- Reactivity of 1-nitronaphthalene and 1,3-dinitronaphthalene with conjugated dienes. An easy access to N-naphthylpyrroles
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1-Nitronaphthalene reacts at high temperature with poor and moderately reactive dienes affording N-naphthylpyrroles while, with the same dienes, 1,3-dinitronaphthalene exhibits the dienophilic character of naphthalenic C3-C4 bond producing the corresponding phenanthrenes through a classical Diels-Alder process.
- Paredes, Elisa,Kneeteman, María,Gonzalez-Sierra, Manuel,Mancini, Pedro M.E.
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- Excited-State Proton-Transfer Reactions of Naphthylammonium Ion-18-Crown-6 Complexes
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Proton-transfer reactions in the excited singlet state of naphthylammonium ion-18-crown-6 complexes in MeOH-H2O (9:1) mixtures have been studied by means of the single photon counting method with fluorimetry.It is found that the complex formation of naphthylammonium ions with 18-crown-6 decreases markedly the proton-transfer rate (k1) in the excited state, resulting in an increase of its lifetime.The back protonation rate in the excited state is negligibly small compared with those of the other decay processes; there is no excited-state prototropic equilibrium in the naphthylammonium ion-crown complexes (RN(1+)H3-crown).The one-way proton transfer reaction is elucidated by the presence of the excited neutral amine-crown complex (RNH2-crown)* produced by deprotonation of (RN(1+)H3-crown)*, where protonation to the amino group is structurally blocked by 18-crown-6 and the naphthyl group (R) of the complex.However, proton-induced quenching (k'q) occurs effectively especially in the 1-naphthylammonium ion-crown complex.The ground-state association constants (Kg) of the complexes can be determined easily by the fluorescence titration method.Temperature effects upon the excited-state proton-transfer reactions of the complexes have been also carried out in order to study their thermodynamic properties.A Corey-Pauling-Kolton model of the anilinium ion-18-crown-6 complex proposed by Izatt et al. is strongly supported by the present work.
- Shizuka, Haruo,Kameta, Kosei,Shinozaki, Tsutomu
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- One-step catalytic amination of naphthalene to naphthylamine with exceptional yield
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One-step amination of aromatic compounds to arylamines is a promising strategy with high atom economy and less environmental pollution. We propose for the first time a direct catalytic amination of naphthalene to naphthylamine and hydroxylamine using vanadium catalysts under mild conditions. Naphthylamine was obtained in 70% yield over the V2O5/HZSM-5 cayalyst in a one-step amination of naphthalene, which is higher than the yield obtained by state-of-the-art processes. The Br?nsted acid sites, and the V-O-V and VO bonds of monovanadate in the V2O5/HZSM-5 catalyst are the active sites for the amination reaction and are responsible for the naphthalene activation and formation of NH3+ that acts as the active amination reagent. A possible reaction mechanism was also proposed by investigating real-time IR and in situ DRIFTS. This proposed one-step amination of naphthalene is superior to traditional nonselective nitration and hydrogenation processes, and some findings offer new insights to produce arylamines from aromatic compounds.
- Hao, Fang,Wang, Xin,Huang, Linfang,Xiong, Wei,Liu, Pingle,Luo, Hean
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- Hydrolysis of naptalam and structurally related amides: Inhibition by dissolved metal ions and metal (hydr)oxide surfaces
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In metal ion-free solutions, the secondary amide naptalam hydrolyzes more rapidly as the pH is decreased; intramolecular nucleophilic attack by a carboxylate side group is very likely involved. Millimolar levels of dissolved Cu(II) and Zn(II) inhibit hydr
- Huang, Ching-Hua,Stone, Alan T.
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- Selective optical detection of HSO4 ? via hydrolysis of a simple Schiff Base
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A very simple Schiff Base derived from 1-Naphthylamine and 4-(Trifluoromethy) benzaldehyde (L) was prepared as a selective colorimetric and turn-on fluorescent sensor for hydrogen sulfate. In the CH3CN:H2O (3:2, v/v) solvent system, L shows a highly selective colorimetric response to HSO4 ? ions by changing its color from yellow to colorless immediately. In addition, the weakly fluorescent receptor L shows a highly selective enhancement of fluorescence intensity at 425?nm for HSO4 ? upon excitation at 320?nm. The recognition process is proven to be hardly influenced by the other tested competitive anions. The sensing is suggested to involve a hydrolysis process promoted by HSO4 ? which has been further supported by UV–Vis, 1H NMR and HRMS spectroscopic studies. Applicability of L to detect HSO4 ? in tap water has been demonstrated. An easy-to-prepare test strip of L has also been made for the naked-eye detection of HSO4 ? in real samples.
- Dong, Zhen Ming,Wang, Jia Na,Wang, Wei,Chao, Jian Bin,Wang, Yu
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- Biocatalytic Aromaticity-Breaking Epoxidation of Naphthalene and Nucleophilic Ring-Opening Reactions
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Aromatic hydroxylation reactions catalyzed by heme-thiolate enzymes proceed via an epoxide intermediate. These aromatic epoxides could be valuable building blocks for organic synthesis giving access to a range of chiral trans-disubstituted cyclohexadiene
- Zhang, Wuyuan,Li, Huanhuan,Younes, Sabry H. H.,Gómez De Santos, Patricia,Tieves, Florian,Grogan, Gideon,Pabst, Martin,Alcalde, Miguel,Whitwood, Adrian C.,Hollmann, Frank
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- Biomimetic chirality sensing with pyridoxal-5′-phosphate
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Pyridoxal-5′-phosphate (PLP) is introduced to a biomimetic indicator displacement assay for simultaneous determination of the absolute configuration, enantiomeric composition and concentration of unprotected amino acids, amino alcohols and amines. The chiroptical assay is based on fast imine metathesis with a PLP aryl imine probe to capture the target compound for circular dichroism and fluorescence sensing analysis. The substrate binding yields characteristic Cotton effects that provide information about the target compound ee and the synchronous release of the indicator results in a nonenantioselective off-on fluorescence response that is independent of the enantiomeric sample composition and readily correlated to the total analyte concentration.
- Pilicer, Samantha L.,Bakhshi, Pegah R.,Bentley, Keith W.,Wolf, Christian
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- PHOTOCHEMISTRY OF NAPHTHYL AND PYRENYL AZIDES: CHEMICAL PROPERTIES OF THE TRANSIENT INTERMEDIATES PROBED BY LASER SPECTROSCOPY
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The photochemistry of 1-naphthyl azide, 2-naphthyl azide, 1-pyrenyl azide, and 2-pyrenyl azide was examined in inert (benzene) and reactive (diethylamine) solvents.These studies employ a combination of product analysis, low-temperature spectroscopy, and laser-flash photolysis to reveal the chemical and physical properties of the highly reactive, short-lived intermediates formed in these reactions.In all cases two intermediates account for the observations.One of these is the triplet nitrene and the other is a ground-state singlet transient identified as an azirine.The relationship between these intermediates controls the chemical outcome of the reaction.
- Schrock, Alan A.,Schuster, Gary B.
