- Half-Sandwich Ruthenium Complexes Bearing Hemilabile κ2-(C,S)?Thioether-Functionalized NHC Ligands: Application to Amide Synthesis from Alcohol and Amine
-
Amide synthesis is one of the most crucial transformations in chemistry and biology. Among various catalytic systems, N-heterocyclic carbene (NHC)-based ruthenium (Ru) catalyst systems have been proven to be active for direct synthesis of amides by sustainable acceptorless dehydrogenative Coupling of primary alcohols with amines. Most often, these catalytic systems usually use monodentate NHC and thus require an additional ligand to obtain high reactivity and selectivity. In this work, a series of cationic Ru(II)(η6-p-cymene) complexes with thioether-functionalized N-heterocyclic carbene ligands (imidazole and benzimidazole-based) have been prepared and fully characterized. These complexes have then been used in the amidation reaction and the most promising one (i. e. 3 c) has been applied on a large range of substrates. High conversions albeit with moderate yields have generally been obtained.
- Achard, Thierry,Bellemin-Laponnaz, Stéphane,Chen, Weighang,Egly, Julien,Maisse-Fran?ois, Aline
-
supporting information
(2022/01/20)
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- IrIII-Catalyzed direct syntheses of amides and esters using nitriles as acid equivalents: A photochemical pathway
-
An unprecedented IrIII[df(CF3)ppy]2(dtbbpy)PF6-catalyzed simple photochemical process for direct addition of amines and alcohols to the relatively less reactive nitrile triple bond is described herein. Various amides and esters are synthesized as the reaction products, with nitriles being the acid equivalents. A mini-library of different types of amides and esters is made using this mild and efficient process, which uses only 1 mol% of photocatalyst under visible light irradiation (λ = 445 nm). The reaction strategy is also efficient for gram-scale synthesis.
- Talukdar, Ranadeep
-
supporting information
p. 5303 - 5308
(2020/04/17)
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- Catalytic conversion of ketones to esters: Via C(O)-C bond cleavage under transition-metal free conditions
-
The catalytic conversion of ketones to esters via C(O)-C bond cleavage under transition-metal free conditions is reported. This catalytic process proceeds under solvent-free conditions and offers an easy operational procedure, broad substrate scope with excellent selectivity, and reaction scalability. This journal is
- Subaramanian, Murugan,Ramar, Palmurukan M.,Rana, Jagannath,Gupta, Virendra Kumar,Balaraman, Ekambaram
-
supporting information
p. 8143 - 8146
(2020/09/09)
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- Simple and rapid p-methoxybenzylation of hydroxy and amide groups at room temperature by NaOt-Bu and DMSO
-
The p-methoxybenzylation of hydroxy and amide groups by p-methoxybenzyl chloride utilizing NaOt-Bu in DMSO is described. p-Methoxybenzylation of sterically hindered menthol using NaOt-Bu in DMSO proceeded faster than the commonly used methods which use Na
- Hamada, Shohei,Sugimoto, Koichi,Iida, Masashi,Furuta, Takumi
-
supporting information
(2019/11/13)
-
- Bu 4 NI-Catalyzed C-C Bond Cleavage and Oxidative Esteri??cation of Allyl Alcohols with Toluene Derivatives
-
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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- A metal-free approach for the synthesis of amides/esters with pyridinium salts of phenacyl bromides via oxidative C–C bond cleavage
-
An efficient, simple, and metal-free synthetic approach for the N- and O-benzoylation of various amines/benzyl alcohols with pyridinium salts of phenacyl bromides is demonstrated to generate the corresponding amides and esters. This protocol facilitates the oxidative cleavage of a C–C bond followed by formation of a new C–N/C–O bond in the presence of K2CO3. Various pyridinium salts of phenacyl bromides can be readily transformed into a variety of amides and esters which is an alternative method for the conventional amidation and esterification in organic synthesis. High functional group tolerance, broad substrate scope and operational simplicity are the prominent advantages of the current protocol.
