Hydrochloric Acid → 3-Methyl-2-(3-pyridyl)indole hydrochloride

Participants

Reaction Steps

3-Methyl-2-pyridin-3-yl-1H-indole hydrochloride is synthesized based on the method described in U.S. Pat. No. 3,468,894. A flask is charged with 3-propionylpyridine (1.004 g, 7.279 mmol), phenylhydrazine hydrochloride (1.010 g, 6.915 mmol) and ethanol (15 mL). The mixture is heated to reflux for 1 h and cooled to room temperature. To a portion of the reaction mixture (2.5 mL) is added HCl (4M in dioxane, 1 mL, 4 mmol) and the mixture is heated to reflux. After 3 h, the mixture is concentrated in vacuo. The solid is dissolved in the minimum amount of boiling methanol (17 mL) and allowed to cool slowly to room temperature. A solid precipitates and after cooling to 0° C. for 30 min, the yellow solid is filtered off, washed with portions of cold methanol and dried under high vacuum to give 3-methyl-2-pyridin-3-yl-1H-indole hydrochloride as yellow needles. 1H NMR (400 MHz, MeOD) δ ppm (HCl salt) 2.56 (s, 3H), 7.09-7.13 (m, 1H), 7.23-7.26 (m, 1H), 7.43 (d, J=8.1 Hz, 1H), 7.63 (d, J=8.1 Hz, 1H), 8.14-8.18 (m, 1H), 8.74 (d, J=5.8 Hz, 1H), 8.83-8.85 (m, 1H), 9.08 (s, 1H).

Provenance & Evidence