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1.
Electrochemical bromination of alkyl aromatic compounds by two-phase electrolysis yields the corresponding α, α-dibrominated products. The reaction has been carried out in a single-compartment electrochemical cell using aqueous sodium bromide (40–50%), containing a catalytic amount of HBr as electrolyte, and chloroform, containing an alkyl aromatic compound, as the organic phase with a Pt plate as anode at 10–15°C. Two-phase electrolysis results in high yields (70–90%) of dibromomethyl, bis(bromomethyl), and bis(dibromomethyl) arenes, depending upon the charge passed. 相似文献
2.
T. Raju K. Kulangiappar M. Anbu Kulandainathan A. Muthukumaran 《Tetrahedron letters》2005,46(41):7047-7050
Electrochemical bromination of toluene and substituted toluenes by two-phase electrolysis yields the corresponding α-brominated products. The reaction has been carried out in a single compartment cell with platinum electrodes at 0 °C in chloroform using an aqueous sodium bromide solution (60%) containing a catalytic amount of HBr. Two-phase electrolysis results in high yields (60-95%) of monobromo compounds with very high regioselectivity (>95%). 相似文献
3.
T. Raju K. Kulangiappar M. Anbu Kulandainathan U. Uma R. Malini A. Muthukumaran 《Tetrahedron letters》2006,47(27):4581-4584
Direct bromination of a wide range of aromatic compounds possessing electron-donating groups, such as methoxy, hydroxy or amino groups, have been carried out by two-phase electrolysis. This electrochemical method results in high yields (70-98%) of monobromo compounds and usually with high regioselectivity (>95%) for the para position. 相似文献
4.
5.
Indirect cathodic amination of benzene with hydroxylamine in the presence of Ti(IV)/Ti(III) mediator system in aqueous media containing 4–11 mol/L H2SO4 and 13–5.5 mol/L AcOH has been studied. Aniline, diphenyl, and isomeric phenylenediamines are the electrolysis products at 25–60°C. The increase in temperature favors the formation of the monoamino compound. Aniline yield with respect to hydroxylamine at complete conversion of the latter has reached 78.7%, mass fraction of aniline being 97.1%. 相似文献
6.
Gregory B. Kharas Valeria A. Sloan-Lyon Monika Cieszynski John D. A. Manuel Steve L. Mei John B. Mubang Jr. 《高分子科学杂志,A辑:纯化学与应用化学》2016,53(12):729-733
Novel trisubstituted ethylenes, ring-disubstituted propyl 2-cyano-3-phenyl-2-propenoates, RPhCH = C(CN)CO2C3H7 (where R is 2-bromo-5-methoxy, 3-bromo-4-methoxy, 5-bromo-2-methoxy, 2-chloro-3-methoxy, 3-chloro-4-methoxy, 2-fluoro-3-methoxy, 2-fluoro-4-methoxy, 3-fluoro-4-methyl, 4-fluoro-3-phenoxy) were prepared and copolymerized with styrene. The monomers were synthesized by the piperidine catalyzed Knoevenagel condensation of ring-substituted benzaldehydes and propyl cyanoacetate and characterized by CHN elemental analysis, IR, 1H- and 13C-NMR. All the ethylenes were copolymerized with styrene (M1) in solution with radical initiation (ABCN) at 70°C. The composition of the copolymers was calculated from nitrogen analysis, and the structures were analyzed by IR, 1H and 13C-NMR, GPC, DSC, and TGA. Decomposition of the copolymers in nitrogen occurred in two steps, first in the 200–500°C range with residue (3–7% wt.), which then decomposed in the 500–800°C range. 相似文献
7.
Gregory B. Kharas William S. Schjerven Uriel A. Baray Samantha Chan Michael T. Cole Alexander F. Haddad 《高分子科学杂志,A辑:纯化学与应用化学》2016,53(4):191-195
Electrophilic trisubstituted ethylenes, ring-disubstituted butyl 2-cyano-3-phenyl-2-propenoates, RPhCH?C(CN)CO2C4H9 (where R is 2-fluoro-5-methoxy, 2-fluoro-6-methoxy, 3-fluoro-4-methoxy, 4-fluoro-3-methoxy, 5-fluoro-2-methoxy, 3-fluoro-2-methyl, 3-fluoro-4-methyl, 4-fluoro-2-methyl, 4-fluoro-3-methyl, 5-fluoro-2-methyl were prepared and copolymerized with styrene. The monomers were synthesized by the piperidine catalyzed Knoevenagel condensation of ring-disubstituted benzaldehydes and butyl cyanoacetate, and characterized by CHN analysis, IR, 1H and 13C-NMR. All the ethylenes were copoly-merized with styrene (M1) in solution with radical initiation (ABCN) at 70°C. The compositions of the copolymers were calculated from nitrogen analysis and the structures were analyzed by IR, 1H and 13C-NMR. Decomposition of the copolymers in nitrogen occurred in two steps, first in the 200–500°C range with residue (1.2–3.5% wt.), which then decomposed in the 500–800°C range. 相似文献
8.
