- Size-Driven Inversion of Selectivity in Esterification Reactions: Secondary Beat Primary Alcohols
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Relative rates for the Lewis base-mediated acylation of secondary and primary alcohols carrying large aromatic side chains with anhydrides differing in size and electronic structure have been measured. While primary alcohols react faster than secondary ones in transformations with monosubstituted benzoic anhydride derivatives, relative reactivities are inverted in reactions with sterically biased 1-naphthyl anhydrides. Further analysis of reaction rates shows that increasing substrate size leads to an actual acceleration of the acylation process, the effect being larger for secondary as compared to primary alcohols. Computational results indicate that acylation rates are guided by noncovalent interactions (NCIs) between the catalyst ring system and the DED substituents in the alcohol and anhydride reactants. Thereby stronger NCIs are formed for secondary alcohols than for primary alcohols.
- Mayr, Stefanie,Marin-Luna, Marta,Zipse, Hendrik
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p. 3456 - 3489
(2021/03/01)
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- TBHP/ n -Bu 4 PBr-Promoted Oxidative Cross-Dehydrogenative Coupling of Aryl Methanols: A Facile Synthesis of Symmetrical Carboxylic Anhydride Derivatives
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A transition-metal-free oxidative cross-dehydrogenative coupling reaction has been developed for the preparation of symmetrical carboxylic anhydrides through self-coupling dual C-O bond formations of aryl methanols. In the presence of a catalytic amount of tetrabutylphosphonium bromide (TBPB) as transfer agent and aqueous tert -butyl hydroperoxide (TBHP) as oxidant and reactant, methylene groups of aryl methanols were efficiently oxidized to C=O and coupled with the peroxide oxygen from TBHP to form a diverse array of symmetrical carboxylic anhydride derivatives.
- Adib, Mehdi,Pashazadeh, Rahim
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supporting information
p. 136 - 140
(2017/12/27)
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- Acid anhydrides and the unexpected N,N-diethylamides derived from the reaction of carboxylic acids with Ph3P/I2/Et3N
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The formation of acid anhydrides from the phosphorous-mediated activation of carboxylic acids was investigated. Under various systems, activation of benzoic acid in the presence of base led to the formation of benzoic anhydride at different rates depending on the reactivity of the reagents. Using the Ph3P-I2/Et3N combination, most aryl acids were converted into the corresponding anhydrides in high yields within 5-10 min. However, for nitro-substituted derivatives, unexpectedly, N,N-diethylamides were isolated without anhydride formation. These results indicated the pronounced effect of substituents in governing these potential side reactions which can significantly affect the yields of acylation reactions promoted by phosphonium species.
- Phakhodee, Wong,Duangkamol, Chuthamat,Wangngae, Sirilak,Pattarawarapan, Mookda
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supporting information
p. 325 - 328
(2016/01/12)
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- TBHP-promoted and iodide-catalyzed synthesis of anhydrides via cross dehydrogenative coupling (CDC) of aldehydes
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We have successfully developed a transition metal free green methodology for the synthesis of carboxylic anhydrides from aldehydes via CDC pathway and have also demonstrated the reaction mechanism. The developed method has also been successfully applied for the synthesis of amides.
- Singha, Raju,Ghosh, Munmun,Nuree, Yasin,Ray, Jayanta K.
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supporting information
p. 1325 - 1327
(2018/03/29)
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- Cu(I) catalyzed synthesis of anhydrides from aldehydes via CDC-pathway at ambient temperature
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A one-pot simple and concise methodology has been developed for synthesizing aromatic carboxylic anhydrides starting from easily accessible aromatic aldehydes using cuprous chloride as the catalyst and TBHP as the oxidant in DMSO solvent to garner moderate to good yields via radical pathway in short and convenient reaction time at room temperature.
- Nuree, Yasin,Singha, Raju,Ghosh, Munmun,Roy, Pronay,Ray, Jayanta K.
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supporting information
p. 1479 - 1482
(2016/03/12)
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- Metal-free cross-dehydrogenative coupling of aryl aldehydes to give symmetrical carboxylic anhydrides promoted by the TBHP/nBu4PBr system
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A novel, efficient, and metal-free dual C–O bond formation reaction for the synthesis of carboxylic anhydrides from aryl aldehydes via cross-dehydrogenative coupling is described. Heating a mixture of aromatic aldehydes and an aqueous solution of tert-butyl hydroperoxide as oxidant in the presence of catalytic nBu4PBr in chlorobenzene at 80?°C for 3?h afforded the corresponding carboxylic anhydrides in good to excellent yields.
- Adib, Mehdi,Pashazadeh, Rahim,Rajai-Daryasarei, Saideh,Mirzaei, Peiman,Jamal Addin Gohari, Seyed
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supporting information
p. 3071 - 3074
(2016/07/06)
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- Oxidative self-coupling of aldehydes in the presence of CuCl2/TBHP system: Direct access to symmetrical anhydrides
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A simple synthesis of symmetrical anhydrides has been developed. Using tert-butylhydroperoxide (TBHP) as the oxidant and copper(II) chloride as the catalyst in acetonitrile, various aromatic and heteroaromatic aldehydes were reacted to provide symmetrical anhydrides in modest to good yields.
- Saberi, Dariush,Shojaeyan, Fatemeh,Niknam, Khodabakhsh
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p. 566 - 569
(2016/01/20)
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- Light-enabled synthesis of anhydrides and amides
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Recently, we have demonstrated that the photogeneration of Vilsmeier-Haack reagents is possible using only dimethylformamide (DMF) and tetrabromomethane (CBr4) in the bromination of alcohols. Extending these findings to carboxylic acid substrates has produced a mild and facile approach to the in situ formation of symmetric anhydrides, which were conveniently converted to amide derivatives in a one-pot process. The efficient protocols discussed herein are marked by use of UVA LEDs (365 nm), which have reduced the reaction times and come with a low setup cost.
