- A Facile Regioselective Aromatic Fluorination of N-Aryl-N-hydroxyamides with Diethylaminosulfur Trifluoride (DAST)
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Treatment of N-aryl-N-hydroxyamides with diethylaminosulfur trifluoride (DAST) under conventional reaction conditions results in removal of the hydroxy function and introduction of a fluorine atom at the para position of the aromatic ring, in high yield.
- Kikugawa, Yasuo,Matsumoto, Kazuhiro,Mitsui, Kimiyo,Sakamoto, Takeshi
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- Synthesis method of o-bromo-p-fluoroacetyl aniline
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The invention relates to a synthesis method of o-bromo-p-fluoroacetyl aniline, and belongs to the technical field of synthesis of chemical intermediates. According to the preparation method, potassium fluoride and parachloronitrobenzene are taken as starting raw materials, halogen exchange, reduction, acylation reaction and bromination reaction are carried out, then the o-bromo-p-fluoroacetyl aniline is prepared, and the synthesis method which is high in operability, high in product yield and high in purity is provided for synthesis of the o-bromo-p-fluoroacetyl aniline.
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- Arylquinolinecarboxamides: Synthesis, in vitro and in silico studies against Mycobacterium tuberculosis
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A series of fourteen 6-substituted-2-(methoxyquinolin-3-yl) methyl)-N-(pyridin-3-ylmethyl) benzamides was prepared from commercially available anilines in five simple and convenient synthetic steps. The structures of all new products were confirmed by routine spectroscopic methods: IR, 1H and 13C NMR, and HRMS (electrospray ionization). The resulting arylquinolinecarboxamides were subjected to biological screening assay for in vitro inhibitory activity against Mycobacterium tuberculosis (Mtb) H37Rv strain. Several compounds exhibited modest antitubercular activity with compounds 8–11, 15 and 19 exhibiting MIC90 values in the range of 32–85 μM. The antitubercular data suggested that inhibition of Mtb can be imparted by the introduction of a non-polar substituent on C-6 of the quinoline scaffold. Further, to understand the possible mode of action of the series, the reported compounds and bedaquiline were subjected to in silico docking studies against MtbATPase to determine their potential to interfere with the mycobacterial adenosine triphosphate (ATP) synthase. The results showed that these compounds have the potential to serve as antimycobacterial agents. In silico ADME pharmacokinetic prediction results showed the ability of these arylquinolinecarcboxamides to be absorbed, distributed, metabolized and excreted efficiently.
- Bokosi, Fostino R. B.,Beteck, Richard M.,Jordaan, Audrey,Seldon, Ronnet,Warner, Digby F.,Tshiwawa, Tendamudzimu,Lobb, Kevin,Khanye, Setshaba D.
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supporting information
p. 2140 - 2151
(2021/07/21)
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- Paracetamol and other acetanilide analogs as inter-molecular hydrogen bonding assisted diamagnetic CEST MRI contrast agents
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Paracetamol and a few other acetanilide derivatives are reported as a special class of diamagnetic Chemical Exchange Saturation Transfer (diaCEST) MRI contrast agents, that exhibit contrast only when the molecules form inter-molecular hydrogen bonding mediated molecular chains or sheets. Without the protection of the hydrogen bonding their contrast producing labile proton exchanges too quickly with the solvent to produce any appreciable contrast. Through a number of variable temperature experiments we demonstrate that under the conditions when the hydrogen bond network breaks and the high exchange returns back, the contrast drops quickly. The well-known analgesic drug paracetamol shows 12% contrast at a concentration of 15 mM at physiological conditions. With the proven safety track-record for human consumption and appreciable physiological contrast, paracetamol shows promise as a diaCEST agent forin vivostudies.
- Chakraborty, Subhayan,Peruncheralathan,Ghosh, Arindam
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p. 6526 - 6534
(2021/02/21)
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- Synthesis, crystal structure, anticancer and molecular docking studies of quinolinone-thiazolidinone hybrid molecules
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A new series of quinolone-thiazolidinone hybrid molecules 8a-o were prepared. Quinoline compounds were synthesized by Meth-Cohn synthesis and were condensed with 2,3-disubstituted thiazolidinone. These molecules were screened for their anticancer activities against MDA-MB-231 and MCF-7 cell line using MTT assay. Potent compounds were tested for their cytotoxicity on normal HEK 293 cell lines and most potent compound was tested for its cell cycle analysis. Molecular docking and molecular dynamic studies were performed on human N-acetyl transferase (hNAT-1) protein using Schrodinger molecular docking toolkit. Compound 8n emerged as potent with IC50 8.16?μM against MDA-MB-231 cell line followed by 8e with IC50 17.68?μM. Compound 8n arrested cell cycle at G2/M phase and was non-toxic to human normal kidney cell line. The potent compound 8n binds well with human NAT-1 protein with remarkable hydrogen bonding and π–π interactions. Molecular dynamic studies of 8n further confirm the target for these molecules. Target quinolinone-thiazolidinones were found to be new class of compounds targeting hNAT-1 and can serve as new lead compounds in drug discovery.
- Krishnappagowda, Lokanath Neratur,Kumar, Vasantha,Pai, Vinitha R.,Poojary, Boja,Rai, Vaishali M.,Shivalingegowda, Naveen,Udupi, Vishwanatha
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- Method for catalyzing one-pot hydrogenation and amidation of nitroaromatic hydrocarbon and carboxylic acid by visible light
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The invention discloses a method for catalyzing one-pot hydrogenation and amidation reaction of nitroaromatic hydrocarbon and carboxylic acid by visible light. The method comprises the following steps: preparing Pt nanoparticles uniformly dispersed on an N-doped titanium dioxide/titanium carbide (MXene) heterojunction as a photocatalyst (3% Pt/N-TiO2/Ti3C2), and applying the catalyst to a cascade reaction of an aromatic nitro compound and carboxylic acid to prepare an amide product. The 3% Pt/N-TiO2/Ti3C2 has excellent tandem hydrogenation and amidation activity and chemical selectivity of an aromatic nitro compound and carboxylic acid under the irradiation of visible light. The excellent catalytic performance of 3% Pt/N-TiO2/Ti3C2 is attributed to the close contact of TiO2 and conductive Ti3C2, and the separation efficiency of photo-induced electrons and holes is improved through charge short-range directional transmission. The preparation method of the catalyst is simple and easy to operate, the catalyst can be used for photocatalytic efficient one-pot hydrogenation and amidation reactions, the reaction conditions are mild, and the catalyst is easy to recycle.