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- A new access to 1-naphthylamines by an equivalent Semmler-Wolff reaction
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A new access to 1-naphthylamines from the corresponding 3,4-dihydro-1(2H)-naphthalenones (α-tetralones) is described. It proceeds in a two-step sequence: preparation of the benzyl Schiff's base of an α-tetralone followed by aromatization over palladium ca
- Janin,Bisagni
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- Relationship between azo dye structure and rat hepatic azoreductase activity
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The rate of reduction was determined for a variety of azo dyes using the rat hepatic azoreductase enzyme system. In decreasing order, the rates of reduction for the azo dyes expressed as nmol of arylamine product formed/min/0.25 g of liver were amaranth (33.2), azosulfamide (32.5), orange G (12.4), 1,2-dimethyl-4-p-(carboxyphenylazo)-5-hydroxybenzene (CPA) (9.27), brilliant crystal scarlet (8.00), sulfachrysoidine (7.27), and Sudan I (1.03). A comparison of the partition coefficient with its rate of reduction indicated that the water-soluble azo dyes were reduced more rapidly than the lipid-soluble ones. Furthermore, higher rates of reduction were observed for those dyes containing electron-withdrawing groups on the aromatic rings.
- Shargel,Banijamali,Kuttab
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- Synthesis of sterically congested 1,5-disubstituted-1,2,3-Triazoles using chloromagnesium acetylides and hindered 1-naphthyl azides
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Sterically congested 1-(2-methoxy-1-naphthyl)-5-substituted-1,2,3-triazoles can be prepared from sterically hindered 2-methoxy-1-azidonaphthalene and chloromagnesium acetylides, including 2-substituted phenylacetylides. Catalytic methods using Cp?RuCl(PPh
- Mahadari, Muni Kumar,Tague, Andrew J.,Keller, Paul A.,Pyne, Stephen G.
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- Rearrangement of 2-Quinolyl- and 1-Isoquinolylcarbenes to Naphthylnitrenes
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2-Quinolylcarbene 23 and 1-isoquinolylcarbene 33 are generated by flash vacuum thermolysis (FVT) of the corresponding triazolo[1,5-a]quinoline and triazolo[5,1-a]isoquinoline 19 and 29, as well as 2-(5-tetrazolyl)quinoline and 1-(5-tetrazolyl)isoquinoline 20 and 30, respectively. These carbenes rearrange to 1- and 2-naphthylnitrene 21 and 31, respectively, and the nitrenes are also generated by FVT of 1- and 2-naphthyl azides 18 and 28. The products of FVT of both the nitrene and carbene precursors are the 2- and 3-cyanoindenes 26 and 27 together with the nitrene dimers, viz. azonaphthalenes 25 and 35, and the H-abstraction products, aminonaphthalenes 24 and 34. All the azide, triazole, and tetrazole precursors yield 3-cyanoindene 26 as the principal ring contraction product under conditions of low FVT temperature (340-400 °C) and high pressure (1 Torr N2 as carrier gas for the purpose of collisional deactivation). This ring contraction reaction is strongly subject to chemical activation, which caused extensive isomerization of 3-cyanoindene to 2-cyanoindene under conditions of low pressure (10-3 Torr). 2-Cyanoindene is calculated to be ca. 1.7 kcal/mol below 3-cyanoindene in energy; accordingly, high-temperature FVT of these cyanoindenes always gives mixtures of the two compounds with the 2-cyano isomer dominating. Photolysis of trizolo[1,5-a]quinoline 19 and triazolo[5,1-a]isoquinoline 29 in Ar matrixes causes partial ring opening to the corresponding 2-diazomethylquinoline 19′ and 1-diazomethylisoquinoline 29′. The photolysis of the former gives rise to a small amount of the cyclic ketenimine 22, the intermediate connecting 2-quinolylcarbene and 1-naphthylnitrene.
- Lan, Nguyen Mong,Burgard, Riko,Wentrup, Curt
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- A photoswitchable “turn-on” fluorescent chemosensor: Quinoline-naphthalene duo for nanomolar detection of aluminum and bisulfite ions and its multifarious applications
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A quinoline-naphthalene duo-based Schiff base probe (R) was synthesized and characterized by the usual spectroscopic and single-crystal X-ray crystallographic techniques. Probe R detects Al3+ and HSO3? ions via the fluorescent turn-on approach by dual pathways i.e., i) when probe R interacts with Al3+, the restriction of C[sbnd]N single bond rotation, blocking of both photoinduced electron transfer (PET) and C[dbnd]N isomerization were observed, and ii) when the sensor R interacts with HSO3?, imine (CH = N) bond was cleaved via hydrolysis and produced the respective aldehyde and amine behaving as a chemodosimeter. The binding stoichiometric ratio of R + Al3+ (1:1) was confirmed by Job's plot, emission titration profile, NMR, and mass spectrometric analyses. This probe R is highly selective to both Al3+ -ions and HSO3? -ions, without any interference of other potentially competing cations and anions. Limit of detection (LOD) and quantification (LOQ) of R with Al3+ and HSO3? were downed to nanomolar concentrations, which is much lower than the recommended level of drinking water/food fixed by the World Health Organization (WHO). Furthermore, probe R was utilized in the detection of Al3+ and HSO3? ions in highly contaminated real samples, bioimaging in E. coli cells, multiple-targeting molecular logic gate, and in bovine serum albumin (BSA) binding.
- Abiram, Angamuthu,Immanuel David, Charles,Jayaraj, Haritha,Kayalvizhi, Rajendran,Nandhakumar, Raju,Parimala Devi, Duraisamy,Prabakaran, Gunasekaran,Rajesh Kannan, Velu,Velmurugan, Krishnasamy
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- Structural and Reactivity Comparisons of JosiPhos CyPF-Cy and a Simplified Variant ("CyPBn-Cy") in Nickel-Catalyzed C(sp2)-N Cross-Couplings
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The synthesis and characterization of the new complexes (CyPBn-Cy)NiCl2 and (CyPBn-Cy)Ni(o-tol)Cl are reported (CyPBn-Cy = o-di(cyclohexyl)phosphino-benzyl-di(cyclohexyl)phosphine), along with a head-to-head structural and reactivity comparison of (L)Ni(o-tol)Cl precatalyst complexes (L = JosiPhos CyPF-Cy and CyPBn-Cy) in the Ni-catalyzed cross-couplings of (hetero)aryl chlorides or phenol-derived electrophiles with ammonia or furfurylamine. The structures of these precatalysts were found not to differ significantly (e.g., coordination geometry and % buried volume), and these similarities were, generally speaking, reflected in the observed catalytic behavior of these precatalysts, with notable exceptions including reactions involving the hindered electrophile 2-chloro-m-xylene, where (CyPBn-Cy)Ni(o-tol)Cl proved superior; the N-arylation of furfurylamine by use of 1-(N,N-diethylcarbamoyl)-naphthalene, where CyPF-Cy proved to be the preferred ligand; and monoarylation (CyPBn-Cy) versus diarylation (CyPF-Cy) selectivity in the cross-coupling of furfurylamine with 2-chloro-6-methoxypyridine. In studying the time-course of the cross-coupling of furfurylamine and 1-chloronaphthalene, significantly faster conversion to product and higher overall yield were noted when using CyPBn-Cy. These results confirm that CyPBn-Cy can be viewed as being competitive with, and complementary to, the well-established JosiPhos ligand CyPF-Cy in this class of Ni-catalyzed cross-couplings.
- Bodé, Nicholas E.,Ferguson, Michael J.,Stradiotto, Mark,Tassone, Joseph P.
