Hydrochloric Acid → 4-bromo-6-methoxy-1H-indole

Participants

Reaction Conditions

Reaction Steps

N-(3-Bromo-5-methoxy-phenyl)-N-hydroxy-acetamide (360 mg, 1.384 mmol) was dissolved in vinyl acetate (1.92 mL, 20.8 mmol), and Li2PdCl4 (18.2 mg, 69 μmol) was added. The reaction mixture was stirred for 3 hours 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 20 mL of MeOH. 1N aqueous NaOH (2.61 mL, 2.61 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 (1.3 mL, 2.6 mmol), followed by addition of 500 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 (20 g SiO2, EtOAc/heptane in a gradient from 0/100 to 1/4) to yield the title compound as a liquid (145 mg, 46% over 2 steps). 1H-NMR (600 MHz; DMSO-d6): 11.26 (brs, 1H), 7.31 (dd, 1H), 6.93 (d, 1H), 6.90 (d, 1H), 6.29 (dd, 1H), 3.78 (s, 3H).

Provenance & Evidence