- Highly selective amidation of benzylic alcohols with nitriles. A modified ritter reaction
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Benzyl alcohols react selectively with different nitriles in the presence of a catalytic amount of boron trifluoride and produce amides in high yields. Deactivated p-nitrobenzyl, allylic, primary, secondary, and tertiary saturated alcohols do not react.
- Firouzabadi,Sardarian,Badparva
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- Rapid multiphase carbonylation reactions by using a microtube reactor: Applications in positron emission tomography 11C-radiolabeling
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Taking the tube: A silica-supported palladium catalyst packed into teflon tubing is a simple, low-cost, and effective method for carrying out carbonylative cross-coupling reactions of arylhalides with amines and radiolabeled carbon monoxide gas. In carbonylation reactions, the microtube reactor displays enhanced yields over a short time period (12 min) compared with batch methods. (Chemical Equation Presented).
- Miller, Philip W.,Long, Nicholas J.,De Mello, Andrew J.,Vilar, Ramon,Audrain, Helene,Bender, Dirk,Passchier, Jan,Gee, Antony
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- 2-Pyridon-1-yl Diphenyl Phosphate. A Useful New Reagent for the Synthesis of Amides and Peptides
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2-Pyridon-1-yl diphenyl phosphate is found to be a useful coupling agent for the synthesis of amides and practically racemization-free peptides.
- Kim, Sunggak,Kim, Sung Soo
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- High-load, oligomeric monoamine hydrochloride: facile generation via ROM polymerization and application as an electrophile scavenger
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A new high-load, oligomeric monoamine hydrochloride (OMAm·HCl) derived from ring-opening metathesis polymerization (ROMP) of norbornene methylamine is reported. This oligomeric amine has been shown to be an effective scavenger of acid chlorides, sulfonyl chlorides, and isocyanates. The reagent can be synthesized in a straightforward protocol from the Diels-Alder reaction of dicyclopentadiene (DCPD) 1 with allylamine (neat), formation of the corresponding ammonium salt and subsequent ROM polymerization to afford the desired oligomeric ammonium salts.
- Stoianova, Diana S.,Yao, Lei,Rolfe, Alan,Samarakoon, Thiwanka,Hanson, Paul R.
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- Reaction of nitrones with trimethylsilyiketene
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Trimethylsilylketene smoothly reacts with α,N-diarylnitrones to give oxindoles in good yields. On the other hand, the reaction of trimethylsilylketene with N-arylmethylnitrones gives a mixture of N,N- diacylamines and N-acylamines.
- Takaoka, Kiyo,Aoyama, Toyohiko,Shioiri, Takayuki
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- Ru(II)-Catalyzed C-H Activation: Amide-Directed 1,4-Addition of the Ortho C-H Bond to Maleimides
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Maleimide has been used as a selective coupling partner to generate conjugate addition products exclusively. The typical Heck-type oxidative coupling that occurs when alkenes are used is avoided by choosing maleimide as an alkene, which cannot undergo β-hydride elimination due to the unavailability of a syn-periplanar β-hydrogen atom. The amide nitrogen, which is notorious for undergoing tandem reactions to generate spirocyclic or annulation products under cross-coupling conditions, remains innocent in this report. Along with the substrate scope, a robustness screen has been performed to analyze the performance of amide as a directing group in the presence of other directing groups and also to examine the tolerance of the reaction conditions for other frequently encountered functional groups.
- Keshri, Puspam,Bettadapur, Kiran R.,Lanke, Veeranjaneyulu,Prabhu, Kandikere Ramaiah
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- Photocatalytic Generation of Nitrenes for Rapid Diaziridination
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A blue LED, an organic photocatalyst (rose bengal), and the Lewis acid like oxidant PhI(OAc)2 were utilized to generate nitrene intermediates through reactions of 1,2-diols and aliphatic amines under mild reaction conditions. A versatile and rapid diaziridination strategy was established to construct functionalized 1,2-disubstituted diaziridines, diaziridines with chiral substituents, and 1,2,3-trisubstituted analogues with excellent reaction rates, yields, and stereoselectivities. Control and labeling experiments to elucidate the mechanism of this elegant metal-free photocatalyzed cyclization reaction were performed.
- Mondal, Ramij R.,Khamarui, Saikat,Maiti, Dilip K.
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- In situ synthesis of metallophthalocyanines into pores of MIL-101: A novel and green strategy for preparation of host–guest catalysts
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A novel strategy is developed to encapsulate metallophthalocyanines (MPcs, M?=?Cu, Ni and Co) into MIL-101 to give MPcs@MIL-101 via in situ synthesis of MPcs from component fragments in 1-butyl-3-methylimidazolium bromide as an ionic liquid. This strategy overcomes some drawbacks of existing methods for encapsulation of MPcs into metal–organic frameworks. The chemical and structural properties of MPcs@MIL-101 were determined using scanning electron microscopy, powder X-ray diffraction, and Fourier transformation infrared and flame atomic absorption spectroscopies. The results showed that CuPc@MIL-101, which was used as a ‘ship-in-a-bottle’ catalyst, demonstrates excellent catalytic performance in the oxidative amidation of aldehydes with amine salts. It is confirmed that CuPc@MIL-101 can be reused up to five times without significant loss of its activity.
- Boroujeni, Mahmoud Borjian,Hashemzadeh, Alireza,Shaabani, Ahmad,Amini, Mostafa M.
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- Rapid carbonylative coupling reactions using palladium(i) dimers: Applications to 11CO-radiolabelling for the synthesis of PET tracers
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Palladium dimers with sterically hindered phosphines have been shown to be excellent pre-catalysts for the aminocarbonylation of aryl halides to yield amides and one of them has been successfully employed as a pre-catalyst for the synthesis of 11C-radiolabelled amides for PET imaging.
- Buscemi, Gabriella,Miller, Philip W.,Kealey, Steven,Gee, Antony D.,Long, Nicholas J.,Passchier, Jan,Vilar, Ramon
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- Application of thio-Ugi adducts for the preparation of benzo[ b ]thiophene and S-heterocycle library via copper catalyzed intramolecular C-S bond formation
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Fused heterocycles, such as benzo[b]thiophene, thiochroman, benzo[b][1,4]thiazine, and 1,4-benzothiazepine were generated from thio-Ugi adducts containing a thioamide group through copper-catalyzed intramolecular C-S bond formation under microwave irradiation.
- Kim, Yong-Sang,Kwak, Se Hun,Gong, Young-Dae
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- Kinetics of the Reactions of Phenylchlorocarbene with Alkyl Azides
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The reactions of phenylchlorocarbene with several alkyl azides lead to C-chloroimines (and derived N-alkylbenzamides) with absolute rate constants of ca. 1-4 x 107 M-1 s-1.
- Moss, Robert A.,Jang, Eun G.,Krogh-Jespersen, Karsten
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- Polyethylene glycol as a recyclable reaction medium for gold-catalysed direct oxidative amide synthesis from aldehydes and amines
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Polyethylene glycol (PEG) was used as the recyclable reaction medium for gold-catalysed oxidative amidation of aldehydes with amines by using tert-butyl hydroperoxide (TBHP, 70% aqueous) as the oxidant. The reaction proceeded efficiently to provide the corresponding products in moderate to good yields under mild conditions. Both the catalysts and solvent can be easily recovered and reused by simple extraction without significant loss of activity.
- Jiang, Hui-Liang,Zhao, Jie
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- A Versatile Approach to Dynamic Amide Bond Formation with Imine Nucleophiles
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Dynamic covalent chemistry has rapidly become an important approach to access supramolecular structures. While the products generated in these reactions are held together by covalent bonds, the reversible nature of the transformations can limit the utility of many these systems in creating robust materials. We describe herein a method to form stable and commonly employed amide bonds by exploiting the reversible coupling of imines and acyl chlorides. The reaction employs easily accessible reagents, is dynamic under ambient conditions, without catalysts, and can be trapped with simple hydrolysis. This offers an approach to create broad families of amide products under thermodynamic control, including the selective formation of amide macrocycles or polymers.
- Arndtsen, Bruce A.,Erguven, Huseyin,Keyzer, Evan N.
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- Selective N-Monoalkylation of Amide Derivatives with Trialkyl Phosphates
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A highly selective and easily handled monoalkylation of primary amide derivatives by using trialkyl phosphates as alkylating reagents in cyclopentyl methyl ether (CPME) was developed. Various monoalkylated amide derivatives were efficiently synthesized by changing the alkyl moiety (e.g., methyl, ethyl, butyl, or benzyl) of the trialkyl phosphate. These phosphate reagents are relatively stable and easily available, and CPME is a useful solvent in process chemistry.
- Asai, Shota,Ban, Kazuho,Monguchi, Yasunari,Sajiki, Hironao,Sawama, Yoshinari
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- Aminolysis of esters or lactones promoted by NaHMDS-A general and efficient method for the preparation of N-aryl amides
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An efficient method for the preparation of N-aryl amides from anilines, esters or lactones promoted by NaHMDS is described. Advantages of this new method include high yields and mild reaction conditions which tolerate functional groups such as ketones and halides.
