DABCO (20 mg) was added to a solution of ethyl 3-[7-(5-{5-methyl-6-[(1-methylethyl)oxy]-3-pyridinyl}-1,2,4-oxadiazol-3-yl)-1H-indol-3-yl]propanoate (D119) (188 mg) in dimethyl carbonate (2 mL) and DMF (0.2 mL). The resulting mixture was stirred at reflux for 1 day. After cooling, the reaction was quenched with water, and extracted with EtOAc for 3 times. The combined organic solution was washed with brine, dried over anhydrous sodium sulfate. The dried solution was concentrated. The residue was dissolved in iPrOH (8 mL) and water (8 mL). Sodium hydroxide (40 mg) was added to the mixture. The resulting mixture was heated at 70° C. for 30 mins. Then 0.5 M HCl solution was added until pH was about 6. The solvent was concentrated, and the residue was dissolved in water. The precipitated solid was purified by Mass Directed Auto Prep to afford 3-[1-methyl-7-(5-{5-methyl-6-[(1-methylethyl)oxy]-3-pyridinyl}-1,2,4-oxadiazol-3-yl)-1H-indol-3-yl]propanoic acid (E17) (19 mg) as a white solid. δH (DMSO-d6, 400 MHz): 1.35 (6H, d), 2.23 (3H, s), 2.60 (2H, t), 2.96 (2H, t), 3.62 (3H, s), 5.40 (1H, m), 7.16 (1H, d), 7.19 (1H, s), 7.43 (1H, d), 7.79 (1H, d), 8.29 (1H, s), 8.84 (1H, d), 12.12 (1H, br s). MS (ES): C23H24N4O4 requires 420; found 421.2 (M+H+).
