Acetic Acid → 1-Carbamoyl-1H-indole-3-carboxylic acid benzyl ester

Participants

Reaction Steps

To a solution of 1H-indole-3-carboxylic acid benzyl ester (3.5 g, 13.9 mmol) in THF (70 mL) at 5° C., was added NaH (60% in mineral oil, 557 mg, 13.9 mmol). The mixture was stirred at 5° C. for 30 min before slow dropwise addition of chlorosulfonyl isocyanate (2.42 mL, 27.9 mmol) maintaining the temperature between 5° C. and 10° C. The pale yellow solution was further stirred at RT for 3.5 h. Acetic acid (22.5 mL) was added (exothermic), and the resulting solution was stirred at RT for 1.5 h before addition of ice cubes and water (100 mL). The white thick suspension was stirred at RT for 30 min and the precipitate was filtered-off, taken up in MeOH and filtered-off again to afford the desired compound. 1H-NMR (400 MHz, DMSO): δ (ppm) 8.64 (s, 1H), 8.29 (d, 1H), 8.04 (d, 1H), 7.90 (m, 2H), 7.50 (d, 2H), 7.42 (t, 2H), 7.36-7.30 (m, 3H), 5.38 (s, 2H).

Provenance & Evidence