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p. 2915 - 2922
(2021/08/27)
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- Porous polymeric ligand promoted copper-catalyzed C-N coupling of (hetero)aryl chlorides under visible-light irradiation
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A porous polymeric ligand (PPL) has been synthesized and complexed with copper to generate a heterogeneous catalyst (Cu@PPL) that has facilitated the efficient C-N coupling with various (hetero)aryl chlorides under mild conditions of visible-light irradiation at 80 °C (58 examples, up to 99% yields). This method could be applied to both aqueous ammonia and substituted amines, and is compatible to a variety of functional groups and heterocycles, as well as allows tandem C-N couplings with conjunctive dihalides. Furthermore, the heterogeneous characteristic of Cu@PPL has enabled a straightforward catalyst separation in multiple times of recycling with negligible catalytic efficiency loss by simple filtration, affording reaction mixtures containing less than 1 ppm of Cu residue. [Figure not available: see fulltext.]
- Wang, Erfei,Chen, Kaixuan,Chen, Yinan,Zhang, Jiawei,Lin, Xinrong,Chen, Mao
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- Ligand compound for copper catalyzed aryl halide coupling reaction, catalytic system and coupling reaction
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The invention provides a ligand compound capable of being used for copper catalyzed aryl halide coupling reaction, the ligand compound is a three-class compound containing a 2-(substituted or non-substituted) aminopyridine nitrogen-oxygen group, and the invention also provides a catalytic system for the aryl halide coupling reaction. Thecatalytic system comprises a copper catalyst, a compound containing a 2-(substituted or non-substituted) aminopyridine nitrogen-oxygen group adopted as a ligand, alkali and a solvent, and meanwhile, the invention also provides a system for the aryl halide coupling reaction adopting the catalyst system. The compound containing the 2-(substituted or non-substituted) aminopyridine nitrogen oxygen group can be used as the ligand for the copper catalyzed aryl chloride coupling reaction, and the ligand is stable under a strong alkaline condition and can well maintain catalytic activity when being used for the copper-catalyzed aryl chloride coupling reaction. In addition, the copper catalyst adopting the compound as the ligand can particularly effectively promote coupling of copper catalyzed aryl chloride and various nucleophilic reagents which are difficult to generate under conventional conditions, C-N, C-O and C-S bonds are generated, and numerous useful small molecule compounds are synthesized. Therefore, the aryl halide coupling reaction has a very good large-scale application prospect by adopting the copper catalysis system of the ligand.
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Paragraph 0111-0118; 0120
(2021/05/29)
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- Synthesis of Substituted Anilines from Cyclohexanones Using Pd/C-Ethylene System and Its Application to Indole Synthesis
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The synthesis of anilines and indoles from cyclohexanones using a Pd/C-ethylene system is reported. A simple combination of NH4OAc and K2CO3 under nonaerobic conditions was found to be the most suitable to perform this reaction. Hydrogen transfer between cyclohexanone and ethylene generates the desired products. The reaction tolerates a variety of substitutions on the starting cyclohexanones.
- Maeda, Katsumi,Matsubara, Ryosuke,Hayashi, Masahiko
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supporting information
p. 1530 - 1534
(2021/03/08)
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- Selective Carbon-Carbon Bond Amination with Redox-Active Aminating Reagents: A Direct Approach to Anilines?
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Amines are among the most fundamental motifs in chemical synthesis, and the introduction of amine building blocks via selective C—C bond cleavage allows the construction of nitrogen compounds from simple hydrocarbons through direct skeleton modification. Herein, we report a novel method for the preparation of anilines from alkylarenes via Schmidt-type rearrangement using redox-active amination reagents, which are easily prepared from hydroxylamine. Primary amines and secondary amines were prepared from corresponding alkylarenes or benzyl alcohols under mild conditions. Good compatibility and valuable applications of the transformation were also displayed.
- Qiu, Xu,Wang, Yachong,Su, Lingyu,Jin, Rui,Song, Song,Qin, Qixue,Li, Junhua,Zong, Baoning,Jiao, Ning
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p. 3011 - 3016
(2021/09/13)
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- Minimization of Back-Electron Transfer Enables the Elusive sp3 C?H Functionalization of Secondary Anilines
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Anilines are some of the most used class of substrates for application in photoinduced electron transfer. N,N-Dialkyl-derivatives enable radical generation α to the N-atom by oxidation followed by deprotonation. This approach is however elusive to monosubstituted anilines owing to fast back-electron transfer (BET). Here we demonstrate that BET can be minimised by using photoredox catalysis in the presence of an exogenous alkylamine. This approach synergistically aids aniline SET oxidation and then accelerates the following deprotonation. In this way, the generation of α-anilinoalkyl radicals is now possible and these species can be used in a general sense to achieve divergent sp3 C?H functionalization.
- Zhao, Huaibo,Leonori, Daniele
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supporting information
p. 7669 - 7674
(2021/03/08)
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- Indirect reduction of CO2and recycling of polymers by manganese-catalyzed transfer hydrogenation of amides, carbamates, urea derivatives, and polyurethanes
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The reduction of polar bonds, in particular carbonyl groups, is of fundamental importance in organic chemistry and biology. Herein, we report a manganese pincer complex as a versatile catalyst for the transfer hydrogenation of amides, carbamates, urea derivatives, and even polyurethanes leading to the corresponding alcohols, amines, and methanol as products. Since these compound classes can be prepared using CO2as a C1 building block the reported reaction represents an approach to the indirect reduction of CO2. Notably, these are the first examples on the reduction of carbamates and urea derivatives as well as on the C-N bond cleavage in amides by transfer hydrogenation. The general applicability of this methodology is highlighted by the successful reduction of 12 urea derivatives, 26 carbamates and 11 amides. The corresponding amines, alcohols and methanol were obtained in good to excellent yields up to 97%. Furthermore, polyurethanes were successfully converted which represents a viable strategy towards a circular economy. Based on control experiments and the observed intermediates a feasible mechanism is proposed.
- Liu, Xin,Werner, Thomas
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p. 10590 - 10597
(2021/08/20)
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- Cu-Catalyzed Cross-Coupling of Nitroarenes with Aryl Boronic Acids to Construct Diarylamines
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The development and study of a simple copper-catalyzed reaction of nitroarenes with aryl boronic acids to form diarylamines that uses phenyl silane as the stoichiometric terminal reductant is described. This cross-coupling reaction requires as little as 2 mol % of CuX and 4 mol % of diphosphine for success and tolerates a broad range of functional groups on either the nitroarene or the aryl boronic acid to afford the amine in good yield. Mechanistic investigations established that the cross-coupling reaction proceeds via a nitrosoarene intermediate and that copper is required to catalyze both the deoxygenation of the nitroarene to afford the nitrosoarene and C-NAr bond formation of the nitrosoarene with the aryl boronic acid.
- Guan, Xinyu,Zhu, Haoran,Driver, Tom G.
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p. 12417 - 12422
(2021/10/12)
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- A polyamine dendritic polymer-copper complex: A reusable catalyst for the additive-free amination of aryl bromides, and iodides
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A porphyrin-initiated amine-functionalized polyepichlorohydrin dendritic polymer (PPECH-Amine) was effectively synthesized, and its water-soluble copper complex (PPECH-Amine-Cu) was developed by treating it with copper acetate. PPECH-Amine and PPECH-Amine-Cu were characterised by different spectroscopic and microscopic techniques. PPECH-Amine-Cu was identified as a reusable catalyst for the amination of bromo- and iodo-benzene derivatives in aqueous media. Due to the presence of residual amino groups in the PPECH-Amine-Cu catalyst, the protocol does not need any additional base additive, as ammonia itself acts as a base and a coupling partner. Due to the good water-soluble nature of this catalyst, it can be easily separated and reused up to six reaction cycles without any loss in its activity.
