Hydrochloric Acid → 1-isopropyl-6-methoxy-1H-indole-4-carboxylic acid

Participants

Reaction Conditions

Reaction Steps

Freshly prepared sodium methoxide (500 mg in 5 mL methanol) was added to a stirred suspension of 6-bromo-1-isopropyl-1H-indole-4-carboxylic acid methyl ester (500 mg, 1.68 mmol) and CuI (480 mg, 2.53 mmol) in NMP (8 mL) and then heated at 120° C. for 2 h. The reaction mixture was cooled to room temperature, diluted with water (5 mL) and acidified with 1N HCl. The reaction mixture was filtered through Celite and washed with EtOAc (5 mL). Separated the EtOAc layer from filtrate, dried over anhydrous Na2SO4 and concentrated under reduced pressure to furnish the crude 1-isopropyl-6-methoxy-1H-indole-4-carboxylic acid (700 mg), which was used in the next stage without further purification. 1H NMR (400 MHz, DMSO-d6): δ 1.44 (d, J=6.4 Hz, 6H), 3.84 (s, 3H), 4.80-4.76 (m, 1H), 6.87 (d, 1H), 7.33 (t, J=3.2 Hz, 2H), 7.49 (d, J=3.2 Hz, 1H), 12.65 (bs, 1H). LCMS (ES+): m/z=234.11 [M+H].

Provenance & Evidence