- Direct carbodiimide-mediated conjugation of carboxylates using pyridinium p-toluenesulfonate and tertiary amines as additives
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The use of carboxylates in the carbodiimide-mediated coupling to amines was investigated. The addition of pyridinium p-toluenesulfonate (PPTS) and a tertiary amine was found to significantly improve acylation yields by up to 70%.
- Ficht, Simon,R?glin, Lars,Ziehe, Matthias,Breyer, David,Seitz, Oliver
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Read Online
- Fluorous-tethered amine bases for organic and parallel synthesis: Scope and limitations
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The synthesis of fluorous-tethered amine bases is described. These novel fluorous-tethered reagents promote reactions, remove acidic by-products, and scavenge electrophiles. They are readily separated from the reaction mixture by solid phase extraction on a novel mixed sorbent SPE (SCX/fluorous silica gel) delivering products in high yields and purities.
- Lindsley, Craig W,Zhao, Zhijian,Leister, William H,Strauss, Kimberly A
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- Synthesis, characterization and cytotoxic evaluation of inclusion complexes between Riparin A and β-cyclodextrin
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This study performed a physicochemical characterization of the inclusion complex generated between Riparin A and β-cyclodextrin (Rip A/β-CD) and compared the cytotoxic potential of the incorporated Rip A upon Artemia salina larvae. Samples were analyzed by phase solubility diagram, dissolution profile, differential scanning calorimetry, X-ray diffraction, infrared spectroscopy, proton nuclear magnetic resonance, scanning electron microscopy and artemicidal action. Riparin A/β-cyclodextrin complexes presented increased water solubility, AL type solubility diagram and Kst constant of 373?L/mol. Thermal analysis demonstrated reduction of the melt peak of complexed Rip A at 116.2?°C. Infrared spectroscopy confirmed generation of inclusion complexes, 1H NMR pointed out the interaction with H-3 of β-CD cavities, alterations in the crystalline natures of Rip A when incorporated within β-CD were observed and inclusion complexes presented higher cytotoxic on A.?salina nauplii, with CL50 value of 117.2 (84.9–161.8) μg/mL. So, Rip A was incorporated into β-CDs with high efficiency and water solubility of Rip A was improved. Such solubility was corroborated by cytotoxic evaluation and these outcomes support the improvement of biological properties for complexes between Riparin A/β-cyclodextrin.
- Araújo, éverton José Ferreira de,Silva, Oskar Almeida,Rezende-Júnior, Luís Mário,Sousa, Ian Jhemes Oliveira,Araújo, Danielle Yasmin Moura Lopes de,Carvalho, Rusbene Bruno Fonseca de,Pereira, Sean Telles,Gutierrez, Stanley Juan Chavez,Ferreira, Paulo Michel Pinheiro,Lima, Francisco das Chagas Alves
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Read Online
- 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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- Enhancement of the carbamate activation rate enabled syntheses of tetracyclic benzolactams: 8-oxoberbines and their 5- And 7-membered C-ring homologues
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A route to the direct amidation of aromatic-ring-tetheredN-carbamoyl tetrahydroisoquinoline substrates was developed. This route enabled general access to 8-oxoberberines and their 5- and 7- membered C-ring homologues. It overcomes the undesired tandem side-reactions that result in the destruction of the isoquinoline backbone, which inevitably occurred under our previously reported superacidic carbamate activation method.
- Kurouchi, Hiroaki
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supporting information
p. 653 - 658
(2021/02/06)
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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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- 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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p. 2339 - 2358
(2021/02/03)
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- Sustainable triazine-based dehydro-condensation agents for amide synthesis
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Conventional methods employed today for the synthesis of amides often lack of economic and environmental sustainability. Triazine-derived quaternary ammonium salts, e.g., 4-(4,6-dimethoxy-1,3,5-triazin-2-yl)-4-methylmorpholinium chloride (DMTMM(Cl)), emerged as promising dehydro-condensation agents for amide synthesis, although suffering of limited stability and high costs. In the present work, a simple protocol for the synthesis of amides mediated by 2-chloro-4,6-dimethoxy-1,3,5-triazine (CDMT) and a tert-amine has been described and data are compared to DMTMM(Cl) and other CDMT-derived quaternary ammonium salts (DMT-Ams(X), X: Cl? or ClO4?). Different tert-amines (Ams) were tested for the synthesis of various DMT-Ams(Cl), but only DMTMM(Cl) could be isolated and employed for dehydro-condensation reactions, while all CDMT/tert-amine systems tested were efficient as dehydro-condensation agents. Interestingly, in best reaction conditions, CDMT and 1,4-dimethylpiperazine gave N-phenethyl benzamide in 93% yield in 15 min, with up to half the amount of tert-amine consumption. The efficiency of CDMT/tert-amine was further compared to more stable triazine quaternary ammonium salts having a perchlorate counter anion (DMT-Ams(ClO4)). Overall CDMT/tert-amine systems appear to be a viable and more economical alternative to most dehydro-condensation agents employed today.
