Sodium hydroxide (100 mg, 2.5 mmol) was added to a suspension of 4-[4-(3-chloro-4-fluoro-phenyl)-thiazol-2-yl]-2′-nitro-biphenyl-2-carboxylic acid methyl ester (100 mg) in a mixture of water (2 mL) and dioxane (4 mL). The reaction mixture was stirred at 50° C. for 2 h. An additional portion of water (2 mL) was added and the reaction mixture was stirred at 50° C. for a further 2 h. The reaction mixture was evaporated to dryness and water (5 mL) was added. The mixture was filtered and the filtrate was made acidic to pH 3-4 by the addition of concentrated HCl. The precipitate was collected by filtration and dried to give 4-[4-(3-chloro-4-fluoro-phenyl)-thiazol-2-yl]-2′-nitro-biphenyl-2-carboxylic acid (60 mg, 41% for two steps). 1H NMR (300 MHz, DMSO-d6) δ 13.18 (br s, 1H), 8.56 (s, 1H), 8.39 (s, 1H), 8.27 (d, J=8.3 Hz, 1H), 8.08-8.16 (m, 2H), 7.79 (t, J=7.4 Hz, 1H), 7.66 (t, J=7.9 Hz, 1H), 7.41-7.58 (m, 3H).
