- Catalytic Asymmetric Construction of Tertiary Carbon Centers Featuring an α-Difluoromethyl Group with CF2H-CH2-NH2as the "building Block"
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We report here for the first time a novel difluoromethylated ketimine building block condensed by thioisatin and difluoroethylamine, offering efficient access to a broad range of enantioenriched products bearing difluoroethylamine units (27 examples, ≤98% yield, >99% ee) in the presence of quinine-derived squaramide. Further transformation of the intermediate would generate a variety of versatile functional blocks like α-difluoromethyl amines, β-amino acid, and β-diamine with retention of the enantiomeric excess at the difluoromethyl-bound carbon.
- Gao, Fengyun,Guo, Yifei,Sun, Mengmeng,Wang, Yalan,Yang, Changyan,Wang, Yuqiang,Wang, Kairong,Yan, Wenjin
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supporting information
p. 2584 - 2589
(2021/04/13)
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- Dipolar HCP materials as alternatives to DMF solvent for azide-based synthesis
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Hypercrosslinked polymers HCP-DMF and HCP-DMF-SO3H containing abundant and flexible DMF moieties were designed and synthesized. Benefitting from the solvation microenvironment provided by the pseudo-DMF moities, the polar HCPs manifested outstanding performances in the conversions of NaN3 to benzylic azides and 1,2,3-triazoles in EtOH (95%), respectively, avoiding the use of risky DMF and improving the separation processes of the products.
- Bai, Rongxian,Gao, Feng,Gu, Yanlong,Li, Minghao
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supporting information
p. 7499 - 7505
(2021/10/12)
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- Active Base Hybrid Organosilica Materials based on Pyrrolidine Builder Units for Fine Chemicals Production
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The catalytic activity of “pyrrolidine type” fragments included or anchored in the mesoporous silica supports or polymeric frameworks have been fully reported for enantioselective transformation. Nevertheless, low attention was focused on their catalytic abilities to perform base-catalyzed reaction. Accordingly, hybrid materials including pyrrolidine fragments in the mesoporous silica supports were prepared following different synthesis methods, such as micellar and fluoride sol-gel routes in absence of structural directing agents. Their great catalytic performance was explored for various base-catalyzed reactions to the formation of C?C bond through Knoevenagel, Claisen-Schmidt and Henry condensations under microwave irradiation. The benefits of microwave irradiation combined with suitable catalytic properties of pyrrolidine hybrid materials with strong base sites and high accessibility to active centers, allowed carrying out successfully base-catalyzed condensation reactions for the production of fine chemicals. Moreover, the hybrid catalyst exhibited high selectivity and good stability over different catalytic cycles contributing to environmental sustainability.
- Llopis, Sebastián,Velty, Alexandra,Díaz, Urbano
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p. 5012 - 5024
(2021/10/19)
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- Microwave-assisted rapid synthesis of spirooxindole-pyrrolizidine analogues and their activity as anti-amyloidogenic agents
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A library of Sox-pyrrolizidines was rapidly prepared by microwave-assisted, one-pot, three-component, 1,3-dipolar cycloaddition of azomethine ylides from l-proline and isatin, with various β-nitrostyrenes. Nitro-Sox compounds, 4b, 4d and 4e inhibit HEWL amyloid fibril formation by ThT studies with percentages of fluorescence intensity of 55.4, 42.9 and 40.3%, respectively. Further studies with MTT assay, Raman spectroscopy, TEM and molecular docking supported these promising candidates for activity against amyloid misfolding, a phenomenon leading to Alzheimer's disease pathology.
- de Silva, Nilamuni H.,Pyreddy, Suneela,Blanch, Ewan W.,Hügel, Helmut M.,Maniam, Subashani
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supporting information
(2021/07/07)
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- Organocatalytic Asymmetric Synthesis of Aza-Spirooxindoles via Michael/Friedel-Crafts Cascade Reaction of 1,3-Nitroenynes and 3-Pyrrolyloxindoles
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An asymmetric [3+3] cyclization of nitroenynes and 3-pyrrolyloxindoles has been realized with a chiral bifunctional squaramide catalyst. This Michael/Friedel-Crafts cascade strategy provides a facile and efficient access to enantioenriched polycyclic aza-spirooxindoles with 32-95% isolated yields and excellent stereocontrol under mild reaction conditions.
- Ni, Qijian,Wang, Xuyang,Zeng, Da,Wu, Qianling,Song, Xiaoxiao
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supporting information
p. 2273 - 2278
(2021/04/05)
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- Skeletally Tunable Seven-Membered-Ring Fused Pyrroles
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We describe a copper-mediated method that enables the synthesis of seven-membered-ring fused pyrroles (7-mrFPs). The protocol proceeds via an in situ spiro-intermediate ring expansion and tolerates a library of 7-mrFP derivatives with a broad range of functional groups in a simple step with tangible parameters and substrate adaptations. These rare 7-mrFPs are now accessible on a millimolar scale, and selected examples exhibit high antioxidant activity.
- Andreou, Dimitrios,Essien, Nsikak B.,Pubill-Ulldemolins, Cristina,Terzidis, Michael A.,Papadopoulos, Athanasios N.,Kostakis, George E.,Lykakis, Ioannis N.
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supporting information
p. 6685 - 6690
(2021/09/11)
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- Four-Step Domino Reaction Enables Fully Controlled Non-Statistical Synthesis of Hexaarylbenzene with Six Different Aryl Groups**
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Hexaarylbenzene (HAB) derivatives are versatile aromatic systems playing a significant role as chromophores, liquid crystalline materials, molecular receptors, molecular-scale devices, organic light-emitting diodes and candidates for organic electronics. Statistical synthesis of simple symmetrical HABs is known via cyclotrimerization or Diels–Alder reactions. By contrast, the synthesis of more complex, asymmetrical systems, and without involvement of statistical steps, remains an unsolved problem. Here we present a generally applicable synthetic strategy to access asymmetrical HAB via an atom-economical and high-yielding metal-free four-step domino reaction using nitrostyrenes and α,α-dicyanoolefins as easily available starting materials. Resulting domino product—functionalized triarylbenzene (TAB)—can be used as a key starting compound to furnish asymmetrically substituted hexaarylbenzenes in high overall yield and without involvement of statistical steps. This straightforward domino process represents a distinct approach to create diverse and still unexplored HAB scaffolds, containing six different aromatic rings around central benzene core.
