- 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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- Half-Sandwich Ruthenium Complexes Bearing Hemilabile κ2-(C,S)?Thioether-Functionalized NHC Ligands: Application to Amide Synthesis from Alcohol and Amine
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Amide synthesis is one of the most crucial transformations in chemistry and biology. Among various catalytic systems, N-heterocyclic carbene (NHC)-based ruthenium (Ru) catalyst systems have been proven to be active for direct synthesis of amides by sustainable acceptorless dehydrogenative Coupling of primary alcohols with amines. Most often, these catalytic systems usually use monodentate NHC and thus require an additional ligand to obtain high reactivity and selectivity. In this work, a series of cationic Ru(II)(η6-p-cymene) complexes with thioether-functionalized N-heterocyclic carbene ligands (imidazole and benzimidazole-based) have been prepared and fully characterized. These complexes have then been used in the amidation reaction and the most promising one (i. e. 3 c) has been applied on a large range of substrates. High conversions albeit with moderate yields have generally been obtained.
- Achard, Thierry,Bellemin-Laponnaz, Stéphane,Chen, Weighang,Egly, Julien,Maisse-Fran?ois, Aline
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supporting information
(2022/01/20)
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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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- 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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supporting information
p. 1681 - 1686
(2021/03/03)
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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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- Well-defined N-heterocyclic carbene/ruthenium complexes for the alcohol amidation with amines: The dual role of cesium carbonate and improved activities applying an added ligand
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Dehydrogenative amide bond formation from alcohols and amines has been regarded as an atom-economic and sustainable process. Among various catalytic systems, N-heterocyclic carbene (NHC)-based Ru catalytic systems have attracted growing interest due to the outstanding properties of NHCs as ligands. Herein, an NHC/Ru complex (1) was prepared and its structure was further confirmed with X-ray crystallography. In the presence of Cs2CO3, two NHC/Ru-based catalytic systems were disclosed to be active for this amide synthesis. System A, which did not contain any added ligand, required a catalyst loading of 1.00 mol%. Interestingly, improved catalytic performance was realized by the addition of an NHC precursor (L). Optimization of the amounts of L and other conditions gave rise to system B, a much more potent system with the Ru loading as low as 0.25 mol%. Moreover, an NHC-Ru-carbonate complex 6 was identified from the refluxing toluene of 1 and Cs2CO3, and further investigations revealed that 6 was an important intermediate for this catalytic reaction. Based on the above results, we claimed that the role of Cs2CO3 was to facilitate the formation of key intermediate 6. On the other hand, it provided the optimized basicity for the selective amide formation.
- Wang, Wan-Qiang,Yuan, Ye,Miao, Yang,Yu, Bao-Yi,Wang, Hua-Jing,Wang, Zhi-Qin,Sang, Wei,Chen, Cheng,Verpoort, Francis
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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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- An unprecedented cobalt-catalyzed selective aroylation of primary amines with aroyl peroxides
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A novel and facile cobalt-catalyzed selective aroylation of primary amines with aroyl peroxides was developed for the synthesis of aryl amides. It was unprecedented that C[sbnd]N bond formation product was selectively generated without the common N[sbnd]O bond formation product. Aroyl peroxides act as the sole aroylation reagent without additional base or oxidant. The reactions proceeded under mild conditions and showed broad substrates scope with a series of primary amines and aroyl peroxides.
- Li, Dong,Li, Jiale,Li, Juanjuan,Yuan, Songdong,Zhang, Qian
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supporting information
(2020/09/16)
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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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- Reductive Amidation without an External Hydrogen Source Using Rhodium on Carbon Matrix as a Catalyst
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An efficient method for preparation of secondary amides from primary amides and aldehydes using rhodium on carbon matrix as catalyst was developed. The method does not require any external hydrogen source and carbon monoxide is used as a reducing agent. The most active rhodium catalysts were characterized by BET, TEM and XPS techniques. Unexpectedly, it was found that heterogeneous rhodium on carbon matrix works as precatalyst for homogenous active species due to leaching of rhodium to the solution. Various secondary amides were synthesized and checked for antifungal activity. 4-Methoxy-N-(4-methoxybenzyl)benzamide demonstrated promising activity against Rhizoctonia Solani.
