To a solution of ethyl 4-[[4-(4-isopropylphenyl)-2,2-dimethyl-(2H)-thiochromen-6-yl]-ethynyl]-benzoate (Compound 228, 89.0 mg, 0.19 mmol) in 3.0 mL THF and 3.0 mL EtOH was added NaOH (80.0 mg, 2.0 mmol, 2.0 mL of a 1M aqueous solution). The resulting solution was heated to 45° C. and stirred overnight. Upon cooling to room temperature the reaction mixture was acidified with 10% aqueous HCl and extracted with EtOAc. The combined organic layers were washed with H2O, saturated aqueous NaCl, and dried (Na2SO4) before removing the solvent under reduced pressure. The residual solid was recrystallized from CH3CN to give 78.0 mg (93%) of the title compound as a pale-yellow solid. 1H NMR (300 MHz, d6 -acetone) δ: 8.00 (2H, d, J=8.4 Hz), 7.58 (2H, d, J=8.4 Hz), 7.45-7.21 (7H, m), 5.93 (1H, s), 2.95 (1H, hept, J=7.0 Hz), 1.47 (6H, s), 1.25 (6H, d, J=7.0 Hz).
