6-Fluoroindole

1065183-63-2

399-51-9

The general procedure for the synthesis of 6-fluoroindole from the compound (CAS: 1065183-63-2) is as follows: Intermediate 110: Synthesis of 6-fluoro-1H-indole. In a 1 L high-pressure reactor, (4-fluoro-2-nitrophenyl)acetaldehyde semicarbazone (27.0 g, 0.110 mol) was suspended in THF (750 mL) with stirring. To this suspension was added a slurry of Rh/C (5 wt%) in toluene and Fe(OAc)2 (2.9 g, 0.017 mol), where the amount of Rh was 3.5 g, 0.002 mol. The reactor was charged with H2 to 50 atm and the reaction was stirred for 2 days at room temperature. After completion of the reaction, the mixture was filtered through a diatomaceous earth pad and washed with MeOH (150 mL). The filtrate was concentrated to give a black oil, which was partitioned between DCM (500 mL) and water (300 mL). The organic layer was separated and the aqueous phase was extracted with DCM (2 x 200 mL). The organic phases were combined, washed with brine (200 mL), dried over anhydrous Na2SO4 and concentrated under reduced pressure. The residue was dissolved in DCM (100 mL) and decolorized by a fast silica gel column. After filtration, the filtrate was concentrated under reduced pressure to give 12.9 g (87% yield) of 6-fluoroindole. 1H NMR (300 MHz, DMSO-d6) δ: 11.11 (1H, s), 7.49 (1H, dd, J = 8.6, 5.5 Hz), 7.30 (1H, t, J = 2.4 Hz), 7.13 (1H, dd, J = 10.3, 2.4 Hz), 6.81 (1H, ddd, J = 11.0, 7.6, 2.4 Hz), 6.40-6.38 (1H, m).