Sodium Hydroxide → [(R)-4-(3-bromo-5-trifluoromethyl-benzenesulfonylamino)-4,5,6,7-tetrahydro-indazol-1-yl]-acetic acid

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Reaction Steps

To a solution of [(R)-4-(3-bromo-5-trifluoromethyl-benzenesulfonylamino)-4,5,6,7-tetrahydro-indazol-1-yl]-acetic acid ethyl ester (18.0 mg, 0.035 mmol) in tetrahydrofuran (2 mL) was added an aqueous solution of sodium hydroxide (1 N, 2 mL). The resulting mixture was stirred at room temperature for 2 hours, then extracted with diethyl ether (6 mL). The organic layer was discarded. The aqueous layer was acidified with concentrated hydrochloric acid to pH 4 and then stirred with diethyl ether (2 mL) and petroleum ether (6 mL) at room temperature for 2 hours. The resulting mixture was filtered to afford [(R)-4-(3-bromo-5-trifluoromethyl-benzenesulfonylamino)-4,5,6,7-tetrahydro-indazol-1-yl]-acetic acid (13.3 mg, 78.8%) as a white powder. 1H NMR (400 MHz, CD3OD) δ ppm 8.34 (s, 1 H), 8.20 (s, 2 H), 6.81 (s, 1 H), 4.80 (s, 2 H), 4.48 (t, 1 H), 2.50 (m, 2 H), 2.00-1.72 (m, 4 H). MS calcd. for C16H15BrF3N3O4S 481, obsd. (ESI+) [(M+H)+] 482.

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