[Cl:1][C:2]1[CH:7]=[CH:6][C:5]([C:8]2([CH2:16][S:17][CH2:18][C:19]([O:21]CC)=[O:20])[O:13][CH2:12][C:11]([CH3:15])([CH3:14])[CH2:10][O:9]2)=[CH:4][CH:3]=1.[Li+].[OH-]>C1COCC1.O>[Cl:1][C:2]1[CH:7]=[CH:6][C:5]([C:8]2([CH2:16][S:17][CH2:18][C:19]([OH:21])=[O:20])[O:9][CH2:10][C:11]([CH3:15])([CH3:14])[CH2:12][O:13]2)=[CH:4][CH:3]=1Ethyl ({[2-(4-chlorophenyl)-5,5-dimethyl-1,3-dioxan-2-yl]methyl}thio)acetate (3.36 g, 9.36 mmol) was dissolved in THF (45 ml) and cooled to 0° C. LiOH (0.79 g, 18.8 mmol) in water (12 ml) was added and the mixture was stirred for 18 h at room temperature. The solvents were evaporated. The crude product was extracted between water and diethyl ether. The aqueous layer was acidified using 2M HCl to pH 6 and extracted twice with CH2Cl2. The combined CH2Cl2 layers were dried (Na2SO4) and concentrated under reduced pressure to afford 2.98 g (96%) of the title compound as an yellow oil. 1H-NMR (CDCl3, 300 MHz): δ 0.62 (s, 3H), 1.34 (s, 3H), 2.95 (s, 2H), 3.34 (s, 2H), 3.45 (s, 4H), 7.4 (m, 4H)
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