65749-05-5Relevant articles and documents
Selective mono-C-methylations of arylacetonitriles and arylacetates with dimethylcarbonate: A mechanistic investigation
Tundo, Pietro,Selva, Maurizio,Perosa, Alvise,Memoli, Sofia
, p. 1071 - 1077 (2007/10/03)
The very high mono-C-methylation selectivity (>99%) of arylacetic acid derivatives (ArCH2X; X = CN, CO2Me) with dimethyl carbonate (DMC) is due to a mechanism that involves consecutive methoxycarbonylation, methylation, and demethoxycarbonylation steps. Important aspects of this mechanism are clarified herein by a kinetic investigation. In the case of arylacetonitriles, at 140°C, the comparison of the rate constants of model reactions involving 2-phenyl propionitrile, phenylacetonitrile, 2-methoxycarbonylphenylacetonitrile, and 2-methyl-2-methoxy carbonylphenyl acetonitrile (compounds 1a-4a, respectively) with DMC indicates that the methylation process is the fastest and the irreversible step, which drives the overall reaction to completion. The situation is reversed for arylacetic esters, where the methylation is more difficult than the demethoxycarbonylation reaction; therefore, a higher reaction temperature is required.
THE ADDITION REACTION OF DIALKYL CARBONATES TO KETONES
Selva, Maurizio,Marques, Carlos Alberto,Tundo, Pietro
, p. 515 - 518 (2007/10/02)
The reaction of benzyl phenyl ketone with dimethyl carbonate gives methyl benzoate and methyl phenylacetate; diethyl carbonate gives the corresponding ethyl esters.The reaction takes place at high temperature (about 200 deg C) and in the presence of potassium carbonate as a catalyst.Other benzyl ketones react similarly.Aliphatic ketones yield a less selective addition.Accordingly, cyclohexanone with dimethyl carbonate gives dimethyl pimelate.The reaction is a retro-Claisen condensation, which occurs through the intermediate formation of the alkoxycarbonyl derivative.
Enzymes in organic synthesis 50. Probing the dimensions of the large hydrophobic binding region of the active site of pig liver esterase using substituted aryl malonate substrates
Toone,Jones
, p. 1041 - 1052 (2007/10/02)
The active side model reported recently for the synthetically useful enzyme pig liver esterase (PLE) permits the structural specificity and stereoselectivity of the enzyme to be interpreted and predicted for a wide range of substrates. The specifications