- Manasa, Kesari Lakshmi,Tangella, Yellaiah,Krishna, Namballa Hari,Alvala, Mallika
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p. 1864 - 1871
(2019/08/12)
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- Base-Promoted Amidation and Esterification of Imidazolium Salts via Acyl C-C bond Cleavage: Access to Aromatic Amides and Esters
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Imidazolium salts have been effectively employed as suitable acyl transfer agents in amidation and esterification in organic synthesis. The weak acyl C(O)-C imidazolium bond was exploited to generate acyl electrophiles, which further react with amines and alcohols to afford amides and esters. The broad substrate scope of anilines and benzylic amines and base-promoted conditions are the benefits of this route. Interestingly, phenol, benzylic alcohols, and a biologically active alcohol can also be subjected to esterification under the optimized conditions.
- Karthik, Shanmugam,Muthuvel, Karthick,Gandhi, Thirumanavelan
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p. 738 - 751
(2019/01/24)
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- Esterification of Tertiary Amides by Alcohols Through C?N Bond Cleavage over CeO2
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CeO2 has been found to promote ester forming alcoholysis reactions of tertiary amides. The present catalytic system is operationally simple, recyclable, and it does not require additives. The esterification process displays a wide substrate scope (>45 examples; up to 93 % isolated yield). Results of a density functional theory (DFT) study combined with in situ FT-IR observations indicate that the process proceeds through rate limiting addition of a CeO2 lattice oxygen to the carbonyl group of the adsorbed acetamide species with energy barrier of 17.0 kcal/mol. This value matches well with experimental value (17.9 kcal/mol) obtained from analysis of the Arrhenius plot. Further studies by in situ FT-IR and temperature programmed desorption using probe molecules demonstrate that both acidic and basic properties are important, and consequently, CeO2 showed the best performance for the C?N bond cleavage reaction.
- Toyao, Takashi,Nurnobi Rashed, Md.,Morita, Yoshitsugu,Kamachi, Takashi,Hakim Siddiki,Ali, Md. A.,Touchy,Kon, Kenichi,Maeno, Zen,Yoshizawa, Kazunari,Shimizu, Ken-ichi
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p. 449 - 456
(2018/09/11)
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- Ester Formation via Symbiotic Activation Utilizing Trichloroacetimidate Electrophiles
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Trichloroacetimidates are useful reagents for the synthesis of esters under mild conditions that do not require an exogenous promoter. These conditions avoid the undesired decomposition of substrates with sensitive functional groups that are often observed with the use of strong Lewis or Br?nsted acids. With heating, these reactions have been extended to benzyl esters without electron-donating groups. These inexpensive and convenient methods should find application in the formation of esters in complex substrates.
- Mahajani, Nivedita S.,Meador, Rowan I. L.,Smith, Tomas J.,Canarelli, Sarah E.,Adhikari, Arijit A.,Shah, Jigisha P.,Russo, Christopher M.,Wallach, Daniel R.,Howard, Kyle T.,Millimaci, Alexandra M.,Chisholm, John D.
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p. 7871 - 7882
(2019/06/27)
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- Cross-Dehydrogenating Coupling of Aldehydes with Amines/R-OTBS Ethers by Visible-Light Photoredox Catalysis: Synthesis of Amides, Esters, and Ureas
-
A straightforward synthesis of amides, ureas, and esters is reported by visible-light cross-dehydrogenating coupling (CDC) of aldehydes (or amine carbaldehydes) and amines/R-OTBS ethers by photoredox catalysis. The reaction is found to be general and high yielding. A plausible mechanistic pathway has been proposed for these transformations and is supported by appropriate controlled experiments.
- Pandey, Ganesh,Koley, Suvajit,Talukdar, Ranadeep,Sahani, Pramod Kumar
-
supporting information
p. 5861 - 5865
(2018/09/21)
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- Systematic Evaluation of Sulfoxides as Catalysts in Nucleophilic Substitutions of Alcohols
-
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.
