Methyl iodide → N-Methylcarbazole

Temperature

80 °C

To a solution of carbazole (3.34 g, 20 mmol) in DMF (80 mL) at 0° C. was added NaH (0.72 g, 30 mmol). After heating at 80° C. for 1.5 h, iodomethane (3.4 g, 24 mmol) was added dropwise. The resulting mixture was kept at 80° C. overnight. After cooling down to 0° C., the reaction mixture was carefully quenched with water and extracted with ethyl acetate three times. The combined organic phase was washed with water and brine. Then the organic layer was dried over anhydrous sodium sulfate and the solvent was removed. The residue was purified by silica gel chromatography using petroleum ether and ethyl acetate as eluent (EA:PE=1:5) to afford methylated carbazole 1b (2.78 g) as yellow oil in 77% yield. 1H NMR (400 MHz, CDCl3) δ 8.08 (d, J=8.0 Hz, 2H), 7.46 (t, J=8.0 Hz, 2H), 7.36 (d, J=8.0 Hz, 2H), 7.22 (t, J=8.0 Hz, 2H), 3.79 (s, 3H).13C NMR (400 MHz, CDCl3) δ 140.9, 125.6, 122.7, 120.2, 118.8, 108.4, 28.9.

1. temperatureAfter cooling down to 0° C.
2. customthe reaction mixture was carefully quenched with water
3. extractionextracted with ethyl acetate three times
4. washThe combined organic phase was washed with water and brine
5. dry with materialThen the organic layer was dried over anhydrous sodium sulfate
6. customthe solvent was removed
7. customThe residue was purified by silica gel chromatography

ORD record

ord-5217b3123fcd45d9be21aa43d56db5e2

Source dataset

uspto-grants-2016_02

DOI

10.6084/m9.figshare.5104873.v1

Patent number

US09255933B2