Gregory B. Kharas Yesenia L. Soto Emily L. Divino Mikaela Donovan Mike D. Dotson Deena Kishawi 《高分子科学杂志,A辑:纯化学与应用化学》2017,54(1):1-5
Novel trisubstituted ethylenes, ring-disubstituted propyl 2-cyano-3-phenyl-2-propenoates, RPhCH?C(CN)CO2C3H7 (where R is 2-fluoro-5-methoxy, 2-fluoro-6-methoxy, 3-fluoro-4-methoxy, 4-fluoro-3-methoxy, 5-fluoro-2-methoxy, 2-fluoro-6-methyl, 3-fluoro-2-methyl, 4-fluoro-2-methyl, 4-fluoro-3-methyl, 5-fluoro-2-methyl) were prepared and copolymerized with styrene. The monomers were synthesized by the piperidine catalyzed Knoevenagel condensation of ring-substituted benzaldehydes and propyl cyanoacetate and characterized by CHN elemental analysis, IR, 1H- and 13C-NMR. All the ethylenes were copolymerized with styrene (M1) in solution with radical initiation (ABCN) at 70°C. The composition of the copolymers was calculated from nitrogen analysis, and the structures were analyzed by IR, 1H and 13C-NMR, GPC, DSC, and TGA. Decomposition of the copolymers in nitrogen occurred in two steps, first in the 200–500°C range with residue (1.4–3.0% wt.), which then decomposed in the 500–800°C range. 相似文献
9.
Chemical shifts for tritons in chlorobenzene have been measured in the pure compound and in a dilute solution in cyclohexane using a 64 MHz NMR spectrometer. The order of shifts is o>m>p. Triton shifts in pure bromobenzene, fluorobenzene and toluene have also been measured and the influence of CCl4 solvent on the aromatic triton shifts in toluene explored. Complete resolution of the three aromatic triton positions is achieved in pure toluene, but the ortho and para shifts are not resolved in 25% solution in CCl4. 相似文献
10.
Gregory B. Kharas Emi Hanawa Benjamin L. Hill Katherine T. Flynn Nikesh H. Bajaj Yousef Bittar 《高分子科学杂志,A辑:纯化学与应用化学》2013,50(10):973-976
Novel copolymers of trisubstituted ethylene monomers, alkoxy ring-substituted 2-phenyl-1,1-dicyanoethylenes, RC6H4CH = C(CN)2 (where R is 2-methoxy, 3-methoxy, 4-methoxy, 2-ethoxy, 3-ethoxy, 4-ethoxy, 4-propoxy, 4-buthoxy, 4-hexyloxy) and 4-fluorostyrene were prepared at equimolar monomer feed composition by solution copolymerization in the presence of a radical initiator (ABCN) at 70°C. The composition of the copolymers was calculated from nitrogen analysis, and the structures were analyzed by IR, 1H and 13C-NMR. The order of relative reactivity (1/r 1) for the monomers is 2-methoxy (1.5) > 4-ethoxy (1.0) > 4-methoxy (0.8) > 3-ethoxy (0.7) = 3-methoxy (0.7) > 4-hexyloxy (0.6) = 2-ethoxy (0.6) > 4-butoxy (0.5) = 4-propoxy (0.5). High T g of the copolymers, in comparison with that of poly(4-fluorostyrene) indicates a substantial decrease in chain mobility of the copolymer due to the high dipolar character of the trisubstituted ethylene monomer unit. Decomposition of the copolymers in nitrogen occurred in two steps, first in 284–500°C range with residue (5–9% wt), which then decomposed in the 500–800°C range. 相似文献
11.
