- The "fully Catalytic System" in Mitsunobu Reaction Has Not Been Realized Yet
-
An investigation of the recently reported "fully catalytic Mitsunobu reaction" using catalytic amounts of a phosphine reagent and an azo reagent has shown that although benzyl 4-nitrobenzoate is formed under the fully catalytic conditions, the same result is obtained if the hydrazine catalyst is omitted, indicating that this is not a Mitsunobu reaction. In addition, when the reaction between (-)-ethyl lactate and 4-nitrobenzoic acid was carried out using the "fully catalytic" method, the corresponding ester was formed but in very low yield and with predominant retention of configuration. Unfortunately, the system catalytic in phosphine reagent is incompatible with that in the azo reagent.
- Hirose, Daisuke,Gazvoda, Martin,Ko?mrlj, Janez,Taniguchi, Tsuyoshi
-
-
Read Online
- Photochemical Activation of Aromatic Aldehydes: Synthesis of Amides, Hydroxamic Acids and Esters
-
A cheap, facile and metal-free photochemical protocol for the activation of aromatic aldehydes has been developed. Utilizing thioxanthen-9-one as the photocatalyst and cheap household lamps as the light source, a variety of aromatic aldehydes have been activated and subsequently converted in a one-pot reaction into amides, hydroxamic acids and esters in good to high yields. The applicability of this method was highlighted in the synthesis of Moclobemide, a drug against depression and social anxiety. Extended and detailed mechanistic studies have been conducted, in order to determine a plausible mechanism for the reaction.
- Nikitas, Nikolaos F.,Apostolopoulou, Mary K.,Skolia, Elpida,Tsoukaki, Anna,Kokotos, Christoforos G.
-
supporting information
p. 7915 - 7922
(2021/05/03)
-
- Br?nsted Acid Mediated Nucleophilic Functionalization of Amides through Stable Amide C?N Bond Cleavage; One-Step Synthesis of 2-Substituted Benzothiazoles
-
We have developed a Br?nsted acid mediated synthetic method to directly cleave stable amide C?N bonds by a variety of alcohol and amine nucleophiles. Reverse reactivity was observed and alcoholysis of amides by activated primary and secondary benzylic, and propargylic alcohols have been achieved instead of the expected nucleophilic substitution of alcohols. As an application, 2-substituted benzothiazole derivatives have been synthesized in one pot employing 2-aminothiophenol as nucleophile.
- Biswas, Srijit,Biswas, Subrata,Duari, Surajit,Elsharif, Asma M.,Maity, Srabani,Roy, Arnab
-
supporting information
p. 3569 - 3572
(2021/07/22)
-
- Solar and visible-light active nano Ni/g-C3N4photocatalyst for carbon monoxide (CO) and ligand-free carbonylation reactions
-
In this study, we investigate the amino and alkoxycarbonylation reaction between various substituted aryl halides, benzyl iodides, and iodocyclohexane with different types of amines and alcohols in the absence of carbon monoxide gas and ligands. Similar reactions are carried out at high temperatures, in the presence of appropriate ligands, stoichiometric amounts of bases, and gaseous carbon monoxide, which endanger the health of organic chemists. We present a novel method that does not utilize ligands, bases, gaseous CO, and special conditions. This procedure is a redox reaction carried out by new economic nano Ni/g-C3N4at room temperature and under visible light. Mo(CO)6was used toin situgenerate CO, to resolve the problems caused by the use of CO gas. This protocol has the ability to be used on a gram scale by using a continuous flow reactor.
- Hosseini-Sarvari, Mona,Akrami, Zahra
-
p. 956 - 969
(2021/02/26)
-
- 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
-
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
-
p. 445 - 455
(2020/09/07)
-
- Vitamin B1-catalyzed aerobic oxidative esterification of aromatic aldehydes with alcohols
-
A straightforward aerobic oxidative esterification of aryl aldehydes with alcohols has been developed for the synthesis of substituted esters by employing vitamin B1 as a cost-effective, metal-free, and eco-friendly NHC catalyst. Air is used as a green terminal oxidant. The reaction is a useful addition to the existing NHC-catalytic oxidative esterification.
