To a stirred solution of 5-(4-chlorophenyl)-1,4-dimethyl-3-(4-sulfamoylphenyl)-1H-pyrrole-2-carboxylic acid (compound 49ε, 0.800 g, 1.98 mmol) in DMF (15 ml) was added HOBT (0.333 g, 2.17 mmol) at room temperature followed by the addition of N,O-dimethylhydroxylamine hydrochloride (0.386 g, 3.96 mmol). The reaction mixture was then cooled to 0° C., and to the cooled reaction mixture was added EDC (0.570 g, 2.97 mmol) and triethylamine (0.80 g, 1.10 ml, 7.92 mmol). The reaction mixture was then stirred at room temperature for 15 hr. The progress of the reaction was monitored by TLC. The reaction mixture was then concentrated under reduced pressure. The residue so obtained was taken in ethyl acetate (100 ml) and washed with saturated sodium bicarbonate solution (20 ml) followed by washing with brine (20 ml). The organic layer obtained was dried over anhydrous sodium sulphate, and concentrated under reduced pressure to obtain a crude product. The crude product was then purified by column chromatography over silica gel (100-200 mesh) using 50% ethyl acetate in hexanes as an eluent to obtain the title compound (0.680 g, 76.8%).