-
supporting information
p. 4541 - 4547
(2018/09/13)
-
- 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.
-
supporting information
p. 2980 - 2983
(2018/05/28)
-
- Highly Active Manganese-Mediated Acylation of Alcohols with Acid Chlorides or Anhydrides
-
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)
-
- Mild reductive functionalization of amides into N-sulfonylformamidines
-
The development of a protocol for the reductive functionalization of amides into N-sulfonylformamidines is reported. The one-pot procedure is based on a mild catalytic reduction of tertiary amides into the corresponding enamines by the use of Mo(CO)6 (molybdenum hexacarbonyl) and TMDS (1,1,3,3-tetramethyldisiloxane). The formed enamines were allowed to react with sulfonyl azides to give the target compounds in moderate to good yields.
- Trillo, Paz,Slagbrand, Tove,Tinnis, Fredrik,Adolfsson, Hans
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p. 484 - 487
(2018/08/17)
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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
-
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)
-
- SO2F2-Mediated One-Pot Synthesis of Aryl Carboxylic Acids and Esters from Phenols through a Pd-Catalyzed Insertion of Carbon Monoxide
-
A one-pot Pd-catalyzed carbonylation of phenols into their corresponding aryl carboxylic acids and esters through the insertion of carbon monoxide has been developed. This procedure offers a direct synthesis of aryl carboxylic acids and esters from inexpensive and abundant starting materials (phenols, SO2F2 and CO) under mild conditions. This method tolerates a broad range of functional groups and is also applicable for the modification of complicated natural products.
- Fang, Wan-Yin,Leng, Jing,Qin, Hua-Li
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p. 2323 - 2331
(2017/09/06)
-
- The first total synthesis of anemarchalconyn and anemarcoumarin A
-
Anemarchalconyn (1) and anemarcoumarin A (2), the natural bioactive compounds isolated from the rhizomes of Anemarrhena asphodeloides Bunge (Liliaceae), were first totally synthesized using easily available materials in short, convenient routes with overall yields of 32 and 48%.
- Zhang, Jing-Xia,Li, Zhe-Yu,Wang, Yu-Chi,Ma, Wen-Bo,Hou, Ming,Cao, Sheng-Hua,Tang, Ke-Hui,Dong, Hong-Bo
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p. 903 - 909
(2017/08/22)
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- Sulfonated nanohydroxyapatite functionalized with 2-aminoethyl dihydrogen phosphate (HAP@AEPH2-SO3H) as a reusable solid acid for direct esterification of carboxylic acids with alcohols
-
Sulfonated nanohydroxyapatite functionalized with 2-aminoethyl dihydrogen phosphate (HAP@AEPH2-SO3H) efficiently catalyzed direct esterification of carboxylic acids and alcohols with high selectivity toward the formation of esters in good to excellent yields. Our results clearly show that HAP@AEPH2-SO3H can be easily recovered by simple filtration and reused for subsequent five runs without any significant impact on yields of products. The main advantage of this methodology is easy and ecofriendly catalyst preparation, easy catalyst separation, practical simplicity, safe reaction conditions, recyclable catalyst and high products yields.
- Siavashi, Narges Yousefi,Akhlaghinia, Batool,Zarghani, Monireh
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p. 5789 - 5806
(2016/06/01)
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- Synthesis of esters by in situ formation and trapping of diazoalkanes
-
A general method has been developed for the in situ formation and trapping of diazoalkanes by carboxylic acids to form esters. The method is applicable to a large variety of carboxylic acids using diazo compounds that are formed from the hydrazones of benzaldehydes and aryl ketones. In situ reaction monitoring with IR spectroscopy (ReactIR) was used to demonstrate that slow addition of the hydrazone to a mixture of oxidant and carboxylic acid avoids the buildup of the diazo compound. This method enables the safe preparation of esters from simple precursors without isolation of diazo compounds.
- Squitieri, Richard A.,Shearn-Nance, Galen P.,Hein, Jason E.,Shaw, Jared T.
