Patent ID: 6653503
Filing Date: 2003-11-25
Classification: C07C,C07D,C07H

Abstract:
An accelerated process for preparing a methyl ester having formula (III) said process comprising reacting a carboxylic acid or salt thereof having formula (I) with dimethyl carbonate having formula (II) in the presence of a catalyst selected from the group consisting of 1,8-diazabicyclo[5.4.0]undec-7-ene; 1,4-diazabicyclo[2.2.2]octane; 4-dimethylaminopyridine; and combinations thereof, wherein R1 is selected from the group consisting of an alkyl, aryl, alkoxy, alkenyl, cycloalkyl, benzocycloalkyl, cycloalkylalkyl, aralkyl, heterocyclic, heteroaralkyl, alkoxyalkyl, carboxyalkyl, alkylcarbonyl, alkoxycarbonyl, alkoxycarbonylalkyl, and haloalkyl; and M is selected from the group consisting of hydrogen, a monovalent metal, and a monovalent fractional part of a polyvalent metal,wherein said process is conducted under microwave irradiation at a frequency from 300 MHz to 30 GHz, and at a temperature of from about 120Â° C. to 300Â° C. for a period of microwave irradiation time from about 1 second to about 300 minutes.