- Avudaiappan,Palmurukan,Unnikrishnan,Sreekumar
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p. 1477 - 1484
(2020/02/05)
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- CuIBiOI is an efficient novel catalyst in Ullmann-type CN– couplings with wide scope—A rare non-photocatalyic application
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Preparation of a new, mixed-cationic layered CuIBiOI was prepared and its non-photocatalytic catalytic properties were explored. This solid substance had BiOI-like, lamellar and deflected structure resulting from CuI ion incorporation in the Bi2O2 layers. The as-prepared substance was fully characterized by XRD, Raman, far IR, UV–DR, XP spectroscopies, thermal (TG-DTG) and analytical (ICP-MS, SEM-EDX) methods, electron microscopies (SEM, TEM) as well as BET surface area measurements. By performing Ullmann-type CN– coupling reactions between aryl halides and aqueous ammonia, its catalytic capabilities were tested. The effects of solvents, added base and catalyst loading as well as reaction time and reaction temperature were scrutinized, and a green way for the reaction was identified. The recyclability of the catalyst without the loss of activity and its general applicability for a wide range of aryl halides were also demonstrated.
- Djerdj, Igor,Kónya, Zoltán,Kocsis, Marianna,Kukovecz, ákos,Pálinkó, István,Sipos, Pál,Varga, Gábor
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- Amination reagent as well as preparation method and application thereof
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The invention discloses an amination reagent as well as a preparation method and application thereof. The amination reagent has a structure as shown in a formula disclosed in the invention, wherein Xis selected from any one of I, Cl, Br, NO3 and ClO4, and Y and Z are independently selected from H or alkyl with the carbon atom number of 1-4. The process for preparing the amination reagent is simple, the raw materials are easy to obtain, the cost is low, the yield is stable, and the prepared amination reagent is stable in character, can be stored at room temperature for a long time and can be taken as needed; meanwhile, the prepared amination reagent is efficient in performance, boron substrate applicability is excellent, reaction effect is good, and limitation of amination reaction of organic boron compounds on substrates is greatly expanded.
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Paragraph 0142-0144; 0148-0149; 0180
(2020/03/12)
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- Discovery and characterization of an acridine radical photoreductant
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Photoinduced electron transfer (PET) is a phenomenon whereby the absorption of light by a chemical species provides an energetic driving force for an electron-transfer reaction1–4. This mechanism is relevant in many areas of chemistry, including the study of natural and artificial photosynthesis, photovoltaics and photosensitive materials. In recent years, research in the area of photoredox catalysis has enabled the use of PET for the catalytic generation of both neutral and charged organic free-radical species. These technologies have enabled previously inaccessible chemical transformations and have been widely used in both academic and industrial settings. Such reactions are often catalysed by visible-light-absorbing organic molecules or transition-metal complexes of ruthenium, iridium, chromium or copper5,6. Although various closed-shell organic molecules have been shown to behave as competent electron-transfer catalysts in photoredox reactions, there are only limited reports of PET reactions involving neutral organic radicals as excited-state donors or acceptors. This is unsurprising because the lifetimes of doublet excited states of neutral organic radicals are typically several orders of magnitude shorter than the singlet lifetimes of known transition-metal photoredox catalysts7–11. Here we document the discovery, characterization and reactivity of a neutral acridine radical with a maximum excited-state oxidation potential of ?3.36 volts versus a saturated calomel electrode, which is similarly reducing to elemental lithium, making this radical one of the most potent chemical reductants reported12. Spectroscopic, computational and chemical studies indicate that the formation of a twisted intramolecular charge-transfer species enables the population of higher-energy doublet excited states, leading to the observed potent photoreducing behaviour. We demonstrate that this catalytically generated PET catalyst facilitates several chemical reactions that typically require alkali metal reductants and can be used in other organic transformations that require dissolving metal reductants.
- MacKenzie, Ian A.,Wang, Leifeng,Onuska, Nicholas P. R.,Williams, Olivia F.,Begam, Khadiza,Moran, Andrew M.,Dunietz, Barry D.,Nicewicz, David A.
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- Mild deprotection of the: N-tert -butyloxycarbonyl (N -Boc) group using oxalyl chloride
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We report a mild method for the selective deprotection of the N-Boc group from a structurally diverse set of compounds, encompassing aliphatic, aromatic, and heterocyclic substrates by using oxalyl chloride in methanol. The reactions take place under room temperature conditions for 1-4 h with yields up to 90percent. This mild procedure was applied to a hybrid, medicinally active compound FC1, which is a novel dual inhibitor of IDO1 and DNA Pol gamma. A broader mechanism involving the electrophilic character of oxalyl chloride is postulated for this deprotection strategy. This journal is
- Awuah, Samuel G.,George, Nathaniel,Ofori, Samuel,Parkin, Sean
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p. 24017 - 24026
(2020/07/23)
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- Photocatalytic C-H Amination of Aromatics Overcoming Redox Potential Limitations
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We report the photocatalytic C-H amination of aromatics overcoming redox potential limitations. Radical cations of aromatic compounds are generated photocatalytically using Ru(phen)3(PF6)2, which has a reduction potential at a high oxidation state (Ered(RuIII/RuII) = +1.37 V vs SCE) lower than the oxidation potentials of aromatic substrates (Eox = +1.65 to +2.27 V vs SCE). The radical cations are trapped with pyridine to give N-arylpyridinium ions, which were converted to aromatic amines.
- Ikarashi, Gun,Kano, Naokazu,Morofuji, Tatsuya
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p. 2822 - 2827
(2020/04/16)
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- Aminoazanium of DABCO: An Amination Reagent for Alkyl and Aryl Pinacol Boronates
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The aminoazanium of DABCO (H2N-DABCO) has been developed as a general and practical amination reagent for the direct amination of alkyl and aryl pinacol boronates. This compound is stable and practical for use as a reagent. Various primary, secondary. and tertiary alkyl?Bpin and aryl?Bpin substrates were aminated to give the corresponding amine derivatives. The amination is stereospecific. The anti-Markovnikov hydroamination of olefins was easily achieved by catalytic hydroboration with HBpin and in subsequent situ amination using H2N-DABCO. Moreover, the combination of 1,2-diboration of olefins, using B2pin2, with this amination process achieved the unprecedented 1,2-diamination of olefins. The amination protocol was also successfully extended to aryl pinacol boronates.
- Liu, Xingxing,Zhu, Qing,Chen, Du,Wang, Lu,Jin, Liqun,Liu, Chao
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supporting information
p. 2745 - 2749
(2020/01/25)
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- Superhydrophobic nickel/carbon core-shell nanocomposites for the hydrogen transfer reactions of nitrobenzene and N-heterocycles
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In this work, catalytic hydrogen transfer as an effective, green, convenient and economical strategy is for the first time used to synthesize anilines and N-heterocyclic aromatic compounds from nitrobenzene and N-heterocycles in one step. Nevertheless, how to effectively reduce the possible effects of water on the catalyst by removal of the by-product water, and to further introduce water as the solvent based on green chemistry are still challenges. Since the structures and properties of carbon nanocomposites are easily modified by controllable construction, a one step pyrolysis process is used for controllable construction of micro/nano hierarchical carbon nanocomposites with core-shell structures and magnetic separation performance. Using various characterization methods and model reactions the relationship between the structure of Ni?NCFs (nickel-nitrogen-doped carbon frameworks) and catalytic performance was investigated, and the results show that there is a positive correlation between the catalytic performance and hydrophobicity of catalysts. Besides, the possible catalytically active sites, which are formed by the interaction of pyridinic N and graphitic N in the structure of nitrogen-doped graphene with the surfaces of Ni nanoparticles, should be pivotal to achieving the relatively high catalytic performance of materials. Due to its unique structure, the obtained Ni?NCF-700 catalyst with superhydrophobicity shows extraordinary performances toward the hydrogen transfer reaction of nitrobenzene and N-heterocycles in the aqueous state; meanwhile, it was also found that Ni?NCF-700 still retained its excellent catalytic activity and structural integrity after three cycles. Compared with traditional catalytic systems, our catalytic systems offer a highly effective, green and economical alternative for nitrobenzene and N-heterocycle transformation, and may open up a new avenue for simple construction of structure and activity defined carbon nanocomposite heterogeneous catalysts with superhydrophobicity.