- Mccallum, Terry,Barriault, Louis
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p. 2874 - 2878
(2015/03/30)
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- Carboxylic acid anhydrides via Pd-catalyzed carbonylation of aryl halides at atmospheric CO pressure
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A convenient method has been developed, which allows for the direct transformation of aryl iodides into the corresponding carboxylic acid anhydrides via Pd-catalyzed carbonylation under atmospheric CO pressure. The Royal Society of Chemistry 2012.
- Li, Yang,Xue, Dong,Wang, Chao,Liu, Zhao-Tie,Xiao, Jianliang
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supporting information; experimental part
p. 1320 - 1322
(2012/02/04)
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- Synthesis of symmetric anhydrides using visible light-mediated photoredox catalysis
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A new approach to anhydride formation is reported via activation of C-O bonds by the Vilsmeier-Haack reagent formed by Ru(bpy)3Cl2 and CBr4 in DMF. Various aryl and alkyl carboxylic acids are converted to the corresponding anhydrides in excellent yields.
- Konieczynska, Marlena D.,Dai, Chunhui,Stephenson, Corey R. J.
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supporting information; experimental part
p. 4509 - 4511
(2012/07/31)
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- Substrate activity screening: A fragment-based method for the rapid identification of nonpeptidic protease inhibitors
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A new fragment-based method for the rapid development of novel and distinct classes of nonpeptidic protease inhibitors, Substrate Activity Screening (SAS), is described. This method consists of three steps: (1) a library of N-acyl aminocoumarins with diverse, low molecular weight N-acyl groups is screened to identify protease substrates using a simple fluorescence-based assay, (2) the identified N-acyl aminocoumarin substrates are optimized by rapid analogue synthesis and evaluation, and (3) the optimized substrates are converted to inhibitors by direct replacement of the aminocoumarin with known mechanism-based pharmacophores. The SAS method was successfully applied to the cysteine protease cathepsin S, which is implicated in autoimmune diseases. Multiple distinct classes of nonpeptidic substrates were identified upon screening an N-acyl aminocoumarin library. Two of the nonpeptidic substrate classes were optimized to substrates with >8000-fold improvements in cleavage efficiency for each class. Select nonpeptidic substrates were then directly converted to low molecular weight, novel aldehyde inhibitors with nanomolar affinity to cathepsin S. This study demonstrates the unique characteristics and merits of this first substrate-based method for the rapid identification and optimization of weak fragments and provides the framework for the development of completely nonpeptidic inhibitors to many different proteases.
- Wood, Warren J. L.,Patterson, Andrew W.,Tsuruoka, Hiroyuki,Jain, Rishi K.,Ellman, Jonathan A.
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p. 15521 - 15527
(2007/10/03)
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- A Cheap, Simple and Efficient Method for the Preparation of Symmetrical Carboxylic Acid Anhydrides
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A manipulatively simple and facile one-pot procedure for the synthesis of symmetrical anhydride is reported. Treatment of carboxylic acids with tosyl chloride in K2CO3 media under solvent free conditions gives the corresponding anhydrides in good to excellent yields in a short reaction time via carboxylic sulfonic anhydride as the key intermediate.
- Kazemi, Foad,Sharghi, Hashem,Nasseri, Mohammad Ali
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p. 205 - 207
(2007/10/03)
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- 2-(Trimethylsilyl)ethyl glycosides. Transformation into the corresponding 1-O-acyl sugars.
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(Trimethylsilyl)ethyl 2,3,4,6-tetra-O-acetyl-beta-D-glucopyranoside and (trimethylsilyl)ethyl 2,3,6-tri-O-acetyl-4-O-(2,3,6-tri-O-acetyl-4-O-[2-acetamido-4,6-di-O-ace tyl-2- deoxy-3-O-(2,3,4,6-tetra-O-acetyl-beta-D-galactopyranosyl)-beta-D- galactopyranos
- Ellervik,Magnusson
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p. 826 - 828
(2007/10/02)
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- Palladium-promoted One-step Synthesis of Aromatic Acid Anhydrides from Aromatic Compounds with Carbon Monoxide
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The one-step synthesis of aromatic acid anhydrides from aromatic compounds such as benzene, toluene, anisole, chlorobenzene, furan, and thiophen has been carried out using carbon monoxide, 1,2-dibromoethane, and palladium acetate
- Fujiwara, Yuzo,Kawata, Itaru,Kawauchi, Tomio,Taniguchi, Hiroshi
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p. 132 - 133
(2007/10/02)
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- Reaction of Diazonium Salts with Transition Metals. 6. Preparation of Mixed Acid Anhydrides from Arenediazonium Salts and Sodium Carboxylates under Palladium(0) Catalysis
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The palladium(0)-catalyzed reaction of arenediazonium tetrafluoroborates with carbon monoxide and sodium carboxylates in acetonitrile at 25 deg C gave mixed acid anhydrides, ArCOOCOR (Ar = 3-Me-Ph, 4-Me-Ph, 2-MeO-Ph, 4-Br-Ph, 4-I-Ph, 3-NO2-Ph, 4-NO2-Ph, and Ph; R = H, Me, Et, t-Bu, and Ph) in good yields.Homoaromatic acid anhydrides, (ArCO)2O, were obtained by heating of ArCOOCOMe at 100-120 deg C under vacuum.ArCOOCO-t-Bu can be utilized to obtain the corresponding arenecarboxamides by the reaction with some amines.
- Kikukawa, Kiyoshi,Kono, Kiyoshi,Nagira, Kazuhiko,Wada, Fumio,Matsuda, Tsutomu
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p. 4413 - 4416
(2007/10/02)
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