- Wang,Rosingana,Discordia,Soundararajan,Polniaszek
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- A convenient photocatalytic fluorination of unactivated C-H bonds
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Fluorination reactions are essential to modern medicinal chemistry, thus providing a means to block site-selective metabolic degradation of drugs and access radiotracers for positron emission tomography imaging. Despite current sophistication in fluorination reagents and processes, the fluorination of unactivated C-H bonds remains a significant challenge. Reported herein is a convenient and economic process for direct fluorination of unactivated C-H bonds that exploits the hydrogen abstracting ability of a decatungstate photocatalyst in combination with the mild fluorine atom transfer reagent N-fluorobenzenesulfonimide. This operationally straightforward reaction provides direct access to a wide range of fluorinated organic molecules, including structurally complex natural products, acyl fluorides, and fluorinated amino acid derivatives. The direct fluorination of unactivated C(sp3)-H bonds is catalyzed by the inexpensive photocatalyst tetrabutylammonium decatungstate (TBADT). This convenient reaction provides direct access to a wide range of fluorinated organic molecules, including structurally complex natural products, acyl fluorides, and fluorinated amino acids.
- Halperin, Shira D.,Fan, Hope,Chang, Stanley,Martin, Rainer E.,Britton, Robert
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- Gas-liquid segmented flow microfluidics for screening Pd-catalyzed carbonylation reactions
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Go with the (segmented) flow: A gas-liquid microfluidic reactor system has been developed to study Pd-catalyzed carbonylation reactions over a range of flow regimes and reaction conditions (see picture). The segmented gas-liquid flow regime, in comparison to annular flow, enables reactions to be studied over longer reaction times and without the buildup of unwanted Pd particles. Copyright
- Gong, Xiuqing,Miller, Philip W.,Gee, Antony D.,Long, Nicholas J.,De Mello, Andrew J.,Vilar, Ramon
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- Synthesis of Benzamide Derivatives by the Reaction of Arenes and Isocyanides through a C-H Bond Activation Strategy
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A carbon-carbon bond formation reaction between isocyanides and benzene derivatives is reported. In contrast to traditional cross-coupling reactions, which require aryl halides or pseudohalides, we use a palladium catalyst to generate the aryl-palladium through C-H bond activation of arenes. This method offers an attractive approach to a range of benzamides from readily accessible benzene derivatives.
- Khalaj, Mehdi,Taherkhani, Mahboubeh,Mousavi-Safavi, Seyed Mahmoud,Akbari, Jafar
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- Titration of alkyllithiums with a simple reagent to a blue endpoint
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Reaction of readily available N-benzylbenzamide (1) with a slight excess of BuLi produces a deep blue dianion. Under suitable conditions (THF, -40°C), 1 may be used as a stoichiometric reagent to titrate n-BuLi, s-BuLi, and t-BuLi with good precision. Less reactive alkyllithiums (MeLi and MeLi · LiBr), aryllithiums, and LDA may be titrated at higher temperatures (-20 to 0°C). Titres are comparable to those obtained using the Gilman double titration method, and there appears to be no interference from alkoxides.
- Burchat, Andrew F.,Chong, J. Michael,Nielsen, Nathan
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- A microfluidic approach to the rapid screening of palladium-catalysed aminocarbonylation reactions
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The evaluation and selection of the most appropriate catalyst for a chemical transformation is an important process in many areas of synthetic chemistry. Conventional catalyst screening involving batch reactor systems can be both time-consuming and expensive, resulting in a large number of individual chemical reactions. Continuous flow microfluidic reactors are increasingly viewed as a powerful alternative format for reacting and processing larger numbers of small-scale reactions in a rapid, more controlled and safer fashion. In this study we demonstrate the use of a planar glass microfluidic reactor for performing the three-component palladium-catalysed aminocarbonylation reaction of iodobenzene, benzylamine and carbon monoxide to form N-benzylbenzamide, and screen a series of palladium catalysts over a range of temperatures. N-Benzylbenzamide product yields for this reaction were found to be highly dependent on the nature of the catalyst and reaction temperature. The majority of catalysts gave good to high yields under typical flow conditions at high temperatures (150°C), however the palladium(II) chloride-Xantphos complex [PdCl2 (Xantphos)] proved to be far superior as a catalyst at lower temperatures (75-120°C). The utilised method was found to be an efficent and reliable way for screening a large number of palladium-catalysed carbonylation reactions and may prove useful in screening other gas/liquid phase reactions.
- Miller, Philip W.,Jennings, Lucy E.,DeMello, Andrew J.,Gee, Antony D.,Long, Nicholas J.,Vilar, Ramon
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- A solid-supported arylboronic acid catalyst for direct amidation
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An efficient heterogeneous amidation catalyst has been prepared by co-polymerisation of styrene, DVB with 4-styreneboronic acid, which shows wide substrate applicability and higher reactivity than the equivalent homogeneous phenylboronic acid, suggesting potential cooperative catalytic effects. The catalyst can be easily recovered and reused; suitable for use in packed bed flow reactors.
- Du, Yihao,Barber, Thomas,Lim, Sol Ee,Rzepa, Henry S.,Baxendale, Ian R.,Whiting, Andrew
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- BENZOTRIAZOL-1-YL DIETHYL PHOSPHATE. A NEW CONVENIENT COUPLING REAGENT FOR THE SYNTHESIS OF AMIDES AND PEPTIDES.
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Benzotriazol-1-yl diethyl phosphate is found to be a new convenient coupling reagent for the synthesis of amides and practically racemization-free peptides.
- Kim, Sunggak,Chang, Heung,Ko, Young Kwan
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- An open-source approach to automation in organic synthesis: The flow chemical formation of benzamides using an inline liquid-liquid extraction system and a homemade 3-axis autosampling/product-collection device
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Several open-source hardware and software technologies (RAMPS, Python, PySerial, OpenCV) were used to control an automated flow chemical synthesis system. The system was used to effect the synthesis of a series of benzamides. An inexpensive Raspberry Pi single board computer provided an electronic interface between the control computer and the RAMPS motor driver boards.
- O'Brien, Matthew,Hall, April,Schrauwen, John,van der Made, Joyce
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- A novel approach for the one-pot preparation of α-amino amides by pd-catalyzed double carbohydroamination
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A new domino reaction sequence, a palladium-catalyzed double carbohydroamination, which involves double carbonylation, amine condensation, and hydrogenation from an aryl iodide(1), a primary amine (2), and synthetic gas has been realized as a novel synthetic means for the one-pot synthesis of α-amino amides (3).
- Lin, Yong-Shou,Alper, Howard
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- Cleavage of 1,3-dicarbonyls through oxidative amidation
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A mild and convenient protocol for the oxidative cleavage of 1,3-diketone compounds is described. Under metal-free conditions, the method converts the 1,3-dicarbonyls into amides when treated with (nBu4N)N3 and iodine in the presence of an amine at room temperature. Using this method, a range of 1,3-dicarbonyls with various structural motifs including sterically demanding substituents and ordinary functional groups were easily fragmented, and it is demonstrated that cyclic 1,3-dicarbonyls can be directly transformed into acyclic diamides through ring-opening. Initial mechanistic studies show that diazidation of the enol form is followed by nucleophilic substitution with the amine.
- Biallas, Phillip,H?ring, Andreas P.,Kirsch, Stefan F.
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- Direct, rapid, solvent-free conversion of unactivated esters to amides using lithium hydroxide as a catalyst
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A simple, solvent-free methodology is reported for the direct conversion of esters to amides using lithium hydroxide as a catalyst. The approach allows for the preparation of a range of amide products as well as being applicable to the ring-opening of a representative lactone.
- Miller, Shelli A.,Leadbeater, Nicholas E.
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- Metal-free synthesis of amides by oxidative amidation of aldehydes with amines in PEG/oxidant system
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A simple, inexpensive, and efficient one-pot synthesis of amide derivatives were achieved in good to excellent yields via the directly oxidative amidation of aldehydes with amines under PEG/Oxidant system.
- Liang, Jun,Lv, Jing,Shang, Zhi-Cai
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- Iodide-catalyzed amide synthesis from alcohols and amines
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An efficient method to prepare amides by a cascade strategy was developed. Using nBu4NI or NaI as the catalyst and tert-butyl hydroperoxide as the oxidant, various alcohols reacted with N-hydroxysuccinimide or N-hydroxyphthalimide affording corresponding active esters in moderate to good yield. The resulting active esters were converted into amides smoothly in one pot. The Royal Society of Chemistry 2013.
- Wang, Gao,Yu, Qing-Ying,Wang, Jian,Wang, Shan,Chen, Shan-Yong,Yu, Xiao-Qi
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- Microwave effects in solvent-free esters aminolysis
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Solvent-free ester aminolysis was studied under microwave or conventional heating either in the absence of base or induced by KOtBu with or without a phase transfer agent. The specific microwave effects were shown to be dependent on the conditions and discussed in terms of relative polarities of ground and transition states.
