3-{(4-Methyl-cyclohexanecarbonyl)-[4-(4-nitro-benzoyloxy)-cyclohexyl]-amino}-5-phenyl-thiophene-2-carboxylic acid methyl ester (44 mg, 0.073 mmol) was dissolved in a 4:1 mixture of dioxane:H2O (1 ml) and then LiOH 1N (365 ul, 0.365 mmol) was added. After 4 hours of stirring at room temperature, solvents were removed and then partitioned between 5 ml of H2O acidified to pH 4 and 5 ml of EtOAc. The organic layer was separated and the aqueous phase was washed twice with ethyl acetate (2×5 mL). The combined ethyl acetate layer was dried (Na2SO4) and concentrated. The residue was purified by preparative chromatography (10% MeOH/CH2Cl2) to obtain 15 mg (47%) of 3-[(4-Hydroxy-cyclohexyl)-(4-methyl-cyclohexanecarbonyl)-amino]-5-phenyl-thiophene-2-carboxylic acid.