- Tsygankov, Alexey A.,Makarova, Maria,Afanasyev, Oleg I.,Kashin, Alexey S.,Naumkin, Alexander V.,Loginov, Dmitry A.,Chusov, Denis
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p. 112 - 117
(2019/11/28)
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- Efficient Cobalt Catalyst for Ambient-Temperature Nitrile Dihydroboration, the Elucidation of a Chelate-Assisted Borylation Mechanism, and a New Synthetic Route to Amides
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N,N-Diborylamines have emerged as promising reagents in organic synthesis; however, their efficient preparation and full synthetic utility have yet to be realized. To address both shortcomings, an effective catalyst for nitrile dihydroboration was sought. Heating CoCl2 in the presence of PyEtPDI afforded the six-coordinate Co(II) salt, [(PyEtPDI)CoCl][Cl]. Upon adding 2 equiv of NaEt3BH, hydride transfer to one chelate imine functionality was observed, resulting in the formation of (κ4-N,N,N,N-PyEtIPCHMeNEtPy)Co. Single-crystal X-ray diffraction and density functional theory calculations revealed that this compound possesses a low-spin Co(II) ground state featuring antiferromagnetic coupling to a singly reduced imino(pyridine) moiety. Importantly, (κ4-N,N,N,N-PyEtIPCHMeNEtPy)Co was found to catalyze the dihydroboration of nitriles using HBPin with turnover frequencies of up to 380 h-1 at ambient temperature. Stoichiometric addition experiments revealed that HBPin adds across the Co-Namide bond to generate a hydride intermediate that can react with additional HBPin or nitriles. Computational evaluation of the reaction coordinate revealed that the B-H addition and nitrile insertion steps occur on the antiferromagnetically coupled triplet spin manifold. Interestingly, formation of the borylimine intermediate was found to occur following BPin transfer from the borylated chelate arm to regenerate (κ4-N,N,N,N-PyEtIPCHMeNEtPy)Co. Borylimine reduction is in turn facile and follows the same ligand-assisted borylation pathway. The independent hydroboration of alkyl and aryl imines was also demonstrated at 25 °C. With a series of N,N-diborylamines in hand, their addition to carboxylic acids allowed for the direct synthesis of amides at 120 °C, without the need for an exogenous coupling reagent.
- Ghosh, Chandrani,Kim, Suyeon,Mena, Matthew R.,Kim, Jun-Hyeong,Pal, Raja,Rock, Christopher L.,Groy, Thomas L.,Baik, Mu-Hyun,Trovitch, Ryan J.
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supporting information
p. 15327 - 15337
(2019/10/22)
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- Iron(III)-catalyzed synthesis of selenoesters from α-amino carbonyl derivatives at room temperature
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An Fe(III)-catalyzed efficient method has been developed for the synthesis of selenoester derivatives in high yields through the coupling of α-amino carbonyl/glycine derivatives and diselenides under ambient air. A library of benzoselenoate derivatives having a variety of substituents has been synthesized. A plausible reaction pathway has been predicted. Experimental results suggest that the reaction proceeds through a radical pathway. Operational simplicity, compatibility with various α-amino carbonyls and diselenides, high yields, fast reaction and mild reaction conditions are the notable advantages of this procedure. We have also shown the practical application of the synthesized selenoesters which is useful to generate peptide bonds in biological sciences.
- Chatterjee, Rana,Mukherjee, Anindita,Santra, Sougata,Zyryanov, Grigory V.,Majee, Adinath
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- An Efficient Catalytic Amidation of Esters Promoted by N-Heterocyclic Carbenes
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An efficient NHC-catalyzed amidation between esters and amines or hydrazines is described. This strategy was tolerant for a wide scope of substrates, affording a series of amides (or hydrazides) in good to excellent yields (60-96%) under simple conditions. The approach was also used to synthesize the pharmaceutically relevant antidepressant moclobemide in 85% yield.
- Chen, Ling-Yan,Wu, Mei-Fang
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p. 1595 - 1602
(2019/03/26)
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- Design and synthesis of 3-aminophthalazine derivatives and structural analogues as PDE5 inhibitors: anti-allodynic effect against neuropathic pain in a mouse model
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Neuropathic pain is a chronic pain caused by a lesion or disease affecting the somatosensory nervous system. To date, no specific treatment has been developed to cure this pain. Antidepressants and anticonvulsant drugs are used, but they do not demonstrate universal efficacy, and they often cause detrimental adverse effects. Some studies highlighted the efficacy of sildenafil, a well-known inhibitor of phosphodiesterase 5 (PDE5, (IC50 = 3.3 nM)), in models of pain. Based on these results, we focused our attention on MY 5445, another known PDE5 inhibitor. Homologues, isosteres and structural analogues of MY 5445 were designed and all synthesized compounds were evaluated for their inhibitory activity toward PDE5. Selectivity profiles towards other PDE1-4 isoenzymes, water solubility and stability in acidic medium of the most potent PDE5 inhibitors were determined and the aminophthalazine 16h and its mimetic 41n (3-aminoindazole)were evaluated in comparison to MY 5445 (4b)in vivo in a model of neuropathic pain induced by sciatic nerve cuffing in mice (3 and 0.5 mg/kg, ip twice a day). Both compounds showed the same efficacy on neuropathic allodynia as MY 5445, and thus produced a significant relief of mechanical hypersensitivity after 12 days of treatment.