- Sole, Roberto,Gatto, Vanessa,Conca, Silvia,Bardella, Noemi,Morandini, Andrea,Beghetto, Valentina
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- Method for click construction of amido bond by using pyrimidine condensing agent and application of amido bond in synthesis of amide and polypeptide
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The invention discloses a method for click construction of an amido bond by using a pyrimidine condensing agent and an application of the amido bond in synthesis of amide and polypeptide. The amido bond construction method comprises the following steps: adding an organic solvent dissolved with organic alkali into a carboxylic acid component and an amine component, stirring for reaction, adding an organic solvent dissolved with a pyrimidine condensing agent, continuously stirring for reaction, concentrating, separating and purifying to obtain an amide or polypeptide product. According to the amido bond construction method, the use amount of the condensing agent is small, and the condensing agent is safe, odorless and easy to store and has good atom economy. The amido bond construction reaction time is only several seconds to ten minutes, and the amide or polypeptide synthesis time is greatly shortened. Besides, the amido bond construction reaction can also be quickly carried out in an organic phase-water phase biphasic system and in the organic phase-water phase biphasic system under the condition that alkali is not added, so that a mild and feasible path is provided for the amido bond construction reaction in an alkali-sensitive biological system.
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Paragraph 0160-0163; 0207-0208
(2021/05/29)
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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 0073-0074
(2021/05/12)
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- Synthesis of Amidation Agents and Their Reactivity in Condensation Reactions
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Nowadays, the development of new approaches which smartly bypass the use of harsh reaction conditions and hazardous chemicals covers a pivotal role. In this research paper the synthesis, characterization, and application of novel libraries of triazine bis-quaternary ammonium salts, employed as coupling agents to produce amides is reported. Full characterization of the novel compounds by 1H and 13C NMR, FT-IR spectroscopy, ESI-HRMS, and elemental analysis is provided. Furthermore, a comparison in terms of activity of the preformed triazine compounds versus in situ formulations has been evaluated for the formation of amides in the presence of phenylethylamine and different aliphatic or aromatic acids. A possible correlation between the chemical structure of the triazine and their reactivity for the formation of the triazine bis-quaternary ammonium salts is also reported. Moreover, best performing condensation agents have been further tested for the cross-linking of collagen powder as possible wet white tanning systems, for sustainable and environmentally friendly leather tanning.
- Sole, Roberto,Agostinis, Lodovico,Conca, Silvia,Gatto, Vanessa,Bardella, Noemi,Morandini, Andrea,Buranello, Chiara,Beghetto, Valentina
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supporting information
p. 1672 - 1682
(2021/02/01)
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- Discovery of quinuclidine modulators of cellular progranulin
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Phenotypic screening of an annotated small molecule library identified the quinuclidine tetrahydroisoquinoline solifenacin (1) as a robust enhancer of progranulin secretion with single digit micromolar potency in a murine microglial (BV-2) cell line. Subsequent SAR development led to the identification of 29 with a 38-fold decrease in muscarinic receptor antagonist activity and a 10-fold improvement in BV-2 potency.
- Burnett, Duane A.,Chen, Angela Y.-P.,Koenig, Gerhard,Lanter, James C.,Williamson, Toni,Blain, Jean-Fran?ois
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- Allenone-Mediated Racemization/Epimerization-Free Peptide Bond Formation and Its Application in Peptide Synthesis
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Allenone has been identified as a highly effective peptide coupling reagent for the first time. The peptide bond was formed with an α-carbonyl vinyl ester as the key intermediate, the formation and subsequent aminolysis of which proceed spontaneously in a racemization-/epimerization-free manner. The allenone coupling reagent not only is effective for the synthesis of simple amides and dipeptides but is also amenable to peptide fragment condensation and solid-phase peptide synthesis (SPPS). The robustness of the allenone-mediated peptide bond formation was showcased incisively by the synthesis of carfilzomib, which involved a rare racemization-/epimerization-free N to C peptide elongation strategy. Furthermore, the successful synthesis of the model difficult peptide ACP (65-74) on a solid support suggested that this method was compatible with SPPS. This method combines the advantages of conventional active esters and coupling reagents, while overcoming the disadvantages of both strategies. Thus, this allenone-mediated peptide bond formation strategy represents a disruptive innovation in peptide synthesis.
- Wang, Penghui,Wang, Xuewei,Wang, Zhengning,Zhao, Junfeng
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supporting information
p. 10374 - 10381
(2021/07/26)
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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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- N-acyltriazinedione; a novel acylating reagent synthesized from a triazinone-type condensing reagent
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In this paper, we report the synthesis of N-acyltriazinedione via the unexpected O–N acyl rearrangement of acyloxytriazinone and its utility as an acylating reagent. N-Acyltriazinedione can be isolated by silica gel column chromatography and reacts with amines in the absence of any base to give the corresponding amides in good yields.