- Duan, Zhiying,Liu, Fangfang,Pang, Shaofeng,Su, Qiong,Wang, Yanbin,Xie, Xin,Zhang, Ping,Zhang, Yujing,Zhou, Feng
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p. 1996 - 2010
(2020/04/07)
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- EffectiveN-methylation of nitroarenes with methanol catalyzed by a functionalized NHC-based iridium catalyst: a green approach toN-methyl amines
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Compound [IrBr(CO)2(κC-tBuImCH2PyCH2OMe)] featuring a flexible pyridine/OMe functionalized NHC ligand κ1C coordinated efficiently catalyzes the selectiveN-monomethylation of nitroarenes using methanol as both the reducing agent and the C1 source. A range of functionalized nitroarenes including heterocyclic or sterically hindered derivatives have been efficiently converted to the correspondingN-monomethyl amines in good yields at low catalyst loadings using sub-stoichiometric amounts of Cs2CO3as a base. Mechanistic investigations support a borrowing-hydrogen mechanism in which methanol acts as the hydrogen source and methylating agent. Further, the hydrogen transfer reduction of nitrobenzene to aniline under optimized reaction conditions should proceed through a direct mechanism involving nitrosobenzene andN-phenylhydroxylamine intermediates.
- González-Lainez, Miguel,Jiménez, M. Victoria,Passarelli, Vincenzo,Pérez-Torrente, Jesús J.
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p. 3458 - 3467
(2020/06/17)
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- Nucleophilic aromatic substitution of unactivated fluoroarenes enabled by organic photoredox catalysis
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Nucleophilic aromatic substitution (SNAr) is a classical reaction with well-known reactivity toward electron-poor fluoroarenes. However, electron-neutral and electron-rich fluoro(hetero)arenes are considerably underrepresented. Herein, we present a method for the nucleophilic defluorination of unactivated fluoroarenes enabled by cation radical-accelerated nucleophilic aromatic substitution. The use of organic photoredox catalysis renders this method operationally simple under mild conditions and is amenable to various nucleophile classes, including azoles, amines, and carboxylic acids. Select fluorinated heterocycles can be functionalized using this method. In addition, the late-stage functionalization of pharmaceuticals is also presented. Computational studies demonstrate that the site selectivity of the reaction is dictated by arene electronics.
- Nicewicz, David A.,Pistritto, Vincent A.,Schutzbach-Horton, Megan E.
-
supporting information
p. 17187 - 17194
(2020/11/02)
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- Catalytic Reductions Without External Hydrogen Gas: Broad Scope Hydrogenations with Tetrahydroxydiboron and a Tertiary Amine
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Facile reduction of aryl halides with a combination of 5% Pd/C, B2(OH)4, and 4-methylmorpholine is reported. Aryl bromides, iodides, and chlorides were efficiently reduced. Aryl dihalides containing two different halogen atoms underwent selective reduction: I over Br and Cl, and Br over Cl. Beyond these, aryl triflates were efficiently reduced. This combination was broadly general, effectuating reductions of benzylic halides and ethers, alkenes, alkynes, aldehydes, and azides, as well as for N-Cbz deprotection. A cyano group was unaffected, but a nitro group and a ketone underwent reduction to a low extent. When B2(OD)4 was used for aryl halide reduction, a significant amount of deuteriation occurred. However, H atom incorporation competed and increased in slower reactions. 4-Methylmorpholine was identified as a possible source of H atoms in this, but a combination of only 4-methylmorpholine and Pd/C did not result in reduction. Hydrogen gas has been observed to form with this reagent combination. Experiments aimed at understanding the chemistry led to the proposal of a plausible mechanism and to the identification of N,N-bis(methyl-d3)pyridin-4-amine (DMAP-d6) and B2(OD)4 as an effective combination for full aromatic deuteriation. (Figure presented.).
- Korvinson, Kirill A.,Akula, Hari K.,Malinchak, Casina T.,Sebastian, Dellamol,Wei, Wei,Khandaker, Tashrique A.,Andrzejewska, Magdalena R.,Zajc, Barbara,Lakshman, Mahesh K.
-
supporting information
p. 166 - 176
(2020/01/02)
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- Copper(ii)-catalyzed c-n coupling of aryl halides and n-nucleophiles promoted by quebrachitol or diethylene glycol
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Herein, we report the natural ligand quebrachitol (QCT) as a promoter for a Cu(II) catalyst, which is highly effective for N-Arylation of various amines and related aryl halides. A series of diarylamine derivatives were obtained in high yields by using diethylene glycol (DEG) as both ligand and solvent. The C-N coupling reactions proceed under mild conditions and exhibit good functional group tolerance.
- Chen, Guoliang,Chen, Yuanguang,Du, Fangyu,Fu, Yang,Wu, Ying,Zhou, Qifan
-
supporting information
p. 2161 - 2168
(2019/11/25)
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- Nickel-Catalyzed C-N Cross-Coupling of Ammonia, (Hetero)anilines, and Indoles with Activated (Hetero)aryl Chlorides Enabled by Ligand Design
-
The Ni(II) precatalyst (C1) featuring the phosphonite ancillary ligand Phen-DalPhos (L1) was employed in the cross-coupling of (hetero)anilines with (hetero)aryl chlorides and in the diarylation of ammonia with (hetero)aryl chlorides to afford heteroatom-dense di(hetero)arylamines. The PAd2-DalPhos precatalyst C4 provided complementary reactivity in cross-couplings of indoles with (hetero)aryl chlorides. Taken together, the demonstration of room-temperature reactivity within each of the reaction classes examined and the observation of useful chemoselectivity at low loading (≤0.5 mol % Ni) and on gram-scale distinguishes C1 and C4 from other metal catalysts (i.e., copper, palladium, nickel, or other) within the field of C-N cross-coupling chemistry.
- McGuire, Ryan T.,Paffile, Julia F. J.,Zhou, Yuqiao,Stradiotto, Mark
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p. 9292 - 9297
(2019/10/11)
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- Examining the Impact of Heteroaryl Variants of PAd-DalPhos on Nickel-Catalyzed C(sp2)-N Cross-Couplings
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We report herein on the synthesis of new heteroaryl analogues of PAd-DalPhos and related bis(di(o-tolyl)phosphino) ancillary ligand variants based on pyridine or thiophene backbone structures, and their application in nickel-catalyzed C(sp2)-N cross-couplings under challenging reaction conditions. The 3,4-disubstituted thiophene-based ancillary ligand ThioPAd-DalPhos (L8) was observed to be particularly effective in the nickel-catalyzed C(sp2)-N cross-coupling of primary alkylamines, and the derived precatalyst (L8)NiCl(o-tolyl) (C2) was found to offer improved performance versus the related PAd-DalPhos-derived precatalyst C1 in such transformations. In using C2, cross-couplings of various primary alkylamines and (hetero)aryl-X electrophiles (X = Cl, Br, OTs) proceeded under unprecedentedly mild reaction conditions (0.25-0.50 mol % Ni), including examples conducted at room temperature. Also reported herein are the results of our combined experimental/DFT computational study directed toward gaining insight regarding the improved catalytic performance of C2 versus C1.
