiary alkoxydiphenylphosphines were alternatively formed in situ by adding 2 to the "BuLi-treated alcohols in order to perform the above reactions by a one-pot procedure from alcohols and nucleophiles. The reaction of thus formed 1, DMBQ and carboxylic acids or phenols afforded the corresponding alkylated products, including hindered secondary and tertiary alkylated ones, in good to high yields at room temperature. In the case of using chiral secondary alcohols, the corresponding carboxylic acid alkyl esters were obtained as well in high yields with perfect inversion of stereochemistry by SN2 replacement.
- Shintou, Taichi,Kikuchi, Wataru,Mukaiyama, Teruaki
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p. 1645 - 1667
(2007/10/03)
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- Synthesis of aromatic esters catalyzed by palladium on charcoal: An efficient heterogeneous catalyst for alkoxycarbonylation of aryl iodides
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Palladium on charcoal was found to catalyze the carbonylation of aryl iodides with various aliphatic alcohols as well as less reactive phenols to give the corresponding esters in high yield at 140°C and in the presence of carbon monoxide (1.0 MPa). The carbonylation-polycondensation of 2,7-diiodo-9,10-dihydrophenanthrene with bisphenol-A afforded high molecular weight polyarylate, poly [oxy-1,4-phenylene (1-methylethylidene)-1,4-phenyleneoxycarbonyl (9,10-dihydro-2,7-phenanthrenediyl) carbonyl].
- Ramesh, Chinnasamy,Nakamura, Ryo,Kubota, Yoshihiro,Miwa, Minoru,Sugi, Yoshihiro
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p. 501 - 504
(2007/10/03)
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- Esterification of carboxylic acids with alcohols under microwave irradiation in the presence of zinc triflatet
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The esterification of aliphatic and aromatic carboxylic acids with various alcohols (1°, 2°, 3°, benzylic) was studied under microwave irradiation in the presence of zinc triflate as catalyst; the reaction times were short and the yield of reactions was good to excellent.
- Shekarriz, Marzieh,Taghipoor, Sohrab,Khalili, Ali Asghar,Jamarani, Mohammad Soleymani
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p. 172 - 173
(2007/10/03)
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- Benzylation of carboxylic acids by oxidation-reduction condensation using quinones and benzyloxydiphenylphosphine
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Various carboxylic benzyl esters were obtained in high yields by way of oxidation-reduction condensation in which benzyloxydiphenylphosphine (BDPP), having been prepared easily from chlorodiphenylphosphine and benzyl alcohol, was treated with various carboxylic acids in the presence of 2,6-dimethyl-1,4-benzoquinone(DMBQ) under mild conditions.
- Mukaiyama, Teruaki,Shintou, Taichi,Kikuchi, Wataru
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p. 1126 - 1127
(2007/10/03)
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- Highly selective and efficient catalyst for carbonylation of aryl iodides: Dimeric palladium complex containing carbon-palladium covalent bond
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Dimeric cyclometallated oxime palladium complex containing palladium-carbon covalent bond was found to efficiently catalyze the carbonylation reactions of aryl iodides with various alcohols to give esters in excellent yields with high selectivity. These complexes were also stable under a carbon monoxide atmosphere at high temperatures.
- Ramesh, Chinnasamy,Kubota, Yoshihiro,Miwa, Minoru,Sugi, Yoshihiro
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p. 2171 - 2173
(2007/10/03)
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- Fluorous biphasic esterification directed towards ultimate atom efficiency
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Aperfectly selective esterification that discriminates between primary and sterically hindered or aromatic carboxylic acids occurs in the presence of the fluoroalkyldistannoxane [{Cl(C6F13CH2 CH2)2SnOSn(CH2CH2 -C6F13)2Cl}2] (1). The reaction gives 100% yield with a strict 1:1 ratio of the carboxylic acid and alcohol reactants, and the catalyst can be recycled without any loss of activity.
- Xiang, Jiannan,Orita, Akihiro,Otera, Junzo
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p. 4117 - 4119
(2007/10/03)
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- The Reaction between Acyl Halides and Alcohols: Alkyl Halide vs. Ester Formation
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In the reaction between an acyl halide and an alcohol the thermodynamically favoured products are the free carboxylic acid and the alkyl halide.The initial reaction is, generally, the formation of an ester and HHal.When the alcohol is very prone to yield an alkyl cation upon protonation by HHal, formed H2O exhibited a superior reactivity and competed successfully with the alcohol for the acyl halide making, therefore, ester formation practically confined to a triggering role.But, in those cases where the cation is less easily formed, ester formation was favoured and, consequently, became the necessary elementary step towards alkyl halide formation.Tis final product, on the other hand, might be extremely slow to form in an SN2 reaction between the protonated ester function and the halide ion.In these instances, therefore, as well as in the cases when a basic solvent competes for the proton of HHal, the ester is the final product.A notable exception of the situation above outlined, is given by α-hydroxy-α-phenylbenzeneacetic acid (2y), which appears to undergo direct chlorine-hydroxyl interchange through a quaternary intermediate (E), in the end collapsing to α-chloro-α-phenyl-benzeneacetic acid (4y).Different systems were compared using CH2Cl2 as a solvent under strictly similar conditions.Some 28 different substrates were tested for reaction with AcCl (1a), whereas the action of eight acyl halides (a) against (RS)-α-methylbenzenemethanol (2n) and α-phenylbenzenemethanol (2p), as well as the effect of five different solvents on the reaction between two alcohols (2p and 2-methyl-2-propanol, 2c) with 1a, were observed.
- Strazzolini, Paolo,Giumanini, Angelo G.,Verardo, Giancarlo
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p. 217 - 254
(2007/10/02)
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- Reactions of 3-Aryl-5-methyl-1,2,4-oxadiazoles with Benzyl Alcohol and with Benzylamine
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When heated with benzyl alcohol, 3-aryl-5-methyl-1,2,4-oxadiazoles afford mainly the aryl nitrile, benzyl acetate, and benzaldehyde.A number of other products, including 1,3,5-triazines, have been identified.Benzylamine and 5-methyl-1,2,4-oxadiazoles similarly give aryl nitrile and N-acetylbenzylamine, but the reaction is slower.However, in mixtures of the alcohol and the amine, the amine reacts the faster.Possible reaction mechanisms are discussed.The methyl group of the oxadiazole was shown to exchange its protons with those of benzyl alcohol more readily than the oxadiazole otherwise reacted with benzyl alcohol.
- Brown, Jonathan W.,Clack, Dennis W.,Wilson, David A.
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p. 117 - 122
(2007/10/02)
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- Preparation and Some Reactions of Bis(thioacyl) Sulfides
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Reaction of dithioic acids with dicyclohexylcarbodiimide has been found to give the corresponding bis(thioacyl) sulfides 1 in good yield, which are very useful thioacylating reagents under mild reaction conditions.Most of the aromatic thioanhydrides (1, R = aromatic) are fairly stable green crystals at room temperature, but the aliphatic ones (1, R = aliphatic) are unstable purple oils which dimerize at room temperature to give the dithietanes 5.The reactions with nucleophiles are discussed.
- Kato, Shinzi,Shibahashi, Hiroshi,Katada, Tomonori,Takagi, Takashi,Noda, Ippei,et al.
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p. 1229 - 1244
(2007/10/02)
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