To a solution of ethyl-4-[2,2-dimethyl-4-(5-methyl-thien-2-yl)-benzo[1,2-g]-chrom-3-en-7-yl]benzoate (Compound 11, 18 mg, 0.03 mmol) in methanol (0.5 mL) and THF (1 mL), was added LiOH in water (1M solution, 0.3 mL). The reaction mixture was stirred for 20 hours, the solvent was removed under reduced pressure, the residue dissolved in water (5 mL), washed with ether (10 ml) and the aqueous layer was acidified to PH 5. The aqueous layer was extracted with ethyl acetate (3×20 mL). The combined organic layers were washed with brine, dried, and the solvent was removed under reduced pressure to afford the title compound as a pale yellow solid.