- Bollenbach, Maud,Lugnier, Claire,Kremer, Mélanie,Salvat, Eric,Megat, Salim,Bihel, Frédéric,Bourguignon, Jean-Jacques,Barrot, Michel,Schmitt, Martine
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supporting information
p. 269 - 290
(2019/06/05)
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- Visible light-induced transformation of aldehydes to esters, carboxylic anhydrides and amides
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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
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supporting information
p. 10711 - 10715
(2019/07/15)
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- A metal-free approach for the synthesis of amides/esters with pyridinium salts of phenacyl bromides via oxidative C–C bond cleavage
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An efficient, simple, and metal-free synthetic approach for the N- and O-benzoylation of various amines/benzyl alcohols with pyridinium salts of phenacyl bromides is demonstrated to generate the corresponding amides and esters. This protocol facilitates the oxidative cleavage of a C–C bond followed by formation of a new C–N/C–O bond in the presence of K2CO3. Various pyridinium salts of phenacyl bromides can be readily transformed into a variety of amides and esters which is an alternative method for the conventional amidation and esterification in organic synthesis. High functional group tolerance, broad substrate scope and operational simplicity are the prominent advantages of the current protocol.
- Manasa, Kesari Lakshmi,Tangella, Yellaiah,Krishna, Namballa Hari,Alvala, Mallika
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p. 1864 - 1871
(2019/08/12)
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- Base-Promoted Amidation and Esterification of Imidazolium Salts via Acyl C-C bond Cleavage: Access to Aromatic Amides and Esters
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Imidazolium salts have been effectively employed as suitable acyl transfer agents in amidation and esterification in organic synthesis. The weak acyl C(O)-C imidazolium bond was exploited to generate acyl electrophiles, which further react with amines and alcohols to afford amides and esters. The broad substrate scope of anilines and benzylic amines and base-promoted conditions are the benefits of this route. Interestingly, phenol, benzylic alcohols, and a biologically active alcohol can also be subjected to esterification under the optimized conditions.
- Karthik, Shanmugam,Muthuvel, Karthick,Gandhi, Thirumanavelan
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p. 738 - 751
(2019/01/24)
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- Graphene Oxide: A Metal-Free Carbocatalyst for the Synthesis of Diverse Amides under Solvent-Free Conditions
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An environmentally friendly, inexpensive, carbocatalyst, graphene oxide (GO) promoted efficient, metal-free transamidation of various carboxamides with aliphatic, cyclic, and aromatic amines is demonstrated. The protocol is equally applicable to phthalimide, urea, and thioamide determining its adaptability. The oxygenated functionalities such as carbonyl (?C=O), epoxy (?O?), carboxyl (?COOH) and hydroxyl (?OH), present on graphene oxide surface impart acidic properties to the catalyst. The graphene oxide being heterogeneous in nature, work efficiently under solvent-free reaction conditions providing desired products in good to excellent yields. The one-pot synthesis of 2,3-Dihydro-5H-benzo[b]-1,4-thiazepin-4-one moiety by GO catalyzed Aza Michael addition followed by intramolecular transamidation is also described. A plausible reaction mechanistic pathway involving H-bonding is discussed. The graphene oxide can be recycled and reused up to five cycles without much loss in catalytic activity. (Figure presented.).
- Patel, Khushbu P.,Gayakwad, Eknath M.,Patil, Vilas V.,Shankarling, Ganapati S.
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supporting information
p. 2107 - 2116
(2019/03/26)
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- Efficient N-Heterocyclic Carbene/Ruthenium Catalytic Systems for the Alcohol Amidation with Amines: Involvement of Poly-Carbene Complexes?
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The atom-economic direct amidation of alcohols with amines has been recently highlighted as an attractive and promising transformation. Among the versatile reported catalytic systems, in situ generated N-heterocyclic carbene (NHC)/ruthenium (Ru) catalytic systems have demonstrated their advantages such as easy operation and use of commercial Ru compounds. However, the existing catalyst loadings are relatively high, and additional insights for the in situ catalyst generation are still not well-documented. In this work, a variety of benzimidazole-based NHC precursors were initially synthesized. Through the screening of various NHC precursors and other reaction conditions, active in situ catalytic systems were discovered for the efficient amide synthesis. Notably, the catalyst loading is as low as 0.5 mol %. Furthermore, additional experiments were performed to validate the rationale for the superiority of the current catalytic systems over our previous system. It was observed that the ligand structure is one of the reasons for the higher activity. In addition, the higher ratio of the NHC precursor/[Ru] is another important factor for the improvement. Further HR-MS analysis identified the formation of two mono-NHC-Ru species as major species and two Ru species bearing multiple NHC ligands as minor species. Hopefully, the efficient and readily-accessible catalytic systems reported herein could demonstrate great potential for further practical applications.