- Yamada, Kohei,Lee, Jeongsu,Kota, Mika,Karuo, Yukiko,Kitamura, Masanori,Kunishima, Munetaka
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p. 498 - 502
(2021/05/27)
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- Chemoselective Amide-Forming Ligation Between Acylsilanes and Hydroxylamines Under Aqueous Conditions
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We report the facile amide-forming ligation of acylsilanes with hydroxylamines (ASHA ligation) under aqueous conditions. The ligation is fast, chemoselective, mild, high-yielding and displays excellent functional-group tolerance. Late-stage modifications of an array of marketed drugs, peptides, natural products, and biologically active compounds showcase the robustness and functional-group tolerance of the reaction. The key to the success of the reaction could be the possible formation of the strong Si?O bond via a Brook-type rearrangement. Given its simplicity and efficiency, this ligation has the potential to unfold new applications in the areas of medicinal chemistry and chemical biology.
- Deng, Xingwang,Zhou, Guan,Tian, Jing,Srinivasan, Rajavel
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supporting information
p. 7024 - 7029
(2020/12/29)
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- Visible Light-Driven Efficient Synthesis of Amides from Alcohols using Cu?N?TiO2 Heterogeneous Photocatalyst
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Amides were synthesized from alcohols and amines in high yields using an in situ generated active ester of N-hydroxyimide with our developed Cu?N?TiO2 catalyst at room temperature using oxygen as a sole oxidant under visible light. The catalyst can be easily prepared, robust, and recycled four times without a considerable change in catalytic activity. This developed protocol applies to a wide substrate scope and has good functional group tolerance. The application of this amidation reaction has been successfully demonstrated for the synthesis of moclobemide, an antidepressant drug, and an analog of the itopride drug on a gram scale.
- Singha, Krishnadipti,Ghosh, Subhash Chandra,Panda, Asit Baran
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supporting information
p. 657 - 662
(2021/02/02)
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- Base-Mediated Anti-Markovnikov Hydroamidation of Vinyl Arenes with Arylamides
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We investigated a base-promoted protocol for the intermolecular anti-Markovnikov hydroamidation of vinyl arenes with arylamides to furnish the arylethylbenzamides with excellent chemo- and regioselectivity. The reaction tolerates an extensive variety of functional groups and has been successfully extended with electronically varied handles, aminobenzamides, electron-rich/electron-deficient heterocyclic amides, and vinyl arenes to afford the hydroamidated products. Excellent chemoselectivity was observed for the amide group over amine. The proposed mechanism and vital role of the solvent was well supported by deuterium labeling studies and control experiments.
- Ayushee,Patel, Monika,Meena, Priyanka,Jahan, Kousar,Bharatam, Prasad V.,Verma, Akhilesh K.
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supporting information
p. 565 - 570
(2021/01/26)
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- Diprotonative stabilization of ring-opened carbocationic intermediates: conversion of tetrahydroisoquinoline to triarylmethanes
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Superacid-promoted conversion of tetrahydroisoquinolines to triarylmethanes via tandem reactions of C-N bond scission, Friedel-Crafts alkylation, C-O bond scission, and electrophilic aromatic amidation was developed. Dication formation was important for stabilizing the ring-opened carbocationic intermediate, which is a new role for diprotonation in reaction mechanisms. This journal is
- Kurouchi, Hiroaki
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supporting information
p. 8313 - 8316
(2020/08/17)
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- Volatiles from the Psychrotolerant Bacterium Chryseobacterium polytrichastri
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The flavobacterium Chryseobacterium polytrichastri was investigated for its volatile profile by use of a closed-loop stripping apparatus (CLSA) and subsequent GC-MS analysis. The analyses revealed a rich headspace extract with 71 identified compounds. Compound identification was based on a comparison to library mass spectra for known compounds and on a synthesis of authentic standards for unknowns. Important classes were phenylethyl amides and a series of corresponding imines and pyrroles.
- Lauterbach, Lukas,Dickschat, Jeroen S.
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p. 3608 - 3617
(2020/09/22)
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- Asymmetric Transfer Hydrogenation of Unhindered and Non-Electron-Rich 1-Aryl Dihydroisoquinolines with High Enantioselectivity
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The use of arene/Ru/TsDPEN catalysts bearing a heterocyclic group on the TsDPEN in the asymmetric transfer hydrogenation (ATH) of dihydroisoquinolines (DHIQs) containing meta- or para-substituted aromatic groups at the 1-position results in the formation of products of high enantiomeric excess. Previously, only 1-(ortho-substituted)aryl DHIQs, or with an electron-rich fused ring gave products with high enantioselectivity; therefore, this approach solves a long-standing challenge for imine ATH.