- Dill, Maximilian,Grau, Benedikt W.,Hampel, Frank,Jux, Norbert,Kahnt, Axel,Tsogoeva, Svetlana B.
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supporting information
p. 22307 - 22314
(2021/08/25)
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- tert-Butyl Nitrite Mediated Nitro-Nitratosation of Internal Alkenes
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In an oxygen atmosphere tert-butyl nitrite (TBN) reacts with unsymmetrical internal benzylic alkenes giving nitro-nitratosation product exclusively. The γ-diaryl-substituted styrenes provided better yields compared to γ-alkyl-aryl-substituted styrenes. The higher yields for the former type of substrates is possibly dictated by the additional stability of benzylic radical due to the anchimeric assistance imparted by the γ-substituted phenyl ring. During oxidative nitration, the nitro (NO2) group adds at the non-benzylic site, whereas the nitrato group (ONO2) is attached at the relatively stable benzylic position. Under similar reaction conditions, α,β-unsaturated carboxylic acids, afforded nitroalkenes as the sole product.
- Mir, Bilal Ahmad,Rajamanickam, Suresh,Begum, Pakiza,Patel, Bhisma K.
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p. 2617 - 2625
(2020/05/08)
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- Preparation method of beta-trans-nitroolefin
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The invention relates to a preparation method of beta-trans-nitroolefin. The method comprises: sequentially adding an olefin compound, a nitration reagent and a solvent into a reaction container, mixing the substances uniformly, and carrying out constant temperature reaction for 18h under an illumination condition to obtain a reaction solution; and sequentially carrying out drying, concentration and column chromatography treatment on the reaction solution to obtain the beta-trans-nitroolefin compound. The method is simple and practicable, low in cost and high in product yield, can realize large-scale production, and has good industrial application prospects in the aspects of functional organic material, bioactive compound and drug synthesis.
- -
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Paragraph 0051-0053
(2020/06/17)
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- Ionic-Liquid Controlled Nitration of Double Bond: Highly Selective Synthesis of Nitrostyrenes and Benzonitriles
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Unprecedented in literature, the conversion of aryl alkenes into β-nitrostyrenes (2) or benzonitriles (3) with sodium nitrite can be governed by an appropriate choice of ionic liquid (IL) medium. A general trend was found for the selectivity of these processes, which depends on the nature of IL, with imidazolium-based ILs, such as [Bmim]Cl, that favor the C–H nitration leading to β-nitrostyrenes, while tetraalkylammonium-based ILs, such as TBAA, privilege the C=C bond cleavage affording benzonitriles. Besides a substrate scope, mechanistic hypotheses were provided on the origin of the different selectivity in the two kinds of ILs, based on their own tunable properties such as polarity, viscosity, and solvent cage effects.
- Casiello, Michele,Caputo, Daniela,Fusco, Caterina,Cotugno, Pietro,Rizzi, Vito,Dell'Anna, Maria Michela,D'Accolti, Lucia,Nacci, Angelo
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supporting information
p. 6012 - 6018
(2020/08/24)
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- Molecular Engineering of β-Substituted Oxoporphyrinogens for Hydrogen-Bond Donor Catalysis
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A new class of bifunctional hydrogen-bond donor organocatalyst using oxoporphyrinogens having increased intramolecular hydrogen-bond donor distances is reported. Oxoporphyrinogens are highly non-planar rigid macrocycles containing a multiple hydrogen bond-forming binding site. In this work, we describe the first example of non-planar OxPs as hydrogen-bond donor catalysts prepared using a molecular engineering approach of the binding site for dual activation of substrates. The introduction of β-substituents is key to the catalytic activity and the catalysts are able to catalyze 1,4-conjugate additions and sulfa-Michael additions, as well as, Henry and aza-Henry reactions at low catalyst loadings (≤ 1 mol-%) under mild conditions. Preliminary mechanistic studies have been carried out and a possible reaction mechanism has been proposed based on the bi-functional activation of both substrates through hydrogen-bonding interactions.
- Chahal, Mandeep K.,Payne, Daniel T.,Matsushita, Yoshitaka,Labuta, Jan,Ariga, Katsuhiko,Hill, Jonathan P.
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supporting information
p. 82 - 90
(2020/01/02)
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- Geometrically Selective Denitrative Trifluoromethylthiolation of β-Nitrostyrenes with AgSCF3for (E)-Vinyl Trifluoromethyl Thioethers
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An efficient copper(II)-promoted denitrative trifluoromethylthiolation under mild reaction conditions has been developed for vinyl trifluoromethyl thioethers to construct Cvinyl-SCF3 bonds with stable AgSCF3 as a source of the trifluoromethylthio. This reaction system tolerates a broad range of functional groups to commendably achieve a high product yield and excellent stereoselectivity of E/Z.
- Fang, Ge,Hong, Jianquan,Huang, Shuai,Jiang, Chao,Liu, Yang,Zhang, Wei,Zheng, Changge
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supporting information
(2020/07/03)
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- Chlorination of Conjugated Nitroalkenes with PhICl 2and so 2Cl 2for the Synthesis of α-Chloronitroalkenes
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Chlorination of conjugated nitroalkenes with iodobenzene dichloride or sulfuryl chloride to give target α-chloronitroalkenes in good yields is described. Details of the procedure depend on the donating ability of the nitroalkene substituents. The activity of the described chlorinating agents increases in order 'PhICl 2/Py' 2Cl 2' 2Cl 2/HCl' with the former producing the best yields for highly donating substrates and the latter for non-activated groups. An autocatalytic role of hydrogen chloride and the chemoselectivity of chlorination were also demonstrated.
- Fadeeva, Anastasia A.,Ioffe, Sema L.,Tabolin, Andrey A.