- Perreux, Laurence,Loupy, André,Delmotte, Michel
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- Cobalt(III)-Catalyzed Directed C-H Allylation
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The cobalt(III)-catalyzed allylation was developed for amide-directed C-H activation of arenes, heteroarenes, and olefins. A variety of allyl sources can be employed to introduce this useful functional group.
- Gensch, Tobias,Vásquez-Céspedes, Suhelen,Yu, Da-Gang,Glorius, Frank
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- Synthesis of 2-Amino-4-pyrimidinones from Resin-Bound Guanidines Prepared Using Bis(allyloxycarbonyl)-Protected Triflylguanidine
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We have synthesized novel heterocyclic compounds from resin-bound guanidines. For this purpose, an amine immobilized on a solid support was acylated with protected amino acids. Following the deprotection, the liberated amines were guanidinylated utilizing a new member of the family of diurethane-protected triflyl guanidine reagents, N,N′ -bis(allyloxycarbonyl)-N′-triflylguanidine. The deprotected guanidines were subsequently regioselectively cyclized with β-keto esters yielding novel compounds containing heterocyclic structures in high purities.
- Zapf, Christoph W.,Goodman, Murray
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- Synthesis of Secondary Aromatic Amides via Pd-Catalyzed Aminocarbonylation of Aryl Halides Using Carbamoylsilane as an Amide Source
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Using N-methoxymethyl-N-organylcarbamoyl(trimethyl)silanes as secondary amides source, the direct transformation of aryl halides into the corresponding secondary aromatic amides via palladium-catalyzed aminocarbonylation is described. The reactions tolerated a broad range of functional groups on the aryl ring except big steric hindrance of substituent. The types and the relative position of substituents on the aryl ring impact the coupling efficiency.
- Tong, Wenting,Cao, Pei,Liu, Yanhong,Chen, Jianxin
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- N-linked hydroxylamine resin: Solid-phase synthesis of hydroxamic acids
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A novel hydroxylamine resin for solid-phase synthesis of hydroxamic acids is described. Its facile application is illustrated by the solid-phase synthesis of various hydroxamic acids. Cleavage is induced under acidic conditions by treatment with trifluoroacetic acid, providing hydroxamic acids in high purity and good yields. Copyright Taylor & Francis, Inc.
- Yin, Zheng,Low, KaySiang,Lye, PekLing
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- Reaction of fluoro(phenyl)carbene with Schiff bases: Synthesis of 2-fluoro-2-phenylaziridines
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Fluoro(phenyl)carbene generated by reaction of α-bromo-α- fluorotoluene with potassium tert-butoxide reacts with Schiff bases to afford the corresponding 2-fluoro-2-phenylaziridines. The latter were isolated in low yields due to their instability under the carbene generation conditions. Although the reaction of α,α-dibromo-α-fluorotoluene with zinc and lead involves formation of fluoro(phenyl)carbene, this procedure is not suitable for the synthesis of 2-fluoro-2-phenylaziridines. 2005 Pleiades Publishing, Inc.
- Kusei,Novikov,Khlebnikov
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- Oxidations and oxidative couplings catalyzed by triazolylidene ruthenium complexes
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A series of "RuII(η6-arene)" complexes with 1,2,3-triazolylidene ligands have been prepared and fully characterized. The molecular structure of one of the new complexes has been determined by means of X-ray diffractrometry. The new complexes have been tested in a set of catalytic reactions involving alcohols and amines as substrates, including (i) base-free oxidation of benzylic alcohols to benzaldehydes, (ii) homocoupling of amines to form imines, and (iii) oxidative coupling of amines and alcohols to form amides. The results show the high versatility of the catalysts used and illustrate the application potential of 1,2,3-triazolylidene ligands in the design of effective homogeneous catalysts.
- Prades, Amparo,Peris, Eduardo,Albrecht, Martin
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- Computationally motivated synthesis and enzyme kinetic evaluation of N-(β-d-glucopyranosyl)-1,2,4-triazolecarboxamides as glycogen phosphorylase inhibitors
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Following our recent study of N-(β-d-glucopyranosyl)oxadiazolecarboxamides (Polyk et al., Biorg. Med. Chem. 2013, 21, 5738) revealed as moderate inhibitors of glycogen phosphorylase (GP), in silico docking calculations using Glide have been performed on N-(β-d-glucopyranosyl)-1,2,4-triazolecarboxamides with different aryl substituents predicting more favorable binding at GP. The ligands were subsequently synthesized in moderate yields using N-(2,3,4,6-tetra-O-acetyl-β-D-glucopyranosyl)-tetrazole-5-carboxamide as starting material. Kinetics experiments against rabbit muscle glycogen phosphorylase b (RMGPb) revealed the ligands to be low μM GP inhibitors; the phenyl analogue (Ki = 1 μM) is one of the most potent N-(β-d-glucopyranosyl)-heteroaryl-carboxamide-type inhibitors of the GP catalytic site discovered to date. Based on QM and QM/MM calculations, the potency of the ligands is predicted to arise from favorable intra- and intermolecular hydrogen bonds formed by the most stable solution phase tautomeric (t2) state of the 1,2,4-triazole in a conformationally dynamic system. ADMET property predictions revealed the compounds to have promising pharmacokinetic properties without any toxicity. This study highlights the benefits of a computationally led approach to GP inhibitor design. This journal is
- Begum, Jaida,Varga, Gergely,Docsa, Tibor,Gergely, Pl,Hayes, Joseph M.,Juhsz, Lszl,Somsk, Lszl
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- N-heterocyclic carbenes as ligands in palladium-mediated [ 11C]radiolabelling of [11C]amides for positron emission tomography
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A model palladium-mediated carbonylation reaction synthesizing N-benzylbenzamide from iodobenzene and benzylamine was used to investigate the potential of four N-heterocyclic carbenes (N,N′-bis(diisopropylphenyl)-4, 5-dihydroimidazolinium chloride (I), N,N′-bis(1-mesityl)-4,5- dihydroimidazolinium chloride (II), N,N′-bis(1-mesityl)imidazolium chloride (III) and N,N′-bis(1-adamantyl)imidazolium chloride (IV)) to act as supporting ligands in combination with Pd2(dba)3. Their activities were compared with other Pd-diphosphine complexes after reaction times of 10 and 120 min. Pd2(dba)3 and III were the best performing after 10 min reaction (20%) and was used to synthesize radiolabelled [11C]N-benzylbenzamide in good radiochemical yield (55%) and excellent radiochemical purity (99%). A Cu(Tp*) complex was used to trap the typically unreactive and insoluble [11C]CO which was then released and reacted via the Pd-mediated carbonylation process. Potentially useful side products [11C]N,N′-dibenzylurea and [ 11C]benzoic acid were also observed. Increased amounts of [ 11C]N,N′-dibenzylurea were yielded when PdCl2 was the Pd precursor. Reduced yields of [11C]benzoic acid and therefore improved RCP were seen for III/Pd2(dba)3 over commonly used dppp/Pd2(dba)3 making it more favourable in this case. Copyright
- Jennings, Lucy E.,Kealey, Steven,Miller, Philip W.,Gee, Antony D.,Long, Nicholas J.
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- Tetrathiafulvalene as a trigger for sequential radical translocation and functionalisation
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Aryl diazonium salts react with tetrathiafulvalene to generate aryl radicals which undergo intramolecular hydrogen atom abstractions; the radicals which result lead to (a) oxidised product or (b) undergo an unprecedented carbon-carbon bond formation with the radical-cation of tetrathiafulvalene.
- Begley, Michael J.,Murphy, John A.,Roome, Stephen J.
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- Continuous flow reaction system for the synthesis of 2,2,2-trichloroacetophenone derivatives and its application
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A continuous flow reaction system was developed for the synthesis of 2,2,2-trichloroacetophenone derivatives. When aryl propiolic acids and water were mixed with trichloroisocyanuric acid in DMF at 5 °C, the 2,2,2-trichloroacetophenone derivatives were formed within 5 min with good yields. In addition, the resulting mixture was flowed to react with amines to give the corresponding benzamide. This flow reaction system provided higher yields within shorter times than the batch reaction system.
- Ko, Byeng Ha,Yu, Subeen,Song, Kwang Ho,Lee, Sunwoo
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- Resolution of racemic amines via lipase-catalyzed benzoylation: Chemoenzymatic synthesis of the pharmacologically active isomers of labetalol
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Lipase-catalyzed benzoylation of amines was shown to be feasible, in some cases with high enantioselectivity, and the best results were obtained using immobilized lipase from Candida antarctica (Novozym 435) and methyl benzoate as acyl donor in the presence of molecular sieves. The procedure was optimized for the resolution of (±)-1-methyl-3-phenylpropylamine, a key intermediate in the synthesis of antihypertensive drug labetalol, and the enantiopure (R)-benzamide was then converted into the pharmacologically active isomers of the drug. In comparison with the reported synthesis of chiral isomers of labetalol, this chemoenzymatic route offers the advantage in the lack of any chiral stoichiometric auxiliary.