- Chu, Xue-Qiang,Ge, Danhua,Luo, Xin-Long,Xu, Pei,Yu, Zi-Lun
-
supporting information
p. 30937 - 30942
(2021/11/19)
-
- A metal-free iodine-mediated conversion of hydroxamates to esters
-
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.
-
p. 1353 - 1360
(2020/03/30)
-
- Mechanochemical Palladium-Catalyzed Carbonylative Reactions Using Mo(CO)6
-
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.
-
p. 2576 - 2580
(2020/02/20)
-
- Catalytic Transfer Hydrodebenzylation with Low Palladium Loading
-
A highly-efficient catalytic system for hydrodebenzylation reaction is described. The cleavage of O-benzyl and N-benzyl protecting groups was performed using an uncommonly low palladium loading (0.02–0.3 mol%; TON up to 5000) in a relatively short reaction time. The approach was used for a variety of substrates including pharmaceutically important precursors, and gram-scale deprotection reaction was shown. Transfer conditions together with easy-to-make Pd/C catalyst are the key features of this debenzylation scheme. (Figure presented.).
- Yakukhnov, Sergey A.,Ananikov, Valentine P.
-
supporting information
p. 4781 - 4789
(2019/09/16)
-
- Visible light-induced transformation of aldehydes to esters, carboxylic anhydrides and amides
-
A transition metal- and organophotocatalyst free synthesis of esters, carboxylic anhydrides and amides from aldehydes induced by visible-light has been reported. The proposed methodology can be carried out by the use of sunlight or artificial visible light as a blue LED source. The methodology has a very broad applicability and the desired products are obtained in very satisfactory yields.
- Gaspa, Silvia,Raposo, Inês,Pereira, Leonor,Mulas, Gabriele,Ricci, Pier Carlo,Porcheddu, Andrea,De Luca, Lidia
-
supporting information
p. 10711 - 10715
(2019/07/15)
-
- 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
-
p. 1864 - 1871
(2019/08/12)
-
- Aerobic oxidative esterification and thioesterification of aldehydes using dibromoisocyanuric acid under mild conditions: No metal catalysts required
-
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
-
p. 10833 - 10841
(2018/07/05)
-
- Highly efficient and green esterification of carboxylic acids in deep eutectic solvents without any other additives
-
A protocol that carboxylic acids esterifies with the quaternary ammonium salt of deep eutectic solvent (DES) is presented, which opens a new access to ester using DES as alkylating agent, solvent, and catalyst. The reaction runs smoothly in DES without any other additives. Substituted cinnamic acids, aromatic acids, and aliphatic acids can be esterified in moderate to good yields. The advantages of this reaction include excellent functional group compatibility and simple reaction procedure.
- Yasmin, Sumera,Sheng, Wen-Bing,Peng, Cai-Yun,Rahman, Atta-ur,Liao, Duan-Fang,Choudhary, M. Iqbal,Wanga, Wei
-
supporting information
p. 68 - 75
(2017/12/26)
-
- Mitsunobu Reaction Using Basic Amines as Pronucleophiles
-
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
-
p. 6604 - 6614
(2017/07/15)
-
- Development and Application of a Recyclable High-Load Magnetic Co/C Hybrid ROMP-Derived Benzenesulfonyl Chloride Reagent and Utility of Corresponding Analogues
-
The development and application of high-load, recyclable magnetic Co/C hybrid ROMP-derived benzenesulfonyl chloride and analogues is reported. The regeneration and utility of these reagents in the methylation/alkylation of various carboxylic acids is demonstrated via efficient retrieval of the magnetic reagent with a neodymium magnet. Additional reactions employing the analogue sulfonic acid and in situ generated magnetic benzenesulfonyl azide are also reported.
- Faisal, Saqib,Zang, Qin,Maity, Pradip K.,Brandhofer, Agnes,Kearney, Patrick C.,Reiser, Oliver,Grass, Robert N.,Stoianova, Diana,Hanson, Paul R.