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p. 5278 - 5284
(2016/07/14)
-
- A PROCESS FOR THE SYNTHESIS OF CARBOXYLIC ACID DERIVATIVES
-
The present invention discloses one-pot synthesis of various carboxylic acid derivatives using copper catalyst and sodium cyanide as the cyanide source for bringing in carbonylative coupling in a single step.
- -
-
Page/Page column 7-8; 10
(2015/05/19)
-
- Facile and selective deprotection of PMB ethers and esters using oxalyl chloride
-
Oxalyl chloride, (0.5 equiv) was found to cleave the PMB group from alkyl, aryl PMB ethers, and esters to give corresponding alcohol and acid in good yields. This method offers simple and efficient protocol for the selective deprotection of PMB ether and ester in DCE at ambient temperature.
- Ilangovan, Andivelu,Anandhan, Karnambaram,Kaushik, Mahabir Prasad
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p. 1081 - 1084
(2015/02/19)
-
- Esterification of carboxylic acids with alkyl halides using imidazolium based dicationic ionic liquids containing bis-trifluoromethane sulfonimide anions at room temperature
-
Task-specific room temperature ionic liquids (RTILs) composed of symmetrical N-methylimidazolium rings linked with a short oligo (ethylene glycol) chain (cationic part) and bis-trifluoromethane sulfonimide (NTf2, anionic part) were successfully synthesized, and their physicochemical properties were determined by various modern analytical techniques. The catalytic activity of the synthesized RTILs was evaluated in the esterification reaction of acids with alkyl halides in solvent-free conditions at room temperature. From the screening test, all the synthesized RTILs showed a high yield with significant selectivity for respective esters in a very short reaction time. Especially, 0.1 equimolar of RTIL-1 ([tetraEG(mim)2][NTf2]2) was found to be, the most efficient and reusable catalyst for this reaction. As a result, 100% conversion and up to a 94% yield of the respective ester product was obtained in a 30 min reaction time. This might be due to their synergetic effect of Lewis acidity, wide liquid range, and high miscibility compared to the other homogeneous and heterogeneous catalysts. Beside this, RTIL was easily separated from the reaction mixture and reused several times without any significant loss of catalytic activity and structural property. The present dicationic ionic liquids (ILs) under a solvent-free catalytic system were found to be kinetically fast, naturally benign, and achieved good yields for esterification of carboxylic acids with alkyl halides.
- Jadhav, Arvind H.,Lee, Kyuyoung,Koo, Sangho,Seo, Jeong Gil
-
p. 26197 - 26208
(2015/10/20)
-
- Copper-catalyzed cross-coupling of thiols, alcohols, and oxygen for the synthesis of esters
-
Copper-catalyzed, one-pot, three-component coupling reactions using thiols, alcohols, and oxygen to form a variety of esters in good yields were studied. In the presence of easily oxidized benzylic and allylic alcohols, thiols were selectively oxidized to form thionoesters, which underwent facile S/O exchange to afford esters. Thiols may be used as an alternative benzoyl source under mild aerobic conditions.
- Lim, Seungyeon,Ji, Miran,Wang, Xi,Lee, Chan,Jang, Hye-Young
-
supporting information
p. 591 - 595
(2015/01/30)
-
- Esters of benzoic, 5-arylisoxazole-3-carboxylic and 4,5- dichloroisothiazole-3-carboxylic acids
-
The method of synthesis was developed of esters of benzoic, 2-chlorobenzoic, 5-phenylisoxazole-3-carboxylic, 5-tolylisoxazole-3-carboxylic, and 4,5-dichloroisothiazole-3-carboxylic acids with some aliphatic and substituted aromatic alcohols. The latter were obtained by reduction of aldehydes used in perfumery.
