To a stirred solution of ethyl 4-[1-(5-methyl-thien-2-yl)-3,4-dihydro-4,4-dimethyl-anthracen-8-yl]-benzoate (Compound 3, 33 mg, 0.07 mmol), in THF (2 mL), MeOH (2 mL), was added aqueous LiOH (1M solution, 0.2 mL, 0.2 mmol). After 16 hours, water (2 mL) was added to the reaction mixture, about 50% of the organic solvents were removed by distillation, and the mixture was further diluted the mixture with water (5 mL). The reaction mixture was washed with ether (10 mL) and the aqueous layer was acidified to pH 4 and extracted with ethyl acetate (3×20 mL). The combined organic layers were washed water (5 mL), brine (10 mL), dried with MgSO4 and the solvent was removed by distillation. The product was recrystallized from acetone to obtain the title compound as a white solid.
