Dimethylformamide → 1-Methyl-4-nitro-1H-indole

Participants

Reaction Conditions

Reaction Steps

A 500 mL, three-necked flask equipped with a thermocouple, condenser, and addition funnel was charged with 5-nitroindole (20.0 g, 12.3 mmol), potassium carbonate (4.0 g, 29 mmol), N,N-dimethylformamide (80 mL) and dimethyl carbonate (22 mL, 26.14 mmol). The resulting mixture was heated to reflux. The reaction was monitored by HPLC or TLC (solvent system: 30% ethyl acetate in heptane). An analysis of the reaction mixture after 3 h at reflux, by the above methods, failed to detect any remaining 5-nitroindole. The reaction mixture was then cooled to 10±5° C. and diluted with water (160 mL) which resulted in the formation of a yellow precipitate. After the mixture was stirred at room temperature for 2 h, the solid was collected by filtration, then was washed with water (100 mL) and dried under high vacuum at 60-65° C. for 24 h to give 1-methyl-4-nitroindole (21.1 g, 97.1%) as a yellow solid.

Provenance & Evidence