Gregory B. Kharas Hui Feng Isma S. Shouib Connie Tong Andrew Tsang Darcy Velazquez 《高分子科学杂志,A辑:纯化学与应用化学》2016,53(1):1-5
Novel trisubstituted ethylenes, ring-disubstituted butyl 2-cyano-3-phenyl-2-propenoates, RPhCH?C(CN)CO2C4H9 (where R is 2-bromo-5-methoxy, 3-bromo-4-methoxy, 5-bromo-2-methoxy, 2-chloro-3-methoxy, 3-chloro-4-methoxy, 2-chloro-6-methyl, 3-chloro-4-methyl, 2-fluoro-4-methoxy) were prepared and copolymerized with styrene. The monomers were synthesized by the piperidine catalyzed Knoevenagel condensation of ring-substituted benzaldehydes and butyl cyanoacetate, and characterized by CHN analysis, IR, 1H and 13C-NMR. All the ethylenes were copolymerized with styrene in solution with radical initiation (ABCN) at 70°C. The compositions of the copolymers were calculated from nitrogen analysis and the structures were analyzed by IR, 1H and 13C-NMR. Decomposition of the copolymers in nitrogen occurred in two steps, first in the 200-500ºC range with residue (1-6% wt.), which then decomposed in the 500–800ºC range. 相似文献
12.
Tadej Stropnik 《Tetrahedron letters》2008,49(11):1729-1733
A regioselective method for the bromination of phenols, ethers and anilines using a ZrBr4/diazene mixture is described. The reaction takes place under mild reaction conditions and the bromine atom adds first at the para unsubstituted position with respect to the OH, OR or NR2 group of the activated aromatic substrate. Less reactive compounds such as toluene, phenyl acetate, benzonitrile and trifluoromethylbenzene remain intact under the same conditions. 相似文献
13.
Gregory B. Kharas Lujain A. Alyahya Sara M. Rocus Aisha Ismail Rosio Juarez Alfreda Kavaliauskaite 《高分子科学杂志,A辑:纯化学与应用化学》2016,53(12):725-728
Novel trisubstituted ethylenes, oxy ring-disubstituted propyl 2-cyano-3-phenyl-2-propenoates, RPhCH = C(CN)CO2C3H7 (where R is 4-methoxy-2-methyl, 4-methoxy-3-methyl, 3-ethoxy-4-methoxy, 3,4-dibenzyloxy, 3-benzyloxy-4-methoxy, 4-benzyloxy-3-methoxy) were prepared and copolymerized with styrene. The monomers were synthesized by the piperidine catalyzed Knoevenagel condensation of ring-substituted benzaldehydes and propyl cyanoacetate and characterized by CHN elemental analysis, IR, 1H- and 13C-NMR. All the ethylenes were copolymerized with styrene (M1) in solution with radical initiation (ABCN) at 70°C. The composition of the copolymers was calculated from nitrogen analysis, and the structures were analyzed by IR, 1H and 13C-NMR, GPC, DSC, and TGA. Decomposition of the copolymers in nitrogen occurred in two steps, first in the 200–500°C range with residue (3–22% wt.), which then decomposed in the 500–800°C range. 相似文献
14.
Gregory B. Kharas Carla F. Dos Santos Youya Gao Roberto Godina Paul John Courtney Kent 《高分子科学杂志,A辑:纯化学与应用化学》2016,53(10):600-604
Novel trisubstituted ethylenes, oxy ring-substituted propyl 2-cyano-3-phenyl-2-propenoates, RPhCH?C(CN)CO2C3H7 (where R is 2-methoxy, 3-methoxy, 4-methoxy, 2-ethoxy, 3-ethoxy, 4-ethoxy, 4-propoxy, 4-butoxy, 3-phenoxy, 4-phenoxy) were prepared and copolymerized with styrene. The monomers were synthesized by the piperidine catalyzed Knoevenagel condensation of oxy ring-substituted benzaldehydes and propyl cyanoacetate and characterized by CHN elemental analysis, IR, 1H- and 13C-NMR. All the ethylenes were copolymerized with styrene (M1) in solution with radical initiation (ABCN) at 70°C. The composition of the copolymers was calculated from nitrogen analysis, and the structures were analyzed by IR, 1H and 13C-NMR, GPC, DSC, and TGA. Decomposition of the copolymers in nitrogen occurred in two steps, first in the 200–500°C range with residue (1.2–3.6% wt.), which then decomposed in the 500–800°C range. 相似文献
15.