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Paragraph 0030
(2021/06/09)
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- Visible-light induced one-pot hydrogenation and amidation of nitroaromatics with carboxylic acids over 2D MXene-derived Pt/N-TiO2/Ti3C2
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Pt nanoparticles supported on N doped titanium dioxide/titanium carbide (MXene) heterojunctions were employed as photocatalysts for the tandem reactions between aromatic nitro compounds and carboxylic acids to produce amide products. The 3%Pt/N-TiO2/Ti3C2 heterojunction was prepared by in situ grew TiO2 on Ti3C2 nanosheets and then N doped TiO2 with melamine, Pt nanoparticles with 3.3 nm mean diameter well dispersed on N-TiO2/Ti3C2. 3%Pt/N-TiO2/Ti3C2 had excellent amidation activity and chemoselectivity under visible-light irradiation. The elevated catalytic performance of 3%Pt/N-TiO2/Ti3C2 was owing to the improvement in photogenerated electron and hole separation efficiency through charge short-range directional transmission caused by the intimate contact between the TiO2 and the conductive Ti3C2. This direct hydrogenation along with amidation between nitroaromatics and carboxylic acids own actual merits in the amides produce with no harmful byproducts. In situ DRIFTS spectra verified that the amidation activation with visible light irradiation at 25 °C was much faster than heating.
- Jiang, Heyan,Hu, Zujie,Gan, Chuan,Sun, Bin,Kong, Shuzhen,Bian, Fengxia
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- Cu(OTf)2-Mediated Cross-Coupling of Nitriles and N-Heterocycles with Arylboronic Acids to Generate Nitrilium and Pyridinium Products**
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Metal-catalyzed C–N cross-coupling generally forms C?N bonds by reductive elimination from metal complexes bearing covalent C- and N-ligands. We have identified a Cu-mediated C–N cross-coupling that uses a dative N-ligand in the bond-forming event, which, in contrast to conventional methods, generates reactive cationic products. Mechanistic studies suggest the process operates via transmetalation of an aryl organoboron to a CuII complex bearing neutral N-ligands, such as nitriles or N-heterocycles. Subsequent generation of a putative CuIII complex enables the oxidative C–N coupling to take place, delivering nitrilium intermediates and pyridinium products. The reaction is general for a range of N(sp) and N(sp2) precursors and can be applied to drug synthesis and late-stage N-arylation, and the limitations in the methodology are mechanistically evidenced.
- Bell, Nicola L.,Xu, Chao,Fyfe, James W. B.,Vantourout, Julien C.,Brals, Jeremy,Chabbra, Sonia,Bode, Bela E.,Cordes, David B.,Slawin, Alexandra M. Z.,McGuire, Thomas M.,Watson, Allan J. B.
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supporting information
p. 7935 - 7940
(2021/03/03)
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- Chlorination Reaction of Aromatic Compounds and Unsaturated Carbon-Carbon Bonds with Chlorine on Demand
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Chlorination with chlorine is straightforward, highly reactive, and versatile, but it has significant limitations. In this Letter, we introduce a protocol that could combine the efficiency of electrochemical transformation and the high reactivity of chlorine. By utilizing Cl3CCN as the chloride source, donating up to all three chloride atom, the reaction could generate and consume the chlorine in situ on demand to achieve the chlorination of aromatic compounds and electrodeficient alkenes.
- Liu, Feng,Wu, Na,Cheng, Xu
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supporting information
p. 3015 - 3020
(2021/05/05)
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- Ethyl 2-Cyano-2-(2-nitrobenzenesulfonyloxyimino) Acetate (ortho-NosylOXY)-Mediated Double Beckmann Rearrangement of Ketoximes under Microwave Irradiation: A Mechanistic Perception
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A method for Beckmann rearrangement using ethyl 2-cyano-2-(2-nitrobenzenesulfonyloxyimino) acetate (o-NosylOXY) under microwave irradiation is reported. Ketoximes (19 examples) are converted to the corresponding amides/lactams with 69–97% yields in ~10 minutes without any Lewis acid or co-catalyst. This is an example of halogen-free organocatalytic Beckmann rearrangement. Nuclear magnetic resonance (NMR)- and high-resolution mass spectrometry (HRMS)-based detailed mechanistic investigation suggest that o-NosylOXY acts as an initiator. Such initiators are reported before based on density functional theory (DFT) calculations. However, we report here the HRMS signatures of two transient intermediates, the nitrilium ion and the nitrilium ion's dimeric species. Rigorous NMR-based investigation of the reaction mechanism is performed. Our results indicate that the reported Beckmann rearrangement proceeds via two consecutive rearrangements. (Figure presented.).
- Dev, Dharm,Kalita, Tapasi,Mondal, Tanmay,Mandal, Bhubaneswar
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p. 1427 - 1435
(2021/01/04)
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- Uniting Amide Synthesis and Activation by PIII/PV-Catalyzed Serial Condensation: Three-Component Assembly of 2-Amidopyridines
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An organophosphorus (PIII/PVredox) catalyzed method for the three-component condensation of amines, carboxylic acids, and pyridineN-oxides to generate 2-amidopyridines via serial dehydration is reported. Whereas amide synthesis and functionalization usually occur under divergent reaction conditions, here a phosphetane catalyst (together with a mild bromenium oxidant and terminal hydrosilane reductant) is shown to drive both steps chemoselectively in an auto-tandem catalytic cascade. The ability to both prepare and functionalize amides under the action of a single organocatalytic reactive intermediate enables new possibilities for the efficient and modular preparation of medicinal targets.