- Cheng, Hua,Xiong, Mao-Qian,Zhang, Ni,Wang, Hua-Jing,Miao, Yang,Su, Wei,Yuan, Ye,Chen, Cheng,Verpoort, Francis
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p. 4338 - 4345
(2018/09/06)
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- A Pseudodearomatized PN3P?Ni-H Complex as a Ligand and σ-Nucleophilic Catalyst
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In contrast to the conventional strategy of modifying the reactivities and selectivities of the transition metal and organocatalysts by varying the steric and electronic properties of organic substituent groups, we hereby demonstrate a novel approach that the sigma (σ) nucleophilicity of the imine arm can be significantly enhanced in a pseudodearomatized PN3P? pincer ligand platform to reach unprecedented N-heterocyclic carbene-like reactivity. Accordingly, the imine arm of the PN3P?Ni-H pincer complex efficiently catalyzes the hydrosilylation of aldehydes, cycloaddition of carbon dioxide (CO2) to epoxides, and serves as a ligand in the Ru-catalyzed dehydrogenative acylation of amines with alcohols.
- Li, Huaifeng,Gon?alves, Théo P.,Hu, Jinsong,Zhao, Qianyi,Gong, Dirong,Lai, Zhiping,Wang, Zhixiang,Zheng, Junrong,Huang, Kuo-Wei
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p. 14969 - 14977
(2019/01/03)
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- Nickel-Catalyzed Phosphine Free Direct N-Alkylation of Amides with Alcohols
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Herein, we developed an operational simple, practical, and selective Ni-catalyzed synthesis of secondary amides. Application of renewable alcohols, earth-abundant and nonprecious nickel catalyst facilitates the transformations, releasing water as byproduct. The catalytic system is tolerant to a variety of functional groups including nitrile, allylic ether, and alkene and could be extended to the synthesis of bis-amide, antiemetic drug Tigan, and dopamine D2 receptor antagonist Itopride. Preliminary mechanistic studies revealed the participation of a benzylic C-H bond in the rate-determining step.
- Das, Jagadish,Banerjee, Debasis
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p. 3378 - 3384
(2018/03/26)
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- Latent Bronsted Base Solvent-Assisted Amide Formation from Amines and Acid Chlorides
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Weakly basic amines, including even neutral amines such as nitroaniline and aminocarboxylic acids, react with acid chlorides very efficiently in N, N -dimethylacetamide (DMAC), without addition of a base, to give the corresponding amides in high yields. The role of DMAC and related solvents as latent Bronsted bases was studied in these amidation reactions. Less basic amines, such as aromatic amines, reacted with benzoyl chloride faster than more basic aliphatic amines.
- Otsuka, Rikuto,Maruhashi, Kazuo,Ohwada, Tomohiko
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supporting information
p. 2041 - 2057
(2018/05/04)
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- Direct Amidation of Carboxylic Acids through an Active α-Acyl Enol Ester Intermediate
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The development of a highly efficient and simple protocol for the direct amidation of carboxylic acids is described employing ynoates as novel coupling reagents. The transformation proceeds in good to excellent yields via in situ α-acyl enol ester intermediates formation under mild reaction conditions. This useful method has been demonstrated for a range of substrates to provide a succinct access to structurally diverse amides, including key intermediates of glibenclamide, tiapride hydrochloride, and nateglinide, and can be conducted on a mole scale.
- Xu, Xianjun,Feng, Huangdi,Huang, Liliang,Liu, Xiaohui
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p. 7962 - 7969
(2018/06/18)
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- Three-component synthesis of amidomethylarenes and -heteroarenes over HΒ zeolite under solvent-free conditions
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A highly efficient and eco-friendly protocol has been described for the synthesis of amidomethylarenes and -heteroarenes via one-pot three-component coupling reaction of amides, aldehydes and (hetero)arenes over a heterogeneous catalyst (Hβ zeolite) in solvent-free conditions. The scope and limitations of this catalytic process are demonstrated with various amides and arenes and the corresponding amidoalkylated arene products were obtained in moderate to excellent yields. The preliminary mechanistic insight (control experiments) suggest that bisamide and/or N-(hydroxymethyl)benzamide are probable intermediates in this reaction. Moreover, the catalyst can be reused without any significant loss of the catalytic activity and only water is produced as by-product.