-
supporting information
p. 2274 - 2277
(2017/05/12)
-
- The invention relates to a raw material synthetic ester of carboxylic acid and alcohol method (by machine translation)
-
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 0031-0032
(2017/03/18)
-
- Oxidation-Reduction Condensation of Diazaphosphites for Carbon-Heteroatom Bond Formation Based on Mitsunobu Mechanism
-
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
-
supporting information
p. 544 - 547
(2017/02/10)
-
- 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
-
p. 23041 - 23045
(2017/07/10)
-
- Esterification of the Primary Benzylic C-H Bonds with Carboxylic Acids Catalyzed by Ionic Iron(III) Complexes Containing an Imidazolinium Cation
-
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
-
supporting information
p. 1132 - 1135
(2017/03/14)
-
- ANTIBODIES CONJUGATABLE BY TRANSGLUTAMINASE AND CONJUGATES MADE THEREFROM
-
An antibody has at a heavy chain thereof a C-terminal extension that includes at least one glutamine that is a substrate for transglutaminase, enabling the transglutaminase-mediated preparation antibody-drug conjugates using such antibody.
- -
-
Paragraph 0017; 0054
(2016/09/26)
-
- Advances and mechanistic insight on the catalytic Mitsunobu reaction using recyclable azo reagents
-
Ethyl 2-arylhydrazinecarboxylates can work as organocatalysts for Mitsunobu reactions because they provide ethyl 2-arylazocarboxylates through aerobic oxidation with a catalytic amount of iron phthalocyanine. First, ethyl 2-(3,4-dichlorophenyl)hydrazinecarboxylate has been identified as a potent catalyst, and the reactivity of the catalytic Mitsunobu reaction was improved through strict optimization of the reaction conditions. Investigation of the catalytic properties of ethyl 2-arylhydrazinecarboxylates and the corresponding azo forms led us to the discovery of a new catalyst, ethyl 2-(4-cyanophenyl)hydrazinecarboxylates, which expanded the scope of substrates. The mechanistic study of the Mitsunobu reaction with these new reagents strongly suggested the formation of betaine intermediates as in typical Mitsunobu reactions. The use of atmospheric oxygen as a sacrificial oxidative agent along with the iron catalyst is convenient and safe from the viewpoint of green chemistry. In addition, thermal analysis of the developed Mitsunobu reagents supports sufficient thermal stability compared with typical azo reagents such as diethyl azodicarboxylate (DEAD). The catalytic system realizes a substantial improvement of the Mitsunobu reaction and will be applicable to practical synthesis.
- Hirose, Daisuke,Gazvoda, Martin,Ko?mrlj, Janez,Taniguchi, Tsuyoshi
-
p. 5148 - 5159
(2016/07/29)
-
- Preparation of fluorous Yamaguchi reagents and evaluation of their reactivity in esterification
-
Fluorous Yamaguchi (FY) reagents bearing a perfluoroalkyl chain were prepared and employed in esterification reactions; the yields were similar to those obtained with the traditional Yamaguchi (TY) reagent. Fluorous benzoic acids derived from the FY reagents were separated easily after the reaction. GC analysis revealed that the initial rates of reaction with the FY reagents were higher than those with the TY reagent. The acidities of benzoic acids produced from the FY and TY reagents were predicted by DFT to be similar (1.20 and 0.96, respectively).
- Nishio, Yuya,Kawazu, Akari,Hirano, Shun,Matsubara, Hiroshi
-
supporting information
p. 720 - 725
(2016/01/15)
-
- METHOD OF CONVERTING ALCOHOL TO HALIDE
-
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; 66; 67
(2017/01/02)
-
- NOVEL SINGLE STEP ESTERIFICATION PROCESS OF ALDEHYDES USING A HETEROGENEOUS CATALYST
-
The present invention relates to a novel simple, efficient and single-step process for esterification of aldehydes using a heterogeneous catalyst with high yields. More particularly, the present invention relates to a novel simple, efficient and single-step process for esterification of aldehydes using Titanium superoxide with greater than 80% yields.
