Procedure-B: 2-(4-cyclopropanesulfonylphenyl)-2-(2,4-difluorophenoxy)acetic acid (obtained in step III) was dissolved in DCM. To this solution was added DMF and cooled to 0° C., followed by the addition of oxalyl chloride under stirring. To this mixture, a solution of 2-aminothiazole and pyridine in DCM was added drop wise at 0° C. and was stirred further for 4 h. at room temperature. The reaction mixture was poured into 1N aqueous HCl under stirring, organic layer was again washed with 1N HCl, followed by 5% brine, dried over anhydrous sodium sulfate, solvent was removed under reduced pressure to get the crude compound which was purified by flash chromatography to get the title product.
