[C:1]([C:6]1([S:12][CH2:13][C:14]2[CH:19]=[CH:18][C:17]([O:20][CH3:21])=[CH:16][CH:15]=2)[CH2:11][CH2:10][CH2:9][CH2:8][CH2:7]1)([O:3]CC)=[O:2].[OH-].[Na+].C(O)C.O.[OH-].[Li+]>O.O1CCCC1>[C:1]([C:6]1([S:12][CH2:13][C:14]2[CH:19]=[CH:18][C:17]([O:20][CH3:21])=[CH:16][CH:15]=2)[CH2:11][CH2:10][CH2:9][CH2:8][CH2:7]1)([OH:3])=[O:2]Dissolve 1-(carboethoxy)-1-(4-methoxybenzylthio)cyclohexane (1.45 g, 4.7 mmol) in water (2.5 mL) and tetrahydrofuran (10 mL). Treat with 2.5N sodium hydroxide (4 mL, 10 mmol). Heat at 60° C. for 2 hours, add 95% ethanol (10 mL) and lithium hydroxide monohydrate (0.42 g, 10 mmol) Heat to a gentle reflux for 20 hours, cool and evaporate the solvent in vacuo. Partition between water (50 mL) and ether (50 mL). Separate the aqueous phase and acidify to pH 1. Extract with methylene chloride (50 mL), dry (Na2SO4) and evaporate the solvent in vacuo to give 1-(carboxy)-1-(4-methoxybenzylthio)cyclohexane as a white solid (1.21 g, 92%).
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