Lithium hydroxide, monohydrate → [4-(4-Benzenesulfonylamino-phenyl)-6-fluoro-3-methyl-naphthalen-2-yl]-acetic acid

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Reaction Steps

To a solution of [4-(4-benzenesulfonylamino-phenyl)-6-fluoro-3-methyl-naphthalen-2-yl]-acetic acid methyl ester (38 mg, 0.08 mmol) in THF (2 mL) was added a solution of lithium hydroxide monohydrate (10 mg, 0.25 mmol) in water (1 mL) and methanol (1 mL) plus sodium hydroxide solution (1 ml, 1.0 N) at room temperature. The resulting clear solution was stirred for 4 h and then the solvents were removed under vacuum. The residue was diluted with water (10 mL). The mixture was acidified with 1.0 N hydrochloric acid and extracted with ethyl acetate (2×20 mL). The combined organic extracts were washed with brine solution (20 mL) and dried over anhydrous magnesium sulfate. Filtration of the drying agent and concentration of the solvent under vacuum provided the desired [4-(4-benzenesulfonylamino-phenyl)-6-fluoro-3-methyl-naphthalen-2-yl]-acetic acid (34 mg, 92%) as a light brown foam. 1H NMR (300 MHz, DMSO-d6) δ ppm 12.43 (br. s, 1 H), 10.44 (s, 1 H), 7.88-8.02 (m, 1 H), 7.76-7.87 (m, 3 H), 7.50-7.71 (m, 3 H), 7.33 (t, J=7.7 Hz, 1 H), 7.24 (d, J=8.0 Hz, 2 H), 7.09 (d, J=8.0 Hz, 2 H), 6.58 (d, J=11.2 Hz, 1 H), 3.80 (br. s, 2 H), 2.00 (s, 3 H). HRMS calcd. for C25H19FNO4S [(M−H)−] 448.1024, obsd. 448.1022.

Provenance & Evidence