- Lipshultz, Jeffrey M.,Radosevich, Alexander T.
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supporting information
p. 14487 - 14494
(2021/09/18)
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- Method for synthesizing heteroatom- substituted aromatic compound from styrene compound
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The invention discloses a method for synthesizing a heteroatom-substituted aromatic compound from a styrene compound, which comprises the following steps of: mixing a styrene compound with a general formula (I) and a heteroatom-containing compound with a general formula (II), and reacting in the presence of an acid additive and an organic solvent to obtain a heteroatom-substituted compound with ageneral formula (III). According to the synthesis method disclosed by the invention, a large amount of styrene compounds are used as raw materials and react to generate aromatic amine or phenol compounds under the action of no metal catalysis; and compared with the traditional aromatic amine and phenol synthesis method, the method has the advantages of high yield, simple conditions, low waste discharge amount, no metal participation, simple reaction equipment, easiness in industrial production and the like.
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Paragraph 0141-0143
(2021/02/06)
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- Design, synthesis and biological evaluation of mono- and bisquinoline methanamine derivatives as potential antiplasmodial agents
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Several classes of antimalarial drugs are currently available, although issues of toxicity and the emergence of drug resistant malaria parasites have reduced their overall therapeutic efficiency. Quinoline based antiplasmodial drugs have unequivocally been long-established and continue to inspire the design of new antimalarial agents. Herein, a series of mono- and bisquinoline methanamine derivatives were synthesised through sequential steps; Vilsmeier-Haack, reductive amination, and nucleophilic substitution, and obtained in low to excellent yields. The resulting compounds were investigated for in vitro antiplasmodial activity against the 3D7 chloroquine-sensitive strain of Plasmodium falciparum, and compounds 40 and 59 emerged as the most promising with IC50 values of 0.23 and 0.93 μM, respectively. The most promising compounds were also evaluated in silico by molecular docking protocols for binding affinity to the {0 0 1} fast-growing face of a hemozoin crystal model.
- Bokosi, Fostino R.B.,Beteck, Richard M.,Mbaba, Mziyanda,Mtshare, Thanduxolo E.,Laming, Dustin,Hoppe, Heinrich C.,Khanye, Setshaba D.
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supporting information
(2021/03/01)
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- A novel construction of acetamides from rhodium-catalyzed aminocarbonylation of DMC with nitro compounds
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Dimethyl carbonate (DMC), an environment-friendly compound prepared from CO2, shows diverse reactivities. In this communication, an efficient procedure using DMC as both a C1 building block and solvent in the aminocarbonylation reaction with nitro compounds has been developed. W(CO)6acts both a CO source and a reductant here.
- Bao, Zhi-Peng,Miao, Ren-Guan,Qi, Xinxin,Wu, Xiao-Feng
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supporting information
p. 1955 - 1958
(2021/03/02)
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- Hypervalent Iodine Reagent-Promoted Hofmann-Type Rearrangement/Carboxylation of Primary Amides
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A novel transformation of primary amides to secondary amides promoted by hypervalent iodine reagents was developed. The hypervalent iodine reagent-mediated Hofmann-type rearrangement generated an isocyanate intermediate, which was subsequently trapped by an in situ generated carboxylic acid from the hypervalent iodine reagent to provide the corresponding secondary amides. This method provided a facile and efficient route for the synthesis of secondary amides from primary amides and also revealed novel reactivities of hypervalent iodine reagents.
- Wang, Xia,Yang, Peng,Hu, Bo,Zhang, Qian,Li, Dong
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p. 2820 - 2826
(2021/02/01)
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- Preparation and catalytic evaluation of a palladium catalyst deposited over modified clinoptilolite (Pd&at;MCP) for chemoselective N-formylation and N-acylation of amines
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Novel palladium nanoparticles stabilized by clinoptilolite as a natural inexpensive zeolite prepared and used for N-formylation and N-acylation of amines at room temperature at environmentally benign reaction conditions in good to excellent yields. Pd (II) was immobilized on the surface of clinoptilolite via facile multi-step amine functionalization to obtain a sustainable, recoverable, and highly active nano-catalyst. The structural and morphological characterizations of the catalyst carried out using XRD, FT-IR, BET and TEM techniques. Moreover, the catalyst is easily recovered using simple filtration and reused for 7 consecutive runs without any loss in activity.
- Amirsoleimani, Mina,Khalilzadeh, Mohammad A.,Zareyee, Daryoush
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- Synthesis method of acetanilide derivative
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The invention discloses a method for synthesizing acetanilide derivatives, and belongs to the technical field of organic synthetic intermediates. The method particularly includes steps of adding aniline derivatives, potassium thioacetate, tert-butyl nitrite and acetonitrile into reaction tubes; tightening plugs of the reaction tubes; carrying out magnetic stirring reaction at the temperature of 25DEG C for 4 hours. The aniline derivatives and the potassium thioacetate which is low in cost and easy to operate, is easily available and is stable are used as acetylation reagents, and accordinglya series of acetanilide derivatives can be efficiently synthesized by the aid of the method under the room-temperature conditions. The acetanilide derivatives which are compounds contain arylamine skeletons and can be used for synthesizing and modifying organic synthetic intermediates and medicines, and novel and effective synthesis processes can be provided to screening medicines. The reaction can be accelerated by the tert-butyl nitrite to synthesize the compounds which are the acetanilide derivatives. Compared with existing synthesis methods, the method has the advantages that reaction conditions are simple, raw materials for the acetanilide derivatives are low in cost and easy to operate, are easily available and are stable, and functional groups of substrates are good in tolerance.