- -
-
Page/Page column 8; 9
(2016/06/20)
-
- 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)
-
- Mitsunobu Reactions Catalytic in Phosphine and a Fully Catalytic System
-
The Mitsunobu reaction is renowned for its mild reaction conditions and broad substrate tolerance, but has limited utility in process chemistry and industrial applications due to poor atom economy and the generation of stoichiometric phosphine oxide and hydrazine by-products that complicate purification. A catalytic Mitsunobu reaction using innocuous reagents to recycle these by-products would overcome both of these shortcomings. Herein we report a protocol that is catalytic in phosphine (1-phenylphospholane) employing phenylsilane to recycle the catalyst. Integration of this phosphine catalytic cycle with Taniguchi's azocarboxylate catalytic system provided the first fully catalytic Mitsunobu reaction. Make it catalytic: A catalytic Mitsunobu reaction using innocuous reagents to recycle the stoichiometric phosphine oxide and hydrazine by-products was developed. The reported method is catalytic in 1-phenylphospholane and uses phenylsilane to recycle the catalyst. Integration of this phosphine catalytic cycle with Taniguchi's azocarboxylate catalytic system provided the first fully catalytic Mitsunobu reaction.
- Buonomo, Joseph A.,Aldrich, Courtney C.
-
supporting information
p. 13041 - 13044
(2015/11/02)
-
- The Albicidin Resistance Factor AlbD Is a Serine Endopeptidase That Hydrolyzes Unusual Oligoaromatic-Type Peptides
-
The para-aminobenzoic acid-containing peptide albicidin is a pathogenicity factor synthesized by Xanthomonas albilineans in infections of sugar cane. Albicidin is a nanomolar inhibitor of the bacterial DNA gyrase with a strong activity against various Gram-negative bacteria. The bacterium Pantoea dispersa expresses the hydrolase AlbD, conferring natural resistance against albicidin. We show that AlbD is a novel type of endopeptidase that catalyzes the cleavage of albicidin at a peptide backbone amide bond, thus abolishing its antimicrobial activity. Additionally, we determined the minimal cleavage motif of AlbD with substrates derived by chemical synthesis. Our results clearly identify AlbD as a unique endopeptidase that is the first member of a new subfamily of peptidases. Our findings provide the molecular basis for a natural detoxification mechanism, potentially rendering a new tool in biological chemistry approaches.
- Vieweg, Laura,Kretz, Julian,Pesic, Alexander,Kerwat, Dennis,Gr?tz, Stefan,Royer, Monique,Cociancich, Stéphane,Mainz, Andi,Süssmuth, Roderich D.
-
supporting information
p. 7608 - 7611
(2015/07/02)
-
- Titanium superoxide-a stable recyclable heterogeneous catalyst for oxidative esterification of aldehydes with alkylarenes or alcohols using TBHP as an oxidant
-
Titanium superoxide efficiently catalysed the oxidative esterification of aldehydes with alkylarenes or alcohols, under truly heterogeneous conditions, to afford the corresponding benzyl and alkyl esters in excellent yields. Mechanistic studies have established that this "one pot" direct oxidative esterification process proceeds through a radical pathway, proven by a FTIR spectral study of a titanium superoxide-aldehyde complex as well as spin trapping experiments with TEMPO. The intramolecular version of this protocol has been successfully demonstrated in the concise synthesis of 3-butylphthalide, an anti-convulsant drug.
- Dey, Soumen,Gadakh, Sunita K.,Sudalai
-
p. 10631 - 10640
(2015/11/17)
-
- Ester manufacturing method (by machine translation)
-
PROBLEM TO BE SOLVED: To produce an ester compound by transesterification using an inexpensive and low toxic inorganic compound. SOLUTION: Transesterification of an ester compound and an alcohol compound is carried out under the presence of lanthanum nitrate (for example, lanthanum nitrate hexahydrate) and a phosphine compound (for example, tri-n-octylphosphine), thereby obtaining the ester product. For example, transesterification of dimethyl carbonate and benzyl alcohol is carried out under the presence of 1 mol% of lanthanum nitrate hexahydrate, and 2 mol% of tri-n-octylphosphine, thereby obtaining benzyl methylcarbonate at a yield of >99%. COPYRIGHT: (C)2012,JPO&INPIT
- -
-
Paragraph 0054; 0056
(2017/02/17)
-
- Direct, rapid and convenient synthesis of esters and thioesters using PPh3/N-chlorobenzotriazole system
-
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
-
p. 253 - 263
(2014/02/14)
-
- 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)
-
- 1-PHENYL-2-PYRIDINYL ALKYL ALCOHOL DERIVATIVES AS PHOSPHODIESTERASE INHIBITORS
-
Compounds of formula (I) described herein are inhibitors of the phosphodiesterase 4 (PDE4) enzyme and are useful for the prevention and/or treatment of an allergic disease state or a disease of the respiratory tract characterized by airway obstruction.
