Water → ethyl 5-acetamido-1H-indole-2-carboxylate

Participants

Reaction Steps

Ethyl 5-nitroindole-2-carboxylate (1, 1 g, 4.27 mmol) was dissolved in ethyl acetate (100 mL) and 5% Pd/C (100 mg) was added. The reaction mixture was hydrogenated for 1 h at room temperature at a pressure of 60 lb/inch2. The reaction mixture was filtered and the solvent was removed in vacuo. A grey powder of 2 was obtained and was used without further purification. A solution of acetyl chloride (174 mL, 2.44 mmol) in dichloromethane (5 mL) was added to a solution of 2 (0.417 g, 2.04 mmol) in DMF (2 mL), dichloromethane (5 mL) and triethylamine (339 mL, 2.44 mmol) dropwise at 0° C. under N2. The reaction mixture was allowed to warm up to room temperature and stirred for 2 h. Water (30 mL) was added and the mixture was extracted with ethyl acetate (40 mL×2). The solution was dried using sodium sulfate and solvent was removed in vacuo. A grey powder 3 was obtained (437 mg, 87% yield). An analytical sample was recrystallized in ethyl acetate. mp: 202°-203° C. 1H NMR (DMSO-d6, ppm): 11.74 (s, 1 H, NH), 9.78 (s, 1 h, NH), 7.99 (s, 1 H, Ar--H), 7.38-7.30 (m, 2 H, Ar--H), 7.09-7.08 (m, 1 H, Ar--H), 4.36-4.30 (q, 2 H, J=7.0, 13.7 Hz, CH2 CH3). 2.03 (s, 3 H, CH3CO), 1.36-1.31 (t, 3 H, J=7.0 Hz, CH2CH3). Anal. (C13H14N2O3), C, H, N.

Provenance & Evidence