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Paragraph 0024-0028
(2021/10/27)
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- Efficient nitriding reagent and application thereof
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The invention discloses an efficient nitriding reagent and application thereof, wherein the nitriding reagent comprises nitrogen oxide, an active agent, a reducing agent and an organic solvent. By applying the nitriding reagent, nitrogen-containing compounds such as amide, nitrile and the like can be produced, and the method is simple in condition, low in waste discharge amount and simple in reaction equipment.
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Paragraph 0131-0133
(2021/03/31)
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- 4 - Fluorine substituted aryl amine compound and synthesis method thereof
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The invention discloses a synthesis method of 4 -fluorine substituted aryl amine compound, which comprises the following steps: 1) taking acyl-protected phenylhydroxylamine as a substrate, and generating 4 -fluorine substituted aniline compound under basic conditions by taking sulfonyl fluoride as a fluorine source in a polar solvent. 2) The deprotection is carried out under dilute acid conditions or Pd by catalytic hydrogenation to give the 4 - fluorine-substituted aryl amine compound. 4 - Fluorine substituted aniline compounds which are synthesized by the invention greatly increase the lipophilic property due to the introduction of fluorine atoms, and can be widely applied to preparation of fluorine-containing drugs and pesticide and dye intermediates. , The adopted raw materials are industrial products, are cheap and easily available, and are commercially available. 4 - Fluoroaryl aniline prepared by the method is high in yield, and the product with the purity 90% can be obtained in a yield of more than ≥ 99%. The method is simple to operate and low in cost, is very suitable for industrialization, and can be widely popularized and used.
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Paragraph 0045-0047
(2021/09/22)
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- Method for preparing 2-bromo-5-fluoroaniline
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The invention discloses a method for preparing 2-bromo-5-fluoroaniline, belonging to the field of organic chemical synthesis. The preparation method comprises the following steps: with 4-fluoroanilineas a raw material, reacting 4-fluoroaniline with acetic anhydride to generate 4-fluoroacetanilide; performing nitrification; replacing acetamido groups with bromine; and reducing nitro groups. Thus,the 2-bromo-5-fluoroaniline with high yield and high purity is prepared. The method has the advantages of high product yield, high purity, easy availability of raw materials and simple operation, andis beneficial to industrial production.
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Paragraph 0039; 0041; 0046; 0048; 0055; 0057
(2020/12/31)
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- A one pot protocol to convert nitro-arenes into: N-aryl amides
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A two-step one pot, experimentally simple protocol, based on readily available and inexpensive reagents allowed the conversion of nitro-arenes directly to N-aryl amides. A metal-free reduction of the nitro group, mediated by trichlorosilane, followed by the addition of an anhydride afforded the corresponding N-aryl carboxyamide, that was isolated after a simple aqueous work up in good-excellent yields. When the methodology was applied to the reaction with γ-butyrolactone, the desired N-aryl butanamide derivative was obtained, featuring a chlorine atom at the γ-position, a functionalized handle that can be used for further synthetic manipulation of the reaction product. Such an intermediate has already been employed as a key advanced precursor of pharmaceutically active compounds.
- Massolo, Elisabetta,Pirola, Margherita,Puglisi, Alessandra,Rossi, Sergio,Benaglia, Maurizio
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p. 4040 - 4044
(2020/02/04)
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- Visible-light-induced Beckmann rearrangement by organic photoredox catalysis
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A facile and general strategy for efficient direct conversion of oximes to amides using an inexpensive organic photocatalyst and visible light is described. This radical Beckmann rearrangement can be performed under mild conditions. Various alkyl aryl ketoximes and diaryl ketoximes can be effectively converted into the corresponding amides in excellent yields.
- Tang, Li,Wang, Zhi-Lv,Wan, Hai-Lan,He, Yan-Hong,Guan, Zhi
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supporting information
p. 6182 - 6186
(2020/09/01)
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- Nitromethane as a nitrogen donor in Schmidt-type formation of amides and nitriles
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The Schmidt reaction has been an efficient and widely used synthetic approach to amides and nitriles since its discovery in 1923. However, its application often entails the use of volatile, potentially explosive, and highly toxic azide reagents. Here, we report a sequence whereby triflic anhydride and formic and acetic acids activate the bulk chemical nitromethane to serve as a nitrogen donor in place of azides in Schmidt-like reactions. This protocol further expands the substrate scope to alkynes and simple alkyl benzenes for the preparation of amides and nitriles.
- Jiao, Ning,Liu, Jianzhong,Qiu, Xu,Song, Song,Wei, Jialiang,Wen, Xiaojin,Zhang, Cheng,Zhang, Ziyao
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supporting information
p. 281 - 285
(2020/01/28)
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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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- Method for preparing amide by visible light-induced metal-free participation (by machine translation)
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The method for preparing the amide in the, preparation method of the novel amide disclosed by the invention has the advantages that, the reaction: conditions are mild, the 9 - reaction conditions are mild, and the yield 71%. of the reaction conditions is not lower than the reaction conditions . (by machine translation)
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Paragraph 0035-0038
(2020/02/14)
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- Synthesis and antileishmanial activity of fluorinated rhodacyanine analogues: The ‘fluorine-walk’ analysis
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In a search for potent antileishmanial drug candidates, eighteen rhodacyanine analogues bearing fluorine or perfluoroalkyl substituents at various positions were synthesized. These compounds were tested for their inhibitory activities against Leishmania martiniquensis and L. orientalis. This ‘fluorine-walk’ analysis revealed that the introduction of fluorine atom at C-5, 6, 5′, or 6′ on the benzothiazole units led to significant enhancement of the activity, correlating with the less negative reduction potentials of the fluorinated analogues confirmed by the electrochemical study. On the other hand, [sbnd]CF3 and [sbnd]OCF3 groups were found to have detrimental effects, which agreed with the poor aqueous solubility predicted by the in silico ADMET analysis. In addition, some of the analogues including the difluorinated species showed exceptional potency against the promastigote and axenic amastigote stages (IC50 = 40–85 nM), with the activities surpassing both amphotericin B and miltefosine.