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supporting information
p. 2679 - 2688
(2020/11/02)
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- A photocatalyst-free photo-induced denitroalkylation of β-nitrostyrenes with 4-alkyl substituted Hantzsch esters at room temperature
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A photocatalyst-free stereoselectively photo-induced strategy for the denitroalkylation of β-nitrostyrenes using 4-alkyl substituted Hantzsch esters as the alkyl source under xenon lamp irradiation is developed. The reaction proceeds at room temperature and affords the corresponding products in moderate to excellent yields. The oxidant di-t-butyl peroxide serves as an efficient radical initiator under irradiation of a Xenon lamp, initiating alkyl radicals from the 4-alkyl substituted Hantzsch esters.
- Duan, Chunying,Hao, Xinyu,Jin, Kun,Li, Yaming,Wang, Jiaao,Zhang, Rong,Zhang, Siyu
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supporting information
(2020/02/18)
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- NCC Pincer Ni (II) Complexes Catalyzed Hydrophosphination of Nitroalkenes with Diphenylphosphine
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An efficient NCC pincer Ni (II)-catalyzed hydrophosphination of nitroalkenes with diphenylphosphine has been developed. Under the optimized conditions, both (hetero)aromatic and aliphatic nitroalkenes were well tolerated, irrespective of electronic effect, to provide the corresponding products in up to 99% yield.
- Yan, Jing,Wang, Yan-Bing,Hou, Senyao,Shi, Linlin,Zhu, Xinju,Hao, Xin-Qi,Song, Mao-Ping
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- Co-Polymeric Nanosponges from Cellulose Biomass as Heterogeneous Catalysts for amine-catalyzed Organic Reactions
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Heterogeneous catalysts prepared from biomass waste sources are attracting increasing interest. The reasons rely on the possibility of combining the virtuous approach of circular economy with the consolidated advantages of heterogeneous catalysis, namely the recycling of the system and the possibility to drive selectivity towards desired products. Herein we report a highly porous cellulose-based nanosponge (CNS) and its use as a recoverable catalyst for Henry and Knoevenagel reactions, two classical amino-catalyzed transformations. The material is obtained by cross-linking between TEMPO-oxidized cellulose nanofibers (TOCNF) and branched polyethyleneimine 25 kDa (bPEI) in the presence of citric acid. CNS have been developed as sorbent materials for water remediation but their use as heterogeneous catalysts was never investigated. The fully characterized micro- and nano-porous system guarantees a complete penetration of CNS, allowing reagents to diffuse within. Indeed, by modulating reaction conditions (catalyst loading, temperature, solvent, microwave versus conventional heating, relative ratio of reagents) it was possible to drive selectivity towards the desired products, while maintaining high efficiency in terms of conversion. The catalyst could be re-used several times without losing in catalytic efficiency. In most cases the products’ distribution is quite different from homogeneous conditions, this much more emphasizing the importance of this heterogeneous solution.
- Riva, Laura,Punta, Carlo,Sacchetti, Alessandro
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p. 6214 - 6222
(2020/10/02)
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- Preparation method of nitroolefin derivative with nitrate as nitro source
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The invention relates to a nitroolefin derivative with nitrate as nitro source and a preparation method thereof. Under the atmosphere of nitrogen, an olefin compound, nitrate, trimethylchlorosilane (TMSC1) and copper salt are stirred in acetonitrile at 0-30 DEG C; in addition, the reaction degree is monitored by using a TLC point plate; after the olefin compound is completely consumed, alkali is added to an obtained mixture to be stirred for 20-30 min; then after a solvent is removed from an obtained mixture by using a rotary evaporator, the nitroolefin derivative can be obtained through silicagel column purification. Compared with the prior art, the nitroolefin derivative with the nitrate as the nitro source, provided by the invention, has the advantages of mild reaction condition, high yield, high E type selectivity and the like.
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-
Paragraph 0042; 0049-0054; 0073-0075
(2019/08/20)
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- Metal-free, room temperature, acid-K2S2O8 mediated method for the nitration of olefins: An easy approach for the synthesis of nitroolefins
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Here, we have developed a simple, room temperature method for the nitration of olefins by using inexpensive sodium nitrite as a source of nitro groups in the presence of trifluoroacetic acid (TFA) and potassium persulfate (K2S2O8) under an open atmosphere. Styrenes and mono-substituted olefins give stereo-selective corresponding E-nitroolefins under optimized conditions, however, 1,1-bisubstituted olefins give a mixture of E- and Z-nitroolefins. The optimized conditions work well with electron-donating, electron-withdrawing, un-substituted and heterocyclic styrenes and mono-substituted olefins and give corresponding nitroolefins with good to excellent yields.
- Ambala, Srinivas,Singh, Rohit,Singh, Maninder,Cham, Pankaj Singh,Gupta, Ria,Munagala, Gurunadham,Yempalla, Kushalava Reddy,Vishwakarma, Ram A.,Singh, Parvinder Pal
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p. 30428 - 30431
(2019/10/04)
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- Synthetic Diversity from a Versatile and Radical Nitrating Reagent
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We leverage the slow liberation of nitrogen dioxide from a newly discovered, inexpensive succinimide-derived reagent to allow for the C?H diversification of alkenes and alkynes. Beyond furnishing a library of aryl β-nitroalkenes, this reagent provides unparalleled access to β-nitrohydrins and β-nitroethers. Detailed mechanistic studies strongly suggest that a mesolytic N?N bond fragmentation liberates a nitryl radical. Using in situ photo-sensitized, electron paramagnetic resonance spectroscopy, we observed direct evidence of a nitryl radical in solution by nitrone spin-trapping. To further exhibit versatility of N-nitrosuccinimide under photoredox conditions, the late-stage diversification of an extensive number of C?H partners to prepare isoxazolines and isoxazoles is presented. This approach allows for the formation of an in situ nitrile oxide from a ketone partner, the presence of which is detected by the formation of the corresponding furoxan when conducted in the absence of a dipolarophile. This 1,3-dipolar cycloaddition with nitrile oxides and alkenes or alkynes proceeds in a single-operational step using a mild, regioselective, and general protocol with broad chemoselectivity.