- Barrios-Rivera, Jonathan,Xu, Yingjian,Wills, Martin
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supporting information
p. 6283 - 6287
(2020/09/02)
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- Copper-Catalyzed Radical N-Demethylation of Amides Using N-Fluorobenzenesulfonimide as an Oxidant
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An unprecedented N-demethylation of N-methyl amides has been developed by use of N-fluorobenzenesulfonimide as an oxidant with the aid of a copper catalyst. The conversion of amides to carbinolamines involves successive single-electron transfer, hydrogen-atom transfer, and hydrolysis, and is accompanied by formation of N-(phenylsulfonyl)benzenesulfonamide. Carbinolamines spontaneously decompose to N-demethylated amides and formaldehyde, because of their inherent instability.
- Yi, Xuewen,Yi, Xuewen,Lei, Siyu,Liu, Wangsheng,Che, Fengrui,Yu, Chunzheng,Liu, Xuesong,Wang, Zonghua,Zhou, Xin,Zhang, Yuexia
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p. 4583 - 4587
(2020/05/05)
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- N-demethylation method for amide and application thereof
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The invention discloses an N-demethylation method for amide and application thereof. The method comprises the following steps: heating raw amide to 40-120 DEG C under the action of N-fluorodibenzenesulfonamide and a bivalent copper salt, and carrying out a reaction to obtain demethylated amide. The chemical structural formula of the raw amide is described in the specification; the chemical structural formula of the demethylated amide is described in the specification; and in the formulas, R1 is selected from aryl, alkyl and alkenyl groups, and R2 is selected from aryl, alkyl and alkenyl groups. With the method, N-demethylation of amide can be achieved; and the method has the advantages of mild reaction conditions, easiness in operation, low cost and the like.
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Paragraph 0131-0139; 0144
(2020/06/30)
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- Direct amidation of non-activated carboxylic acid and amine derivatives catalyzed by TiCp2Cl2
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This paper described a mild and efficient direct amidation of non-activated carboxylic acid and amine derivatives catalyzed by TiCp2Cl2. Arylacetic acid derivatives reacted with different amines to afford the corresponding amides in good to excellent yield except of aniline. Aryl formic acids failed to react with aniline but smoothly reacted with aliphatic amines and benzylamine in moderate to good yield, fatty acids reacting with benzyl and aliphatic amines give amides in good to excellent yield. Chiral amino acids derivatives were transformed into amides without racemization in moderate yield. The possible mechanism of direct amidation catalyzed by TiCp2Cl2 was discussed. This catalytic method is very suitable for the amidation of low sterically hindered arylacetic acid, fatty acids with different low sterically hindered amines except aniline, as well as the amidation of aryl formic acid with benzyl and aliphatic amines.
- Wang, Hui,Dong, Wei,Hou, Zhipeng,Cheng, Lidan,Li, Xiufen,Huang, Longjiang
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- Copper-catalyzed aerobic oxidative C-C bond cleavage of simple ketones for the synthesis of amides
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A Cu-catalyzed oxidative amidation of simple ketones with amines via carbon-carbon (C-C) bond cleavage has been developed. A number of aryl and alkyl ketones could be easily converted to amides using cheap copper salt as the catalyst and O2 as the oxidant with a wide range of amines, including primary and secondary amines. This method shows a notable advantage of the broad scope for the substrate, thus providing a practical approach to amides. A plausible mechanism is proposed based on the preliminary experiments.
- Li, Ke,Liu, Wei,Liu, Yu-Feng,Yang, Guo-Ping,Zeng, Kai
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p. 6958 - 6964
(2020/10/02)
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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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- Rhodium-Catalyzed Addition of Organozinc Iodides to Carbon-11 Isocyanates
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Amides were prepared using rhodium-catalyzed coupling of organozinc iodides and carbon-11 (11C, t1/2 = 20.4 min) isocyanates. Nonradioactive isocyanates and sp3 or sp2 organozinc iodides generated amides in yields of 13%-87%. Incorporation of cyclotron-produced [11C]CO2 into 11C-amide products proceeded in yields of 5%-99%. The synthetic utility of the methodology was demonstrated through the isolation of [11C]N-(4-fluorophenyl)-4-methoxybenzamide ([11C]6g) with a molar activity of 267 GBq μmol-1 and 12% radiochemical yield in 21 min from the beginning of synthesis.
- Fouad, Moustafa H.,Ismailani, Uzair S.,Mair, Braeden A.,Munch, Maxime,Rotstein, Benjamin H.
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p. 2746 - 2750
(2020/04/16)
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- Visible Light-Induced Amide Bond Formation
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A metal-, base-, and additive-free amide bond formation reaction was developed under an organic photoredox catalyst. This green approach showed excellent functional selectivity without affecting other functional groups such as alcohols, phenols, ethers, esters, halogens, or heterocycles. This method featured a broad substrate scope, good compatibility with water and air, and high yields (≤95%). The potential utilities were demonstrated by the synthesis of important drug molecules such as paracetamol, melatonin, moclobemide, and acetazolamide.