- Lasing, Thitiya,Phumee, Atchara,Siriyasatien, Padet,Chitchak, Kantima,Vanalabhpatana, Parichatr,Mak, Kit-Kay,Hee Ng, Chew,Vilaivan, Tirayut,Khotavivattana, Tanatorn
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supporting information
(2019/12/09)
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- An Electrochemical Beckmann Rearrangement: Traditional Reaction via Modern Radical Mechanism
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Abstract: Electrosynthesis as a potential means of introducing heteroatoms into the carbon framework is rarely studied. Herein, the electrochemical Beckmann rearrangement, i. e. the direct electrolysis of ketoximes to amides, is presented for the first time. Using a constant current as the driving force, the reaction can be easily carried out under neutral conditions at room temperature. Based on a series of mechanistic studies, a novel radical Beckmann rearrangement mechanism is proposed. This electrochemical Beckmann rearrangement does not follow the trans-migration rule of the classical Beckmann rearrangement.
- Tang, Li,Wang, Zhi-Lv,He, Yan-Hong,Guan, Zhi
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p. 4929 - 4936
(2020/08/21)
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- Direct synthesis of secondary amides from ketones through Beckmann rearrangement using O-(mesitylsulfonyl)hydroxylamine
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The Beckmann rearrangement is a versatile method for the preparation of secondary amides from ketones via oxime intermediates and has been widely used in the synthesis of bioactive natural products and pharmaceuticals. Herein, we have developed a highly efficient direct method for the preparation of secondary amides and lactams from ketones using O-(mesitylsulfonyl)hydroxylamine (MSH). The reactions proceed rapidly at room temperature under mild condition without requiring any additive, and tolerate multiple functional groups. A simple aqueous work-up often furnished the products in excellent yield with high purity.
- Chandra, Dinesh,Verma, Saumya,Pandey, Chandra Bhan,Yadav, Ajay K.,Kumar, Puneet,Tiwari, Bhoopendra,Jat, Jawahar L.
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supporting information
(2020/03/23)
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- Zinc(II)-Catalyzed Synthesis of Secondary Amides from Ketones via Beckmann Rearrangement Using Hydroxylamine-O-sulfonic Acid in Aqueous Media
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A zinc(II)-catalyzed single-step protocol for the Beckmann rearrangement using hydroxylamine-O-sulfonic acid (HOSA) as the nitrogen source in water was developed. This direct method efficiently produces secondary amides under open atmosphere in a pure form after basic aqueous workup. It isenvironmentally benign and operationally simple.
- Verma, Saumya,Kumar, Puneet,Khatana, Anil K.,Chandra, Dinesh,Yadav, Ajay K.,Tiwari, Bhoopendra,Jat, Jawahar L.
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p. 3272 - 3276
(2020/11/02)
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- Rhodium(III)-Catalyzed Directed C-H Dienylation of Anilides with Allenes Leads to Highly Conjugated Systems
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Allenes are unique coupling partners in transition-metal-catalyzed C-H functionalization leading to a variety of products via alkenylation, allenylation, allylation, and annulation reactions. The outcome is governed by both the reactivity of the allene and the formation and stability of the organometallic intermediate. An efficient Rh(III)-catalyzed, weakly coordinating group-directed dienylation of electronically unbiased allenes is developed using an N-acyl amino acid as a ligand. Further elaboration of the dienylated products to construct polycyclic compounds is also described.
- Ghosh, Chiranjit,Nagtilak, Prajyot Jayadev,Kapur, Manmohan
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supporting information
(2019/05/08)
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- Synthesis, antibacterial activity and docking studies of substituted quinolone thiosemicarbazones
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Fifteen 2-quinolone thiosemicarbazone derivatives of which eleven were new, were synthesized at room temperature. The key intermediate was the quinolone carbaldehyde, from which thiosemicarbazones were formed by the reaction of thiosemicarbazides with the aldehyde moiety. The structures of the synthesized compounds were elucidated by 1D and 2D-NMR spectroscopy and mass spectrometry. The synthesized compounds showed antibacterial activity with MBCs in the range 0.80 to 36.49 mM against Staphylococcus aureus, Staphylococcus aureus Rosenbach (MRSA), Pseudomonas aeruginosa, Klebsiella pneumoniae, Escherichia coli and Salmonella typhimurium. The best activity was seen when a larger halogen such as chlorine and bromine were substituted at C-6 on the quinolone scaffold and when a planar phenyl group was present on the thiosemicarbazone moiety. Activity was reduced when a smaller fluorine atom was present at C-6 or when a methyl group was attached to the thiosemicarbazone. This group of compounds showed a high negative binding affinity, which suggested promising antimcrobial activity. The 6-chloro derivative with a phenyl group on the thiosemicarbazone had the greatest negative binding affinity.
- Govender, Hogantharanni,Mocktar, Chunderika,Kumalo, Hezekiel M.,Koorbanally, Neil A.
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p. 1074 - 1081
(2019/06/10)
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- General rhodium-catalyzed oxidative cross-coupling reactions between anilines: Synthesis of unsymmetrical 2,2′-diaminobiaryls
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Described herein is a dual chelation-assisted RhCl3-catalyzed oxidative C-H/C-H cross-coupling reaction of aniline derivatives. The highlight of this methodology is the chemo- and regioselective cross-coupling between electronically similar substrates, which represents a highly challenging task in oxidative Ar-H/Ar-H cross-coupling reactions. Furthermore, this Cp?-free catalytic reaction tolerates a range of functional groups and requires only a low molar ratio of coupling partners. These features expedite the synthesis of unsymmetrical 2,2′-diaminobiaryls.
