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

Temperature

10 °C

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.

1. customA 500 mL, three-necked flask equipped with a thermocouple, condenser, and addition funnel
2. temperatureThe resulting mixture was heated to reflux
3. temperatureAn analysis of the reaction mixture after 3 h at reflux, by the above methods
4. customresulted in the formation of a yellow precipitate
5. filtrationthe solid was collected by filtration
6. washwas washed with water (100 mL)
7. customdried under high vacuum at 60-65° C. for 24 h

ORD record

ord-8b58c092db7243f980eda0a563b1a2cf

Source dataset

uspto-grants-2001_12

DOI

10.6084/m9.figshare.5104873.v1

Patent number

US06326501B1