- Zhang, Kun,Jelier, Benson,Passera, Alessandro,Jeschke, Gunnar,Katayev, Dmitry
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supporting information
p. 12929 - 12939
(2019/09/17)
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- Visible light-mediated intermolecular [2 + 2] photocycloaddition of 1-aryl-2-nitroethenes and olefins
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Despite the importance of cyclobutanes there are not many direct [2 + 2] photocycloaddition reactions which can be performed with visible light in the absence of a catalyst. A notable exception is the reaction of 1-aryl-2-nitroethenes and olefins which can be performed at a wavelength of λ = 419 nm or λ = 424 nm in CH2Cl2 as the solvent. In the present study, a total of 15 1-aryl-2-nitroethenes were found to undergo a [2 + 2] photocycloaddition with 2,3-dimethyl-2-butene (28-86% yield) and a set of 12 olefins was studied in their photocycloaddition to 1-phenyl-2-nitroethene (37-88% yield). All mechanistic results are in agreement with a triplet reaction pathway and with the intermediacy of a 1,4-diradical.
- Mohr, Lisa-Marie,Bauer, Andreas,Jandl, Christian,Bach, Thorsten
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supporting information
p. 7192 - 7203
(2019/08/07)
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- A chiral bicyclic skeleton-tethered bipyridine-Zn(OTf)2 complex as a Lewis acid: Enantioselective Friedel-Crafts alkylation of indoles with nitroalkenes
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A conformationally rigid chiral bicyclic skeleton tethered bipyridine-Zn(OTf)2 complex facilitated the enantioselective Friedel-Crafts alkylation of indoles with trans-β-nitroarylalkenes in an enantioselective manner at elevated temperature. Indoles reacted smoothly with β-nitroarylalkenes to generate the corresponding 3-(2-nitroalkyl)indoles in good to excellent yields (up to 94%) with moderate to excellent enantioselectivities (up to 91%). The stereochemical outcome of the product from indole and trans-β-nitrostyrene in the presence of the CRCB tethered bipyridine-Zn(OTf)2 complex and the DFT calculation of the CRCB tethered bipyridine-Zn:trans-β-nitrostyrene complex support the si-face attack of indole on trans-β-nitrostyrene.
- Venkatanna, Kesa,Yeswanth Kumar, Santhakumar,Karthick, Muthupandi,Padmanaban, Ramanathan,Ramaraj Ramanathan, Chinnasamy
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p. 4077 - 4086
(2019/04/30)
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- Iodine monobromide catalysed regioselective synthesis of 3-arylquinolines from α-aminoacetophenones and: Trans -β-nitrostyrenes
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A simple and efficient method for regioselective synthesis of 3-arylquinolines is described from α-aminoacetophenones and trans-β-nitrostyrenes using 20 mol% iodine monobromide as a catalyst in acetonitrile solvent at 80 °C. The present method involves tandem reaction of α-aminoacetophenones and trans-β-nitrostyrenes, formation of two new C-C bonds and cleavage of one C-C bond in a single step. The salient features of the protocol are metal- and oxidant-free reaction conditions, broad substrate scope, and good yields.
- Gattu, Radhakrishna,Mondal, Santa,Ali, Saghir,Khan, Abu T.
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supporting information
p. 347 - 353
(2019/01/10)
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- Concerted catalysis by nanocellulose and proline in organocatalytic Michael additions
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Cellulose nanofibers (CNFs) have recently attracted much attention as catalysts in various reactions. Organocatalysts have emerged as sustainable alternatives to metal-based catalysts in green organic synthesis, with concerted systems containing CNFs that are expected to provide next-generation catalysis. Herein, for the first time, we report that a representative organocatalyst comprising an unexpected combination of 2,2,6,6-tetramethylpiperidine 1-oxyl (TEMPO)-oxidized CNFs and proline shows significantly enhanced catalytic activity in an asymmetric Michael addition.
- Ranaivoarimanana, Naliharifetra Jessica,Kanomata, Kyohei,Kitaoka, Takuya
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supporting information
(2019/04/05)
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- A diversity-oriented synthesis of polyheterocycles: Via the cyclocondensation of azomethine imine
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Pd-Catalyzed sequential reactions to afford skeletally diverse molecules are described. The reaction involved azomethine imine formation and a cyclocondensation reaction as individual steps. The methodology provides excellent regio- and stereocontrol. Skeletal diversity was ensured by changing the electrophilic counterpart of azomethine imine. Due to its broader diversity and complexity, the DOS methodology is likely to benefit drug discovery and development in the future.
- Ansari, Arshad J.,Pathare, Ramdas S.,Kumawat, Anita,Maurya, Antim K.,Verma, Sarika,Agnihotri, Vijai K.,Joshi, Rahul,Metre, Ramesh K.,Sharon, Ashoke,Pardasani,Sawant, Devesh M.
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supporting information
p. 13721 - 13724
(2019/09/16)
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- Facile Synthesis of 1,3,5-Triarylbenzenes and 4-Aryl-NH-1,2,3-Triazoles Using Mesoporous Pd-MCM-41 as Reusable Catalyst
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We report mesoporous nano-Pd-MCM-41 catalyzed rapid and efficient synthesis of 1,3,5-triarylbenzenes via de-nitrative cyclotrimerization of β-nitrostyrenes. All the reactions were very fast and high yielding. The Pd-MCM-41 was also very effective in catalyzing de-nitrative [3+2] cycloaddition of β-nitrostyrenes with TMSN3 to synthesize 4-aryl-NH-1,2,3-triazoles. The catalyst was reused at least up to eight times with minimum loss of catalytic activity.
