A suspension of the {9-[(2,6-difluorophenyl)methyl]-5-carbamoylcarbazol-4-yl}oxyacetic acid, methyl ester (85 mg, 0.2 mM) and 0.22 mL (0.22 mM) of 1 N NaOH in 5 mL of ethanol was stirred for 18 hours at 25° C. A small volume of diethyl ether/hexanes was added, then cooled in the refrigerator. The resultant white precipitate was collected by filtration, washed with a small amount of EtOH/diethyl ether/hexanes, then dried in vacuo to afford 82 mg (95%) of the {9-[(2,6-difluorophenyl)methyl]-5-carbamoylcarbazol-4-yl}oxyacetic acid, sodium salt as a white powder. 1H NMR (DMSO-d6) δ 7.6 (d, 1H, J=8 Hz), 7.55 (br s, 1H), 7.45-7.3 (m, 3H), 7.25 (t, 1H, J=8 Hz), 7.1-7.0 (m, 4H), 6.5 (d, 1H, J=8 Hz), 5.65 (s, 2H), and 4.3 (s, 2H). IR (KBr, cm−1) 3470, 3360, 1658, and 1606. MS (ES) m/e 409, 411, 433.