- Dikusar,Potkin,Zhukovskaya,Murashova,Petkevich,Kletskov,Zolotar',Chepik
-
p. 1179 - 1185
(2014/08/05)
-
- Proton-exchanged montmorillonite-mediated reactions of methoxybenzyl esters and ethers
-
Proton-exchanged montmorillonite (H-mont) was found to be an eco-friendly and cost-effective catalyst for the generation of O-methylated quinone methides (QM) from the corresponding p or o-methoxybenzyl esters and ethers. Nucleophilic trapping of the O-methylated QM with arenes, alcohols, 1,3-dicarbonyl compounds, silyl enol ethers, and allylsilanes has been carried out, respectively, leading to eco-friendly benzylation reactions. Using this protocol, H-mont-mediated deprotection of PMB-protected esters and ethers have been realized for the first time. This work would pave the way for further exploration in O-alkylated QM that are of chemical and biological significance.
- Chen, Dongyin,Xu, Chang,Deng, Jie,Jiang, Chunhuan,Wen, Xiaoan,Kong, Lingyi,Zhang, Ji,Sun, Hongbin
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p. 1975 - 1983
(2014/03/21)
-
- Montmorillonite K10 and KSF clays as acidic and green catalysts for effective esterification of phenols and alcohols under MWI
-
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
-
p. 1837 - 1840
(2015/01/09)
-
- Versatile and sustainable alcoholysis of amides by a reusable CeO 2 catalyst
-
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
-
p. 35803 - 35807
(2014/11/07)
-
- Copper(I) bromide-catalyzed carbonylative coupling of aryl halides with phenols, alcohols and amines using sodium cyanide as C1 source: A synthesis of carboxylic acid derivatives
-
A new carbon monoxide-free synthesis of carboxylate derivatives via carbonylative coupling of aryl bromides with phenols, alcohols, amines and acids in the presence of copper(I) bromide as catalyst and sodium cyanide in a stoichiometric amount has been developed. Its intramolecular version provides for the preparation of lactones (e.g., isochroman-1-ones and isobenzfuranones), imides, anhydrides and lactams in excellent yields (73-96%).
- Prasad, Pragati K,Sudalai, Arumugam
-
supporting information
p. 2231 - 2238
(2014/07/21)
-
- Spontaneous formation of PMB esters using 4-methoxybenzyl-2,2,2- trichloroacetimidate
-
Carboxylic acids are converted to the corresponding 4-methoxybenzyl (PMB) esters with 4-methoxybenzyl-2,2,2-trichloroacetimidate in the absence of an acid catalyst. This operationally simple procedure is a highly effective method for the formation of PMB esters. The reaction is promoted by the carboxylic acids themselves in excellent yields (72-99%). Sterically hindered carboxylic acids, which provide lower yields with other imidates, are esterified in higher yield with the more reactive PMB imidate. No racemization is observed in the case of carboxylic acids bearing an α-stereocenter, and no isomerization is observed with Z-α,β-unsaturated acids. This method may therefore find use in the esterification of complex or sensitive substrates where more common techniques lead to decomposition.
- Shah, Jigisha P.,Russo, Christopher M.,Howard, Kyle T.,Chisholm, John D.
-
supporting information
p. 1740 - 1742
(2014/03/21)
-
- A convenient approach for the deprotection and scavenging of the PMB group using POCl3
-
A convenient and high yielding approach for the deprotection and scavenging of the p-methoxybenzyl (PMB) group in PMB ethers and PMB esters was developed using POCl3 as the reagent. 4-Methoxybenzyl chloride, a starting material used for the preparation of PMB ethers and esters was regenerated in the deprotection step. This mild and selective procedure tolerates several acid sensitive functional groups. The Royal Society of Chemistry 2013.
- Ilangovan, Andivelu,Saravanakumar, Shanmugasundar,Malayappasamy, Subramani,Manickam, Govindaswamy
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p. 14814 - 14828
(2013/09/02)
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- CeO2 as a versatile and reusable catalyst for transesterification of esters with alcohols under solvent-free conditions
-
CeO2 acted as an efficient and reusable heterogeneous catalyst for transesterification of esters with alcohols under the solvent-free conditions at 160 °C. Among the 11 kinds of metal oxides, CeO2 is the most suitable catalyst in terms of catalytic activity, leaching-resistance and reusability. This catalytic system tolerates various esters and alcohols, and valuable esters such as heteroaromatic esters and benzyl benzoates are produced, demonstrating a practical utility of the system. On the basis of kinetic analysis and in situ IR studies of adsorbed species, a reaction mechanism is proposed, in which proton abstraction of alcohol by a Lewis base site of CeO2 to yield alkoxide species is the rate-limiting step.