- Clark, Jillian S. K.,McGuire, Ryan T.,Lavoie, Christopher M.,Ferguson, Michael J.,Stradiotto, Mark
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p. 167 - 175
(2018/09/25)
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- Pyridyl Radical Cation for C?H Amination of Arenes
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Electron-transfer photocatalysis provides access to the elusive and unprecedented N-pyridyl radical cation from selected N-substituted pyridinium reagents. The resulting C(sp2)?H functionalization of (hetero)arenes furnishes versatile intermediates for the development of valuable aminated aryl scaffolds. Mechanistic studies that include the first spectroscopic evidence of a spin-trapped N-pyridyl radical adduct implicate SET-triggered, pseudo-mesolytic cleavage of the N?X pyridinium reagents mediated by visible light.
- R?ssler, Simon L.,Jelier, Benson J.,Tripet, Pascal F.,Shemet, Andrej,Jeschke, Gunnar,Togni, Antonio,Carreira, Erick M.
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supporting information
p. 526 - 531
(2019/01/04)
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- Method for preparing aromatic amine compounds from aromatic nitro compounds by catalytic reduction of nano porous gold catalyst
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The invention discloses a method for preparing aromatic amine compounds from aromatic nitro compounds by catalytic reduction of a nano porous gold catalyst. The nano porous gold catalyst and the aromatic nitro compounds are taken as substrates and subjected to a reaction in methanol with ammonia borane as a hydrogen source at the room temperature, and a product is obtained. The high probability ofagglomeration of conventional granular catalysts is prevented, the nano porous gold catalyst shows excellent structural stability and good recycling efficiency, has excellent universality, especiallyfor the aromatic nitro compounds, and has green and mild catalytic conditions, high yield and good selectivity. The yield of m-nitroaniline from m-nitrotoluene can reach 98%. Moreover, the catalyst can be centrifugally recovered and can be recycled without other treatment, the yield of preparing m-nitroaniline from m-nitrotoluene by catalyzing can still reach 88% after being recycled five times,and thus, waste is effectively avoided. The catalyst shows high activity during the reaction and excellent stability under the reaction conditions.
- -
-
Paragraph 0024; 0025
(2019/07/04)
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- Direct conversion of phenols into primary anilines with hydrazine catalyzed by palladium
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Primary anilines are essential building blocks to synthesize various pharmaceuticals, agrochemicals, pigments, electronic materials, and others. To date, the syntheses of primary anilines mostly rely on the reduction of nitroarenes or the transition-metal-catalyzed Ullmann, Buchwald-Hartwig and Chan-Lam cross-coupling reactions with ammonia, in which non-renewable petroleum-based chemicals are typically used as feedstocks via multiple step syntheses. A long-standing scientific challenge is to synthesize various primary anilines directly from renewable sources. Herein, we report a general method to directly convert a broad range of phenols into the corresponding primary anilines with the cheap and widely available hydrazine as both amine and hydride sources with simple Pd/C as the catalyst.
- Qiu, Zihang,Lv, Leiyang,Li, Jianbin,Li, Chen-Chen,Li, Chao-Jun
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p. 4775 - 4781
(2019/05/16)
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- Metal-free Semiconductor Photocatalysis for sp2 C?H Functionalization with Molecular Oxygen
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Designing metal-free catalysts for solar energy conversion is a long-standing challenge in semiconductor photoredox catalysis (SPC). With visible-light-responsive hexagonal boron carbon nitride (h-BCN) as a non-metal photocatalyst, this system affords C?H/N?H coupling products with broad substitution tolerance and high efficiency with molecular oxygen as the terminal oxidant. The catalyst exhibits remarkable performance for the selective C?H functionalization of electron-rich arenes to C?N products (yields up to 95 %) and good stability (6 recycles). Both nitrogen heteroarenes and amine salts are competent coupling nucleophiles. Mechanically, the reactive oxygen species are superoxide anion radical (O2?.) and H2O2, which are proved by electron spin resonance (ESR) data, KI-starch, and control experiments. In addition, kinetic isotope effect (KIE) experiments indicate that C?H bond cleavage is not involved in the rate limiting step. This semiconductor-based photoredox system allows for C?H amination free of any metals, ligands, strong oxidants, and additives. It provides a complementary avenue to C?H functionalizations and enables synthetic applications efficiently in a sustainable manner.
- Zheng, Meifang,Ghosh, Indrajit,K?nig, Burkhard,Wang, Xinchen
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p. 703 - 706
(2019/01/04)
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- Deacetylative Amination of Acetyl Arenes and Alkanes with C-C Bond Cleavage
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The Br?nsted acid-catalyzed synthesis of primary amines from acetyl arenes and alkanes with C-C bond cleavage is described. Although the conversion from an acetyl group to amine has traditionally required multiple steps, the method described herein, which uses an oxime reagent as an amino group source, achieves the transformation directly via domino transoximation/Beckmann rearrangement/Pinner reaction. The method was also applied to the synthesis of γ-aminobutyric acids, such as baclophen and rolipram.
- Hyodo, Kengo,Hasegawa, Genna,Maki, Hiroya,Uchida, Kingo
-
supporting information
p. 2818 - 2822
(2019/04/25)
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- PRODUCTION METHOD OF PRIMARY AMINE COMPOUND
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PROBLEM TO BE SOLVED: To provide a simple production method of a primary amine compound unnecessary for complicated procedures and toxic sodium azide or the like. SOLUTION: A production method of a primary amine compound includes a step for reacting a ketone compound and an oxime compound in the presence of alcohol and an acid catalyst. Preferably, the acid catalyst is hydrochloric acid, sulfuric acid, methanesulfonic acid, camphorsulfonic acid, a tosyl acid hydrate, trifluoromethane sulfonic acid or a boron trifluoride diethyl ether complex. SELECTED DRAWING: None COPYRIGHT: (C)2019,JPOandINPIT
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-
Paragraph 0029
(2019/09/20)
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- Microballs Containing Ni(0)Pd(0) Nanoparticles for Highly Selective Micellar Catalysis in Water
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Both Ni(0) complexes and nanoparticles (NPs) are unstable in water, which poses a significant hindrance to their application in aqueous synthetic catalysis. To overcome these barriers, ligated Ni(0) nanoparticles (diameter 1 nm) containing a minimum amount of Pd(0) in the microballs formed of amphiphile PS-750-M are developed and applied in the highly selective carbamate cleavage. Selectivity and functional group tolerance are thoroughly investigated. Control experiments revealed the importance of an individual component of the nanocatalyst. Use of our proline-based amphiphile PS-750-M is critical for achieving microball architecture, the stability of nanoparticles, and desired catalytic activity. Once formed, microballs can be isolated and stored at ambient temperature. Catalyst is thoroughly characterized by X-ray photoelectron spectroscopy, scanning electron microscopy, high-resolution transmission electron microscopy, thermogravimetric analysis, infrared, and cyclic voltammetry. For selective catalysis, zero oxidation state of both Ni and Pd is crucial. On the basis of catalyst characterization and control experiments, the plausible reaction mechanism is proposed.