- Saha, Arijit,Wu, Chia-Ming,Peng, Rui,Koodali, Ranjit,Banerjee, Subhash
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p. 104 - 111
(2019/01/04)
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- Combined Photoredox/Enzymatic C?H Benzylic Hydroxylations
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Chemical transformations that install heteroatoms into C?H bonds are of significant interest because they streamline the construction of value-added small molecules. Direct C?H oxyfunctionalization, or the one step conversion of a C?H bond to a C?O bond, could be a highly enabling transformation due to the prevalence of the resulting enantioenriched alcohols in pharmaceuticals and natural products,. Here we report a single-flask photoredox/enzymatic process for direct C?H hydroxylation that proceeds with broad reactivity, chemoselectivity and enantioselectivity. This unified strategy advances general photoredox and enzymatic catalysis synergy and enables chemoenzymatic processes for powerful and selective oxidative transformations.
- Betori, Rick C.,May, Catherine M.,Scheidt, Karl A.
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supporting information
p. 16490 - 16494
(2019/11/03)
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- Cinnamic acid derivative and preparation method and application thereof
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The invention provides a cinnamic acid derivative. The cinnamic acid derivative is of the structure as shown in the formula I. The invention also provides two methods for preparing the cinnamic acid derivative. The two methods depend on a single bond or double bonds in the structure shown in the formula I. The invention further provides a pesticide. The pesticide comprises the cinnamic acid derivative. In addition, the invention provides a sterilization method. The sterilization method includes the step of applying the cinnamic acid derivative or the pesticide to crops. The crops include rice,wheat, fruit trees and vegetables. The low-toxicity, low-residue-content and high-activity environment-friendly cinnamic acid derivative is developed, and the cinnamic acid derivative pesticide can replace traditional high-toxicity and high-residue-content pesticides.
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-
Paragraph 0171-0173
(2019/10/22)
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- Structural tuning enables piezochromic and photochemical properties in N-aryl-β-enaminones
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An efficient synthesis of N-aryl-β-enaminones via Et3N-mediated, one-pot three-component reaction of 4-hydroxycoumarin/dimedone, β-nitrostyrene/2-(2-nitrovinyl)thiophene, and arylamine in toluene under refluxed conditions is herein presented. Some prepared compounds were found to exhibit piezochromic properties. The XRD and SEM measurements of the piezochromic compound showed substantial crystal packing and morphology changes before and after grinding. Further, one prepared compound was found to be light-sensitive and can be converted to a furo[3,2-b]pyridin-2(4H)-one derivative upon UV irradiation. A plausible mechanism for this photochemical reaction was proposed.
- Hsieh, Wan-Chi,Manjappa, Kiran B.,Yang, Ding-Yah
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p. 34088 - 34094
(2019/11/13)
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- tert-Butyl Nitrite Mediated Different Functionalizations of Internal Alkenes: Paths to Furoxans and Nitroalkenes
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tert-Butyl nitrite (TBN) reacts differently with various internal alkenes leading to interesting and useful products. Synthesis of 1,2,5-oxadiazole-N-oxides (furoxans) has been achieved from internal alkenes using tert-butyl nitrite (TBN), quinoline and K2S2O8. Under an identical reaction condition α,β-unsaturated carboxylic acids and cyclic and acyclic internal alkenes both afforded nitroalkenes as the sole product via decarboxylative and direct nitration path respectively. (Figure presented.).
- Mir, Bilal Ahmad,Singh, Sarangthem Joychandra,Kumar, Ritush,Patel, Bhisma K.
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p. 3801 - 3809
(2018/09/18)
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- Synthesis, antiproliferative and pro-apoptotic effects of nitrostyrenes and related compounds in Burkitt’s lymphoma
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Background: Cancers of the lymphatic cells (lymphomas) account for approximately 12% of malignant diseases worldwide. The nitrostyrene scaffold is identified as a lead target structure for the development of particularly effective compounds targeting Burkitt’s lymphoma (BL). Objectives: The aims of the curent study were to synthesise a panel of nitrostyrene compounds and to evaluate their activity in Burkitt’s lymphoma (BL). Methods: A panel of structurally varied compounds were designed and synthesised using Henry Knoevenagel condensation reactions. Single crystal X-Ray analysis confirmed the E configuration for six examples of these novel structures. A number of nitrostyrene-related compounds were also investigated including 1,3-bis(aryl)-2-nitropropenes together with heterocyclic scaffolds containing the nitrovinyl pharmacophore such as 3-nitro-2-phenyl-2H-chromenes. The antiproliferative activities of the compounds were evaluated using the BL cell lines EBV- MUTU-1 and EBV+ DG-75 (chemoresistant) to establish preliminary structure-activity relationships. Results: Lead compounds with optimized nitrostyrene scaffolds and 3-nitro-2-phenyl-2Hchromene structures were successfully established with typical IC50 values of 0.45 μM and 0.47 μM in MUTU-1 cells and 1.41 μM and 1.92 μM, respectively, in DG-75 cells. The mechanism of cell death was identified as apoptotic and the lead compound was found to elicit comparable apoptotic effects to Taxol in Burkitt’s lymphoma cell lines MUTU-1 and DG-75. Conclusion: This class of pharmaceutically active compounds with potential for the treatment of Burkitt’s lymphoma suggest a potential role for nitrostyrene based agents in chemotherapy.
- Byrne, Andrew J.,Bright, Sandra A.,Fayne, Darren,McKeown, James P.,McCabe, Thomas,Twamley, Brendan,Williams, Clive,Meegan, Mary J.
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p. 181 - 199
(2018/03/13)
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- Direct dihalo-alkoxylation of nitroalkenes leading to β,β-dihalo-β-nitroethyl alkyl ethers
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A highly efficient one-pot synthesis of β,β-dihalo-β-nitroethyl alkyl ethers is achieved by the treatment of nitroalkenes with alcohols and N-halosuccinimides in the presence of sodium hydride. The notable advantages of this protocol are that it involves simple experimental manipulations and tolerates a wide range of functional groups. Further transformations of the obtained ethers, such as allylation and conversion to β,β-dihalogenated vinyl ethers, are also investigated.