- Chevella, Durgaiah,Mameda, Naresh,Kodumuri, Srujana,Banothu, Rammurthy,Gajula, Krishna Sai,Kutepov, Boris Ivanovich,Nama, Narender
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- Ruthenium-Catalyzed Reductive Amidation without an External Hydrogen Source
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A catalytic reaction between aldehydes and primary amides that leads to N-alkylated amides was investigated. The developed protocol employs carbon monoxide as a deoxygenative agent and, therefore, avoids the use of an external hydrogen source. Cyclopentad
- Yagafarov, Niyaz Z.,Muratov, Karim M.,Biriukov, Klim,Usanov, Dmitry L.,Chusova, Olga,Perekalin, Dmitry S.,Chusov, Denis
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supporting information
p. 557 - 563
(2018/02/09)
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- A process for preparing N - alkyl amide method (by machine translation)
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The invention discloses a method for preparing N - alkyl amide of the method. In the reaction container, joins the nitrile, oxime, transition metal catalyst iridium complex [Cp * IrCl2 ]2 , Toluene; the reaction mixture in 100 °C reaction under 6 hours, cooling to room temperature; then the alcohol and alkali compound is added, the reaction mixture in the 130 °C react again under 12 hours later, then through the column separation, to obtain the target compound. The invention from the fully commercialized nitrile, proceed wowo and mellow, in the participation of transition metal iridium catalyst, to directly obtain N - alkyl amide, the reaction exhibits three significant advantages: 1) the use of the commercialization of the starting material; 2) low catalyst load; 3) is environment-friendly and easy to control. Therefore, the reaction in accordance with the requirement of green chemistry, has broad prospects of development. (by machine translation)
- -
-
Paragraph 0041; 0042; 0043; 0044; 0045
(2017/08/19)
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- A high-efficient method for the amidation of carboxylic acids promoted by triphenylphosphine oxide and oxalyl chloride
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A effective amidation reaction of carboxylic acids with various amines promoted by triphenylphosphine oxide and oxalyl chloride under mild and neutral conditions has been developed. The feature of this procedure was the using and recycling of triphenylphosphine oxide at room temperature in 0.5?h. Furthermore a plausible mechanism also be deduced with the help of 31P NMR spectroscopy.
- Jiang, Lixue,Yu, Jing,Niu, Fanfan,Zhang, Derundong,Sun, Xiaoling
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- Palladium-Catalyzed Direct Synthesis of Phenanthridones from Benzamides through Tandem N–H/C–H Arylation
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We report a palladium-catalyzed method for the direct synthesis of phenanthridones from benzamides in a single step. Unlike previous reports, the current protocol does not need any directing groups or any harsh conditions. This methodology has a wide functional group tolerance therefore a series of phenanthridones were synthesized with a yield up to 87 %. The efficacy of this protocol was further explored by synthesizing some important naturally occurring amaryllidaceae alkaloids in a single step with very good yields.
- Banerji, Biswadip,Chatterjee, Satadru,Chandrasekhar,Nayan, Chinmay,Killi, Sunil Kumar
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supporting information
p. 5214 - 5218
(2017/09/29)
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- Sulfur–Fluoride Exchange (SuFEx)-Mediated Synthesis of Sterically Hindered and Electron-Deficient Secondary and Tertiary Amides via Acyl Fluoride Intermediates
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Amide bond formation is one of the most executed reactions in chemistry and biology. This is largely due to the ubiquity of the amide functional group in biological molecules, natural products and pharmaceutically important drugs. We report here the development of “SuFExAmide”: a new sulfur–fluoride exchange (SuFEx) click chemistry based protocol for the efficient amidation of carboxylic acids via acyl fluoride intermediates. We have developed benzene-1,3-disulfonyl fluoride as a cost effective, powerful and versatile coupling agent, which delivers challenging secondary and tertiary amides in excellent yields from sterically hindered and electron-deficient amines. The straightforward method offers significant benefits over existing protocols in terms of substrate scope, efficiency and ease of operation and is demonstrated by the synthesis of 44 amides, including GNF6702, an antiprotozoal drug candidate. In the majority of cases, the amide products are obtained in high yield without the need for excess reagents or chromatographic purification.
- Smedley, Christopher J.,Barrow, Andrew S.,Spiteri, Christian,Giel, Marie-Claire,Sharma, Pallavi,Moses, John E.
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p. 9990 - 9995
(2017/08/01)
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- An Unconventional Reaction of 2,2-Diazido Acylacetates with Amines
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We have discovered that 2,2-diazido acylacetates, a class of compounds with essentially unknown reactivity, can be coupled to amines through a new strategy that does not involve any reagents. 2,2-Diazido acetate is the unconventional leaving group under carbon–carbon bond cleavage. This reaction leads to the construction of amide bonds, tolerates various functionalities and is performed equally well in numerous solvents under experimentally simple conditions. We also demonstrate that the isolation of the 2,2-diazido acylacetate compounds can be circumvented: Acylacetates were easily fragmented when treated with (Bu4N)N3 and iodine in the presence of an amine at room temperature. By using this method, a broad range of acylacetates with various structural motifs were directly transformed into amides.
- H?ring, Andreas P.,Biallas, Phillip,Kirsch, Stefan F.
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supporting information
p. 1526 - 1539
(2017/04/01)
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- Metal-Free Benzylic C?H Amination via Electrochemically Generated Benzylaminosulfonium Ions
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Electrochemical oxidation of toluene derivatives in the presence of N-tosyldiphenylsulfilimine gave the corresponding benzylaminosulfonium ions, which were treated with tetrabutylammonium iodide under non-electrolytic conditions to give N-tosylbenzylamines. The transformation serves as a metal- and chemical-oxidant-free method for benzylic C?H amination. Because of high oxidation potential of N-tosyldiphenylsulfilimine the present method can be applied to synthesis of various benzylamines from functionalized toluene derivatives.