- Song, Wangze,Dong, Kun,Li, Ming
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supporting information
p. 371 - 375
(2019/11/29)
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- Preparation method for (S)-1-phenyl-1,2,3,4-tetrahydroisoquinoline
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The invention relates to a medical intermediate, in particular to a preparation method for (S)-1-phenyl-1,2,3,4-tetrahydroisoquinoline. Benzoyl chloride or benzoic acid, phenylethylamine, alkali metalhydroxide and water are mixed to react, N-(2-phenethyl)benzamide, phosphorus pentoxide and phosphorus chloride at a certain ratio are mixed and heated with organic solvent, obtained 1-phenyl-3,4-dihydroisoquinoline, a first alcohol solvent and borohydride are mixed to react, the obtained 1-phenyl-1,2,3,4-dihydroisoquinoline, a second alcohol solvent, water and D-tartaric acid are mixed and heatedto react, the obtained (S)-1-phenyl-1,2,3,4-tetrahydroisoquinoline tartrate, alkali metal hydroxide and water are mixed to obtain a target product. The preparation method for (S)-1-phenyl-1,2,3,4-tetrahydroisoquinoline has the advantages of simpleness in operation and aftertreatment.
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Paragraph 0022; 0023
(2019/03/31)
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- Josiphos-Type Binaphane Ligands for Iridium-Catalyzed Enantioselective Hydrogenation of 1-Aryl-Substituted Dihydroisoquinolines
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Convenient synthesis and useful application of a series of Josiphos-type binaphane ligands were described. The iridium complexes of these chiral diphosphines displayed excellent enantioselectivity and good reactivity in the asymmetric hydrogenation of challenging 1-aryl-substituted dihydroisoquinoline substrates (full conversions, up to >99% ee, 4000 TON). The use of 40% HBr (aqueous solution) as an additive dramatically improved the asymmetric induction of these catalysts. This transformation provided a highly efficient and enantioselective access to chiral 1-aryl-substituted tetrahydroisoquinolines, which were of great importance and common in natural products and biologically active molecules.
- Nie, Huifang,Zhu, Yupu,Hu, Xiaomu,Wei, Zhao,Yao, Lin,Zhou, Gang,Wang, Pingan,Jiang, Ru,Zhang, Shengyong
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supporting information
p. 8641 - 8645
(2019/10/17)
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- Tf2O-Mediated Intermolecular Coupling of Secondary Amides with Enamines or Ketones: A Versatile and Direct Access to β-Enaminones
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Based on the Tf2O-mediated intermolecular reaction of secondary amides with enamines derived from ketones, a novel approach to β-enaminones has been developed. The reaction is widely functional group tolerant and highly chemoselective. In the presence of 4 ? molecular sieves, the method can be extended to the one-pot condensation of secondary amides with ketones for NH β-enaminones synthesis.
- Liu, Yong-Peng,Zhu, Cheng-Jie,Yu, Cun-Cun,Wang, Ai-E,Huang, Pei-Qiang
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supporting information
p. 7169 - 7174
(2019/11/16)
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- Amide bond synthesis via silver(I) N-heterocyclic carbene-catalyzed and tert-butyl hydroperoxide-mediated oxidative coupling of alcohols with amines under base free conditions
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We present a base free method for amide bond construction via oxidative coupling of alcohols with amines catalyzed by Silver(I) N-heterocyclic carbenes (Ag(I)-NHCs) and mediated by tert-butyl hydroperoxide (TBHP) in ethanol. The results of controlled experiments suggest that the oxidative coupling proceeds through the formation of aldehyde, then subsequent attack by amine to give hemiaminal, which can then be oxidized to amide.
- Balaboina, Ramesh,Thirukovela, Narasimha Swamy,Vadde, Ravinder,Vasam, Chandra Sekhar
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supporting information
p. 847 - 851
(2019/02/20)
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- Development of Triazinone-Based Condensing Reagents for Amide Formation
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Novel triazinone-based condensing reagents have been developed. The palladium-catalyzed O-N allylic rearrangement of 2-(allyloxy)-4,6-dichloro-1,3,5-triazine and subsequent regioselective substitution using alcohols and an amine afforded chlorotriazinones, which can be readily converted using N-methylmorpholine into the corresponding condensing reagents. The condensation of carboxylic acids and amines using these reagents proceeded to afford the desired amides in good yields. In comparison with 4-(4,6-dimethoxy-1,3,5-triazin-2-yl)-4-methylmorpholinium chloride, the newly synthesized triazinone-based condensing reagents exhibited higher reactivity.
