Thionyl Chloride → 1H-indole-3-carbohydrazide

Participants

Reaction Steps

Indole-3-carboxylic acid (500 mg, 3.1 mmol) was stirred at room temperature with thionyl chloride (5 mL, 68 mmol) for 20 hours. The solution was concentrated under vacuum and the residue was taken up in ether (10 mL) and concentrated to dryness (repeated three times) to ensure removal of the thionyl chloride. The resulting solid was dissolved in ether (5 mL) and added to an ice cooled solution of hydrazine hydrate (600 mg, 12 mmol) in tetrahydrofuran (5 mL). After 30 minutes, the solid was collected by filtration, washed with 5% NaOH and water, and dried under vacuum at 50° C. The crude hydrazide was recrystallized from 95% ethanol to provide the title compound. 1H NMR (300 MHz, CD3OD) δ 7.11-7.22 (m, 2 H), 7.42 (dd, J=7, 2 Hz, 1 H), 7.83 (s, 1 H), 8.02-8.08 ppm (m, 1 H); MS (DCI/NH3) m/z 176 (M+H)+.

Provenance & Evidence