- Hayashi, Ryutaro,Shimizu, Akihiro,Song, Yetao,Ashikari, Yosuke,Nokami, Toshiki,Yoshida, Jun-Ichi
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- Dichotomy of Atom-Economical Hydrogen-Free Reductive Amidation vs Exhaustive Reductive Amination
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Rh-catalyzed one-step reductive amidation of aldehydes has been developed. The protocol does not require an external hydrogen source and employs carbon monoxide as a deoxygenative agent. The direction of the reaction can be altered simply by changing the solvent: reaction in THF leads to amides, whereas methanol favors formation of tertiary amines.
- Kolesnikov, Pavel N.,Usanov, Dmitry L.,Muratov, Karim M.,Chusov, Denis
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supporting information
p. 5657 - 5660
(2017/10/25)
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- Method for synthesizing N-alkylamide
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The invention discloses a method for synthesizing N-alkylamide. In a reaction container, adding nitrile, a complex of a transition-metal catalyst gold, a solvent tetrahydrofuran and H2O; reacting a reaction mixture for several hours at the temperature of 130-140 DEG C, cooling the reaction mixture to room temperature, performing vacuum pressure reduction to remove the solvent; adding a compound alcohol, alkali, the complex of a transition-metal catalyst iridium, a solvent toluene, reacting the reaction mixture for several hours at the temperature of 130 DEG C, through column separation, obtaining a target compound. According to the invention, with participation of the transition-metal catalyst, commercial nitrile is hydrolyzed to generate an amide intermediate, and then is subjected to an alkylation reaction with alcohol to obtain N-alkylamide. The reaction has three obvious advantages: 1) the commercial nitrile and alcohol which is almost nontoxic are taken as initial raw materials; 2) only water is generated as a by-product in the reaction, so that the reaction has no harm on environment; and 3) reaction atom economy is high. The reaction accords with green chemistry requirement, and has wide development prospect.
- -
-
Paragraph 0040-0043
(2016/12/07)
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- Palladium-catalyzed carbonylation of aryl halides: An efficient, heterogeneous and phosphine-free catalytic system for aminocarbonylation and alkoxycarbonylation employing Mo(CO)6 as a solid carbon monoxide source
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Immobilized palladium metal-containing magnetic nanoparticles (ImmPd(0)-MNPs) were synthesized and characterized as an immobilized, phosphine-free catalyst for carbonylation reactions, namely the alkoxycarbonylation and aminocarbonylation reactions. Various substituted aryl iodides tolerated the reaction conditions and a wide variety of alcohols and amines were used efficiently. The effects of the solvent, base, and temperature were studied in both the mentioned reactions. The developed catalytic system avoids the use of phosphine ligands and can be reused for up to eight consecutive cycles. The recycled catalyst was characterized by TEM and ICP analysis.
- Hajipour, Abdol-Reza,Tavangar-Rizi, Zeinab,Iranpoor, Nasser
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p. 78468 - 78476
(2016/09/09)
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- Visible-Light-Mediated Synthesis of Amides from Aldehydes and Amines via in Situ Acid Chloride Formation
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An efficient visible-light photocatalysis-based one-pot amide synthesis method was developed; visible-light irradiation of a mixture of an aldehyde, tert-butyl hydrogen peroxide, and N-chlorosuccinimide using a Ru(bpy)3Cl2 photocatalyst afforded an acid chloride, which subsequently reacted with amine to yield the corresponding amide. The reaction was used to synthesize moclobemide and a D3 receptor intermediate.
- Iqbal, Naeem,Cho, Eun Jin
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p. 1905 - 1911
(2016/03/15)
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- Transamidation catalysed by a magnetically separable Fe3O4 nano catalyst under solvent-free conditions
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An environmentally benign protocol for transamidation of carboxamides with different amines under solvent free conditions using magnetically separable nano Fe3O4 as a heterogeneous catalyst is developed. The series of aryl and alkyl amines with long chain alkyl substituents have been selectively converted into transamide products. The current protocol offers a diverse substrate scope with good yield of the product. The Fe3O4 nano catalyst has also been used for formylation of amines via transamidation of dimethyl formamide. Efficient transamidation, ease of work up, simple separation and reusability of the catalyst for up to six runs are the important highlights of this process.
- Thale, Pranila B.,Borase, Pravin N.,Shankarling, Ganapati S.
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p. 52724 - 52728
(2016/06/14)
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- Transamidation of carboxamides with amines over nanosized zeolite beta under solvent-free conditions
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A highly efficient approach to transamidation of carboxamides with amines over nanosized zeolite beta under solvent-free conditions has been successfully demonstrated. Transamidation of a variety of amides with amines produced the respective N-alkyl amides in moderate to excellent yields.