- Yamada, Kohei,Kota, Mika,Takahashi, Kensuke,Fujita, Hikaru,Kitamura, Masanori,Kunishima, Munetaka
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p. 15042 - 15051
(2019/11/19)
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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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- Solifenacin succinate raw medicine synthesis process
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The invention discloses a solifenacin succinate raw medicine synthesis process. 2-phenylethylamine and 3-quinuclidinone hydrochloride are respectively used as starting raw materials for synthesizing afragment A and a fragment B; then, condensation reaction occurs to generate solifenacin; through salt formation, the solifenacin succinate is obtained. The process is characterized in that straight-chain paraffin and water are used as reaction solvents; alkali metal hydroxides or carbonate and bicarbonates of the alkali metal hydroxides are used as acid-binding agents; phenylethylamine and benzoyl chloride take acylation reaction to generate midbodies 1 of solid precipitation fragments A insoluble in reaction solvents; in the post treatment process, filtering is directly performed; isomers ofthe fragment A are subjected to catalytic racemization through alkali metal hydroxides by using dimethylsulfoxide as a solvent, so that the byproduct isomers can be recovered and utilized; in the second-step reaction post treatment of the fragment B, a conventional pressure reduced distillation method is used for obtaining high-purity and high-yield 3-acetoxyquinine acetate. The invention provides a novel synthesis process with the advantages of high yield and economic and environment-friendly effects, and is suitable for industrial mass production.
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Paragraph 0021; 0099; 0100
(2018/08/28)
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- Method of preparing amides by catalyzed reaction of esters and amines
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The invention provides a method of preparing amides by catalyzed reaction of esters and amines. Raw materials in the method are simple and easily obtainable, the method is simple to perform, has no need for adding solvents and has high yield, and the applicable range of substrates is wide. The method comprises the steps of allowing an ester of formula (I) shown in the description and an amine of formula (II) shown in the description to react under the catalysis of the catalyst alkoxy rare-earth metal cluster containing the basic metal sodium to obtain a compound of formula (III) shown in the description; alternatively, allowing the ester of formula (I) and the amine of formula (II) to react under the catalysis of the catalyst alkoxy rare-earth metal cluster containing the basic metal sodium to obtain a compound of formula (V) shown in the description, wherein R1 is selected from alkyl, aryl or heteroaryl, R2, R3 and R4 are independently selected from alkyl alcohol, alkyl, cycloalkyl, heterocyclyl, aryl or heteroaryl, or R3 and R4 are independently selected from alkyl alcohol and alkyl while R3, R4 and atoms connected to them form a ring. The reaction formulas are shown in the description.
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Paragraph 0102; 0104; 0105
(2018/04/27)
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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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- Ruthenium-based catalytic systems incorporating a labile cyclooctadiene ligand with N-heterocyclic carbene precursors for the atom-economic alcohol amidation using amines
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Transition-metal-catalyzed amide-bond formation from alcohols and amines is an atom-economic and eco-friendly route. Herein, we identified a highly active in situ N-heterocyclic carbene (NHC)/ruthenium (Ru) catalytic system for this amide synthesis. Various substrates, including sterically hindered ones, could be directly transformed into the corresponding amides with the catalyst loading as low as 0.25 mol.%. In this system, we replaced the p-cymene ligand of the Ru source with a relatively labile cyclooctadiene (cod) ligand so as to more efficiently obtain the corresponding poly-carbene Ru species. Expectedly, the weaker cod ligand could be more easily substituted with multiple mono-NHC ligands. Further high-resolution mass spectrometry (HRMS) analyses revealed that two tetra-carbene complexes were probably generated from the in situ catalytic system.
- Chen, Cheng,Miao, Yang,De Winter, Kimmy,Wang, Hua-Jing,Demeyere, Patrick,Yuan, Ye,Verpoort, Francis
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- In situ Generated Ruthenium Catalyst Systems Bearing Diverse N-Heterocyclic Carbene Precursors for Atom-Economic Amide Synthesis from Alcohols and Amines
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The transition-metal-catalyzed direct synthesis of amides from alcohols and amines is herein demonstrated as a highly environmentally benign and atom-economic process. Among various catalyst systems, in situ generated N-heterocyclic carbene (NHC)-based ruthenium (Ru) halide catalyst systems have been proven to be active for this transformation. However, these existing catalyst systems usually require an additional ligand to achieve satisfactory results. In this work, through extensive screening of a diverse variety of NHC precursors, we discovered an active in situ catalyst system for efficient amide synthesis without any additional ligand. Notably, this catalyst system was found to be insensitive to the electronic effects of the substrates, and various electron-deficient substrates, which were not highly reactive with our previous catalyst systems, could be employed to afford the corresponding amides efficiently. Furthermore, mechanistic investigations were performed to provide a rationale for the high activity of the optimized catalyst system. NMR-scale reactions indicated that the rapid formation of a Ru hydride intermediate (signal at δ=?7.8 ppm in the 1H NMR spectrum) after the addition of the alcohol substrate should be pivotal in establishing the high catalyst activity. Besides, HRMS analysis provided possible structures of the in situ generated catalyst system.