- -
-
Paragraph 0549; 0550
(2014/06/23)
-
- Discovery of GS-9973, a selective and orally efficacious inhibitor of spleen tyrosine kinase
-
Spleen tyrosine kinase (Syk) is an attractive drug target in autoimmune, inflammatory, and oncology disease indications. The most advanced Syk inhibitor, R406, 1 (or its prodrug form fostamatinib, 2), has shown efficacy in multiple therapeutic indications, but its clinical progress has been hampered by dose-limiting adverse effects that have been attributed, at least in part, to the off-target activities of 1. It is expected that a more selective Syk inhibitor would provide a greater therapeutic window. Herein we report the discovery and optimization of a novel series of imidazo[1,2-a]pyrazine Syk inhibitors. This work culminated in the identification of GS-9973, 68, a highly selective and orally efficacious Syk inhibitor which is currently undergoing clinical evaluation for autoimmune and oncology indications.
- Currie, Kevin S.,Kropf, Jeffrey E.,Lee, Tony,Blomgren, Peter,Xu, Jianjun,Zhao, Zhongdong,Gallion, Steve,Whitney, J. Andrew,Maclin, Deborah,Lansdon, Eric B.,Maciejewski, Patricia,Rossi, Ann Marie,Rong, Hong,Macaluso, Jennifer,Barbosa, James,Di Paolo, Julie A.,Mitchell, Scott A.
-
p. 3856 - 3873
(2014/05/20)
-
- Base-catalyzed retro-Claisen condensation: A convenient esterification of alcohols via C-C bond cleavage of ketones to afford acylating sources
-
The base-catalyzed esterification of alcohols via retro-Claisen condensation has been demonstrated for the first time. A variety of alcohols including aryl- and heteroaryl methanols as well as aliphatic ones underwent efficient acylation to give the ester products in reasonable to good yields upon isolation. Not only conventional 1,3-diketones but also strong electron-withdrawing group containing acetophenones could serve as the acylating suppliers. The synthetic protocol is operationally simple and adaptable to a broad substrate scope. It complements the existed esterification via the retro-Claisen condensation, and enlarges this benign synthetic methodology.
- Xie, Feng,Yan, Fengxia,Chen, Mengmeng,Zhang, Min
-
p. 29502 - 29508
(2014/08/05)
-
- Electrogenerated N-heterocyclic carbene in ionic liquid: An insight into the mechanism of the oxidative esterification of aromatic aldehydes
-
An N-heterocyclic carbene (NHC), generated by cathodic reduction of BMIm BF4, mediates the oxidative esterification of aromatic aldehydes with organic bromides in the corresponding ionic liquid as solvent. The product recovery by simple extractive work-up with diethyl ether allowed the ionic liquid to be recycled up to 9 times for subsequent electrolyses, with no significant loss in the product yield. The isolation of an intermediate, whose structure was confirmed by synthesis and transformation into the ester, provided the key for a mechanistic insight into the reaction.
- Forte, Gianpiero,Chiarotto, Isabella,Inesi, Achille,Loreto, Maria Antonietta,Feroci, Marta
-
p. 1773 - 1781
(2014/06/09)
-
- Facile esterification of carboxylic acid using amide functionalized benzimidazolium dicationic ionic liquids
-
Herein, we report the synthesis of a new series of amide functionalized dicationic benzimidazolium based ionic liquids (DBimILs) and appraised their efficacy towards perceptive esterification of carboxylic acids with alkyl/allyl/aryl halides in presence of triethylamine. The amide groups present in this new series of DBimILs are expected to form hydrogen bonding with the carboxylic acids and this could facilitate the esterification reactions under mild conditions devoid of any added catalyst or organic solvent. The plausible mechanism for the enhanced catalytic activity in presence of this new series of ILs has been proposed. The corresponding alkyl/allyl/aryl esters isolated from this reaction were of high purity after simple extraction, which wipe out the necessity for further purification. This protocol addresses clean methodology and the efficient recyclability as well as reusability of the catalyst.
