Hydrochloric Acid → 4-chloro-6-fluoro-1H-indole

Temperature

60 °C

N-(3-Chloro-5-fluoro-phenyl)-N-hydroxy-acetamide (200 mg, 982 μmol) was dissolved in vinyl acetate (1.81 mL, 19.6 mmol), and Li2PdCl4 (25.7 mg, 98 μmol) was added. The reaction mixture was stirred for 3 hr at 60° C. The reaction mixture was diluted with EtOAc and brine; the organic layer was separated and concentrated under reduced pressure to give a solid, which was dissolved in 8 mL of MeOH. 1N aqueous NaOH (1.89 mL, 1.89 mmol) was added, and the reaction was stirred for two hours at room temperature. The reaction mixture was quenched by addition of 2 N aqueous HCl (0.95 mL, 1.9 mmol), followed by addition of 300 mg of Na2CO3. After addition of 50 mL of EtOAc, the organic layers were separated, dried over Na2SO4, filtered, and concentrated. The residue was purified by column chromatography (12 g SiO2; EtOAc/heptane in a gradient from 0/100 to 1/4) to yield the title compound as a liquid (72 mg, 45% over 2 steps). 1H-NMR (DMSO-d6): 11.52 (brs, 1H), 7.45 (d, 1H), 7.20 (d, 1H), 7.05 (d, 1H), 6.45 (d, 1H).

1. customthe organic layer was separated
2. concentrationconcentrated under reduced pressure
3. customto give a solid, which
4. stirringthe reaction was stirred for two hours at room temperature
5. customthe organic layers were separated
6. dry with materialdried over Na2SO4
7. filtrationfiltered
8. concentrationconcentrated
9. customThe residue was purified by column chromatography (12 g SiO2

ORD record

ord-3556d2ca8f51459cb61d9895a9ad4fa4

Source dataset

uspto-grants-2016_05

DOI

10.6084/m9.figshare.5104873.v1

Patent number

US09334271B2