Patent ID: 7932391

Claim:
A method of preparing a compound of formula (I): comprising preparing a compound of formula (V): by direct alkaline hydrolysis of a compound of formula (IV): in a mixture of 20% to 50% aqueous base and a first organic solvent, in the presence of a first phase transfer catalyst (PTC) at an alkaline hydrolysis temperature of 60° C. to 130° C.; and reacting the compound of formula (V) with a methylation agent in an aqueous alkaline solution catalyzed by a second phase transfer catalyst (PTC) in H 2 O or a second organic solvent or a mixture thereof at an esterification temperature of 0° C. to 100° C., wherein X is selected from the group consisting of hydrogen, fluoro, chloro, bromo and iodo atoms and M is an alkali metal ion.