- Tamura, Masazumi,Hakim Siddiki,Shimizu, Ken-Ichi
-
p. 1641 - 1646
(2013/09/24)
-
- Benzoyl peroxide-imidazole: A novel and efficient reagent for the mild conversion of alcohols or phenols into benzoates
-
A very mild, one-pot, and expedient protocol for the conversion of alcohols and phenols into their corresponding benzoates using imidazole and benzoyl peroxide as a novel reagent is described.
- Nowrouzi, Najmeh,Alizadeh, Seyedeh Zahra
-
p. 2412 - 2414
(2013/06/26)
-
- Benzylation of hydroxy groups with tertiary amine as a base
-
The benzylation of hydroxy groups in the presence of tertiary amines is described. A mixture of an alcohol and a benzyl halide afforded the corresponding benzyl ether in good to excellent yields in the presence of diisopropylethylamine. The importance of solventless conditions was observed. The reaction showed high tolerance to many functional groups including benzoate, even at a reaction temperature of 150 °C. Sodium iodide was found to be an efficient catalyst to accelerate the reaction.
- Gathirwa, Jeremiah W.,Maki, Toshihide
-
experimental part
p. 370 - 375
(2012/01/14)
-
- Novel and efficient method for esterification catalyzed by 1-glycyl-3-methyl imidazolium chloride-iron (III) complex
-
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
-
p. 983 - 990
(2013/02/23)
-
- Organocatalytic selective benzoylation of alcohols with trichloromethyl phenyl ketone: Inverse selectivity in benzoylation of alcohols containing phenol or aromatic amine functionality
-
Trichloromethyl phenyl ketone benzoylates primary and secondary aliphatic alcoholic groups in compounds also containing a phenolic group in the presence of 2-10 mol % of PMDETA organocatalyst at room temperature in high yields and excellent selectivity. It also shows the potential to selectively benzoylate primary alcoholic groups of aminoarylalkanols and primary-secondary diols as well as primary amino group of alkyl amines in the presence of aryl amines under similar conditions. A rationale for the selectivity and efficiency of the reaction has been provided.
- Ram, Ram N.,Soni, Vineet Kumar,Gupta, Dharmendra Kumar
-
p. 9068 - 9075
(2012/11/07)
-
- Solvent-free transesterification in a ball-mill over alumina surface
-
An efficient procedure for transesterification has been developed in a ball-mill in the absence of any solvent, acid/base or metal catalyst. A variety of methyl, ethyl, allyl esters have been transesterified to higher benzyl and other esters in high yields by this procedure.
- Chatterjee, Tanmay,Saha, Debasree,Ranu, Brindaban C.
-
experimental part
p. 4142 - 4144
(2012/08/28)
-
- Dual Bronsted acid/nucleophilic activation of carbonylimidazole derivatives
-
Carbonylimidazole derivatives have been found to be highly active acylation reagents for esterification and amidation in the presence of pyridinium salts. These reactions are thought to involve both Bronsted acid and nucleophilic catalysis. This mode of activation has been applied to the synthesis of difficult to access oxazolidinones, as well as esters and amides. Finally, the use of pyridinium salts has been shown to accelerate the esterification of carboxylic acids with imidazole carbamates.
