67216-72-2Relevant academic research and scientific papers
Triflic acid catalyzed reductive coupling reactions of carbonyl compounds with O-, S-, and N-nucleophiles
Gellert, Beate A.,Kahlcke, Nils,Feurer, Markus,Roth, Stefanie
supporting information; experimental part, p. 12203 - 12209 (2011/11/07)
Highly efficient metal-free reductive coupling reactions of aldehydes and ketones with a range of nucleophiles in the presence of triflic acid (1-5 mol %) as the catalyst are presented. The reactions can be performed at ambient temperature without exclusion of moisture or air. A range of symmetrical and unsymmetrical ethers were obtained by this method in high yields and short reaction times. For the first time, the influence of additional functionalization has been studied. Furthermore, the formation of thioethers from ketones (by addition of unmodified thiols) and of sulfonamides from either aldehydes or ketones has been achieved under catalytic conditions.
New method for the synthesis of benzyl alkyl ethers mediated by FeSO 4
Joshi, Girdhar,Adimurthy, Subbarayappa
experimental part, p. 720 - 728 (2011/03/22)
The synthesis of benzyl alkyl ethers from benzyl bromides and alcohols using FeSO4 as a recoverable and reusable mediator has been described without use of base and cosolvent under mild conditions.
A kinetic model for water reactivity (avoiding activities) for hydrolyses in aqueous mixtures - Selectivities for solvolyses of 4-substituted benzyl derivatives in alcohol-water mixtures
Bentley, T. William,Koo, In Sun,Choi, Hojune,Llewellyn, Gareth
, p. 251 - 256 (2008/09/20)
For solvolyses of various benzyl substrates in ethanol-water (EW) and methanol-water (MW) mixtures, product selectivities (S) are reported for chlorides at 75°C defined as follows using molar concentrations: S= ([ether product]/[alcohol product]) × ([water]/[alcohol solvent]). The results support earlier evidence that solvolyses of 4-nitrobenzyl substrates are S N2 processes, which are not susceptible to mechanistic changes over the whole range of solvents from water to alcohol. S values at 25 and/or 45°C in EW and MW, and additional kinetic data including kinetic solvent isotope effects (KSIE) are reported for solvolyses of 4-nitrobenzyl mesylate and tosylate. A kinetic model, explaining both rates and product, is proposed; a general medium effect due to solvent polarity is combined in one parameter with solvent effects on the nucleophilicity of the water and alcohol molecules acting as nucleophiles in SN2 reactions. According to this model, as alcohol is added to water the rate of reaction decreases due to a decrease in solvent polarity, but the nucleophilicity of water increases relative to alcohol. The availability of experimental rate and product data over the whole range of solvent compositions from alcohol to water, reveals limitations of alternative approaches using activities. Copyright
Highly efficient indium-catalyzed chemoselective allylation-etherification and reductive etherification of aromatic aldehydes with functional silanes
Yang, Ming-Song,Xu, Li-Wen,Qiu, Hua-Yu,Lai, Guo-Qiao,Jiang, Jian-Xiong
, p. 253 - 256 (2008/03/30)
Indium(III) chloride is an effective Lewis acid catalyst for one-pot allylation-etherification and reductive etherification of aromatic aldehydes with functional silanes, allyltriethoxysilane, and triethoxysilane, at room temperature to afford corresponding ethers in excellent yields. Additionally, the InCl3-catalyzed reactions in the presence of TMSCl offer significant advantages in its ease of working-up for the preparation of unsymmetrical ethers under mild conditions.
Iodine catalyzed selective O-alkylation of alcohols with orthoesters
Kumar,Anjaneyulu,Joyasawal, Sipak,Pawan Chakravarthy,Naveen Kumar,Yadav
, p. 189 - 192 (2008/02/13)
In the present communication O-alkylation of a number of allylic and benzylic alcohols has been described.
Correlation of the rates of solvolysis of (arylmethyl)methylphenyl-sulfonium ions
Kevill, Dennis N.,Ismail, Norsaadah H.J.
, p. 1865 - 1868 (2007/10/03)
The specific rates of solvolysis of the benzylmethylphenylsulfonium ion (prepared as the trifluoromethanesulfonate salt) and five benzylic ring-substituted derivatives can be satisfactorily correlated using NT solvent nucleophilicity values. Addition of a secondary term, governed by the aromatic ring parameter (I), shows the sensitivities towards changes in this parameter to fall and those towards changes in NT to rise with increasing electron-withdrawing ability of the substituent. The Hammett ρ values with electron-withdrawing substituents (based on ρ+ values) vary from -0.9 in 95% acetone to -1.8 in 97% 2,2,2-trifluoroethanol. These Grunwald-Winstein and Hammett analyses are compared to those previously reported, with essentially the same solvents and substituents, for solvolyses of arylmethyl p-toluenesulfonates.
