- Metal-free aerobic oxidative esterification of aromatic aldehydes promoted by potassium fluoride (KF)
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We investigated the oxidative esterification of aldehydes with alcohols/phenols to produce a range of esters. In this approach, we conducted the reaction under metal-free conditions at room temperature. The reactions were promoted by potassium fluoride (KF) as the additive, resulting in the desired product in good to high yields. This procedure was found to be effective for the production of aryl esters, which are challenging in most of the available reports. It is vital for this procedure not to exclude air as the source of oxygen.
- Soltani, Roghaye,Ghaderi, Arash
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- Pd-catalysed decarboxylative Suzuki reactions and orthogonal Cu-based O-arylation of aromatic carboxylic acids
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Pd-catalysed decarboxylative Suzuki reactions and orthogonal Cu-based O-arylation reactions of aromatic carboxylic acids are reported. The new reactions may provide alternative routes for the synthesis of some biaryls and aromatic carboxylic esters. The Royal Society of Chemistry 2011.
- Dai, Jian-Jun,Liu, Jing-Hui,Luo, Dong-Fen,Liu, Lei
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supporting information; experimental part
p. 677 - 679
(2011/03/22)
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- Evidence of substituent-induced electronic interplay. Effect of the remote aromatic ring substituent of phenyl benzoates on the sensitivity of the carbonyl unit to electronic effects of phenyl or benzoyl ring substituents
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Carbonyl carbon 13C NMR chemical shifts δC(C=O) measured in this work for a wide set of substituted phenyl benzoates p-Y-C 6H4CO2C6H4-p-X (X = NO2, CN, Cl, Br, H, Me, or MeO; Y = NO2, Cl, H, Me, MeO, or NMe2) have been used as a tool to study substituent effects on the carbonyl unit. The goal of the work was to study the cross-interaction between X and Y in that respect. Both the phenyl substituents X and the benzoyl substituents Y have a reverse effect on δC(C=O). Electron-withdrawing substituents cause shielding while electron-donating ones have an opposite influence, with both inductive and resonance effects being significant. The presence of cross-interaction between X and Y could be clearly verified. Electronic effects of the remote aromatic ring substituents systematically modify the sensitivity of the C=O group to the electronic effects of the phenyl or benzoyl ring substituents. Electron-withdrawing substituents in one ring decrease the sensitivity of δC(C=O) to the substitution of another ring, while electron-donating substituents inversely affect the sensitivity. It is suggested that the results can be explained by substituent-sensitive balance of the contributions of different resonance structures (electron delocalization, Scheme 1).
- Neuvonen, Helmi,Neuvonen, Kari,Pasanen, Paavo
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p. 3794 - 3800
(2007/10/03)
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- p-Methoxybenzoyl p-Nitrobenzoyl Peroxide Revisited: Catalysis by Silica
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The decomposition of p-methoxybenzoyl p-nitrobenzoyl peroxide (1) in benzene/silica slurries at room temperature is faster than in benzene solution by 5 orders of magnitude.The first product of the reaction is entirely or mainly the carboxy inversion compound, p-methoxyphenyl p-nitrobenzoyl carbonate (2), which also decomposes on the silica.The products from experiments in which 2 is the initial reagent are the same as those from the peroxide.The most important are p-methoxyphenyl p-nitrobenzoate, p-methoxyphenol, and p-nitrobenzoic acid.The absence within the limits of GC/MS of anisic acid, p-methoxybiphenyl, p-nitrobiphenyl, p-nitrophenyl anisate, p-methoxy-p'-nitrobiphenyl, phenyl p-nitrobenzoate, phenyl anisate, and phenyl p-nitrobenzoate indicates that the decomposition of 1 under these conditions produces no free radicals.
- Leffler, John E.,Barbas, John T.,Flowers, G. Craig
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p. 2286 - 2287
(2007/10/02)
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- LIQUID CRYSTALLINE PROPERTIES OF 4-N-ALKOXYPHENYL 4-NITROBENZOATES.
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Twelve 4-alkoxyphenyl esters of 4-nitrobenzoic acid were synthesized. The mesophases were identified and the transition temperatures and enthalpies determined. The above series shows considerable similarity to the reverse analogues, i. e. , the 4-nitro-phenyl 4-n-alkoxybenzoates.
- Galewski,Sobczyk
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- Studies on the Friedel-Crafts Reaction. XVI, Preparation of Isomeric 2-Acyl- and 3-Acyl-4-methoxy Phenols
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Acylation of 4-methoxy phenol according to Friedel and Crafts, as well as the rearrangement of its esters according to Fries lead always to 2-acyl-4-methoxy phenols or to their demethylated compounds.The unknown 3-acyl-4-methoxyphenols were prepared in two steps: First, the ester is acylated with the corresponding acyl chloride and SnCl4 in nitromethane.In the second step the resulting ketoesters are hydrolysed.This is a general method.The yields of meta-acylphenols are between 40 and 90percent.The isomeric 2-acyl-4-methoxyphenols which were partly unknown or accessible only in low yields have also been prepared for comparative spectral studies (UV, IR, NMR, MS) of ortho- and meta-acylphenols. - Keywords: Friedel-Crafts acylation; Fries rearrangement; Ketoesters; Spectral data
- Martin, Robert
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p. 1155 - 1164
(2007/10/02)
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