Water → Indole

Participants

Reaction Steps

To a stirred and cooled (0° C.) solution of ethyl-5-chloroindole-2-carboxylate (1.052 g, 4.70 mmol) in DMF (25 mL) under N2, was added NaH (60% in oil, 230 mg, 5.64 mmol) portionwise. After the end of gas evolution, phenylsulfonyl chloride (0.72 mL, 5.64 mmol) was added. The reaction mixture was stirred for 1H (TLC monitoring, eluant dichloromethane). A little amount of water was added carefully and DMF was evaporated. Crude residue was dissolved in EtOAc and washed with water and brine. After drying and evaporation of solvents the compound was purified by chromatography on silica gel (eluant:cyclohexane/EtOAc 9/1 to 7/3) to afford protected indole (1.547 g, 90% yield. Off-white solid; 1H NMR (d6-DMSO) δ 1.30 (t, J=7.2 Hz, 3H), 4.35 (q, J=7.2 Hz, 2H), 7.37 (s, 1H), 7.53 (dd, J=2.2 and 9.1 Hz), 7.62-7.77 (m, 3H), 7.80 (d, J=2.2 Hz, 1H), 7.99 (m, 2H), 8.06 (d, J=9.1 Hz); MS (ESI, E1+) m/z=364 (MH+).

Provenance & Evidence