- Durgaiah, Chevella,Naresh, Mameda,Swamy, Peraka,Srujana, Kodumuri,Rammurthy, Banothu,Narender, Nama
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- Tert -Butyl Peroxybenzoate Mediated Selective and Mild N-Benzoylation of Ammonia/Amines under Catalyst- and Solvent-Free Conditions
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A new protocol for the synthesis of amides from tert-butyl peroxybenzoate (TBPB) and ammonia/amines has been developed under catalyst- and solvent-free conditions. The ammonia, primary and secondary amines reacted smoothly with TBPB to furnish the corresponding primary, secondary, and tertiary amides in excellent yields. TBPB proved to be an efficient and highly chemoselective benzoylating reagent for aliphatic amines in the presence of aromatic amines/hydroxyl groups.
- Yadav, Dilip Kumar T.,Bhanage, Bhalchandra M.
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supporting information
p. 1862 - 1866
(2015/08/06)
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- C-N Coupling of Amides with Alcohols Catalyzed by N-Heterocyclic Carbene-Phosphine Iridium Complexes
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N-Heterocyclic carbene-phosphine iridium complexes (NHC-Ir) were developed/found to be a highly reactive catalyst for N-monoalkylation of amides with alcohols via hydrogen transfer. The reaction produced the desired product in high isolated yields using a wide range of substrates with low catalyst loading and short reaction times.
- Kerdphon, Sutthichat,Quan, Xu,Parihar, Vijay Singh,Andersson, Pher G.
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p. 11529 - 11537
(2015/12/04)
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- Combination of gold and iridium catalysts for the synthesis of N-alkylated amides from nitriles and alcohols
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An alternative and efficient approach for the synthesis of N-alkylated amides from nitriles and alcohols was proposed and accomplished. By the combination of [(IPr)Au(NTf2)] (IPr = 1,3-bis(diisopropylphenyl)imidazol-2-ylidene) and [CpIrCl2]2 (Cp = η5-pentamethylcyclopentadienyl), a series of nitriles were first hydrated to give amides, in which the resulting amides were further N-alkylated with a variety of alcohols as alkylating agents to afford N-alkylated amides with good to excellent yields. Compared with previous methods for the synthesis of N-alkylated amides from nitriles and alcohols as starting materials, this protocol could be accomplished with high atom economy under more environmentally benign conditions.
- Li, Feng,Ma, Juan,Lu, Lei,Bao, Xiaofeng,Tang, Wanying
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p. 1953 - 1960
(2015/04/27)
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- Catalytic role of PPh3 and its polymer bound analog in the amidation of carboxylic acids mediated by 2,4,6-trichloro-1,3,5-triazine
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Abstract The catalytic role of PPh3 and its polymer bound analog was investigated in the 2,4,6-trichloro-1,3,5-triazine (TCT) mediated amidation of carboxylic acids. In the presence of inorganic bases which were inert toward TCT, carboxylic acids rapidly reacted with amines to afford amides in good to excellent yields. The described method also enabled the synthesis of optically active protected dipeptides without racemization. Formation of triazinylphosphonium chloride during the PPh3 catalyzed acid activation was confirmed based on 31P NMR studies.
- Duangkamol, Chuthamat,Jaita, Subin,Wangngae, Sirilak,Phakhodee, Wong,Pattarawarapan, Mookda
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supporting information
p. 4997 - 5001
(2015/08/03)
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- A One-Pot, fast, and efficient amidation of carboxylic acids, α-amino acids and sulfonic acids using pph3/n-chlorobenzotriazole system
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Triphenylphosphine (PPh3)/N-chlorobenzotriazole (NCBT), and amine (primary and secondary aliphatic amines and also substituted anilines) in CH2Cl2 efficiently converted carboxylic acids, α-amino acids, and sulfonic acids to the corresponding amides and sulfonamides at room temperature. Good to excellent yields, inexpensive, and fast reaction conditions are the important features of this procedure.
- Rouhi-Saadabad, Hamed,Akhlaghinia, Batool
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p. 1703 - 1714
(2015/09/15)
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- An azobenzene-containing metal-organic framework as an efficient heterogeneous catalyst for direct amidation of benzoic acids: Synthesis of bioactive compounds
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An azobenzene-containing zirconium metal-organic framework was demonstrated to be an effective heterogeneous catalyst for the direct amidation of benzoic acids in tetrahydrofuran at 70°C. This finding was applied to the synthesis of several important, representative bioactive compounds.
- Hoang, Linh T. M.,Ngo, Long H.,Nguyen, Ha L.,Nguyen, Hanh T. H.,Nguyen, Chung K.,Nguyen, Binh T.,Ton, Quang T.,Nguyen, Hong K. D.,Cordova, Kyle E.,Truong, Thanh
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supporting information
p. 17132 - 17135
(2015/12/04)
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- Efficient conversion of acids and esters to amides and transamidation of primary amides using OSU-6
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OSU-6, an MCM-41 type hexagonal mesoporous silica with strong Bronsted acid properties, has been used to promote the high-yield conversion of carboxylic acids and esters to carboxamides as well as transamidations of primary amides in a one-pot solventless approach. A metal-free heterogeneous catalyst that promotes all of these processes has not been previously reported. OSU-6 enables these transformations to proceed in shorter times and at lower temperatures for a broad range of substrates. An added benefit is that the catalyst can be recycled and reused multiple times without significant loss of activity.
