Potassium Hydroxide → 7-(5-{3-chloro-4-[(1-methylethyl)oxy]phenyl}-1,2,4-oxadiazol-3-yl)-1-methyl-1H-indole-3-carboxylic acid

Participants

Reaction Conditions

Reaction Steps

To a solution of 7-(5-{3-chloro-4-[(1-methylethyl)oxy]phenyl}-1,2,4-oxadiazol-3-yl)-1-methyl-1H-indole-3-carbaldehyde (D61) (1.4 g) in THF (20 mL) was added KMnO4 (1.1 g) and aqueous KOH (10 mL). The reaction mixture was stirred at 55° C. overnight. After cooled to room temperature, the mixture was diluted with THF (30 mL), and filtered. The filtrate was concentrated and the aqueous suspension was acidified with aqueous HCl (2 M) to pH 5-6. The resulting white solid was collected, washed with water, dried in vacuo to give the crude compound, which was purified by column chromatography (10% ethyl acetate in hexane) to afford 7-(5-{3-chloro-4-[(1-methylethyl)oxy]phenyl}-1,2,4-oxadiazol-3-yl)-1-methyl-1H-indole-3-carboxylic acid (D95) as a white solid (1.3 g). δH (DMSO-d6, 400 MHz): 1.36 (6H, d), 3.74 (3H, s), 4.88 (1H, m), 7.35 (1H, dd), 7.45 (1H, d), 7.53 (1H, dd), 8.12 (1H, d), 8.14 (1H, d), 8.20 (1H, d), 8.32 (1H, dd), 12.15 (1H, s). MS (ES): C21H18ClN3O4 requires 411. found 412.1 (M+H+).

Provenance & Evidence