- Cheng, Hua,Xiong, Mao-Qian,Cheng, Chuan-Xiang,Wang, Hua-Jing,Lu, Qiang,Liu, Hong-Fu,Yao, Fu-Bin,Chen, Cheng,Verpoort, Francis
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p. 440 - 448
(2018/02/06)
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- The Broad Aryl Acid Specificity of the Amide Bond Synthetase McbA Suggests Potential for the Biocatalytic Synthesis of Amides
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Amide bond formation is one of the most important reactions in pharmaceutical synthetic chemistry. The development of sustainable methods for amide bond formation, including those that are catalyzed by enzymes, is therefore of significant interest. The ATP-dependent amide bond synthetase (ABS) enzyme McbA, from Marinactinospora thermotolerans, catalyzes the formation of amides as part of the biosynthetic pathway towards the marinacarboline secondary metabolites. The reaction proceeds via an adenylate intermediate, with both adenylation and amidation steps catalyzed within one active site. In this study, McbA was applied to the synthesis of pharmaceutical-type amides from a range of aryl carboxylic acids with partner amines provided at 1–5 molar equivalents. The structure of McbA revealed the structural determinants of aryl acid substrate tolerance and differences in conformation associated with the two half reactions catalyzed. The catalytic performance of McbA, coupled with the structure, suggest that this and other ABS enzymes may be engineered for applications in the sustainable synthesis of pharmaceutically relevant (chiral) amides.
- Petchey, Mark,Cuetos, Anibal,Rowlinson, Benjamin,Dannevald, Stephanie,Frese, Amina,Sutton, Peter W.,Lovelock, Sarah,Lloyd, Richard C.,Fairlamb, Ian J. S.,Grogan, Gideon
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supporting information
p. 11584 - 11588
(2018/09/10)
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- Preparation method of acetylene amide mediated thioacid amide and application of acetylene amide mediated thioacid amide in thiopeptide synthesis
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The invention discloses an acetylene amide mediated method for selectively synthesizing carbonyl thioesters and ordinary thioesters. The ordinary thioesters are further used for preparing amides and peptides, and the carbonyl thioesters are used for preparing thioamides and thiopeptides. An addition reaction is carried out between acetylene amide in m-xylene and thiocarboxylic acid to selectivelyobtain the carbonyl thioester and ordinary thioester of which the ratio is 3:1 under the condition of 40 DEG C below zero; the ordinary thioesters can carry out a combination reaction with amines to produce amides and peptides; and the carbonyl can carry out a combination reaction with the amines to produce thioamides and thiopeptides. The method disclosed by the invention is mild in reaction conditions, free of any metal catalyst, high in reaction speed, high in yield, simple in operation and wide in application range. With respect to chiral thiocarboxylic acid in a position alpha of carboxyl, when thioamide bonds or thiopeptide bonds are formed from the carbonyl thioesters or when amido bonds or peptide bonds are formed from the ordinary thioesters, any racemization phenomenon can be avoided.
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Paragraph 0056
(2018/09/21)
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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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- A carbonylation reaction of carbon monoxide in the method of preparing amide
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The invention belongs to the technical field of synthesis of amides, discloses a process for the carbonylation of carbon monoxide in the method of preparing amide, the method is to cheap and easy to obtain the halogenated aromatic hydrocarbon and organic amine compounds as the substrate of reaction, to carbon monoxide as carbonyl source, under light-struck, halogenated aromatic hydrocarbons are cracked to produce free radical, by free-radical addition process to obtain the amide compound. Compared with the traditional carbonylation reaction, the carbon monoxide pressure is extremely low, can react to the atmospheric pressure. This process does not need to rely on any metal catalyst of the booster, mild reaction conditions, environmental protection, with a shorter synthetic route and high utilization efficiency of the atoms, the reaction system with higher substrate tolerance, green sustainable light source as the driving force, the atom economy is high, application prospect.
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Paragraph 0024; 0025; 0026; 0027; 0028-0032; 0105-0106; 0146
(2018/07/30)
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- Identification of an Imine Reductase for Asymmetric Reduction of Bulky Dihydroisoquinolines
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A new imine reductase from Stackebrandtia nassauensis (SnIR) was identified, which displayed over 25- to 1400-fold greater catalytic efficiency for 1-methyl-3,4-dihydroisoquinoline (1-Me DHIQ) compared to other imine reductases reported. Subsequently, an efficient SnIR-catalyzed process was developed by simply optimizing the amount of cosolvent, and up to 15 g L-1 1-Me DHIQ was converted completely without a feeding strategy. Furthermore, the reaction proceeded well for a panel of dihydroisoquinolines, affording the corresponding tetrahydroisoquinolines (mostly in S-configuration) in good yields (up to 81%) and with moderate to excellent enantioselectivities (up to 99% ee).