- Sanfilippo, Claudia,Paternò, Alfio Adriano,Patti, Angela
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- Ligand preferences in ytterbium ions complexation with carboxylate-based metal-organic frameworks
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Two coordination polymers of ytterbium were synthesized by employing 4,4′,4″-s-triazine-2,4,6-triyl-tribenzoic acid (H3TATB), 4,4′,4-benzene-1,3,5-triyl-tribenzoic acid (H3BTB), and 3,5-pyridinedicarboxylic acid (3,5-PDC) ligands and were characterized by single-crystal X-ray diffraction analysis. Reaction of ytterbium(III) chloride in the presence of H3BTB and 3,5-PDC ligands gives preferred complexation with the 3,5-PDC ligand, producing [Yb2(3,5-PDC)(ClO4)3][NH(Me)3] (1). However, under exactly the same reaction conditions, reaction of ytterbium(III) chloride in the presence of 3,5-PDC and H3TATB resulted in complexation with H3TATB to form [(CH3)2NH2][Yb4(TATB)4(HCO2)(H2O)2]·3H2O (2). The crystal structure results showed a layered structure for 1 and a metal-organic framework structure for 2. This indicates that the complexation preference of the ytterbium ion is H3TATB?≥?3,5-PDC?≥?H3BTB. Conversely, the uncomplexed ligand in the metal-organic framework (2) is an auxiliary agent during the synthesis, which shows polytopic linker controls crystal properties, to form suitable crystals for single-crystal structure determination. The prepared coordination compounds were used as heterogeneous catalysts in an oxidation amidation reaction with different aldehydes and benzylamine hydrochloride.
- Hashemzadeh, Alireza,Amini, Mostafa M.,Khavasi, Hamid Reza,Ng, Seik Weng
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- To catalyze or not to catalyze? Insight into direct amide bond formation from amines and carboxylic acids under thermal and catalyzed conditions
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Kinetic studies show that the direct formation of amides from amines and carboxylic acids without catalyst does occur under relatively low temperature conditions, but is highly substrate dependent. Boric and boronic acid-based catalysts improve the reacti
- Arnold, Kenny,Davies, Bryan,Giles, Richard L.,Grosjean, Christophe,Smith, Gillian E.,Whiting, Andrew
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- Generation of Oxyphosphonium Ions by Photoredox/Cobaloxime Catalysis for Scalable Amide and Peptide Synthesis in Batch and Continuous-Flow
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Phosphine-mediated deoxygenative nucleophilic substitutions, such as the Mitsunobu reaction, are of great importance in organic synthesis. However, the conventional protocols require stoichiometric oxidants to trigger the formation of the oxyphosphonium i
- Chen, Xiangyang,Houk, Kendall N.,Mo, Jia-Nan,Su, Junqi,Umanzor, Alexander,Zhang, Zheng,Zhao, Jiannan
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supporting information
(2022/01/06)
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- TBAI-catalyzed C–N bond formation through oxidative coupling of benzyl bromides with amines: a new avenue to the synthesis of amides
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A new green approach for the synthesis of amide through TBAI-catalyzed oxidative coupling of benzyl bromides with amine was developed in the presence of tert-butyl hydroperoxide (TBHP) as an oxidant. Various electron-donating and withdrawing groups containing benzyl bromides and various amines, were subjected to the reaction and transformed to the corresponding amide in good to excellent yields.
- Kumar, Dhirendra,Maury, Suresh Kumar,Kumari, Savita,Kamal, Arsala,Singh, Himanshu Kumar,Singh, Sundaram,Srivastava, Vandana
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supporting information
p. 424 - 432
(2022/02/09)
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- Chemoselective Cleavage of Acylsulfonamides and Sulfonamides by Aluminum Halides
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The chemoselective cleavage of C-N bonds of amides, sulfonamides, and acylsulfonamides by aluminum halides is described. AlCl3and AlI3display complementary reactivities toward N-alkyl and N-acyl moieties. N-Alkylacylsulfonamides, sec
- Sang, Dayong,Dong, Bingqian,Liu, Yunfeng,Tian, Juan
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p. 3586 - 3595
(2022/02/25)
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- Photocatalysis in Aqueous Micellar Media Enables Divergent C-H Arylation and N-Dealkylation of Benzamides
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Photocatalysis in aqueous micellar media has recently opened wide avenues to activate strong carbon-halide bonds. So far, however, it has mainly explored strongly reducing conditions, restricting the available chemical space to radical or anionic reactivity. Here, we demonstrate a controllable, photocatalytic strategy that channels the reaction of chlorinated benzamides via either a radical or a cationic pathway, enabling a chemodivergent C-H arylation or N-dealkylation. The catalytic system operates under mild conditions with methylene blue as a photocatalyst and blue LEDs as the light source. Factors determining the reactivity of substrates, their selectivity, and preliminary mechanistic studies are presented.
- Cybularczyk-Cecotka, Martyna,Predygier, J?drzej,Crespi, Stefano,Szczepanik, Joanna,Giedyk, MacIej
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p. 3543 - 3549
(2022/03/27)
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- TETRADENTATE DIAMINODIPHOSPHINE LIGAND AND TRANSITION METAL COMPLEX, AND METHOD FOR MANUFACTURING SAME AND APPLICATION FOR SAME
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The present invention relates to a transition metal complex having a PNNP4 ligand, which is easy to manufacture and handle and is relatively inexpensively available, and a method for manufacturing the same, as well as a method using this transition metal complex as a catalyst for hydrogenation reduction of ketones, esters and amides to manufacture corresponding alcohols, aldehydes, hemiacetals and hemiaminals, a method using this transition metal complex as a catalyst for oxidation of alcohols, hemiacetals and hemiaminals to manufacture corresponding carbonyl compounds, and a method using this transition metal complex as a catalyst for dehydrogenation condensation between alcohols and amines to manufacture alkylamines.
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- Reductive N-alkylation of primary amides using nickel-nanoparticles
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Here we report Ni-nanoparticles as reusable catalysts for reductive N-alkylation of amides. These Ni-nanoparticles based catalysts have been prepared by the template synthesis of tartaric acid and 2-methyl imidazole ligated Ni-complex on SiO2 and subsequent pyrolysis under argon. Applying optimal Ni-nanostructured catalyst, N-alkylation of aromatic and heterocyclic primary amides with different aldehydes in presence of molecular hydrogen was performed to access structurally diverse N-alkylated amides in good to excellent yields. In addition, the applicability of this N-alkylation protocol has been demonstrated for the selective functionalization of primary amide group in Levetiracetam drug.
- Alenad, Asma M.,Alshammari, Ahmad S.,Jagadeesh, Rajenahally V.,Murugesan, Kathiravan,Sohail, Manzar
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- Br?nsted Acid Mediated Nucleophilic Functionalization of Amides through Stable Amide C?N Bond Cleavage; One-Step Synthesis of 2-Substituted Benzothiazoles
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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
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supporting information
p. 3569 - 3572
(2021/07/22)
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- Atom Transfer Radical Polymerization-Inspired Room Temperature (sp3)C-N Coupling
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A simple nonphotochemical procedure is reported for Cu(I)-catalyzed C-N coupling of aliphatic halides with amines and amides. The process is loosely based on the Goldberg reaction but takes place readily at room temperature. It uses Cu(I)Br, a commonly used and inexpensive atom transfer radical polymerization precatalyst, along with the cheap ligand N,N,N′,N″,N″-pentamethyldiethylenetriamine, to activate the R-X bond of the substrate via inner-sphere electron transfer. The procedure brings about productive C-N bond formation between a range of alkyl halide substrates with heterocyclic aromatic amines and amides. The mechanism of the coupling step, which was elucidated through application of computational methods, proceeds via a unique Cu(I) → Cu(II) → Cu(III) → Cu(I) catalytic cycle, involving (a) inner-sphere electron transfer from Cu(I) to the alkyl halide to generate the alkyl radical; (b) successive coordination of the N-nucleophile and the radical to Cu(II); and finally reductive elimination. In the absence of a nucleophile, debrominative homocoupling of the alkyl halide occurs. Control experiments rule out SN-type mechanisms for C-N bond formation.
- Coote, Michelle L.,Fung, Alfred. K. K.,Sherburn, Michael S.,Yu, Li-Juan
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p. 9723 - 9732
(2021/07/20)
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- Crystal structure of 1-(2,4,6-trichlorobenzoyloxy) benzotriazole (TCB-OBt): observation of uncommon intermolecular oxygen-oxygen interaction and synthetic application in amidation
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Herein, we investigated the supramolecular assembly of a modified Yamaguchi reagent TCB-OBt. Interestingly, each molecule is interconnected through novel chalcogen-chalcogen (O?O) interaction, π-π stacking, and aromatic C-H?O interaction. Hirshfeld surface analysis confirmed the existence of uncommon O?O interactions. A well-organized supramolecular layer structure and helical arrangement were observed in the crystal structure. TCB-OBt crystallized in the O-substituted desmotropic form. DFT calculations suggest that the O-substituted form is more stable than theN-substituted form (TCB-(N)-OBt). Morphology analysis indicates the formation of a fantastically well organized, continuous block-shaped system. Furthermore, the designed reagent works as an efficient activating reagent for amide bond formation with good yields under mild reaction conditions. Use of this reagent avoided intractable acid chlorides, and this new mixed-anhydride-based reagent may further be applicable for many other organic transformations.
