Lithium hydroxide, monohydrate → 1-isopropyl-6-methoxy-1H-indole-4-carboxylic acid

Participants

Reaction Steps

To a stirred solution of 1-isopropyl-6-methoxy-1H-indole-4-carboxylic acid methyl ester (320 mg, 1.29 mmol) in THF (2 mL) was added LiOH.H2O (160 mg, 3.88 mmol) in water (2 mL) at room temperature and heated at reflux for 2 h. The THF was removed under reduced pressure and the resulting aqueous layer was acidified with 1 N HCl (pH˜6) and extracted with ethyl acetate (2×5 mL). The combined organic layer was dried over anhydrous Na2SO4 and concentrated to afford 1-isopropyl-6-methoxy-1H-indole-4-carboxylic acid (210 mg). 1H NMR (400 MHz, DMSO-d6): δ 1.42 (d, 6H), 3.88 (s, 3H), 4.85 (m, 1H), 6.81 (d, J=2.8 Hz, 1H), 7.26 (s, 2H), 7.45 (s, 1H), 12.68 (s, 1H).

Provenance & Evidence