- Hao, Feiyue,Yokoyama, Soichi,Nishiwaki, Nagatoshi
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p. 2768 - 2775
(2018/04/26)
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- Highly Enantioselective Michael Addition of Dithiomalonates to Nitroolefins Catalyzed by New Bifunctional Chiral Thioureas
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We report a highly efficient asymmetric Michael addition of dithiomalonates to trans -β-nitroole?ns catalyzed by versatile cinchona-based bifunctional thioureas, which provides the corresponding adducts in high yields (up to 92%) and with excellent enanti
- Yuan, Jia-Ni,Liu, Hui-Xia,Tian, Qin-Qin,Ji, Nan,Shen, Kuo,He, Wei
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supporting information
p. 2577 - 2586
(2018/05/03)
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- Mechanistic Studies on the Michael Addition of Amines and Hydrazines to Nitrostyrenes: Nitroalkane Elimination via a Retro-aza-Henry-Type Process
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In this article we report on the mechanistic studies of the Michael addition of amines and hydrazines to nitrostyrenes. Under the present conditions, the corresponding N-alkyl/aryl substituted benzyl imines and N-methyl/phenyl substituted benzyl hydrazones were observed via a retro-aza-Henry-type process. By combining organic synthesis and characterization experiments with computational chemistry calculations, we reveal that this reaction proceeds via a protic solvent-mediated mechanism. Experiments in deuterated methanol CD3OD reveal the synthesis and isolation of the corresponding deuterated intermediated Michael adduct, results that support the proposed slovent-mediated pathway. From the synthetic point of view, the reaction occurs under mild, noncatalytic conditions and can be used as a useful platform to yield the biologically important N-methyl pyrazoles in a one-pot manner, simple starting with the corresponding nitrostyrenes and the methylhydrazine.
- Kallitsakis, Michael G.,Tancini, Peter D.,Dixit, Mudit,Mpourmpakis, Giannis,Lykakis, Ioannis N.
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supporting information
p. 1176 - 1184
(2018/02/09)
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- Squaramide-Linked Chloramphenicol Base Hybrid Catalysts for the Asymmetric Michael Addition of 2,3-Dihydrobenzofuran-2-carboxylates to Nitroolefins
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An array of hybrid catalysts incorporating a chloramphenicol base moiety linked to another chiral scaffold through a squaramide linker were developed and successfully used in the Michael addition of 2,3-dihydrobenzofuran-2-carboxylates to nitroolefins. Control experiments suggested that the hybrid catalysts were more reactive than nonhybridized bifunctional catalysts, and matching of the chirality between the two scaffolds was crucial for high reactivity and stereoselectivity. These hybrid organocatalysts could be used with a variety of substrates. At a 0.5 mol-% catalyst loading, a range of 2,3-dihydrobenzofuran-2-carboxylates derivatives bearing quaternary and tertiary stereogenic centers were obtained in high yields (up to 98 %) with excellent enantioselectivities (up to 99 % ee) and moderate diastereoselectivities (up to 8:92 dr).
- Yan, Linjie,Huang, Guanxin,Wang, Haifeng,Xiong, Fangjun,Peng, Haihui,Chen, Fener
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supporting information
p. 99 - 103
(2018/01/17)
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- Copper-Promoted Regioselective Synthesis of Polysubstituted Pyrroles from Aldehydes, Amines, and Nitroalkenes via 1,2-Phenyl/Alkyl Migration
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The facile copper-catalyzed synthesis of polysubstituted pyrroles from aldehydes, amines, and β-nitroalkenes is reported. Remarkably, the use of α-methyl-substituted aldehydes provides efficient access to a series of tetra- and pentasubstituted pyrroles via an overwhelming 1,2-phenyl/alkyl migration. The present methodology is also accessible to non α-substituted aldehydes, yielding the corresponding trisubstituted pyrroles. On the contrary, the use of ketones, in place of aldehydes, does not promote the organic transformation, signifying the necessity of α-substituted aldehydes. The reaction proceeds under mild catalytic conditions with low catalyst loading (0.3-1 mol %), a broad scope, very good functional-group tolerance, and high yields and can be easily scaled up to more than 3 mmol of product, thus highlighting a useful synthetic application of the present catalytic protocol. Based on formal kinetic studies, a possible radical pathway is proposed that involves the formation of an allylic nitrogen radical intermediate, which in turn reacts with the nitroalkene to yield the desired pyrrole framework via a radical 1,2-phenyl or alkyl migration.
- Andreou, Dimitrios,Kallitsakis, Michael G.,Loukopoulos, Edward,Gabriel, Catherine,Kostakis, George E.,Lykakis, Ioannis N.
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p. 2104 - 2113
(2018/02/23)
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- Sulfonation of carbonized xylan-type hemicellulose: A renewable and effective biomass-based biocatalyst for the synthesis of O- and N-heterocycles
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The application of biomass-based carbonaceous solid acids in catalysis is attracting increasing attention in the field of chemistry. In this study, a heterogeneous carbon-based solid acid biocatalyst (CXH-SO3H) with regular spherical structure was synthesized from xylan-type hemicellulose (XH) by a simple two-step method. The catalyst was successfully applied in the synthesis of O- and N-heterocycles with yields of 80-99% and 60-97%, respectively. In view of environment and economy, CXH-SO3H shows the merits of environmental friendliness, easy operation, simple work-up, excellent yields, and the avoidance of use of organic solvents and expensive catalysts. Moreover, the as-synthesized solid acid catalyst could be used for several cycles without significant loss in its catalytic activity. The results of FT-IR, XRD, and SEM showed that no distinct differences in physico-chemical structures of CXH-SO3H were observed. Thus, the eco-friendly CXH-SO3H catalyst is a promising candidate for green synthesis of O- and N-heterocycles from low-cost feed-stocks and has good prospect in partially substituting commercially available solid and liquid acid catalysts and precious metal catalysts.