- Dolai, Gobinda,Giri, Rajat Subhra,Mandal, Bhubaneswar,Roy, Sayanta,Sen, Srijit
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p. 19804 - 19811
(2021/11/12)
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- Radical-Mediated Activation of Esters with a Copper/Selectfluor System: Synthesis of Bulky Amides and Peptides
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Herein, we describe a new approach for the activation of esters via a radical-mediated process enabled by a copper/Selectfluor system. A variety of para-methoxybenzyl esters derived from bulky carboxylic acids and amino acids can be easily converted into the corresponding acyl fluorides, directly used in the one-pot synthesis of amides and peptides. As a proof of concept, this method was applied to the iterative formation of sterically hindered amide bonds.
- Matsumoto, Akira,Wang, Zhe,Maruoka, Keiji
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p. 5401 - 5411
(2021/04/12)
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- A practical and sustainable protocol for direct amidation of unactivated esters under transition-metal-free and solvent-free conditions
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In this paper, a NaOtBu-mediated synthesis approach was developed for direct amidation of unactivated esters with amines under transition-metal-free and solvent-free conditions, affording a series of amides in good to excellent yields at room temperature. In particular, an environmentally friendly and practical workup procedure, which circumvents the use of organic solvents and chromatography in most cases, was disclosed. Moreover, the gram-scale production of representative products3a,3wand3auwas efficiently realized by applying operationally simple, sustainable and practical procedures. Furthermore, this approach was also applicable to the synthesis of valuable molecules such as moclobemide (a powerful antidepressant), benodanil and fenfuram (two commercial agricultural fungicides). These results demonstrate that this protocol has the potential to streamline amide synthesis in industry. Meanwhile, quantitative green metrics of all the target products were evaluated, implying that the present protocol is advantageous over the reported ones in terms of environmental friendliness and sustainability. Finally, additional experiments and computational calculations were carried out to elucidate the mechanistic insight of this transformation, and one plausible mechanism was provided on the basis of these results and the related literature reports.
- Chen, Cheng,Cheng, Hua,Du, Min-Chen,Qian, Liang,Qin, Xin,Sang, Wei,Yao, Wei-Zhong,Yuan, Ye,Zhang, Rui
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supporting information
p. 3972 - 3982
(2021/06/17)
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- Manganese Catalyzed Direct Amidation of Esters with Amines
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The transition metal catalyzed amide bond forming reaction of esters with amines has been developed as an advanced approach for overcoming the shortcomings of traditional methods. The broad scope of substrates in transition metal catalyzed amidations remains a challenge. Here, a manganese(I)-catalyzed method for the direct synthesis of amides from a various number of esters and amines is reported with unprecedented substrate scope using a low catalyst loading. A wide range of aromatic, aliphatic, and heterocyclic esters, even in fatty acid esters, reacted with a diverse range of primary aryl amines, primary alkyl amines, and secondary alkyl amines to form amides. It is noteworthy that this approach provides the first example of the transition metal catalyzed amide bond forming reaction from fatty acid esters and amines. The acid-base mechanism for the manganese(I)-catalyzed direct amidation of esters with amines was elucidated by DFT calculations.
- Fu, Zhengqiang,Wang, Xinghua,Tao, Sheng,Bu, Qingqing,Wei, Donghui,Liu, Ning
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supporting information
p. 2339 - 2358
(2021/02/03)
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- Zirconium Oxide-Catalyzed Direct Amidation of Unactivated Esters under Continuous-Flow Conditions
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A sustainable and environmentally benign direct amidation reaction of unactivated esters with amines has been developed in a continuous-flow system. A commercially available amorphous zirconium oxide was found to be an efficient catalyst for this reaction. While the typical amidation of esters with amines requires a stoichiometric amount of a promoter or metal activator, the present continuous-flow method enabled the direct amidation reaction under additive-free conditions with an extensive diversity towards various functional groups. High yields of the products were obtained with a nearly equimolar proportion of starting materials to reduce byproduct formation, which renders this process applicable for use in a sequential-flow system. (Figure presented.).
- Rashed, Md. Nurnobi,Masuda, Koichiro,Ichitsuka, Tomohiro,Koumura, Nagatoshi,Sato, Kazuhiko,Kobayashi, Shū
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p. 2529 - 2535
(2021/02/01)
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- 6-Halo-2-pyridone as an efficient organocatalyst for ester aminolysis
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It was found that 6-halo-2-pyridones catalysed ester aminolysis in which not only reactive aryl esters but also relatively less reactive methyl and benzyl esters could be used as a substrate. The reaction could be performed without strictly dry and anaerobic conditions and the 6-chloro-2-pyridone catalyst could be recovered quantitatively after reaction. The method could be applied to dipeptide synthesis from methyl or benzyl esters of amino acids, where a high enantiomeric purity of the products was maintained. The mechanism involving dual activation of ester and amine substrates through hydrogen bonding between catalyst and substrates is proposed where 6-halo-2-pyridones act as a bifunctional Br?nsted acid/base catalyst.
- Okamoto, Sentaro,Watanabe, Yusuke,Yamada, Takeshi
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p. 24588 - 24593
(2021/07/29)
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- Ammonia-borane as a Catalyst for the Direct Amidation of Carboxylic Acids
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Ammonia-borane serves as an efficient substoichiometric (10%) precatalyst for the direct amidation of both aromatic and aliphatic carboxylic acids. In situ generation of amine-boranes precedes the amidation and, unlike the amidation with stoichiometric amine-boranes, this process is facile with 1 equiv of the acid. This methodology has high functional group tolerance and chromatography-free purification but is not amenable for esterification. The latter feature has been exploited to prepare hydroxyl- and thiol-containing amides.
- Ramachandran, P. Veeraraghavan,Hamann, Henry J.
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supporting information
p. 2938 - 2942
(2021/05/04)
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- Efficient and accessible silane-mediated direct amide coupling of carboxylic acids and amines
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A straightforward method for the direct synthesis of amides from amines and carboxylic acids without exclusion of air or moisture using diphenylsilane with N-methylpyrrolidine has been developed. Various amides are made efficiently, and broad functional group compatibility is shown through a Glorius robustness study. A gram-scale synthesis demonstrates the scalability of this method. This journal is
- D'Amaral, Melissa C.,Jamkhou, Nick,Adler, Marc J.
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supporting information
p. 288 - 295
(2021/01/28)
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- Benzyne-Mediated Esterification Reaction
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A benzyne-mediated esterification of carboxylic acids and alcohols under mild conditions has been realized, which is made possible via a selective nucleophilic addition of carboxylic acid to benzyne in the presence of alcohol. After a subsequent transesterification with alcohol, the corresponding esters can be produced efficiently. This benzyne-mediated protocol can be used on the modification of Ibuprofen, cholesterol, estradiol, and synthesis of nandrolone phenylpropionate. In addition, benzyne can also be used to promote lactonization and amidation reaction.
- Li, Yang,Shi, Jiarong,Zhao, Jinlong
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supporting information
p. 7274 - 7278
(2021/10/01)
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- Method for preparing amide from carboxylic acid under irradiation of blue light by taking iridium and cobalt complexes as catalysts
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The invention relates to a method for preparing amide from carboxylic acid under the irradiation of blue light by taking iridium and cobalt complexes as catalysts, and belongs to the field of chemistry. The method comprises the following step of: by taking R substituted carboxylic acid and R1' and R2' substituted amines as raw materials, triphenylphosphine as a deoxidizing agent, [Ir(dF(CF3)ppy)2(dtbbpy)]PF6 as a photocatalyst and Co(dmgH)(dmgH2)Cl2 as a metal complex catalyst, reacting in dichloromethane in an inert atmosphere and under the irradiation of blue light to obtain an amide compound, wherein R is an aryl group, a heteroaryl group, a protected amino group, a substituted alkyl group, a substituted aryl group or a substituted protected amino group, R1' is a hydrogen group, a substituted alkyl group, a phenyl group or a substituted phenyl group, and R2' is a hydrogen group, a substituted alkyl group, a phenyl group or a substituted phenyl group.
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-
Paragraph 0071-0072
(2021/05/12)
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- Concise synthesis of: N -phosphorylated amides through three-component reactions
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N-Phosphorylated amides continue to be an unparalleled asset for the development of pharmaceutical molecules, and the importance of this framework has inspired researchers to look for concise and efficient methods for the synthesis of this unit. In this work, a new strategy was developed in which a one-pot synthesis of N-phosphorylated amides was achieved by a three-component reaction with carboxylic acids, phosphorus chlorides and azides under mild reaction conditions. To our knowledge, this is the first study in which this framework was constructed through a multicomponent reaction, which is innovative, efficient and economical. This journal is
- Yang, Shang-Dong,Zhang, Tao,Zhou, Linlin,Zhu, Yuan-Yuan
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supporting information
p. 9417 - 9421
(2021/12/09)
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- Photochemical Activation of Aromatic Aldehydes: Synthesis of Amides, Hydroxamic Acids and Esters
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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.
