Sodium Hydroxide → HCID 21958963, Verbindung

A solution of 2-(3-chloro-4-methanesulfonyl-phenyl)-3-(3-oxo-cyclopentyl)-propionic acid methyl ester (1.02 g, 2.84 mmol) in methanol (7.1 mL) was treated with a 1N aqueous sodium hydroxide solution (6.0 mL, 6.0 mmol). The reaction mixture was stirred at 25° C. for 16 h. The reaction mixture was then concentrated in vacuo to remove methanol. The resulting aqueous residue was diluted with water (100 mL) and acidified to pH=3 with a 1N aqueous hydrochloric acid solution then extracted with ethyl acetate (2×150 mL). The combined organic layers were washed with a saturated aqueous sodium chloride solution (100 mL), dried over sodium sulfate, filtered, and concentrated in vacuo. The resulting yellow oily solid was triturated with ethyl acetate/petroleum ether to afford 2-(3-chloro-4-methanesulfonyl-phenyl)-3-(3-oxo-cyclopentyl)-propionic acid (800.0 mg, 82%) as a white solid: mp 164–167° C.; (ES)+-HRMS m/e calcd for C15H17ClO5S (M+H)+ 345.0558 found 345.0561.