Electron-transfer versus Nucleophilic Substitution in the Reactions of α-Halogenated 4-Nitrotoluenes with Base
Kam, Toh-Seok,Lim, Tuck-Meng
, p. 147 - 150 (2007/10/02)
A comparative study of the reactions of 4-nitrobenzyl and 4-nitrobenzylidene halides (ArCHXY; Ar = 4-NO2C6H4-; X = H or Halogen; Y = Halogen) with alkali shows that the reaction is sensitive to the nature of the side chain halogen substituent(s) as well as the reaction conditions.In alcoholic alkali, only 4-nitrobenzyl chloride (ArCH2Cl) reacts smoothly via the electron transfer (ET)-radical pathway to give mainly dimeric products while the corresponding bromide (ArCH2Br) and iodide (ArCH2I) give exclusively SN products.The ET pathway is enhanced for these substrates by the application of phase-transfer catalysis.In the case of the 4-nitrobenzylidene dihalides (ArCHXY; X = Y = Cl; X = Cl, Y = Br; X = Y = Br; X = F, Y = Br) it is also shown that although progressive bromine substitution suppresses the ET pathway, application of phase-transfer catalysis minimises competing solvolytic reactions and enhances the radical reaction.
Changes of Selectivity in the Reactions of Substituted 4-Nitrobenzyl Sulfonates with Nucleophilic Reagents
Dietze, Paul,Jencks, William P.
, p. 5880 - 5886 (2007/10/02)
The selectivities for anionic nucleophilic reagents are larger for reaction with 4-nitrobenzyl mesylate than with the corresponding triflate.Selectivities were determined over a range of rate constants of ca. 1E4 for nucleophiles and ca. 1E5 for 4-nitrobenzyl sulfonates in 20:80 CH3CN/HOH (v:v) at 25 deg C, ionic strength 0.5 M (NaClO4).The slope of a correlation of log (kN/kHOH) for the two compounds is 1.12.Larger increases in selectivity of up to 11-fold were observed with more basic nucleophiles.The size of the additional increase is roughly proportional tothe basicity of the nucleophile, and it is suggested that reaction of the partially desolvated species may contribute to these differences.The results are described by a positive interaction coefficient pxy = s'/ log kHOH = s1g/ log knuc = 0.026.No significant change in selectivity of p-nitrobenzyl tosylate, nosylate, and triflate toward substituted anilines was observed over a 5-6-fold range of amine reactivity.The values of βnuc = 0.31 and 0.26 for the reactions of substituted anilines and aliphatic amines, respectively, with 4-nitrobenzyl tosylate do not differ significantly (70:30 EtOH/HOH (v:v), 25 deg C).The tosylate anion is a stronger nucleophile than water toward 4-nitrobenzyl triflate.It is concluded that SN2 substitution reactions do follow the Hammond postulate, or "Bema Hapothle", but that the small magnitude of the changes in selectivity requires the examination of a large range of reactivity for both the nucleophile and the substrate.
Synthetic Approaches to some Aza-analogues of Benzimidazole N-Oxides. Part 1. The Imidazopyridine Series
Andrews, Adrian F.,Smith, David M.,Hodson, Harold F.,Thorogood, Peter B.
, p. 2995 - 3006 (2007/10/02)
The 3-oxide of 2-p-nitrophenylimidazopyridine (8) may be obtained in good yield by base-induced cyclisation of 2-nitro-3-(p-nitrobenzylamino)pyridine (18).It is also obtained in lower yield, along with p-nitrobenzoic acid and other cleavage products, by the corresponding reactions of bases with the N-ethoxycarbonyl, N-methylsulphonyl, and N-p-tolylsulphonyl derivatives of 2-nitro-3-(p-nitrobenzylamino)pyridine .Cleavage is the main reaction when N-(2-nitro-3-pyridyl)-N-phenacylmethanesulphonamide (17) is treated with bases: phenylglyoxal, or its Schiff base with 3-amino-2-nitropyridine, are possible intermediates in the cleavage process. 3-Nitro-2-(p-nitrobenzylamino)pyridine (31) is similarly cyclised in basic media to give the 1-oxide of 2-p-nitrophenylimidazopyridine (32).