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supporting information
p. 7915 - 7922
(2021/05/03)
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- PCl3-mediated transesterification and aminolysis of tert-butyl esters via acid chloride formation
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A PCl3-mediated conversion of tert-butyl esters into esters and amides in one-pot under air is developed. This novel protocol is highlighted by the synthesis of skeletons of bioactive molecules and gram-scale reactions. Mechanistic studies revealed that this transformation involves the formation of an acid chloride in situ, which is followed by reactions with alcohols or amines to afford the desired products.
- Wu, Xiaofang,Zhou, Lei,Li, Fangshao,Xiao, Jing
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p. 491 - 497
(2021/01/20)
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- Hydrosilylative reduction of primary amides to primary amines catalyzed by a terminal [Ni-OH] complex
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A terminal [Ni-OH] complex1, supported by triflamide-functionalized NHC ligands, catalyzes the hydrosilylative reduction of a range of primary amides into primary amines in good to excellent yields under base-free conditions with key functional group tolerance. Catalyst1is also effective for the reduction of a variety of tertiary and secondary amides. In contrast to literature reports, the reactivity of1towards amide reduction follows an inverse trend,i.e., 1° amide > 3° amide > 2° amide. The reaction does not follow a usual dehydration pathway.
- Bera, Jitendra K.,Pandey, Pragati
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supporting information
p. 9204 - 9207
(2021/09/20)
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- Synthesis of Benzoisoselenazolones via Rh(III)-Catalyzed Direct Annulative Selenation by Using Elemental Selenium
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Isoselenazolone derivatives have attracted significant research interest because of their potent therapeutic activities and indispensable applications in organic synthesis. Efficient construction of functionalized isoselenazolone scaffolds is still challenging, and thus new synthetic approaches with improved operational simplicity have been of particular interest. In this manuscript, we introduce a rhodium-catalyzed direct selenium annulation by using stable and tractable elemental selenium. A series of benzamides as well as acrylamides were successfully coupled with selenium under mild reaction conditions, and the obtained isoselenazolones could be pivotal synthetic precursors for several organoselenium compounds. Based on the designed control experiments and X-ray absorption spectroscopy measurements, we propose an unprecedented selenation mechanism involving a highly electrophilic Se(IV) species as the reactive selenium donor. The reaction mechanism was further verified by a computational study.
- Xu-Xu, Qing-Feng,Nishii, Yuji,Uetake, Yuta,Sakurai, Hidehiro,Miura, Masahiro
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supporting information
p. 17952 - 17959
(2021/11/16)
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- Hydrogenation of Secondary Amides using Phosphane Oxide and Frustrated Lewis Pair Catalysis
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The metal-free catalytic hydrogenation of secondary carboxylic acid amides is developed. The reduction is realized by two new catalytic reactions. First, the amide is converted into the imidoyl chloride by triphosgene (CO(OCCl3)2) using novel phosphorus(V) catalysts. Second, the in situ generated imidoyl chlorides are hydrogenated in high yields by an FLP-catalyst. Mechanistic and quantum mechanical calculations support an autoinduced catalytic cycle for the hydrogenation with chloride acting as unusual Lewis base for FLP-mediated H2-activation.
- K?ring, Laura,Sitte, Nikolai A.,Bursch, Markus,Grimme, Stefan,Paradies, Jan
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supporting information
p. 14179 - 14183
(2021/09/03)
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- Effect of Precatalyst Oxidation State in C-N Cross-Couplings with 2-Phosphinoimidazole-Derived Bimetallic Pd(I) and Pd(II) Complexes
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We report the catalytic activity of two phosphinoimidazole-derived bimetallic palladium complexes in Pd-catalyzed amination reactions. Our studies demonstrate that the starting oxidation state (Pd(I) or Pd(II)) of the dimeric complex has a significant effect on the efficiency of the catalytic reaction. The corresponding Pd(I) complex shows higher reactivity in Buchwald-Hartwig aminations, while the Pd(II) complex is much more reactive in carbonylative amination reactions. These new dimeric palladium complexes provide good to excellent reactivity and yields in the amination reactions tested.
- Martinez, Erin E.,Moreno, Mariur Rodriguez,Barksdale, Caleb A.,Michaelis, David J.
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supporting information
p. 2763 - 2767
(2021/08/27)
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- Cubic CuxZrO100-x as an efficient and selective catalyst for the oxidation of aromatics active methyl, alcohol, and amine groups
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The local structure of a supported active metal plays a vital role in determining the desired product's selectivity in heterogeneous catalysis. Herein, we have developed a simple protocol for the synthesis of Cu doped on cubic ZrO2 mixed metal oxide catalysts and used it for the selective oxidation of various functional groups. The catalyst was synthesized by varying the wt.% of Cu (1–20%) on ZrO2 by co-precipitation, followed by hydrothermal treatment. The X-ray diffraction pattern of the catalysts confirmed the formation of the cubic phase of ZrO2, and the growth of CuO occurred along the (1 1 1) plane. The microscopy analysis revealed the uniform distribution of Cu on the ZrO2 surface, while XPS analysis confirmed the presence of copper in the +2 oxidation state. The synthesized catalyst with 2 wt% loading of Cu on ZrO2 showed excellent liquid-phase oxidation properties and gave good to best conversion of active methyl groups, alcohols, and amines with high selectivities to corresponding ketones, aldehydes, and amides, respectively, under milder reaction conditions. Furthermore, the synthesized catalyst showed a broader substrate scope for the various substituted active methyl groups, alcohols, and amines with good conversion and selectivity.
- Bankar, Balasaheb D.,Advani, Jacky H.,Biradar, Ankush V.
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- N -Heterocyclic carbene (NHC) catalyzed amidation of aldehydes with amines via the tandem N -hydroxysuccinimide ester formation
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A facile method for the amidation of aldehydes by a cascade approach was developed. This methodology, reported for the first time, uses a N-heterocyclic carbene (NHC) as the catalyst, and N-hydroxysuccinimide (NHS) mediated synthesis of amides utilising TBHP as the oxidant. Various substituted aldehydes reacted smoothly with NHS giving the corresponding active esters in moderate to good yields, which facilely converted into amides in one pot. In addition, the drug moclobemide was synthesized to represent the practical utility of the developed methodology. This journal is
- Singh, Ashmita,Narula
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p. 7486 - 7490
(2021/05/13)
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- Dehydrogenative amide synthesis from alcohols and amines utilizing N-heterocyclic carbene-based ruthenium complexes as efficient catalysts: The influence of catalyst loadings, ancillary and added ligands
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The metal-catalyzed dehydrogenative coupling of alcohols and amines to access amides has been recognized as an atom-economic and environmental-friendly process. Apart from the formation of the amide products, three other kinds of compounds (esters, imines and amines) may also be produced. Therefore, it is of vital importance to investigate product distribution in this transformation. Herein, N-heterocyclic carbene-based Ru (NHC/Ru) complexes [Ru-1]-[Ru-5] with different ancillary ligands were prepared and characterized. Based on these complexes, we selected condition A (without an added NHC precursor) and condition B (with an added NHC precursor) to comprehensively explore the selectivity and yield of the desired amides. After careful evaluation of various parameters, the Ru loadings, added NHC precursors and the electronic/steric properties of ancillary NHC ligands were found to have considerable influence on this catalytic process.
- Wang, Wan-Qiang,Wang, Zhi-Qin,Sang, Wei,Zhang, Rui,Cheng, Hua,Chen, Cheng,Peng, Da-Yong
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- Fluorinated solvent-assisted photocatalytic aerobic oxidative amidation of alcoholsviavisible-light-mediated HKUST-1/Cs-POMoW catalysis
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Considering the irreplaceable importance of photocatalytic functionalization reactions and the widespread attention paid to the use of metal-organic frameworks, especially their modified variants, for this purpose in recent years, different types of HKUST-1/POMoW composites were prepared through the immobilization of a series of Keggin-type polyoxometalates (POMs; POW = H3PW12O40, POMo = H3PMo12O40, and POMoW = H3PMo6W6O40) on HKUST-1 as a metal-organic framework (HKUST-1; Cu3(1,3,5-benzenetricarboxilicacid)2). Then, to produce HKUST-1/Cs-POM, the substitution of H+cations with Cs+ones as counter cations was carried out. The prepared composites were fully characterized with the PXRD (powder X-ray diffraction), FT-IR (Fourier transform infrared spectroscopy), BET and BJH (sorption of N2), TGA (thermo-gravimetric analysis), SEM (scanning electron microscopy), EDX (energy dispersive X-ray), TEM (transmission electron microscopy), UV-vis DRS (diffuse reflectance UV-vis spectroscopy), photoluminescence (PL) spectroscopy and ICP-AES (inductively coupled plasma atomic emission spectroscopy) techniques. The great importance?of the amide functional group and the attractiveness of photocatalytic oxidative functionalization?reactions led us to study the formation of this functional group using the prepared catalytic system in line with our previous research in this field. The HKUST-1/Cs-POMoW composite showed a raised photocatalytic performance compared to the discrete components, HKUST-1 and Cs-POMs, in aerobic oxidative amidation of alcohols under illumination with visible light, owing to the presence of catalytically active Cs-POMs deposited on the MOF particles. Besides, the combination of composite components mitigated the recombination rate of the electron-hole pairs, raising its photocatalytic activity. The attractiveness of fluorine solvents for oxidation reactions has led to the study of their role in the efficiency of oxidative amidation of alcohols and their significant effect on the efficiency of the process has been confirmed. The Cu-MOF/POM catalyst showed excellent stability during the reaction, and no significant decrease in its ability was observed during five consecutive cycles.