- Shi, Yang,Liu, Jiahui,Yang, Yudong,You, Jingsong
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supporting information
p. 5475 - 5478
(2019/05/16)
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- SO2F2-Activated Efficient Beckmann Rearrangement of Ketoximes for Accessing Amides and Lactams
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A novel, mild and practical protocol for the efficient activation of the Beckmann rearrangement utilizing the readily available and economical sulfuryl fluoride (SO2F2 gas) has been developed. The substrate scope of the operationally simple methodology has been demonstrated by 37 examples with good to nearly quantitative isolated yields (over 90 % yield in most cases) in a short time, including B(OH)2, COOH, NH2, and OH substituted substrates. A tentative mechanism was proposed involving formation and elimination of key intermediate, sulfonyl ester.
- Zhang, Guofu,Zhao, Yiyong,Xuan, Lidi,Ding, Chengrong
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supporting information
p. 4911 - 4915
(2019/07/31)
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- Polystyrene-supported phosphine oxide-catalysed Beckmann rearrangement of ketoximes in 1,1,1,3,3,3-hexafluoro-2-propanol
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A polystyrene-supported phosphine oxide-catalysed Beckmann rearrangement of ketoximes in 1,1,1,3,3,3-hexafluoro-2-propanol (HFIP) has been developed. Good substrate compatibility, mild reaction conditions, good yields as well as the reusability of the catalyst/solvent made this procedure more environmentally benign.
- Wang, Yaoyao,Chen, Qun,He, Mingyang,Wang, Liang
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p. 210 - 214
(2018/12/04)
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- Vilsmeier-Haack reagent mediated synthetic transformations with an immobilized iridium complex photoredox catalyst
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An immobilized iridium complex photocatalyst Ir(ppy)2(PDVB-py) was synthesized by immobilization of the iridium complex onto the nanoporous vinylpyridine-divinylbenzene copolymer (PDVB-py). Its application for the synthesis of amides, nitriles, and anhydrides was reported via reactions under the action of the visible-light-driven in situ generated Vilsmeier-Haack reagent from CBr4 in DMF. The results showed that this heterogeneous photocatalyst has extremely high activity and excellent stability to be recycled five times.
- Zhi, Peng,Xi, Zi-Wei,Wang, Dan-Yan,Wang, Wei,Liang, Xue-Zheng,Tao, Fei-Fei,Shen, Run-Pu,Shen, Yong-Miao
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p. 709 - 717
(2019/01/10)
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- Synthesis of acetamides from aryl amines and acetonitrile by diazotization under metal-free conditions
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An efficient and metal-free coupling reaction has been developed that affords acetamides from the corresponding aryl amines and acetonitrile. This method tolerates a wide range of functional groups and is selective toward aryl amines. Preliminary mechanistic studies were conducted.
- Duan, Pan,Guo, Yu,Kang, Huan,Li, Yi-Na,Wen, Xianghao,Xiao, Fang,Zeng, Yao-Fu,Zhang, Na-Na
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supporting information
p. 2169 - 2172
(2019/11/25)
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- Method for synthesizing N-phenylacetamide compounds
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The present invention provides a method for synthesizing N-phenylacetamide compounds. The synthesis method takes an azide terminal olefin compound represented by a formula (I) as a raw material, sodium trifluoromethanesulfonate as an additive, potassium persulfate as an oxidant, and acetonitrile as a solvent, and a reaction is carried out at 80 DEG C for 5 hours, so that a corresponding target product is obtained. The synthesis method of the invention has the characteristics of small environmental hazard, mild reaction conditions, simple operation and the like.
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Paragraph 0048-0059
(2019/03/26)
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- Synthesis of diverse libraries of carboxamides via chemoselective N-acylation of amines by carboxylic acids employing Br?nsted acidic IL [BMIM(SO3H)][OTf]
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Chemoselective N-acylation of amines with carboxylic acids as acyl electrophiles and Br?nsted acidic IL [BMIM(SO3H)][OTf] as promoter is reported under both thermal and microwave irradiation to produce libraries of carboxamides in good to excellent yields after a simple workup. The protocol is compatible with structurally diverse 1° and 2° amines and works in the presence of sensitive functional groups such as thiols and phenols. The potential for recycling and reuse of the IL is also demonstrated.
- Savanur, Hemantkumar M.,Malunavar, Shruti S.,Prabhala, Pavankumar,Sutar, Suraj M.,Kalkhambkar, Rajesh G.,Laali, Kenneth K.
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supporting information
(2019/09/30)
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- Amide Synthesis from Thiocarboxylic Acids and Amines by Spontaneous Reaction and Electrosynthesis
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Amide bond formation is one of the most important basic reactions in chemistry. A catalyst-free approach for constructing amide bonds from thiocarboxylic acids and amines was developed. The mechanistic studies showed that the disulfide was the key intermediate for this amide synthesis. Thiobenzoic acids could be automatically oxidized to disulfides in air, thioaliphatic acids could be electro-oxidized to disulfides, and the resulting disulfides reacted with amines to give the corresponding amides. By this method, various amides could be easily synthesized in excellent yields without using any catalyst or activator. The successful synthesis of bioactive compounds also highlights the synthetic utility of this strategy in medicinal chemistry.
- Tang, Li,Matuska, Jack H.,Huang, Yu-Han,He, Yan-Hong,Guan, Zhi
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p. 2570 - 2575
(2019/06/13)
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- Copper-Catalyzed Acetylation of Electron-Rich Phenols and Anilines
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An approach has been developed for the copper-catalyzed acetylation of phenols and anilines with potassium thioacetate as an acetylating reagent. Although only electron-rich phenols and anilines are compatible with this protocol, the reaction can provide moderate to high yields under mild conditions. Compared with other acetylating reagents, the current reagent has certain advantages, such as its low cost, easy availability, stability, insensitivity to water or air, and ease of storage.