- Bihani, Manisha,Bora, Pranjal P.,Nachtegaal, Maarten,Jasinski, Jacek B.,Plummer, Scott,Gallou, Fabrice,Handa, Sachin
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p. 7520 - 7526
(2019/08/15)
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- Ru-Catalyzed Deoxygenative Transfer Hydrogenation of Amides to Amines with Formic Acid/Triethylamine
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A ruthenium(II)-catalyzed deoxygenative transfer hydrogenation of amides to amines using HCO2H/NEt3 as the reducing agent is reported for the first time. The catalyst system consisting of [Ru(2-methylallyl)2(COD)], 1,1,1-tris(diphenylphosphinomethyl) ethane (triphos) and Bis(trifluoromethane sulfonimide) (HNTf2) performed well for deoxygenative reduction of various secondary and tertiary amides into the corresponding amines in high yields with excellent selectivities, and exhibits high tolerance toward functional groups including those that are reduction-sensitive. The choice of hydrogen source and acid co-catalyst is critical for catalysis. Mechanistic studies suggest that the reductive amination of the in situ generated alcohol and amine via borrowing hydrogen is the dominant pathway. (Figure presented.).
- Pan, Yixiao,Luo, Zhenli,Xu, Xin,Zhao, Haoqiang,Han, Jiahong,Xu, Lijin,Fan, Qinghua,Xiao, Jianliang
-
supporting information
p. 3800 - 3806
(2019/07/12)
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- Method for catalyzing amino protection by imidazole hydrochloride
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The invention provides an amino protection method which realizes multi-substituted amino protection by using imidazole hydrochloric acid as an accelerator to push derivatives of primary amine, secondary amine and acrylamide to perform Michael addition at a relatively low temperature, wherein the imidazole hydrochloric acid promotes a carbon-nitrogen bond to crack back to the derivatives of primaryamine and acrylamide at a high temperature. The method provided by the invention is simple and economical, high in practicability, free of any other catalysts or additives, capable of protecting amino to have good functional group tolerance and excellent yield and purity, short in reaction time, free from harsh reaction conditions and suitable for industrial production.
- -
-
Paragraph 0024; 0044-0048
(2019/08/01)
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- Michael addition reaction catalyzed by imidazolium chloride to protect amino groups and construct medium ring heterocycles
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An effective approach for amino protection and construction of a seven-membered ring has been developed. The method uses imidazolium chloride to carry out the Michael addition reaction at low temperatures and perform amino deprotection or construction of a seven-membered ring at high temperatures.
- Dai, Zeshu,Li, Dan,Li, Yanwu,Li, Zhiyao,Luo, Wen,Shang, Suqin,Tian, Qingqiang,Wang, Xuetong,Yuan, Jianyong,Zhang, Ying
-
supporting information
(2019/12/04)
-
- AMINATION AND HYDROXYLATION OF ARYLMETAL COMPOUNDS
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In one aspect, the present disclosure provides methods of preparing a primary or secondary amine and hydroxylated aromatic compounds. In some embodiments, the aromatic compound may be unsubstituted, substituted, or contain one or more heteroatoms within the rings of the aromatic compound. The methods described herein may be carried out without the need for transition metal catalysts or harsh reaction conditions.
- -
-
Paragraph 0098; 0134; 0135; 0148
(2018/03/25)
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- Highly efficient nitrobenzene and alkyl/aryl azide reduction in stainless steel jars without catalyst addition
-
The mechanochemical and selective reduction of aryl nitro and aryl/alkyl azide derivatives, with either formate salts or hydrazine, to the corresponding, synthetically useful amines occurs in excellent yields in a planetary ball mill without the addition of a catalyst. This newly developed and solvent-free protocol is efficient, fast and does not require the addition of a metal hydrogenation catalyst as the stainless steel jar itself fulfils that role. The method has been applied to a broad range of compounds and excellent yields have been obtained. The formylation of alkyl amines has been successfully performed, by means of mechanochemical activation, in the presence of ammonium formate alone.
- Martina, Katia,Baricco, Francesca,Tagliapietra, Silvia,Moran, Maria Jesus,Cravotto, Giancarlo,Cintas, Pedro
-
supporting information
p. 18881 - 18888
(2018/11/26)
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- Visible-light-driven Efficient Photocatalytic Reduction of Organic Azides to Amines over CdS Sheet–rGO Nanocomposite
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CdS sheet–rGO nanocomposite as a heterogeneous photocatalyst enables visible-light-induced photocatalytic reduction of aromatic, heteroaromatic, aliphatic and sulfonyl azides to the corresponding amines using hydrazine hydrate as a reductant. The reaction shows excellent conversion and chemoselectivity towards the formation of the amine without self-photoactivated azo compounds. In the adopted strategy, CdS not only accelerates the formation of nitrene through photoactivation of azide but also enhances the decomposition of azide to a certain extent, which entirely suppressed formation of the azo compound. The developed CdS sheet-rGO nanocomposite catalyst is very active, providing excellent results under irradiation with a 40 W simple household CFL lamp.
- Singha, Krishnadipti,Mondal, Aniruddha,Ghosh, Subhash Chandra,Panda, Asit Baran
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p. 255 - 260
(2018/01/15)
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- Controlled Transformations of Aryl Halides in a Flow System: Selective Synthesis of Aryl Azides and Aniline Derivatives
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Copper-mediated nitrogenation of aryl halides with sodium azide can result in either aryl azides or aniline derivatives. The selectivity of the transformation is highly dependent on reaction time and temperature, which led to contradictory literature results with respect to product selectivity and the conditions applied. The advantages of a strictly controlled flow reactor environment were exploited in order to facilitate selective haloarene transformations. Reaction conditions were carefully investigated to understand their role on product selectivity. Aryl azides and aryl amines were successfully prepared from the same starting materials using the same auxiliaries by means of precise control over residence time and reaction temperature, thereby ensuring time-, cost- and atom-efficient syntheses. (Figure presented.).
- Georgiádes, ádám,?tv?s, Sándor B.,Fül?p, Ferenc
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p. 1841 - 1849
(2018/04/09)
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- STABILIZATION OF ACTIVE METAL CATALYSTS AT METAL-ORGANIC FRAMEWORK NODES FOR HIGHLY EFFICIENT ORGANIC TRANSFORMATIONS
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Metal-organic framework (MOFs) compositions based on post?synthetic metalation of secondary building unit (SBU) terminal or bridging OH or OH2 groups with metal precursors or other post-synthetic manipulations are described. The MOFs provide a versatile family of recyclable and reusable single-site solid catalysts for catalyzing a variety of asymmetric organic transformations, including the regioselective boryiation and siiylation of benzyiic C—H bonds, the hydrogenation of aikenes, imines, carbonyls, nitroarenes, and heterocycles, hydroboration, hydrophosphination, and cyclization reactions. The solid catalysts can also be integrated into a flow reactor or a supercritical fluid reactor.
- -
-
Paragraph 0354-0356; 0359
(2019/01/07)
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- Ethyl 6-Hydroxyfulvene-1-Carboxylate: A Reagent Discriminating Primary Amines from Secondary Amines
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A highly chemo-selective reaction was observed when ethyl 6-hydroxyfulvene-1-carboxylate 1 was treated with different nucleophiles such as primary amines, secondary amines, alcohols, and thiols. Among them, only primary amines are reactive toward 1 to afford the condensation products 3, which exhibit good stability under both weakly acidic and basic conditions. The condensation process proved to be reversible between different primary amines. On the basis of this observation, the chemical selectivity of typical primary aromatic amines was evaluated quantitatively by determining equilibrium constants of the condensation reactions with aniline as a reference. Moreover, the primary amines of 3 can be readily released upon treatment with aqueous ammonia, making 6-hydroxyfulvene-1-carboxylate 1 a promising protecting reagent for primary amines.