- Azarkhosh, Zahra,Heydari, Akbar,Karimi, Meghdad,Mahjoub, Alireza,Mohebali, Haleh,Sadeghi, Samira,Safarifard, Vahid
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supporting information
p. 14024 - 14035
(2021/08/16)
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- Near-Ambient-Temperature Dehydrogenative Synthesis of the Amide Bond: Mechanistic Insight and Applications
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The current existing methods for the amide bond synthesis via acceptorless dehydrogenative coupling of amines and alcohols all require high reaction temperatures for effective catalysis, typically involving reflux in toluene, limiting their potential practical applications. Herein, we report a system for this reaction that proceeds under mild conditions (reflux in diethyl ether, boiling point 34.6 °C) using ruthenium PNNH complexes. The low-temperature activity stems from the ability of Ru-PNNH complexes to activate alcohol and hemiaminals at near-ambient temperatures through the assistance of the terminal N-H proton. Mechanistic studies reveal the presence of an unexpected aldehyde-bound ruthenium species during the reaction, which is also the catalytic resting state. We further utilize the low-temperature activity to synthesize several simple amide bond-containing commercially available pharmaceutical drugs from the corresponding amines and alcohols via the dehydrogenative coupling method.
- Kar, Sayan,Xie, Yinjun,Zhou, Quan Quan,Diskin-Posner, Yael,Ben-David, Yehoshoa,Milstein, David
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p. 7383 - 7393
(2021/06/30)
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- Direct synthesis of amides and imines by dehydrogenative homo or cross-coupling of amines and alcohols catalyzed by Cu-MOF
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Oxidative dehydrogenative homo-coupling of amines to imines and cross-coupling of amines with alcohols to amides was achieved with high to moderate yields at room temperature in THF using Cu-MOF as an efficient and recyclable heterogeneous catalyst under mild conditions. Different primary benzyl amines and alcohols could be utilized for the synthesis of a wide variety of amides and imines. The Cu-MOF catalyst could be recycled and reused four times without loss of catalytic activity.
- Anbardan, Soheil Zamani,Bozcheloei, Abolfazl Hassani,Mokhtari, Javad,Yari, Ahmad
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p. 20788 - 20793
(2021/07/01)
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- Copper and N-Heterocyclic Carbene-Catalyzed Oxidative Amidation of Aldehydes with Amines
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A one-pot two-step oxidative process has been developed for the tert-butyl hydroperoxide mediated transformation of aldehydes and amines into amides catalyzed by copper(I) iodide and an N-heterocyclic carbene. The process is additive-free and does not require the amine to be transformed into its hydrochloride salts. The method is simple and practicable, has a broad substrate scope, and uses economical, feasible, and abundant reagents.
- Singh, Ashmita,Narula, Anudeep Kumar
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supporting information
p. 718 - 722
(2021/02/26)
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- Weak base-promoted selective rearrangement of oxaziridines to amidesviavisible-light photoredox catalysis
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The selective rearrangement of oxaziridines to amidesviaa single electron transfer (SET) pathway is unexplored. In this study, we present a weak base-promoted selective rearrangement of oxaziridines to amidesviavisible-light photoredox catalysis. The developed method shows excellent functional group tolerance with a broad substrate scope and good to excellent yields. Furthermore, control experiments and density functional theory (DFT) calculations are performed to gain insight into the reactivity and selectivity.
- Park, Jin,Park, Sehoon,Jang, Gwang Seok,Kim, Ran Hui,Jung, Jaehoon,Woo, Sang Kook
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p. 9995 - 9998
(2021/10/06)
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- Silver-Catalyzed Hydroboration of C-X (X = C, O, N) Multiple Bonds
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AgSbF6 was developed as an effective catalyst for the hydroboration of various unsaturated functionalities (nitriles, alkenes, and aldehydes). This atom-economic chemoselective protocol works effectively under low catalyst loading, base- A nd solvent-free moderate conditions. Importantly, this process shows excellent functional group tolerance and compatibility with structurally and electronically diverse substrates (>50 examples). Mechanistic investigations revealed that the reaction proceeds via a radical pathway. Further, the obtained N,N-diborylamines were showcased to be useful precursors for amide synthesis.
- Pandey, Vipin K.,Tiwari, Chandra Shekhar,Rit, Arnab
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p. 1681 - 1686
(2021/03/03)
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- CuO-decorated magnetite-reduced graphene oxide: a robust and promising heterogeneous catalyst for the oxidative amidation of methylarenes in waterviabenzylic sp3C-H activation
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A magnetite-reduced graphene oxide-supported CuO nanocomposite (rGO/Fe3O4-CuO) was preparedviaa facile chemical method and characterized by Fourier-transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), UV-vis spectroscopy, scanning electron microscopy (SEM), transmission electron microscopy (TEM), energy dispersive spectroscopy (EDS), Brunauer-Emmett-Teller (BET) analysis, vibrating-sample magnetometry (VSM), and thermogravimetric (TG) analysis. The catalytic activity of the rGO/Fe3O4-CuO nanocomposite was probed in the direct oxidative amidation reaction of methylarenes with free amines. Various aromatic and aliphatic amides were prepared efficiently at room temperature from cheap raw chemicals usingtert-butyl hydroperoxide (TBHP) as a “green” oxidant and low-toxicity TBAI in water. This method combines the oxidation of methylarenes and amide bond formation into a single operation. Moreover, the synthesized nanocomposites can be separated from the reaction mixtures using an external magnet and reused in six consecutive runs without a noticeable decrease in the catalytic activity.
- Ebrahimi, Edris,Khalafi-Nezhad, Ali,Khalili, Dariush,Rousta, Marzieh
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p. 20007 - 20020
(2021/11/12)
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- Metal-Free Selective Modification of Secondary Amides: Application in Late-Stage Diversification of Peptides
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Here we solve a long-standing challenge of the site-selective modification of secondary amides and present a simple two-step, metal-free approach to selectively modify a particular secondary amide in molecules containing multiple primary and secondary amides. Density functional theory (DFT) provides insight into the activation of C-N bonds. This study encompasses distinct chemical advances for late-stage modification of peptides thus harnessing the amides for the incorporation of various functional groups into natural and synthetic molecules.
- Adebomi, Victor,Sriram, Mahesh,Streety, Xavier,Raj, Monika
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p. 6189 - 6193
(2021/08/01)
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- UV-Light-Induced N-Acylation of Amines with α-Diketones
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Herein, we develop a mild method for N-acylation of primary and secondary amines with α-diketones induced by ultraviolet (UV) light. Forty-six examples with various functional groups are explored at room temperature with irradiation by three 26 W UV lamps (350-380 nm). The yield reaches 97%. The gram scale experiment product yield is 76%. Moreover, this system can be applied to the synthesis of several amino acid derivatives. Mechanistic studies show that benzoin is generated in situ from benzil under UV irradiation.
- Xu, Zhihui,Yang, Tianbao,Tang, Niu,Ou, Yifeng,Yin, Shuang-Feng,Kambe, Nobuaki,Qiu, Renhua
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supporting information
p. 5329 - 5333
(2021/07/21)
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- Iron-catalyzed oxidative amidation of acylhydrazines with amines
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A new approach for amide bond formation via a mild and efficient Iron-catalyzed cross-coupling reaction of acylhydrazines and amines using TBHP as oxidant is described. This protocol is compatible with a wide range of amines and acylhydrazines. In addition, the synthetic application of the reaction is presented.
- Wang, Yi-Jie,Zhang, Guo-Yu,Shoberu, Adedamola,Zou, Jian-Ping
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supporting information
(2021/08/18)
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- Carboxylic Acid Deoxyfluorination and One-Pot Amide Bond Formation Using Pentafluoropyridine (PFP)
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This work describes the application of pentafluoropyridine (PFP), a cheap commercially available reagent, in the deoxyfluorination of carboxylic acids to acyl fluorides. The acyl fluorides can be formed from a range of acids under mild conditions. We also demonstrate that PFP can be utilized in a one-pot amide bond formation via in situ generation of acyl fluorides. This one-pot deoxyfluorination amide bond-forming reaction gives ready access to amides in yields of ≤94%.
