79341-72-3Relevant articles and documents
Application of novel dimethyl carbonate methylation catalyst in preparation α- methyl phenylacetic acid
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Paragraph 0046-0051; 0056-0057, (2020/03/17)
The invention relates to the field, of medicine synthesis, and concretely relates to a novel dimethyl carbonate methylation catalyst α - in preparation IV methylbenzene acetic acid. as starting material I for preparing a target product, methylbenzeneacetic acid, by a methylation, decarboxylation and hydrolysis reaction, under the action of a catalyst by using a catalyst as a representative low-cost catalyst, in the form of a quaternary amine salt, and a catalyst prepared by using the catalyst as a representative low-cost catalyst, such as potassium α - potassium bromide acetate, as a catalyst, and a catalyst used in the, hydrolysis reaction of the quaternary, amine salt. IV. 98%. The preparation method comprises the following steps: preparing a target product from the quaternary ammonium. salt solution.
Method for preparing loxoprofen intermediate
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Paragraph 0098; 0099, (2016/10/10)
A method for preparing a loxoprofen intermediate comprises the following steps that 1, on the presence of sodium alkoxide, benzyl cyanide and dimethyl carbonate are subjected to methylation in an organic solvent, and 2-(phenyl cyano) sodium propionate is obtained; 2, 2-(phenyl cyano) sodium propionate and dimethyl sulfate react in an organic solvent to obtain 2-(phenyl cyano) methyl propionate; 4, 2-(phenyl cyano) methyl propionate reacts under the alkaline condition to obtain 2-phenyl propionitrile; 4, 2-phenyl propionitrile is hydrolyzed under the alkaline condition, acid is added for acidizing after the reaction to obtain 2-phenylpropionic acid; 5, 2-phenylpropionic acid, hydrobromic acid and paraformaldehyde are mixed and subjected to a bromine methylation reaction under the acidic condition, and 2-(4-tribromomethyl phenyl) propionic acid is obtained.According to the method, a new synthesis route is designed, product selectivity is good, the purity is high, the conversion rate is high, and few by-products are generated; the raw materials are simple and easy to obtain, the production conditions are mild, the process is simple, production cost is low, and pollution is small.
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.
