Lithium Hydroxide → 4,6-dimethyl-1H-indole-2-carboxylic Acid

Participants

Reaction Steps

A mixture of 4,6-dimethyl-1H-indole-2-carboxylic acid ethyl ester (22 g, 0.1 mol) and lithium hydroxide (4.8 g, 0.2 mol) in 400 ml of ethanol was heated at reflux overnight. The solvent was removed under reduced pressure and the residue was dissolved in water and neutralized with 10% HCl to pH<3. The resulting precipitates were filtered and washed with water and dried in vacuo at 40° C. to give white solids (18 g, 95%). 1H NMR (DMSO-d6, 400 MHz): δ 12.73 (brs, 1H, exchangeable with D2O, NH), 11.55 (brs, 1H, exchangeable with D2O, NH), 7.06 (s, 1H), 7.03 (s, 1H), 6.69 (s, 1H), 2.44 (s, 3H), 2.35 (s, 3H).

Provenance & Evidence