Base-free oxidation of alcohols to esters at room temperature and atmospheric conditions using nanoscale Co-based catalysts
The direct oxidation of alcohols to esters with molecular oxygen is an attractive and crucial process for the synthesis of fine chemicals. To date, the heterogeneous catalyst systems that have been identified are based on noble metals or have required the addition of base additives. Here, we show that Co nanoparticles embedded in nitrogen-doped graphite catalyze the aerobic oxidation of alcohols to esters at room temperature under base-free and atmospheric conditions. Our Co@C-N catalytic system features a broad substrate scope for aromatic and aliphatic alcohols as well as diols, giving their corresponding esters in good to excellent yields. This apparently environmentally benign process provides a new strategy with which to achieve selective oxidation of alcohols.
Immobilised Candida antarctica B as efficient catalyst for the synthesis of local anaesthetic intermediates
We hereby present the development of new reaction conditions for the CALB catalysed esterification of substituted benzoic acids. Using cyclohexane as the reaction media a number of heptyl benzoates have been easily isolated in good to excellent yields (up to 100% at 80 C, 20-24 h). Moreover, the catalytic system has been successfully applied to the synthesis of local anaesthetics intermediates also showing good productivity in recycling experiments.
Giunta, Daniela,Masia, Maria Paola,Marchetti, Mauro,Morrone, Raffaele,Solinas, Maurizio
supporting information
p. 5122 - 5125
(2013/08/28)
N-heterocyclic carbene-catalyzed oxidative esterification reaction of aldehydes with alkyl halides under aerobic conditions
An efficient N-heterocyclic carbene-catalyzed oxidative esterification reaction of aldehydes with alkyl halides or alkyl 4-methylbenzenesulfonate is reported. It was worth noting that (1) the configuration of alkyl halides or alkyl 4-methylbenzenesulfonates was inverted completely, and (2) the presence of oxygen was crucial for this transformation. The reaction proceeded smoothly under mild conditions and various esters were afforded in moderate to good yields. In addition, we have developed an efficient tandem oxidation/ esterification reaction of alcohols. This methodology provides a rare example of a reaction of the Breslow intermediate to sp3-carbon centered electrophiles. An efficient oxidative esterification reaction of aldehydes with alkyl halides or alkyl 4-methylbenzenesulfonates catalyzed by N-heterocyclic carbenes is reported. Oxygenwas crucial for the reaction, and the configuration of alkyl 4-methylbenzenesulfonate was completely inverted. Copyright
Smectogenic Salts Formed by Combination of Alkyl p-Aminobenzoates and p-Ethyl- or p-Chlorobenzenesulfonic Acid
Two series of smectogenic salts were obtained by combining alkyl p-aminobenzoates with p-ethyl- and p-chlorobenzenesulfonic acids, respectively.The shortest ester alkyl chain required to generate a smectic A phase is nonyl when the former sulfonic acid is employed but the chain may be as short as butyl when the latter is employed.The smectic A-isotropic transition temperature in the second series is significantly higher than that in the first series, indicating that the terminal substituent on the anion is as crucial as that in non-ionic mesogens in determining the mesophase stability. - Keywords: Smectic, alkyl p-aminobenzoates, benzenesulfonates
Matsunaga, Y.,Sakamoto S.,Togashi, A.,Tsujimoto, M.
p. 161 - 166
(2007/10/02)
Esterification Using a Polymer-Supported Phosphine Reagent
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Amos, Richard A.,Emblidge, Robert W.,Havens, Nick
p. 3598 - 3600
(2007/10/02)
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