- Heller, Stephen T.,Fu, Tingting,Sarpong, Richmond
-
supporting information; experimental part
p. 1970 - 1973
(2012/06/01)
-
- A simple and convenient method for preparation of carboxylic acid alkyl esters, phenolic and thioesters using chlorodiphenylphosphine/I2 and imidazole reagent system
-
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
-
experimental part
p. 9596 - 9601
(2011/01/03)
-
- 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
-
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
-
supporting information; experimental part
p. 4436 - 4443
(2010/11/05)
-
- Inhibitory effects of benzyl benzoate and its derivatives on angiotensin II-induced hypertension
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Hypertension is a lifestyle-related disease which often leads to serious conditions such as heart disease and cerebral hemorrhage. Angiotensin II (Ang II) plays an important role in regulating cardiovascular homeostasis. Consequently, antagonists that block the interaction of Ang II with its receptors are thought to be effective in the suppression of hypertension. In this study, we searched for plant compounds that had antagonist-like activity toward Ang II receptors. From among 435 plant samples, we found that EtOH extract from the resin of sweet gum Liquidambar styraciflua strongly inhibited Ang II signaling. We isolated benzyl benzoate and benzyl cinnamate from this extract and found that those compounds inhibited the function of Ang II in a dose-dependent manner without cytotoxicity. An in vivo study showed that benzyl benzoate significantly suppressed Ang II-induced hypertension in mice. In addition, we synthesized more than 40 derivatives of benzyl benzoate and found that the meta-methyl and 3-methylbenzyl 2′-nitrobenzoate derivatives showed about 10-fold higher activity than benzyl benzoate itself. Thus, benzyl benzoate, its derivatives, and benzyl cinnamate may be useful for reducing hypertension.
- Ohno, Osamu,Ye, Mao,Koyama, Tomoyuki,Yazawa, Kazunaga,Mura, Emi,Matsumoto, Hiroshi,Ichino, Takao,Yamada, Kaoru,Nakamura, Kazuhiko,Ohno, Tomohiro,Yamaguchi, Kohji,Ishida, Junji,Fukamizu, Akiyoshi,Uemura, Daisuke
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experimental part
p. 7843 - 7852
(2009/04/11)
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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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- Multipolymer solution-phase reactions: Application to the mitsunobu reaction
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The realization of the first polymer-on-polymer Mitsunobu reaction, in which a polymeric phosphine is used simultaneously with a polymeric azodicarboxylate, is reported. This strategy employs the use of soluble oligomers generated from ring-opening methathesis polymerization. 31P NMR analysis revealed that the two polymers were interacting to generate the Mitsunobu products. Application to several substrates, as well as comparison experiments with other polymeric reagents, is described. Copyright
- Harned, Andrew M.,He, Helen Song,Toy, Patrick H.,Flynn, Daniel L.,Hanson, Paul R.
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- Efficient method for the preparation of inverted alkyl carboxylates and phenyl carboxylates via oxidation-reduction condensation using 2,6-dimethyl-1,4-benzoquinone or simple 1,4-benzoquinone
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Oxidation-reduction condensation using in situ formed alkoxydiphenylphosphines, 2,6-dimethy-1,4-benzoquinone, and carboxylic acids provides a useful method for the preparation of inverted tertiary alkyl carboxylates from the corresponding chiral tertiary alcohols under mild and neutral conditions. Similarly, it has afforded alkyl carboxylates successfully in good-to-high yields by the combined use of alkoxydiphenylphosphines having primary, secondary, or tertiary alkoxy groups, carboxylic acids, and simple 1,4-benzoquinone. When chiral secondary or tertiary alcohols are used, the corresponding inverted secondary or tertiary alkyl carboxylates are also obtained in good-to-high yields. In addition, a convenient method for the preparation of phenyl carboxylates in high yields has been established by utilizing oxidation-reduction condensation in toluene at 110 °C using phenoxydiphenylphosphines in situ-formed from phenols and chlorodiphenylphosphine, 2,6-dimethyl-1,4-benzoquinone, and carboxylic acids.