- Nammalwar, Baskar,Muddala, Nagendra Prasad,Watts, Field M.,Bunce, Richard A.
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p. 9101 - 9111
(2015/11/09)
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- Copper(I)-Catalyzed Reductive Cross-Coupling of N-Tosylhydrazones with Amides: A Straightforward Method for the Construction of C(sp3)- N Amide Bonds from Aldehydes
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A method for the one-pot synthesis of substituted amides from aldehydes and amides is presented. Namely, condensation of aldehydes with N-tosylhydrazide generated the N-tosylhydrazones which were then reductively cross-coupled in situ with primary or secondary amides in the presence of a copper catalyst to afford secondary or tertiary amides, respectively. The reaction proceeded efficiently for a wide range of aldehydes and amides under the optimized conditions, i.e., 10 mol% of tetrakis(acetonitrile)copper(I) tetrafluoroborate [Cu(CH3CN)4BF4], 1 mol% of tetra-n-butylammonium iodide [(n-Bu)4NI], and sodium hydroxide [NaOH] as base in tetrahydrofuran (THF) at 80 C. As a result, the method provides a straightforward route for the synthesis of substituted amides from readily available aldehydes via a transition metal-catalyzed C(sp3)- N amide bond forming reaction.
- Xu, Peng,Han, Fu-She,Wang, Yan-Hua
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supporting information
p. 3441 - 3446
(2016/01/25)
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- A flexible approach to Pd-catalyzed carbonylations via aroyl dimethylaminopyridinium salts
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4-Dimethylaminopyridine (DMAP) is shown to undergo Pd/PtBu3 catalyzed coupling with aryl halides and carbon monoxide to form electrophilic aroyl-DMAP salts. The reaction is easily scalable to prepare multigram quantities with low catalyst loadings, while the precipitation of these salts as they form leads to products with low impurities. These reagents rapidly react with a variety of nucleophiles, including those that contain potentially incompatible functional groups under standard carbonylative conditions.
- Quesnel, Jeffrey S.,Fabrikant, Alexander,Arndtsen, Bruce A.
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p. 295 - 300
(2015/12/30)
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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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p. 93248 - 93251
(2015/11/17)
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- A novel nickel-catalyzed synthesis of thioesters, esters and amides from aryl iodides in the presence of chromium hexacarbonyl
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This study describes our findings on a novel and cheap NiCl2 catalytic system under ligand-free conditions for the efficient thiocarbonylation, alkoxycarbonylation and amidocarbonylation reactions of aryl iodides in the presence of Cr(CO)6 as the solid source of carbon monoxide under air. A variety of aryl iodides tolerated the reaction conditions and structurally different thiols, alcohols and amines were used efficiently. The corresponding thioesters, esters and amides were obtained in good to excellent yield at atmospheric pressure under mild reaction conditions.
- Iranpoor, Nasser,Firouzabadi, Habib,Etemadi-Davan, Elham,Nematollahi, Arash,Firouzi, Hamid Reza
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p. 6445 - 6452
(2015/08/11)
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- Bi(OTf)3-Catalyzed Multicomponent α-Amidoalkylation Reactions
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A bismuth(III) triflate catalyzed three-component synthesis of α-substituted amides starting from amides, aldehydes, and (hetero)arenes is reported. The reaction has a broad substrate scope, encompassing formaldehyde as well as aryl and alkyl aldehydes. Low catalyst loadings are required, and water is formed as the only side product. The scope and limitation of this method will be discussed.
- Schneider, Angelika E.,Manolikakes, Georg
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p. 6193 - 6212
(2015/06/30)
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- Ce(III) immobilised on aminated epichlorohydrin-activated agarose matrix - "green" and efficient catalyst for transamidation of carboxamides
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The present study reports the preparation and characterisation of Ce(III) immobilised on an aminated epichlorohydrin-activated agarose matrix (CAEA) as a "green" catalyst. The catalyst was synthesised by the reaction of the epichlorohydrin-activated agarose matrix with ammonia solution, which was then treated with Ce(NO3)3 · 6H2O. The catalyst (CAEA) was characterised by FT-IR, far IR, CHN, XRD, TGA, and ICP techniques. CAEA is shown to be an effective and reusable heterogeneous catalyst for the transamidation of carboxamides with amines under solventfree conditions. The catalyst was successfully applied to the synthesis of a wide range of aromatic and aliphatic amides. High efficiency, mild reaction conditions, easy work-up, simple separation and also reusability are important advantages of this catalyst.
- Zarei, Zeinab,Akhlaghinia, Batool
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p. 1421 - 1437
(2015/09/15)
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