- Ma, Jiliang,Peng, Xinwen,Zhong, Linxin,Sun, Runcang
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supporting information
p. 9140 - 9150
(2018/06/11)
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- Synthesis of Benzo[4,5]imidazo[2,1-b]thiazole by Copper(II)-Catalyzed Thioamination of Nitroalkene with 1H-Benzo[d]imidazole-2-thiol
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A Copper(II)-catalyzed thioamination of β-nitroalkene with 1H-benzo[d]imidazole-2-thiol has been developed for the synthesis of benzo[4,5]imidazo[2,1-b]thiazole derivatives. A variety of N-fused benzoimidazothiazole derivatives are obtained in high yields through successive C?N and C?S bond formations. This protocol is also applicable to β-substituted β-nitroalkenes to afford 2,3-disubstituted benzoimidazothiazoles. (Figure presented.).
- Jana, Sourav,Chakraborty, Amrita,Shirinian, Valerii Z.,Hajra, Alakananda
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supporting information
p. 2402 - 2408
(2018/05/08)
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- A Continuous-Flow, Two-Step, Metal-Free Process for the Synthesis of Differently Substituted Chiral 1,2-Diamino Derivatives
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The enantioselective organocatalytic reduction of aryl-substituted nitroenamines was successfully performed under continuous-flow conditions. After a preliminary screening with a 10-μL microreactor, to establish the best reaction conditions, the reduction was scaled up in a 0.5-mL mesoreactor, without appreciable loss of enantioselectivity, that remained constantly higher than 90%. The in-flow nitro reduction was also accomplished, either by Raney nickel catalyzed hydrogenation or by a metal-free methodology based on the use of the very inexpensive and readily available reducing agent trichlorosilane. The final aim is to develop a two-step, continuous-flow process for the stereoselective, metal-free, catalytic synthesis of differently functionalized chiral 1,2-diamines.
- Pirola, Margherita,Compostella, Maria Elena,Raimondi, Laura,Puglisi, Alessandra,Benaglia, Maurizio
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supporting information
p. 1430 - 1438
(2018/02/09)
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- Access to C5-Alkylated Indolines/Indoles via Michael-Type Friedel-Crafts Alkylation Using Aryl-Nitroolefins
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A straightforward synthetic route toward C5-alkylated indolines/indoles has been developed. The strategy is composed of Zn(OTf)2-catalyzed Friedel-Crafts alkylation of N-benzylindolines with nitroolefins, and a series of diverse indolines was first obtained in up to 99% yield. This reaction provides a direct and practical route to a variety of the C5-alkylated indolines which were also utilized for accessing corresponding indoles. Indoline derivatives with free NH groups could be obtained through an N-deprotection reaction. Moreover, the primary alkyl nitro groups in both indolines and indoles are amenable to further synthetic elaborations, thereby broadening the diversity of the products.
- Ertugrul, Berrak,Kilic, Haydar,Lafzi, Farrokh,Saracoglu, Nurullah
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p. 9018 - 9038
(2018/06/27)
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- Inhibition of LDL oxidation and inflammasome assembly by nitroaliphatic derivatives. Potential use as anti-inflammatory and anti-atherogenic agents
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We have previously shown the antioxidant and anti-inflammatory properties of several para-substituted arylnitroalkenes. Since oxidative stress and inflammation are key processes that drive the initiation and progression of atherosclerosis, in the present work the antioxidant, anti-inflammatory and anti-atherogenic properties of an extended library of aryl-nitroaliphatic derivatives, including several newly designed nitroalkanes, was explored. The antioxidant capacity of the nitroaliphatic compounds, measured using the oxygen radical absorbance capacity assay (ORAC) showed that the p-methylthiophenyl-derivatives were about three times more effective than Trolox to prevent fluorescein oxidation, independently of the presence or the absence of the double bond next to the nitro group. The peroxyl radical scavenger capacity of the p-dimethylaminophenyl-derivatives was even higher, being the reduced form of these compounds even more active. In fact, while the antioxidant capacity of 1-dimethylamino-4-(2-nitro-1Z-ethenyl)benzene and 1-dimethylamino-4-(2-nitro-1Z-propenyl)benzene was 4.2 ± 0.1 and 5.4 ± 0.1 Trolox Eq/mol, respectively; ORAC values obtained with the ethyl and the propyl derivatives were 10 ± 1 and 13 ± 2 Trolox Eq/mol, respectively. The p-dimethylamino-derivatives, especially the nitroalkanes, were also able to prevent LDL oxidation mediated by peroxyl radicals. Oxygen consumption due to the oxidation of fatty acids was delayed in the presence of the dimethylamino substituted compounds, only the alkanes interrupted the chain of lipid oxidations decreasing the rate of oxygen consumption. Although the formation of foam cells in the presence of oxidized-LDL (oxLDL) remained unaffected, the molecules containing the dimethylamino moiety were able to decrease the expression of IL-1β in LPS/INF-γ challenged macrophages.
- Cataldo, Nicolás,Musetti, Bruno,Celano, Laura,Carabio, Claudio,Cassina, Adriana,Cerecetto, Hugo,González, Mercedes,Thomson, Leonor
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p. 178 - 186
(2018/10/15)
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- Method for catalytically synthesizing (E)-beta-nitrostyrene derivatives based on tetraarylporphyrin iron
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The invention discloses a method for catalytically synthesizing (E)-beta-nitrostyrene derivatives based on tetraarylporphyrin iron. According to the method, styrene derivatives are subjected to one-pot reaction in a system containing tetraarylporphyrin iron (III), ammonium iodide and tert-butyl hydroperoxide to generate the (E)-beta-nitrostyrene derivatives. The method is capable of synthesizing beta-nitrostyrene derivatives with high E stereoselectivity with high yield under the mild reaction condition.