- Brittain, William D. G.,Cobb, Steven L.
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p. 5793 - 5798
(2021/08/01)
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- Acetonitrile and benzonitrile as versatile amino sources in copper-catalyzed mild electrochemical C-H amidation reactions
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A mild, efficient electrochemical approach to the site-selective direct C-H amidation of benzene and its derivatives with acetonitrile and benzonitrile has been developed. It has been shown that joint electrochemical oxidation of various arenes in the presence of a copper salt as a catalyst and nitriles leads to the formation of N-phenylacetamide from benzene and N-benzylacetamides from benzyl derivatives (up to 78% yield). A favorable feature of the process is mild conditions (room temperature, ambient pressure, no strong oxidants) that meet the criteria of green chemistry.
- Budnikova, Yulia,Kononov, Alexander,Rizvanov, Ildar,Strekalova, Sofia
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p. 37540 - 37543
(2021/12/07)
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- Metal-free transamidation of benzoylpyrrolidin-2-one and amines under aqueous conditions
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N-Acyl lactam amides, such as benzoylpyrrolidin-2-one, benzoylpiperidin-2-one, and benzoylazepan-2-one reacted with amines in the presence of DTBP and TBAI to afford the transamidated products in good yields. The reactions were conducted under aqueous conditions and good functional group tolerance was achieved. Both aliphatic and aromatic primary amines displayed good activity under metal-free conditions. A radical reaction pathway is proposed.
- Joseph, Devaneyan,Lee, Sunwoo,Park, Myeong Seong
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supporting information
p. 6227 - 6232
(2021/07/28)
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- NH4I-mediated sp3 C-H cross-dehydrogenative coupling of benzylamines with 2-methylquinoline for the synthesis of E-2-styrylquinolines
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Without any metal catalyst, a simple and efficient method for the synthesis of E-2-styrylquinolines through sp3 C-H cross-dehydrogenative coupling of benzylamines with 2-methylquinolines mediated by NH4I under air is successfully developed. The oxidative olefination proceeded through deamination and sp3 C–H bond activation. A plausible mechanism is proposed for the construction of E-2-styrylquinolines.
- Huang, Bin,Li, Xue,Liao, WeiBo,Wang, JiangWei,Zhang, YuanYuan
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p. 903 - 910
(2021/07/17)
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- An Environmentally Benign, Catalyst-Free N?C Bond Cleavage/Formation of Primary, Secondary, and Tertiary Unactivated Amides
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Herein, we report an operationally simple, cheap, and catalyst-free method for the transamidation of a diverse range of unactivated amides furnishing the desired products in excellent yields. This protocol is environmentally friendly and operates under extremely mild conditions without using any promoter or additives. Significantly, this strategy has been implied in the chemoselective synthesis of a pharmaceutical molecule, paracetamol, on a gram-scale with excellent yield. We anticipate that this universally applicable strategy will be of great interest in drug discovery, biochemistry, and organic synthesis.
- Kumar, Vishal,Dhawan, Sanjeev,Girase, Pankaj Sanjay,Singh, Parvesh,Karpoormath, Rajshekhar
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p. 5627 - 5639
(2021/11/11)
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- Photocatalyzed Triplet Sensitization of Oximes Using Visible Light Provides a Route to Nonclassical Beckmann Rearrangement Products
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Oximes are valuable synthetic intermediates for the preparation of a variety of functional groups. To date, the stereoselective synthesis of oximes remains a major challenge, as most current synthetic methods either provide mixtures of E and Z isomers or furnish the thermodynamically preferred E isomer. Herein we report a mild and general method to achieve Z isomers of aryl oximes by photoisomerization of oximes via visible-light-mediated energy transfer (EnT) catalysis. Facile access to (Z)-oximes provides opportunities to achieve regio- and chemoselectivity complementary to those of widely used transformations employing oxime starting materials. We show an enhanced one-pot protocol for photocatalyzed oxime isomerization and subsequent Beckmann rearrangement that enables novel reactivity with alkyl groups migrating preferentially over aryl groups, reversing the regioselectivity of the traditional Beckmann reaction. Chemodivergent N- or O- cyclizations of alkenyl oximes are also demonstrated, leading to nitrones or cyclic oxime ethers, respectively.
- Zhang, Xiao,Rovis, Tomislav
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supporting information
p. 21211 - 21217
(2021/12/27)
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- Catalyst-free synthesis of phenanthridinesviaelectrochemical coupling of 2-isocyanobiphenyls and amines
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Catalyst free synthesis of 6-aryl phenanthridines and amides through an electrochemical reaction is reported in this study. The coupling reaction proceeds by the cathodic reduction ofin situformed diazonium ions, which are formed from anilines and an alkyl nitrite. The generated aryl radical diazonium ions coupled from isocyanides furnished the desired products in good yields. This cascade reaction was conducted in an undivided cell equipped with an RVC as the anode and Pt as the cathode usingnBu4NBF4as the electrolyte at room temperature. A series of detailed mechanistic studies have also been performed, including a radical clock experiment and cyclic voltammetry analysis.
- Malviya, Bhanwar Kumar,Singh, Karandeep,Jaiswal, Pradeep K.,Karnatak, Manvika,Verma, Ved Prakash,Badsara, Satpal Singh,Sharma, Siddharth
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p. 6367 - 6378
(2021/04/16)
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- Practical one-pot amidation of N -Alloc-, N -Boc-, and N -Cbz protected amines under mild conditions
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A facile one-pot synthesis of amides from N-Alloc-, N-Boc-, and N-Cbz-protected amines has been described. The reactions involve the use of isocyanate intermediates, which are generated in situ in the presence of 2-chloropyridine and trifluoromethanesulfonyl anhydride, to react with Grignard reagents to produce the corresponding amides. Using this reaction protocol, a variety of N-Alloc-, N-Boc-, and N-Cbz-protected aliphatic amines and aryl amines were efficiently converted to amides with high yields. This method is highly effective for the synthesis of amides and offers a promising approach for facile amidation.
- Hong, Wan Pyo,Tran, Van Hieu,Kim, Hee-Kwon
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p. 15890 - 15895
(2021/05/19)
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- Solvent-free iron(III) chloride-catalyzed direct amidation of esters
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Amide functional groups are prominent in a broad range of organic compounds with diverse beneficial applications. In this work, we report the synthesis of these functional groups via an iron(iii) chloride-catalyzed direct amidation of esters. The reactions are conducted under solvent-free conditions and found to be compatible with a range of amine and ester substrates generating the desired amides in short reaction times and good to excellent yields at a catalyst loading of 15 mol%.
- Mkhonazi, Blessing D.,Shandu, Malibongwe,Tshinavhe, Ronewa,Simelane, Sandile B.,Moshapo, Paseka T.
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supporting information
(2020/03/17)
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- Graphene oxide: A convenient metal-free carbocatalyst for facilitating amidation of esters with amines
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Herein, we report a graphene oxide (GO) catalyzed condensation of non-activated esters and amines, that can enable diverse amides to be synthesized from abundant ethyl esters forming only volatile alcohol as a by-product. GO accelerates ester to amide conversion in the absence of any additives, unlike other catalysts. A wide range of ester and amine substrates are screened to yield the respective amides in good to excellent yields. The improved catalytic activity can be ascribed to the oxygenated functionalities present on the graphene oxide surface which forms H-bonding with the reactants accelerating the reaction. Improved yields and a wide range of functional group tolerance are some of the important features of the developed protocol.
- Patel, Khushbu P.,Gayakwad, Eknath M.,Shankarling, Ganapati S.
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p. 2661 - 2668
(2020/02/20)
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- The synthesis and structure of pyridine-oxadiazole iridium complexes and catalytic applications: Non-coordinating-anion-tuned selective C–N bond formation
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Several novel pyridine-oxadiazole iridium complexes were synthesized and characterized through X-ray crystallography. The designed iridium complexes revealed surprisingly high catalytic activity in C–N bondformation of amides and benzyl alcohols with the assistance of non-coordinating anions. In an attempt to achieve borrowing hydrogen reactions of amides with benzyl alcohols, N,N'-(phenylmethylene)dibenzamide products were unexpectedly isolated under non-coordinating anion conditions, whereas N-benzylbenzamide products were achieved in the absence of non-coordinating anions. The mechanism explorations excluded the possibility of “silver effect” (silver-assisted or bimetallic catalysis) and revealed that the reactivity of iridium catalyst was varied by non-coordinating anions. This work provided a convenient and useful methodology that allowed the iridium complex to be a chemoselective catalyst and demonstrated the first example of non-coordinating-anion-tuned selective C–N bond formation
- Yao, Wei,Zhang, Yilin,Zhu, Haiyan,Ge, Chenyang,Wang, Dawei
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p. 701 - 705
(2019/09/30)
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