Sodium Hydroxide → 3-[7-(5-{5-chloro-6-[(1-methylethyl)oxy]-3-pyridinyl}-1,2,4-oxadiazol-3-yl)-6-fluoro-1H-indol-3-yl]propanoic acid

Participants

Reaction Conditions

Reaction Steps

To a solution of ethyl 3-[7-(5-{5-chloro-6-[(1-methylethyl)oxy]-3-pyridinyl}-1,2,4-oxadiazol-3-yl)-6-fluoro-1H-indol-3-yl]propanoate (D149) (260 mg) in isopropanol (7 mL) and water (7 mL) was added NaOH (5.5 mL, 0.5 M aq) at room temperature. The reaction suspension was stirred at 90° C. for 2 hours, and the solution turned clear. Isopropanol was removed in vacuo and water (8 mL) was added to the residue. The aqueous solution was acidified to pH=1 and extracted with ethyl acetate (3×10 mL). The combined organic phase was dried over sodium sulphate. The organic solution was concentrated and purified by MDAP to afford 3-[7-(5-{5-chloro-6-[(1-methylethyl)oxy]-3-pyridinyl}-1,2,4-oxadiazol-3-yl)-6-fluoro-1H-indol-3-yl]propanoic acid (E107) (174 mg) as a white solid. δH (DMSO-d6, 400 MHz): 1.34 (6H, d), 2.57 (2H, t), 2.92 (2H, t), 5.40 (1H, m), 7.03 (1H, m), 7.22 (1H, d), 7.74 (1H, m), 8.82 (1H, d), 9.08 (1H, d), 11.04 (1H, s), 12.08 (1H, s). MS (ES): C21H18ClFN4O4 requires 444; found 445.2 (M+H+).

Provenance & Evidence