- Zhang, Jieyu,Ke, Qiumin,Tian, Feitao,Jiang, Bei,Ji, Chang-An,Zhang, Lingling,Yu, Jian,Huang, Dayun,Yan, Guobing
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supporting information
p. 726 - 730
(2019/03/26)
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- Potassium tert-Butoxide Prompted Highly Efficient Transamidation and Its Coordination Radical Mechanism
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A simple and highly efficient protocol was developed for the transamidation of N,N-disubstituted amides with primary amines in the presence of tBuOK, affording desired products in good to excellent yields. This reaction proceeded under nitrogen atmosphere and featured extensive substrate tolerance. Experimental investigation suggested that a coordination radical process enhanced this transformation.
- Tan, Zhiyong,Li, Zhenhua,Ma, Yao,Qin, Jinjing,Yu, Chuanming
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p. 4538 - 4545
(2019/07/18)
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- Hydrative syntheses of amides from alkynes catalyzed by an Au(I) complex containing pyridyl-functionalized NHC ligand
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An Au(I)-NHC complex [L1AuBr] (1) with appended pyridyl group on the ligand scaffold is synthesized and its catalytic efficacy for the direct synthesis of the amide from alkyne and sodium azide in acidic water is evaluated. Catalyst 1 readily converts a wide range of internal and terminal alkynes to the corresponding amides with low catalyst loading in TFA/DCE (2 mL, 1:1 v/v) at room temperature in short reaction time (2 h) and without the use of Ag(I) additive. A related catalyst that is devoid of the pyridyl fragment displays significantly lower activity illustrating the role of the promoter ligand for water activation. Mechanistic studies reveal an initial alkyne hydration to ketone followed by the Schmidt reaction to afford the amide.
- Singh, Kuldeep,Pal, Nilay Kumar,Guha, Chirajyoti,Bera, Jitendra K.
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- Cu(OTf) 2 -Catalyzed Beckmann Rearrangement of Ketones Using Hydroxylamine- O -sulfonic Acid (HOSA)
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The Beckmann rearrangement (BKR) of ketones to secondary amides often requires harsh reaction conditions that limit its practicality and scope. Herein, the Cu(OTf) 2 -catalyzed BKR of ketones under mild reaction conditions using hydroxylamine- O -sulfonic acid (HOSA), a commercial water soluble aminating agent, is described. This method is compatible with most functional groups and directly provides the desired amides in good to excellent yields.
- Anugu, Raghunath Reddy,Chandra, Dinesh,Falck, John R.,Jat, Jawahar L.,Munnuri, Sailu,Verma, Saumya
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p. 3709 - 3714
(2019/09/30)
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- Werner transition-metal complex (WTMC)-mediated mild and efficient chemo-selective acylation of phenols and anilines under solvent-free condition
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Werner-type transition-metal complexes (WTMC) such as [Co(NH3)5Cl]Cl2, Cu[(NH3)4]SO4, Mn(acac)3, Ni[(NH3)6]Cl2, Ni[(en)3]S2O3, and Hg[Co(SCN)4] efficiently promote the chemoselective acetylation of phenols and anilines under solvent-free condition. The results of this study clearly shows that the optimal condition for the acetylation of anilines/phenols (1 mmol) (2a–r) with acetic anhydride (1.2 mmol) in the presence of WTMC (1 mmol) and two drops of H3PO4 on heating for 10 min under solvent-free condition gives the corresponding acetanilides/phenyl acetate (3a–r) in good to excellent yield. Furthermore, the method is simple, efficient, chemoselective, and eco-friendly under solvent-free condition for the acetylation of anilines and phenols promoted by WTMC by using acetic anhydrate as the acetylating agent. The simple preparation of the catalyst, easy procedure of the acetylation reaction, and simple work-up indicate the importance of WTMC for such reactions.
- Sarief, Abdulla,Haque, SK Manirul,Feroze, Syed Mudabbir,Arifuddin, Mohammed
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p. 1104 - 1109
(2018/09/27)
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- Synthesis and Bioactivity of Quinoline-3-carboxamide Derivatives
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Twelve novel substituted 2-chloroquinoline-3-carboxamide derivatives were prepared from acetanilides using the Vilsmeier–Haack reaction, producing 2-chloro-3-carbaldehyde quinolines, followed by oxidation of the 3-carbaldehyde to the carboxylic acid and coupling this group with various anilines. The structures of the synthesized compounds were confirmed by NMR, mass spectrometry, and single crystal X-ray diffraction. The chemical shifts of H-5 and H-8 were shown to be influenced by the substituent at C-6. The substituent at C-6 was also seen to affect the chemical shift of C-5, C-7, and C-8, with C-5 and C-7 being more shielded in 5j (F substituted) in comparison with 5g (Cl substituted) and 5d (CH3 substituted). The compounds showed weak activity in the mM range against Gram-positive and Gram-negative bacteria of which 5b, 5d, and 5f showed the best activity with minimum bactericidal concentration values for 5b being 3.79?mM against methicillin-resistant Staphylococcus aureus and 5d and 5f having minimum bactericidal concentration values of 3.77 and 1.79?mM against S.?aureus ATCC 25923, respectively.
- Govender, Hogantharanni,Mocktar, Chunderika,Koorbanally, Neil A.
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p. 1002 - 1009
(2018/02/15)
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- Regioselective nitration of anilines with Fe(NO3)3·9H2O as a promoter and a nitro source
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An efficient Fe(NO3)3·9H2O promoted ortho-nitration reaction of aniline derivatives has been developed. This reaction may go through a nitrogen dioxide radical (NO2) intermediate, which is generated by the thermal decomposition of iron(iii) nitrate. The practicality of the present method using nontoxic and inexpensive iron reagents has been shown by the broad substrate scope and applications.