It has been shown that Ba (BrF4)2 acted as a highly-active brominating agent. In case of interaction with nitrobenzene, the pure 3-bromo-nitrotoluene is formed. It has been shown that typical electrophilic bromination of the aromatic compound with electron-donating and electron-accepting substituents occurred without any catalysts or hard conditions. 相似文献
16.
Claudia A. Caro Gerardo Cabello Esteban Landaeta Jerónimo Pérez Miguelina González José H. Zagal 《Journal of Coordination Chemistry》2014,67(23-24):4114-4124
The chitosan–(Fe(II), Co(II), and Cu(II)) complexes were prepared by mixing chitosan (Chi) powder with a salicylaldehyde (Sal, 5-hydrogen (–H)) and their 5-bromo (–Br), 5-chloro (–Cl), 5-methoxy (–OCH3), 5-fluoro (–F), 5-methyl (–CH3), and 5-nitro (–NO2) derivatives (groups R) and mixing these with FeCl2 and CuCl2 in ethanol and with Co(CH3COO)2 solutions in butanol at 80 °C over 8 h in heterogeneous phase, followed by extraction with ethanol and butanol, respectively. The complexes were characterized by FTIR and UV–vis spectroscopy, elemental analysis, and cyclic voltammetry. A linear correlation between the metal formal potential versus the Hammett parameters of the substituents was observed. The electron-withdrawing groups shift the redox potential to positive values, as a result of lowering the energy of the highest occupied molecular orbital. The formal potential was used as a measurement for the driving force of chitosan complexes for redox reactions. 相似文献
17.
The title compound 1 , has been shown to give a 1-bromo derivative 2 when subjected to free-radical bromination and a 1-dimethylaminomethyl derivative 3 by reaction under standard Mannich conditions. Vilsmeier formylation, however, furnishes the 3-substituted derivative 4 . 相似文献
18.
Bromine formation in the mixture of solid NaBr and KNO3 was observed and the process was studied in different acidified organic solvent–water mixtures by monitoring the bromination of acetanilide and other compounds, containing activated aromatic substituents. This assay is based on fast bromination reaction of these aromatic compounds, as differently from the assay of Br2, the brominated aromatics can be easily determined by conventional gas chromatography–mass spectrometry (GC–MS) methods. It was found that bromine was generated autocatalytically on the surface of salt crystals and the reaction was characterized by a lag period, the duration of which depended on reaction conditions, and importantly on the type of the organic solvent in the reaction mixture. As the bromine formation could be easily controlled by reaction conditions, it was suggested that the studied reaction might have practical applications as an environmentally friendly and economically feasible bromination method. It was also shown that the bromination of aromatics followed the mechanism of classical electrophilic aromatic substitution reaction. 相似文献
19.
Shinji Watanabe Hitoshi Murayama Miki Murata Yuzuru Masuda Masaru Tanabe Yoshio Imai 《Journal of polymer science. Part A, Polymer chemistry》1998,36(13):2229-2235
New polyarylates having benzopinacolone units were synthesized from 2,2-bis(4-hydroxyphenyl)-1,2-diphenylethanone and aromatic dicarboxylic acid chlorides. The polymers having an inherent viscosity of 0.71–0.94 dL/g were obtained by the two-phase method using toluene as an organic solvent. The polymers were easily soluble in various organic solvents and had high glass transition temperatures in the range of 200–240°C. An aromatic polyether having benzopinacolone unit was also prepared. However, its inherent viscosity was low because of the occurrence of a side reaction. © 1998 John Wiley & Sons, Inc. J. Polym. Sci. A Polym. Chem. 36: 2229–2235, 1998 相似文献
20.
Viktor O. Iaroshenko Sajid Ali Satenik Mkrtchyan Ashot Gevorgyan Tariq Mahmood Babar Volodymyr Semeniuchenko Zahid Hassan Alexander Villinger Peter Langer 《Tetrahedron letters》2012,53(52):7135-7139
A concise and efficient approach to a series of chromen-4-ones with fused thiophene ring has been developed using the Suzuki–Miyaura reaction of bromothiophene-2- and 3-carboxylates with 2-methoxyboronic acids and subsequent cyclization of prepared alkyl (2-methoxy)aryl thiophene-2- and 3-carboxylates under the action of BBr3/KOtBu. Starting bromothiophenes are easily obtained from corresponding commercially available aminothiophenes by diazotization/bromination reaction. 相似文献