- RETRACTED ARTICLE: Unexpected Heterocyclization of Electrophilic Alkenes by Tetranitromethane in the Presence of Triethylamine. Synthesis of 5-Nitroisoxazoles
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A novel reaction of tetranitromethane with electrophilic alkenes in the presence of triethylamine affording substituted 5-nitroisoxazoles is described. Triethylamine reacts with tetranitromethane to generate N-nitrotriethylammonium and trinitromethanide. This process provides the heterocyclization of electrophilic alkenes. A variety of α,β-unsaturated aldehydes, ketones, esters, amides, phosphonates, nitro, and sulfur compounds was involved in the heterocyclization reaction, and a wide range of functionalized 5-nitroisoxazoles was obtained in good to high yields. The scope and limitations of the reaction and the mechanistic proposal are discussed.
- Volkova, Yulia A.,Averina, Elena B.,Vasilenko, Dmitry A.,Sedenkova, Kseniya N.,Grishin, Yuri K.,Bruheim, Per,Kuznetsova, Tamara S.,Zefirov, Nikolai S.
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p. 3192 - 3200
(2019/03/20)
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- Thermodynamic studies of aqueous solutions of ammonium based nitrate protic ionic liquids at different temperatures (288.15?K to 303.15?K)and 101.325?kPa: A volumetric approach
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We report the synthesis of two protic ionic liquids (PILs)through atom–economic neutralization reaction between alkylamine (diethlyamine (DEA)and triethylamine (TEA))and nitric acid. The product ionic liquids are characterized by 1H NMR spectra. The density property of aqueous solutions of synthesized PILs, namely, diethylammonium nitrate (DEAN)and triethylammonium nitrate (TEAN)were measured in the concentration range of ~0.01 ? ~0.5 mol·kg?1for the temperature range of 288.15 K to 303.15 K and at 101.325 kPa. The measured densities were used to calculate the apparent molar volume (V?), partial molar volume of solvent (Vˉ1)and solute (Vˉ2)at all studied temperatures. The limiting apparent molar volumes (V? 0)are reported. The apparent molar expansivity (E?)of PILs at finite concentrations as well as at infinite dilutions are reported at 293.15 and 298.15 K. It is observed that water structure making effect exhibited by cations is governed by the hydration of the cations, while the overall kosmotropic effect depends upon the basicity and shape factor of the cation concerned. The hydrophobic solute–solute interactions and ion–pair formation may be influencing the deviation parameter (BV)of Debye-Hückel equation for volumes. These results are discussed.
- Patil, Kunal R.,Shaikh, Vasim R.,Patil, Sarika K.,Dagade, Dilip H.,Patil, Kesharsingh J.
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- Isolable Adducts of Tertiary Amines and Dinitrogen Trioxide
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Anhydrous dinitrogen trioxide, N2O3, dissolved in toluene or dichloromethane rapidly forms stable adducts with tertiary amines such triethyl-, tribenzyl-, or trihexyl-amine. With DABCO, 1,4-diazabicyclo[2.2.2]octane it forms a free flowing orange solid. The analytical and spectroscopic data for the DABCO adduct indicate a formula of DABCO(N2O3)2 which has been characterized by IR, Raman, and UV/Vis spectroscopy. The R3N-N2O3 adducts are hydrolytically sensitive oils or solids which rapidly react quantitatively with thiols to give RSNO. The reactivity of the amine adducts is variable, and the products include amine N-oxides, ammonium nitrites, and ammonium nitrates depending upon the adduct, conditions, and substrate. Density functional theory, B3LYP/aug-cc-pvtz, has been used to compare the predicted structures and spectroscopic data for mono and bis adducts. Geometry optimization of the R3N N2O3 adduct gives a weakly bound Lewis acid/base adduct with the amine nitrogen closest to the nitrosyl N with a strongly tilted planar ONNO2 unit.
- Rosadiuk, Kristopher A.,Scott Bohle
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p. 4543 - 4549
(2018/10/31)
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- Simple protic ionic liquid [Et3NH][HSO4] as a proficient catalyst for facile synthesis of biscoumarins
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Abstract: We have explored a number of protic ionic liquids (PILs) as a catalyst for the synthesis of biscoumarins by condensation of 4-hydroxycoumarin with an aromatic aldehyde. Methylimidazolium- and triethylammonium-based PILs were synthesized by simple neutralization reaction with protic acids. Triethylammonium hydrogen sulfate [Et3NH][HSO4] was found to be the best among the studied PILs concerning the yield of products and reaction time period. Different biscoumarin derivatives were synthesized based on 4-hydroxycoumarin and various substituted aromatic aldehydes at optimum reaction conditions. Obtained products were separated just by simple filtration. The facile method does not require additional purification for formed products. The catalyst has shown better yields along with outstanding recyclability, providing an environmental benign protocol for the synthesis of biscoumarin derivatives. Graphical Abstract: Screening of simple protic ionic liquids as a catalyst in the synthesis of biscoumarins, out of which [Et3NH][HSO4] was found to be best among the studied PILs.
- Patil, Sandip K.,Awale, Deepak V.,Vadiyar, Madagonda M.,Patil, Suryakant A.,Bhise, Sagar C.,Kolekar, Sanjay S.
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p. 5365 - 5376
(2017/09/23)
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- A Metal-Free and Ionic Liquid-Catalyzed Aerobic Oxidative Bromination in Water
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A metal-free aerobic oxidative bromination of aromatic compounds in water has been developed. Hydrobromic acid is used as a bromine source and 2-methylpyridinium nitrate ionic liquid is used as a recyclable catalyst. Water is used as the reaction mediate. This is the first report of aerobic oxidative bromination using only catalytic amount of metal-free catalyst. This system shows not only high bromine atom economy, but also high bromination selectivity. The possible mechanism and the role of the catalyst in this system have also been discussed.
- Wang, Jian,Chen, Shu-Bin,Wang, Shu-Guang,Li, Jing-Hua
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p. 513 - 517
(2015/03/30)
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- Anhydrous proton exchange membranes at elevated temperatures: Effect of protic ionic liquids and crosslinker on proton conductivity
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A series of novel anhydrous proton exchange membranes (poly(vinyl alcohol)-citric acid-ionic liquid (PVA-CA-IL)) were prepared using the low cost ionic liquids ethylammonium nitrate (EAN), diethylammonium nitrate (DEAN), and triethylammonium nitrate (TEAN) as conductive fillers in PVA support membrane. The properties of the PVA-CA-IL membranes can be controlled by changing the molar ratio of the PVA, ILs and CA. The thermal stability of PVA-CA-IL membrane was measured by thermogravimetric analysis (TGA) and differential scanning calorimetry (DSC), and the microstructure was investigated using scanning electron microscopy (SEM) and the Anton-paar SAX Sess mc2 system (SAXS). The effects of temperature, ILs and crosslinker dosage on proton conductivity were also systematically investigated. The results showed that the PVA-CA-IL membranes had excellent performance. The proton conductivity of PVA-CA-EAN (mole ratio = 1:0.05:0.4) could reach up to 7.8 mS cm-1 at 140 °C. The introduction of ionic liquid into PVA membrane constituted a new and efficient kind of anhydrous proton exchange membrane. This journal is
- Yang, Yi,Gao, Hejun,Zheng, Liqiang
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p. 17683 - 17689
(2015/06/11)
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