- Li, Hao,Tian, Ping,Xu, Jian-He,Zheng, Gao-Wei
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supporting information
p. 3151 - 3154
(2017/06/23)
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- Design, Synthesis, and Biological Evaluation of Tetrahydroisoquinoline-Based Histone Deacetylase 8 Selective Inhibitors
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Histone deacetylase 8 (HDAC8) is a promising drug target for multiple therapeutic applications. Here, we describe the modeling, design, synthesis, and biological evaluation of a novel series of C1-substituted tetrahydroisoquinoline (TIQ)-based HDAC8 inhibitors. Minimization of entropic loss upon ligand binding and use of the unique HDAC8 "open" conformation of the binding site yielded a successful strategy for improvement of both HDAC8 potency and selectivity. The TIQ-based 3g and 3n exhibited the highest 82 and 55 nM HDAC8 potency and 330- and 135-fold selectivity over HDAC1, respectively. Selectivity over other class I isoforms was comparable or better, whereas inhibition of HDAC6, a class II HDAC isoform, was below 50% at 10 μM. The cytotoxicity of 3g and 3n was evaluated in neuroblastoma cell lines, and 3n displayed concentration-dependent cytotoxicity similar to or better than that of PCI-34051. The selectivity of 3g and 3n was confirmed in SH-SY5Y cells as both did not increase the acetylation of histone H3 and α-tubulin. Discovery of the novel TIQ chemotype paves the way for the development of HDAC8 selective inhibitors for therapeutic applications.
- Taha, Taha Y.,Aboukhatwa, Shaimaa M.,Knopp, Rachel C.,Ikegaki, Naohiko,Abdelkarim, Hazem,Neerasa, Jayaprakash,Lu, Yunlong,Neelarapu, Raghupathi,Hanigan, Thomas W.,Thatcher, Gregory R. J.,Petukhov, Pavel A.
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supporting information
p. 824 - 829
(2017/08/16)
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- Triazinone compound
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PROBLEM TO BE SOLVED: To provide a novel compound useful as a dehydration condensation agent. SOLUTION: The present invention provides a triazinone compound represented by formula (I) [where each symbol is as defined in the specifications], and a use of the compound as a dehydration condensation agent. SELECTED DRAWING: None COPYRIGHT: (C)2017,JPOandINPIT
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Paragraph 0279; 0283; 0284
(2017/10/11)
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- Synthesis and characterization of S(-)1-phenyl-1,2,3,4-tetrahydro isoquinoline acetamide analogues
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S(-)1-Phenyl-1,2,3,4-tetrahydro isoquinoline acetamide analogues are prepared by sequence of reactions which involve a metal hydride reduction of 3,4-dihydroisoquinoline followed by separation of S-form with mandelic acid (chiral reagent) by resolution. The product S(-)1-phenyl-1,2,3,4-tetrahydro isoquinoline is treated with halosubstituted acetyl chlorides to obtain tetrahydro isoquinoline acetyl chloride which is further employed to synthesize acetamide derivatives of tetrahydro isoquinoline using various substituted aryl amines. The products were characterized by advanced spectroscopic techniques.
- Krishna Rao,Surendra Babu,Basaveswara Rao,Keshavi,Sundara Rao,Eswara Prasad,Murthy
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p. 1035 - 1038
(2017/03/22)
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- Unique physicochemical and catalytic properties dictated by the B3NO2 ring system
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The expansion of molecular diversity beyond what nature can produce is a fundamental objective in chemical sciences. Despite the rich chemistry of boron-containing heterocycles, the 1,3-dioxa-5-aza-2,4,6-triborinane (DATB) ring system, which is characterized by a six-membered B3NO2 core, remains elusive. Here, we report the synthesis of m-terphenyl-templated DATB derivatives, displaying high stability and peculiar Lewis acidity arising from the three suitably arranged boron atoms. We identify a particular utility for DATB in the dehydrative amidation of carboxylic acids and amines, a reaction of high academic and industrial importance. The three boron sites are proposed to engage in substrate assembly, lowering the entropic cost of the transition state, in contrast with the operative mechanism of previously reported catalysts and amide coupling reagents. The distinct mechanistic pathway dictated by the DATB core will advance not only such amidations, but also other reactions driven by multisite activation.
- Noda, Hidetoshi,Furutachi, Makoto,Asada, Yasuko,Shibasaki, Masakatsu,Kumagai, Naoya
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p. 571 - 577
(2017/06/01)
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- Intensified Microwave-Assisted N-Acylation Procedure - Synthesis and Activity Evaluation of TRPC3 Channel Agonists with a 1,3-Dihydro-2H-benzo[d]imidazol-2-one Core
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Upon controlled microwave heating and using cyanuric chloride as a coupling reagent, an efficient amidation procedure for the synthesis of 1,3-dihydro-2H-benzo[d]imidazol-2-one-based agonists of TRPC3/6 ion channels has been developed. Compared to the few conventional protocols, a drastic reduction in processing time from ca. 2 days down to 10 minutes was achieved accompanied by significantly improved product yields. The robustness of the method was confirmed by 18 additional examples including aromatic, aliphatic, and heterocyclic amines and acids. The obtained agonists were screened for biological activity at 1 μM concentration and few structure-activity relations have been established.
- Guedes de La Cruz, Gema,Svobodova, Barbora,Lichtenegger, Michaela,Tiapko, Oleksandra,Groschner, Klaus,Glasnov, Toma
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p. 695 - 700
(2017/03/21)
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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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