- Yang, Sen,Lu, Dengfu,Zhu, Yuequan,Shi, Mei,Luo, Fan,Gong, Yuefa
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p. 6681 - 6689
(2018/06/11)
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- Method of preparing arylamine by photo-catalyzing C-H activation with semiconductor
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The invention discloses a method of preparing arylamine by photo-catalyzing C-H activation with a semiconductor. The method comprises the following steps of by taking an aromatic compound as a substrate and boron-nitrogen-carbon as a photocatalyst, adding an amino source, a solvent and alkali, performing stirring reaction for 48h under the condition of visible light radiation at room temperature in an oxygen atmosphere, and synthesizing an arylamine compound. The boron-nitrogen-carbon (h-BCN) is a semiconductor polymer photocatalyst which responds to visible light and does not contain metallicelements and has the advantages of low cost, availability, good chemical stability, non toxicity, innocuousness, proper forbidden band width and energy band position and the like. The catalyst is used for synthesizing the arylamine compound, is simple in operation in reaction process, is performed under the visible light, is mild in condition and good in catalytic effect and has the yield, to a target product, reaching 72 percent. The method provided by the invention is simple in technology and low in cost, accords with the actual production needs and has relatively large application potential.
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Paragraph 0012
(2018/10/04)
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- Selective synthesis of mono- and di-methylated amines using methanol and sodium azide as C1 and N1 sources
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A Ru(ii) complex mediated synthesis of various N,N-dimethyl and N-monomethyl amines from organic azides using methanol as a methylating agent is reported. This methodology was successfully applied for a one-pot reaction of bromide derivatives and sodium azide in methanol. Notably, by controlling the reaction time several N-monomethylated and N,N-dimethylated amines were synthesized selectively. The practical applicability of this tandem process was revealed by preparative scale reactions with different organic azides and synthesis of an anti-vertigo drug betahistine. Several kinetic experiments and DFT studies were carried out to understand the mechanism of this transformation.
- Chakrabarti, Kaushik,Mishra, Anju,Panja, Dibyajyoti,Paul, Bhaskar,Kundu, Sabuj
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supporting information
p. 3339 - 3345
(2018/07/29)
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- Metal-free deoxygenation and reductive disilylation of nitroarenes by organosilicon reducing reagents
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A metal-free deoxygenation and reductive disilylation of nitroarenes was achieved using N,N’-bis(trime-thylsilyl)-4,4’-bipyridinylidene (1) under mild and neutral reaction conditions, and a broad functional group tolerance was possible in this reaction. Mono-deoxygenation, giving a synthetically valuable N,O-bis(trimethylsilyl)phe-nylhydroxylamine (7a) as a readily available and safe phenylnitrene source from nitrobenzene, and double-deoxy-genation, giving N,N-bis(trimethylsilyl)anilines 8, were easily controlled by varying the amounts of 1 and reaction temperature as well as adding dibenzothiophene (DBTP). Reaction of 2-arylnitrobenzenes with 1 resulted in the formation of the corresponding carbazoles 14 via in situ-gen-erated phenylnitrene species derived by thermolysis of N,O-bis(trimethylsilyl)phenylhydroxylamines 7, followed by their subsequent intramolecular C H insertion. In addition, the intramolecular N N coupling reaction proceeded in the reduction of 2,2’-dinitrobiphenyl derivatives by 1, giving the corresponding benzo[c]cinnolines.
- Bhattacharjee, Argha,Hosoya, Hiromu,Ikeda, Hideaki,Nishi, Kohei,Tsurugi, Hayato,Mashima, Kazushi
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supporting information
p. 11278 - 11282
(2018/10/20)
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- Development of a novel protocol for chemoselective deprotection of N/O-benzyloxycarbonyl (Cbz) at ambient temperature
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Abstract: A novel protocol for the deprotection of N-benzyloxycarbonyl and O-benzyloxycarbonyl groups by nickel boride generated in situ from NaBH4 and NiCl2·6H2O in methanol at room temperature has been developed to give the corresponding amines and phenols. This protocol is chemoselective as groups like chloro, bromo, amide, ester, pyridine, and tert-butyloxycarbonyl moiety are unaffected under these conditions. The deprotection has also been validated in gram scale reactions, to establish the wider appropriateness of this protocol. Graphical abstract: [Figure not available: see fulltext.].
- Saroha, Mohit,Aggarwal, Komal,Bartwal, Gaurav,Khurana, Jitender M.
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p. 2231 - 2235
(2018/10/02)
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- High yielding electrophilic amination method for arylcopper reagents
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The facilitative effect of some P-, N-, S-, and O-donor ligands in the reaction of arylcoppers with acetone O-(mesitylenesulfonyl)oxime was examined to develop a synthesis method for functionalized primary aryl amines under mild reaction conditions. Our research showed that electrophilic amination of monoaryl coppers with ketoximes can be facilitated using appropriate ligand to supply significant increase in the yield. Also, we have seen that this ligand-facilitated method is applicable in terms of arylcopper and ketoxime type and allows synthesis of primary aryl amines in good to high yields easily at room temperature in very short reaction time.
- Da?kapan, Tahir,?i?ek, Semra
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p. 899 - 906
(2017/04/27)
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- A palladium complex immobilized onto mesoporous silica: a highly efficient and reusable catalytic system for carbon–carbon bond formation and anilines synthesis
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A palladium complex supported on functionalized mesoporous silica MCM-41 proved to be a highly efficient, recoverable catalyst for C–C coupling reactions and amination of aryl halides to afford anilines. The nanocatalyst was characterized by FT-IR spectroscopy, X-ray diffraction, transmission electron microscopy, scanning electron microscopy, thermogravimetric analysis, N2 adsorption–desorption isotherms and inductively coupled plasma analysis. The catalyst could be reused for several consecutive runs without significant loss of activity. The excellent yields of products, simple reaction procedures and short reaction times are the main advantages of this methodology.
- Nikoorazm, Mohsen,Noori, Nourolah,Tahmasbi, Bahman,Faryadi, Sara
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p. 469 - 481
(2017/07/12)
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- A new palladium complex supported on magnetic nanoparticles and applied as an catalyst in amination of aryl halides, Heck and Suzuki reactions
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A simple, efficient and less expensive protocol for the phosphine-free C–C coupling reactions and synthesis of anilines in the presence of 2-aminobenzamide complex of palladium supported on Fe3O4 magnetic nanoparticles (Pd(0)-ABA-Fe3O4) has been reported. The Suzuki reaction was carried out in water or PEG using phenylboronic acid (PhB(OH)2) or sodium tetraphenyl borate (NaBPh4). Pd(0)-ABA-Fe3O4 has been found promising for Heck reaction of butyl acrylate, styrene or acrylonitrile with aryl halides (including Cl, Br and I). Also, Pd(0)-ABA-Fe3O4 has been found as efficient catalyst for the amination of aryl halides using aqueous ammonia. The products have been obtained in short reaction times and high yields. The catalyst was easily separated using an external magnet from the reaction mixture and reused for several runs without significant loss of its catalytic efficiency or palladium leaching. The leaching of catalyst has been examined by hot filtration and ICP-OES technique. The nanomagnetical catalyst was characterized by FTIR, TGA, XRD, VSM, TEM, SEM, EDS, DLS and ICP-OES techniques.
- Ghorbani-Choghamarani, Arash,Tahmasbi, Bahman,Noori, Nourolah,Ghafouri-nejad, Raziyeh
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p. 681 - 693
(2017/01/17)
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