- Gao, Yang,Mao, Yuanyou,Zhang, Biwei,Zhan, Yingying,Huo, Yanping
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supporting information
p. 3881 - 3884
(2018/06/08)
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- Direct Photocatalytic Synthesis of Medium-Sized Lactams by C?C Bond Cleavage
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Reported is a novel two-step ring-expansion strategy for expeditious synthesis of all ring sizes of synthetically challenging (hetero)aryl-fused medium-sized lactams from readily available 5–8-membered cyclic ketones. This step-economic approach features a remote radical (hetero)aryl migration from C to N under visible-light conditions. Broad substrate scope, good functional-group tolerance, high efficiency, and mild reaction conditions make this procedure very attractive. In addition, this method also provides expedient access to 13–15-membered macrolactams upon an additional one-step manipulation. Mechanistic studies indicate that the reaction involves an amidyl radical and is promoted by acid.
- Wang, Na,Gu, Qiang-Shuai,Li, Zhong-Liang,Li, Zhuang,Guo, Yu-Long,Guo, Zhen,Liu, Xin-Yuan
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supporting information
p. 14225 - 14229
(2018/10/15)
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- Scope and mechanism of a true organocatalytic beckmann rearrangement with a boronic acid/perfluoropinacol system under ambient conditions
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Catalytic activation of hydroxyl functionalities is of great interest for the production of pharmaceuticals and commodity chemicals. Here, 2-alkoxycarbonyl- and 2-phenoxycarbonyl-phenylboronic acid were identified as efficient catalysts for the direct and chemoselective activation of oxime N-OH bonds in the Beckmann rearrangement. This classical organic reaction provides a unique approach to prepare functionalized amide products that may be difficult to access using traditional amide coupling between carboxylic acids and amines. Using only 5 mol % of boronic acid catalyst and perfluoropinacol as an additive in a polar solvent mixture, the operationally simple protocol features mild conditions, a broad substrate scope, and a high functional group tolerance. A wide variety of diaryl, aryl-alkyl, heteroaryl-alkyl, and dialkyl oximes react under ambient conditions to afford high yields of amide products. Free alcohols, amides, carboxyesters, and many other functionalities are compatible with the reaction conditions. Investigations of the catalytic cycle revealed a novel boron-induced oxime transesterification providing an acyl oxime intermediate involved in a fully catalytic nonself-propagating Beckmann rearrangement mechanism. The acyl oxime intermediate was prepared independently and was subjected to the reaction conditions. It was found to be self-sufficient; it reacts rapidly, unimolecularly without the need for free oxime. A series of control experiments and 18O labeling studies support a true catalytic pathway involving an ionic transition structure with an active and essential role for the boronyl moiety in both steps of transesterification and rearrangement. According to 11B NMR spectroscopic studies, the additive perfluoropinacol provides a transient, electrophilic boronic ester that is thought to serve as an internal Lewis acid to activate the ortho-carboxyester and accelerate the initial, rate-limiting step of transesterification between the precatalyst and the oxime substrate.
- Mo, Xiaobin,Morgan, Timothy D. R.,Ang, Hwee Ting,Hall, Dennis G.
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supporting information
p. 5264 - 5271
(2018/04/24)
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- Beckmann rearrangement of ketoxime catalyzed by N-methyl-imidazolium hydrosulfate
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Beckmann rearrangement of ketoxime catalyzed by acidic ionic liquid-N-methyl-imidazolium hydrosulfate was studied. Rearrangement of benzophenone oxime gave the desirable product with 45% yield at 90 ?C. When co-catalyst P2O5 was added, the yield could be improved to 91%. The catalyst could be reused three cycles with the same efficiency. Finally, reactions of other ketoximes were also investigated.
- Hu, Hongyu,Cai, Xuting,Xu, Zhuying,Yan, Xiaoyang,Zhao, Shengxian
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- Dichloroimidazolidinedione-Activated Beckmann Rearrangement of Ketoximes for Accessing Amides and Lactams
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A novel protocol for the activation of the Beckmann rearrangement utilizing the readily available and economical geminal dichloroimidazolidinediones (DCIDs) on a substoichiometric scale (10 mol %) has been developed. A unique self-propagating mechanism for the substoichiometric dichloroimidazolidinedione-activated transformation was proposed and validated. The substrate scope of the developed protocol has been demonstrated by 23 examples with good to excellent yields (mostly 90-98%) in a short time (mostly 10-30 min), including a substrate for synthesizing the monomer of nylon-12 and a complicated steroidal substrate on a preparative scale. This research not only unveils for the first time the synthetic potential of substoichiometric amounts of dichloroimidazolidinediones in promoting chemical transformation but also offers yet another important illustration of the self-propagating cycle in the context of the Beckmann rearrangement activated by a structurally novel organic promoter.
- Gao, Yu,Liu, Jingjing,Li, Zhenjiang,Guo, Tianfo,Xu, Songquan,Zhu, Hui,Wei, Fulan,Chen, Siming,Gebru, Hailemariam,Guo, Kai
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p. 2040 - 2049
(2018/02/23)
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- Direct and Catalytic Amide Synthesis from Ketones via Transoximation and Beckmann Rearrangement under Mild Conditions
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The Br?nsted acid-catalyzed synthesis of secondary amides from ketones under mild conditions is described via transoximation and Beckmann rearrangement using O-protected oximes as more stable equivalents of explosive O-protected hydroxylamines. This methodology could be applied to highly rearrangement-selective amide synthesis from α-branched alkyl aryl ketones and performed on a 1-g scale. The presence of water is essential for this reaction, and its role was clarified by isotope-labeling experiments.
- Hyodo, Kengo,Hasegawa, Genna,Oishi, Naoki,Kuroda, Kazuma,Uchida, Kingo
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p. 13080 - 13087
(2018/11/02)
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