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Paragraph 0047; 0069-0071
(2017/08/31)
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- In order to iodide is one pot synthesis nitryl source α, β - unsaturated nitro olefin derivatives (by machine translation)
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The present invention discloses a one-pot synthesis nitryl source iodide is α, β - unsaturated nitro olefin derivatives, vinyl compounds containing four aryl ferrous (III), iodide and tertiary-butyl hydrogen peroxide in acetonitrile solution system a pot of reaction, generating α, β - unsaturated nitro olefin derivatives; the method to achieve the under mild reaction conditions, high yield with high stereo selectivity of the E synthesis of α, β - unsaturated nitro olefin. (by machine translation)
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Paragraph 0055-0058; 0080-0082
(2017/09/01)
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- Α, β - unsaturated nitro olefin derivative synthesis method (by machine translation)
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The invention discloses a α, β - unsaturated nitro olefin derivative synthesis method, vinyl compounds containing four aryl ferrous (III), ammonium halide and tertiary-butyl hydrogen peroxide in the system of the one-pot reaction, generating α, β - unsaturated nitro olefin derivatives; the method to achieve the under mild reaction conditions, high yield with high stereo selectivity of the E synthesis of α, β - unsaturated nitro olefin. (by machine translation)
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Paragraph 0027; 0034; 0057; 0059; 0081; 0082; 0083
(2017/09/05)
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- High-selectivity (E)-beta-nitrostyrene derivative one-pot synthesizing method
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The invention discloses a high-selectivity (E)-beta-nitrostyrene derivative one-pot synthesizing method. In air or sealed environment, styrene derivative generates one-pot reaction in a system containing tetra-acryl ferroporphyrin (III), ammonium iodide and tert-butyl hydroperoxide to generate (E)-beta-nitrostyrene derivative. The method achieves the purpose of synthesizing the beta-nitrostyrene derivative with high E three-dimensional selectivity in high yield under moderate reaction conditions.
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Paragraph 0044-0048; 0070-0072
(2018/03/28)
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- Chloro/bromotrimethylsilane-Cu(NO3)2·3H2O: Safe and efficient reagent system for the decarboxylative ipso-nitration and dibromination of cinnamic acids
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Further synthetic potential of halotrimethylsilane-nitrate salt mixture is revealed. A mixture of TMSX-Cu(NO3)2·3H2O system is found to be an efficient reagent system for both the decarboxylative nitration (ipso-nitration) when X?=?Cl, and dibromination of cinnamic acids, with X?=?Br, under mild conditions. The reactions are safe and simple, affording the corresponding products (E)-β-nitrostyrenes, and anti-2,3-dibromo-3-phenylpropanoic acids in high yields with high selectivity in a relatively short time. Use of hazardous and toxic nitrating systems such as acetyl nitrate and brominating agents such as molecular bromine can be avoided.
- Roshandel, Sahar,Gurung, Laxman,Mathew, Thomas,Prakash, G.K. Surya
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supporting information
p. 2842 - 2845
(2017/06/27)
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- Cyanide-Free and Broadly Applicable Enantioselective Synthetic Platform for Chiral Nitriles through a Biocatalytic Approach
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A cyanide-free platform technology for the synthesis of chiral nitriles by biocatalytic enantioselective dehydration of a wide range of aldoximes is reported. The nitriles were obtained with high enantiomeric excess of >90 % ee (and up to 99 % ee) in many cases, and a “privileged substrate structure” with respect to high enantioselectivity was identified. Furthermore, a surprising phenomenon was observed for the enantiospecificity that is usually not observed in enzyme catalysis. Depending on whether the E or Z isomer of the racemic aldoxime substrate was employed, one or the other enantiomer of the corresponding nitrile was formed preferentially with the same enzyme.
- Betke, Tobias,Rommelmann, Philipp,Oike, Keiko,Asano, Yasuhisa,Gr?ger, Harald
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supporting information
p. 12361 - 12366
(2017/09/06)
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- De novo endo-functionalized organic cages as cooperative multi-hydrogen-bond-donating catalysts
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Two endo-functionalized organic cages as oxyanion hole mimics were achieved via dynamic covalent chemistry, which exhibit good size selectivity, catalytic activity and broad substrate scopes for Friedel-Crafts reactions. The modular character of the synth
- Chen, Hong-Yu,Gou, Meng,Wang, Jiao-Bing
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supporting information
p. 3524 - 3526
(2017/03/31)
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- Direct aziridination of nitroalkenes affording N-alkyl-C-nitroaziridines and the subsequent Lewis acid mediated isomerization to β-nitroenamines
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A mild and highly diastereoselective one-pot synthesis of trans-N-alkyl-C-nitroaziridines was achieved by treatment of nitroalkenes with aliphatic amines and N-chlorosuccinimide. Treatment of the obtained aziridines with a Lewis acid resulted in a facile ring opening reaction, accompanied by rearrangement and isomerization into functionalized (Z)-β-nitroenamines.
- Hao, Feiyue,Asahara, Haruyasu,Nishiwaki, Nagatoshi
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supporting information
p. 5442 - 5445
(2017/11/06)
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- Cooperative Multifunctional Catalysts for Nitrone Synthesis: Platinum Nanoclusters in Amine-Functionalized Metal–Organic Frameworks
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Nitrones are key intermediates in organic synthesis and the pharmaceutical industry. The heterogeneous synthesis of nitrones with multifunctional catalysts is extremely attractive but rarely explored. Herein, we report ultrasmall platinum nanoclusters (PtNCs) encapsulated in amine-functionalized Zr metal–organic framework (MOF), UiO-66-NH2 (Pt@UiO-66-NH2) as a multifunctional catalyst in the one-pot tandem synthesis of nitrones. By virtue of the cooperative interplay among the selective hydrogenation activity provided by the ultrasmall PtNCs and Lewis acidity/basicity/nanoconfinement endowed by UiO-66-NH2, Pt@UiO-66-NH2 exhibits remarkable activity and selectivity, in comparison to Pt/carbon, Pt@UiO-66, and Pd@UiO-66-NH2. Pt@UiO-66-NH2 also outperforms Pt nanoparticles supported on the external surface of the same MOF (Pt/UiO-66-NH2). To our knowledge, this work demonstrates the first examples of one-pot synthesis of nitrones using recyclable multifunctional heterogeneous catalysts.
- Li, Xinle,Zhang, Biying,Tang, Linlin,Goh, Tian Wei,Qi, Shuyan,Volkov, Alexander,Pei, Yuchen,Qi, Zhiyuan,Tsung, Chia-Kuang,Stanley, Levi,Huang, Wenyu
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supporting information
p. 16371 - 16375
(2017/11/28)
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