- Muskawar, Prashant Narayan,Thenmozhi,Gajbhiye, Jayant M.,Bhagat, Pundlik Rambhau
-
p. 214 - 220
(2014/07/08)
-
- Convenient esterification of carboxylic acids by SN2 reaction promoted by a protic ionic-liquid system formed in situ in solvent-free conditions
-
The reaction of esterification of benzoic acid with benzyl chloride was chosen as a model reaction to study the esterification by SN2 promoted by tertiary amine as deprotonating agent. The use of ionic liquid (IL) 1,3-dimethylimidazolium methanesulfonate [MMIm][OMs] as reaction medium has proven to give quantitative yield of the ester, but interestingly the reaction does occur even in solvent-free conditions, where the acid + the amine form a liquid system (a protic IL) in situ. This last methodology was extended to several carboxylic acids in conditions of atom economy (i.e., without excess of any reagent), giving moderately good yields of esters (54-78%) recovered by weight in pure form.
- Cardellini, Fabio,Brinchi, Lucia,Germani, Raimondo,Tiecco, Matteo
-
p. 3248 - 3256
(2015/10/06)
-
- Transition metal free oxidative esterification of alcohols with toluene
-
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
-
supporting information
p. 5383 - 5386
(2013/09/12)
-
- Preparation of esters and amides from carboxylic acids and N-formylation of amines promoted by 1,3,5-triazo-2,4,6-triphosphorine-2,2,4,4,6,6-hexachloride (TAPC)
-
A new method is described for the preparation of esters and amides promoted by TAPC from carboxylic acids using a solvent-free grinding technique. The solvent-free N-formylation of amines is also reported.
- Bahrami, Kiumars,Khodaei, Mohammad M.,Targhan, Homa,Sheikh Arabi, Mehdi
-
supporting information
p. 5064 - 5068
(2013/09/02)
-
- Direct conversion of N -alkoxyamides to carboxylic esters through tandem nbs-mediated oxidative homocoupling and thermal denitrogenation
-
Treatment of N-alkoxyamides with NBS in toluene was found to conveniently afford the corresponding carboxylic esters, including those bearing a bulky or long-chain substituent, in satisfactory to excellent yields. This approach not only represents a convenient and economic approach to a direct transformation of an alkoxyamide moiety into the carboxylic ester functional group, via oxidative homocoupling and the subsequent thermal denitrogenation, but also facilitates the synthesis of sterically hindered carboxylic esters.
- Zhang, Ningning,Yang, Rui,Zhang-Negrerie, Daisy,Du, Yunfei,Zhao, Kang
-
p. 8705 - 8711
(2013/09/24)
-
- Palladium-catalyzed benzylation of carboxylic acids with toluene via benzylic C-H activation
-
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
-
supporting information
p. 4098 - 4101
(2013/09/12)
-
- N-Heterocyclic carbene catalyzed esterification of aromatic aldehydes with alcohols under aerobic conditions
-
A simple, organocatalytic procedure for the direct oxidative esterification of a variety of aromatic aldehydes with alcohols has been described that affords the corresponding aromatic esters in high yields. The method employs N-heterocyclic carbenes as catalysts and molecular O2 as an oxidant under ambient conditions.
