C([O:3][C:4](=[O:18])[C:5]([CH3:17])([S:7]([CH2:10][CH:11]1[CH2:16][CH2:15][O:14][CH2:13][CH2:12]1)(=[O:9])=[O:8])[CH3:6])C.O.[OH-].[Li+]>C([O-])(O)=O.[Na+].[Cl-].[Na+].O>[CH3:17][C:5]([S:7]([CH2:10][CH:11]1[CH2:12][CH2:13][O:14][CH2:15][CH2:16]1)(=[O:9])=[O:8])([CH3:6])[C:4]([OH:18])=[O:3]To a solution of 769 mg (2.77 mmol) of 2-methyl-2-(tetrahydro-pyran-4-ylmethanesulfonyl)-propionic acid ethyl ester in THF/water (1/1, 10 mL) were added 228 mg (5.43 mmol) of lithium hydroxide monohydrate. The reaction was stirred at room temperature for 18 h. The reaction was concentrated under reduced pressure. The residue was dissolved in water (10 mL) and washed with diethyl ether (2×25 mL). The aqueous layer was cooled in an ice bath and then acidified with 1M aqueous HCl solution to pH 2. The acidic aqueous layer was extracted with ethyl acetate (2×50 mL) and with isopropanol/chloroform (3×50 mL). The combined organic extracts were dried over Na2SO4 and filtered. Concentration of the filtrate under reduced pressure afforded 734 mg of 2-methyl-2-(tetrahydro-pyran-4-ylmethanesulfonyl)-propionic acid.
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