- KMnO4-catalyzed chemoselective deprotection of acetate and controllable deacetylation-oxidation in one pot
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A novel and efficient protocol for chemoselective deacetylation under ambient conditions was developed using catalytic KMnO4. The stoichiometric use of KMnO4 highlighted the dual role of a heterogeneous oxidant enabling direct access to aromatic aldehydes in one-pot sequential deacetylation-oxidation. The reaction employed an alternative solvent system and allowed the clean transformation of benzyl acetate to sensitive aldehyde in a single step while preventing over-oxidation to acids. Use of inexpensive and readily accessible KMnO4 as an environmentally benign reagent and the ease of the reaction operation were particularly attractive, and enabled the controlled oxidation and facile cleavage of acetate in a preceding step. This journal is
- Gurawa, Aakanksha,Kumar, Manoj,Rao, Dodla S.,Kashyap, Sudhir
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supporting information
p. 16702 - 16707
(2020/10/27)
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- Biogenic CuFe2O4 magnetic nanoparticles as a green, reusable and excellent nanocatalyst for acetylation reactions under solvent-free conditions
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A convenient green method has been developed for the synthesis of biogenic CuFe2O4 magnetic nanoparticles using tea extracts within a very short reaction time. The prepared nanoparticles with an average size of 8.78 nm have been used as an effective catalyst for the acetylation of various alcohols, phenols and amines in good to excellent yields under solvent-free conditions. The catalyst was characterized by XRD, XPS, VSM, SEM and TEM study. A magnetic study of the fresh and recycled catalyst after the fourth cycle was performed by VSM measurement. The main advantages of this protocol are simple biogenic synthesis of the catalyst, a reusable and heterogeneous catalytic system, and short reaction times with excellent yields.
- Chutia, Rituparna,Chetia, Bolin
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p. 15200 - 15206
(2018/09/29)
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- Ni2B@Cu2O and Ni2B@CuCl2: two new simple and efficient nanocatalysts for?the green one-pot reductive acetylation of nitroarenes and direct N-acetylation of arylamines using solvent-free mechanochemical grinding
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Abstract: Ni2B@Cu2O and Ni2B@CuCl2 are introduced as simple and efficient earth-abundant transition-metal-based nanocomposites for the?green one-pot reductive acetylation of aromatic nitro compounds and direct N-acetylation of arylamines using a solvent-free mechanochemical grinding technique. The designed Ni2B-based nanocomposites were characterized by Fourier-transform infrared (FT-IR) spectroscopy, X-ray diffraction (XRD) analysis, and scanning electron microscopy (SEM) with energy-dispersive X-ray (EDX) spectroscopy. Notable advantages of these methods include broad substrate scope, use of a solvent-free mechanochemical grinding technique, implementation of earth-abundant transition-metal-based nanocomposites as simple and practical catalysts, and short reaction time and high yield at ambient condition. The mentioned methods can also be successfully applied for the?synthesis of a broad range of other amides (especially substituted acetamides) using green chemistry protocols. Also, the recoverability and reusability of the mentioned new nanocomposites were investigated. Graphical abstract: [Figure not available: see fulltext.].
- Zeynizadeh, Behzad,Younesi, Reza,Mousavi, Hossein
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p. 7331 - 7352
(2018/08/25)
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- Sunlight-Driven Forging of Amide/Ester Bonds from Three Independent Components: An Approach to Carbamates
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A photoredox catalytic route to carbamates enabled by visible irradiation (or simply sunlight) has been developed. This process leads to a novel approach to the construction of heterocyclic rings wherein the amide or ester motifs of carbamates were assembled from three isolated components. Large-scale experiments were realized by employing continuous flow techniques, and reuse of photocatalyst demonstrated the green and sustainable aspects of this method.
- Zhao, Yating,Huang, Binbin,Yang, Chao,Chen, Qingqing,Xia, Wujiong
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supporting information
p. 5572 - 5575
(2016/11/17)
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- Mild and efficient palladium-catalyzed direct trifluoroethylation of aromatic systems by C-H activation
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The introduction of trifluoroalkyl groups into aromatic molecules is an important transformation in the field of organic and medicinal chemistry. However, the direct installation of fluoroalkyl groups onto aromatic molecules still represents a challenging and highly demanding synthetic task. Herein, a simple trifluoroethylation process that relies on the palladium-catalyzed C-H activation of aromatic compounds is described. With the utilization of a highly active trifluoroethyl(mesityl)iodonium salt, the developed catalytic method enables the first highly efficient and selective trifluoroethylation of aromatic compounds. The robust catalytic procedure provides the desired products in up to 95 % yield at 25 °C in 1.5 to 3 hours and tolerates a broad range of functional groups. The utilization of hypervalent reagents opens new synthetic possibilities for direct alkylations and fluoroalkylations in the field of transition-metal-catalyzed C-H activation.
- T?th, Balázs L.,Kovács, Szabolcs,Sályi, Gerg?,Novák, Zoltán
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supporting information
p. 1988 - 1992
(2016/02/18)
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- Validation of PqsD as an anti-biofilm target in pseudomonas aeruginosa by development of small-molecule inhibitors
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2-Heptyl-4-hydroxyquinoline (HHQ) and Pseudomonas quinolone signal (PQS) are involved in the regulation of virulence factor production and biofilm formation in Pseudomonas aeruginosa. PqsD is a key enzyme in the biosynthesis of these signal molecules. Using a ligand-based approach, we have identified the first class of PqsD inhibitors. Simplification and rigidization led to fragments with high ligand efficiencies. These small molecules repress HHQ and PQS production and biofilm formation in P. aeruginosa. This validates PqsD as a target for the development of anti-infectives.
- Storz, Michael P.,Maurer, Christine K.,Zimmer, Christina,Wagner, Nathalie,Brengel, Christian,De Jong, Johannes C.,Lucas, Simon,Muesken, Mathias,Haeussler, Susanne,Steinbach, Anke,Hartmann, Rolf W.
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supporting information
p. 16143 - 16146
(2012/11/07)
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- Discovery and development of a new class of potent, selective, orally active oxytocin receptor antagonists
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We report a novel chemical class of potent oxytocin receptor antagonists showing a high degree of selectivity against the closely related vasopressin receptors (Via, V1b, V2). An initial compound, 7, was shown to be active in an animal model of preterm labor when administered by the intravenous but not by the oral route. Stepwise SAR investigations around the different structural elements revealed one position, the arenesulfonyl moiety, to be amenable to structural changes. Consequently, this position was used to introduce a variety of substituents to improve the physicochemical properties. Some of the resulting analogues were found to be superior to 7 both in terms of potency in vitro and aqueous solubility, which translated into significantly improved efficacy in the animal model after intravenous and oral administration. The best compound, 73, potently inhibited oxytocin-induced uterine contractions in nonpregnant rats and reduced spontaneous uterine contractions in late-term pregnant rats.
- Quattropani, Anna,Dorbais, Jér?me,Covini, David,Pittet, Pierre-André,Colovray, Véronique,Thomas, Russell J.,Coxhead, Richard,Halazy, Serge,Scheer, Alexander,Missotten, Marc,Ayala, Guidon,Bradshaw, Charles,De Raemy-Schenk, Anne-Marie,Nichols, Anthony,Cirillo, Rocco,Tos, Enrico Gillio,Giachetti, Claudio,Golzio, Lucia,Marinelli, Paolo,Church, Dennis J.,Barberis, Claude,Chollet, André,Schwarz, Matthias K.
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p. 7882 - 7905
(2007/10/03)
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