- Shintou, Taichi,Fukumoto, Kentaro,Mukaiyama, Teruaki
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p. 1569 - 1579
(2007/10/03)
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- High-Load, ROMP-Generated Oligomeric Bis-acid Chlorides: Design of Soluble and Insoluble Nucleophile Scavengers
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(Equation presented) An efficient strategy for scavenging a host of nucleophiles utilizing an oligomeric bis-acid chloride (OBAC), generated from the ROM polymerization of trans-bicyclo[2.2.1]hept-5-ene-2,3-dicarbonyl dichloride, is described. The reactivity and high load of the OBAC reagent is exploited in the scavenging of amines, alcohols, and thiols that are present in excess following a common benzoylation event. Following the scavenging event, these oligomers can be precipitated with EtOAc and filtered (SiO2), leaving benzoylated nucleophiles in excellent yield and purity.
- Moore, Joel D.,Byrne, Robert J.,Vedantham, Punitha,Flynn, Daniel L.,Hanson, Paul R.
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p. 4241 - 4244
(2007/10/03)
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- Preparation of various carboxylic acid esters from bulky alcohols and carboxylic acids by a new type oxidation-reduction condensation using 2,6-dimethyl-1,4-benzoquinone
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A new-type oxidation-reduction condensation by using 2,6-dimethyl-1,4-benzoquinone (DMBQ), carboxylic acids and in situ formed alkoxydiphenylphosphines (1) including the bulky alkoxy group-substituted ones proceeded smoothly to afford the corresponding carboxylic acid esters in good to high yields. Alkoxydiphenylphosphines were formed in situ by treating either N,N-dimethylaminodiphenylphosphine (Ph2PNMe2) with primary or secondary alcohols or chlorodiphenylphosphine with the lithium salts of primary, secondary and tertiary alcohols.
- Mukaiyama, Teruaki,Kikuchi, Wataru,Shintou, Taichi
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p. 300 - 301
(2007/10/03)
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- Efficient Method for the Preparation of Primary, Inverted Secondary and Tertiary Alkyl Carboxylates from Alcohols and Carboxylic Acids by a New Type of Oxidation-Reduction Condensation Using Simple 1,4-Benzoquinone
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A new type of oxidation-reduction condensation using in situ formed alkoxydiphenylphosphines (i.e., diphenylphosphinite esters), easily available 1,4-benzoquionone and carboxylic acids provides a new and efficient method for the preparation of alkyl carboxylates from the corresponding alcohols under mild and neutral conditions. Further, the yields of the corresponding inverted carboxylates were equally high in the case of chiral secondary or tertiary alcohols.
- Shintou, Taichi,Mukaiyama, Teruaki
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p. 1100 - 1101
(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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- Selective sulfonylation of arenes and benzoylation of alcohols using lithium perchlorate as a catalyst under neutral conditions
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Sulfonylation of aromatics with p-toluenesulfonyl chloride and benzoylation of alcohols with benzoyl chloride using lithium perchlorate as a catalyst is described. The remarkable selectivity under neutral conditions is an attractive feature of this method.
- Bandgar,Kamble,Sadavarte,Uppalla
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p. 735 - 738
(2007/10/03)
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- Efficient and selective conversion of trimethylsilyl and tetrahydropyranyl ethers to their corresponding acetates and benzoates catalyzed by bismuth(III) salts
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A variety of TMS and THP ethers are efficiently converted to their corresponding acetates and benzoates with acetic and benzoic anhydrides in the presence of catalytic amounts of Bi(III) salts such as BiCl3, Bi(TFA)3, and Bi(OTf)sub
- Mohammadpoor-Baltork, Iraj,Khosropour, Ahmad R.
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p. 189 - 193
(2007/10/03)
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- A convenient preparation of p-methoxybenzyl esters
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Carboxylic acids are conveniently and efficiently protected as their p-methoxybenzyl esters under very mild conditions using the pre-formed reagent N,N'-diisopropyl-O-(4-methoxybenzyl)isourea, and this method allows selective protection of carboxylic acids in the presence of other functionalities such as enolisable ketones and alcohol groups.
- Wang,Golding,Potter
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p. 4197 - 4204
(2007/10/03)
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