- Kiran, I. N. Chaithanya,Lalwani, Komal,Sudalai, Arumugam
-
p. 1695 - 1698
(2013/03/13)
-
- N-heterocyclic carbene catalysed oxidative coupling of aldehydes with alcohols/thiols and one-pot oxidation/esterification of allylic alcohols
-
A versatile carbene-catalysed oxidation protocol involving N-heterocyclic carbene catalysts and 2,2,6,6-tetramethylpiperidine N-oxyl (TEMPO) is described for the synthesis of esters, cinnamic acids, and thioesters. A wide range of esters, thioesters, and cinnamic acids were obtained by metal-free coupling of aldehydes with aliphatic, allylic and aromatic alcohols, benzyl mercaptan, and water. In addition to the oxidative coupling of aldehydes with nucleophiles, dehydrogenation of saturated aldehydes and oxidation of allylic alcohols were found under our oxidative coupling conditions. Unlike other TEMPO-mediated oxidative esterification reactions, this reaction does not proceed through a TEMPO ester intermediate to form esters and thioesters. N-Heterocyclic carbene complexes catalyse various oxidative coupling reactions in the presence of TEMPO. A variety of α,β-unsaturated and saturated esters, and aromatic esters and thioesters were synthesised. Copyright
- Ji, Miran,Wang, Xi,Lim, Yu Na,Kang, Ye-Won,Jang, Hye-Young
-
supporting information
p. 7881 - 7885
(2014/01/06)
-
- Transition-metal-free aerobic oxidative cleavage of C-C bonds in α-hydroxy ketones and mechanistic insight to the reaction pathway
-
Clear cut: For the title reaction, O2, the ideal oxidant, was used as the only oxidizing reagent. The dimer intermediate (see scheme) and isotopic labeling control experiments with 18O2 partially disclosed the reaction mec
- Liu, Hui,Dong, Chao,Zhang, Zeguang,Wu, Peiyu,Jiang, Xuefeng
-
supporting information
p. 12570 - 12574
(2013/02/22)
-
- 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)
-
- Transesterification for synthesis of carboxylates using aldehydes as acyl donors via C-H and C-O bond activations
-
A new type of transesterification between aryl, heteroaryl, alkyl N-heteroarene-2-carboxylates and various aldehydes by C-H and C-O bond activations has been developed for the synthesis of versatile carboxylates. A possible mechanism containing oxidative addition of acyl-O bond in parent ester and radical cleavage of sp2 C-H bond in aldehyde is proposed.
- Bao, Yong-Sheng,Chen, Chao-Yue,Huang, Zhi-Zhen
-
p. 8344 - 8349,6
(2020/10/15)
-
- Dimethylbut-2-ynedioate mediated esterification of acids via sp3 C-N bond cleavage of benzylic tertiary amines
-
A straightforward synthetic transformation of tertiary amines to the esterification of equimolar amounts of acids was demonstrated in this manuscript. The present protocol can be regarded as a straightforward synthetic transformation of tertiary amines to the esterification of equimolar amounts of acid. Moreover, the reaction is fundamentally new chemistry for the sp 3 C-N bond cleavage coupled with esterification. The esterification reaction conditions are very mild and functional group-tolerated, such as hydrosilanes, alcohols, phenol, and amino acids. A mechanism is proposed in which the tertiary amine reacts with dimethyl but-2-ynedioate to form zwitterionic salt, and then the zwitterionic intermediate subsequently accept hydrogen to assist the nucleophilic attack of oxygen atom of carboxyl group at the benzyl group of tertiary amine, while a separate reaction pathway leads to esterification.
- Shen, Hao,Lu, Xing,Jiang, Ke-Zhi,Yang, Ke-Fang,Lu, Yixin,Zheng, Zhan-Jiang,Lai, Guo-Qiao,Xu, Li-Wen
-
supporting information
p. 8916 - 8923
(2012/10/29)
-
- NHCs-mediated benzoates formation directly from aromatic aldehydes and alkyl halides
-
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
-
experimental part
p. 3611 - 3615
(2012/06/15)
-
- N-heterocyclic carbene-catalyzed oxidative esterification reaction of aldehydes with alkyl halides under aerobic conditions
-
An efficient N-heterocyclic carbene-catalyzed oxidative esterification reaction of aldehydes with alkyl halides or alkyl 4-methylbenzenesulfonate is reported. It was worth noting that (1) the configuration of alkyl halides or alkyl 4-methylbenzenesulfonates was inverted completely, and (2) the presence of oxygen was crucial for this transformation. The reaction proceeded smoothly under mild conditions and various esters were afforded in moderate to good yields. In addition, we have developed an efficient tandem oxidation/ esterification reaction of alcohols. This methodology provides a rare example of a reaction of the Breslow intermediate to sp3-carbon centered electrophiles. An efficient oxidative esterification reaction of aldehydes with alkyl halides or alkyl 4-methylbenzenesulfonates catalyzed by N-heterocyclic carbenes is reported. Oxygenwas crucial for the reaction, and the configuration of alkyl 4-methylbenzenesulfonate was completely inverted. Copyright
- Xin, Yang-Chun,Shi, Shi-Hui,Xie, Dong-Dong,Hui, Xin-Ping,Xu, Peng-Fei
-
supporting information; experimental part
p. 6527 - 6531
(2011/12/22)
-