5416-80-8

95-20-5

68-12-2

5416-80-8

GENERAL PROCEDURE: Phosphorus oxychloride (POCl3, 1.73 mL, 18.6 mmol) was slowly added dropwise to stirred and ice-bath cooled N,N-dimethylformamide (DMF, 5.0 mL). The reaction mixture was stirred at 1-5 °C for 20 min before a solution of 2-methylindole (15.5 mmol) in DMF (5.0 mL) was slowly added. The resulting reaction mixture was gradually warmed to 35 °C and maintained at this temperature for 40 min. The mixture was then cooled to room temperature. Ice (about 10 g) was added to the mixture, followed by the addition of 5 M sodium hydroxide (NaOH) solution (31 mL, 155 mmol). The reaction mixture was heated at 95 °C for 30 min and then cooled to room temperature. Ice (~10 g) was again added to the mixture and the resulting reaction mixture was stirred for 30 minutes. 2-Methylindole-3-carbaldehyde was collected by filtration and washed several times with distilled water.