Hydrazine hydrate (1:1) → N-(3-bromo-5-methoxy-phenyl)-N-hydroxylamine

3-Bromo-5-nitroanisole (1.5 g, 6.46 mmol) was dissolved in 20 mL of 1,2-dichloroethane and 20 mL of ethanol, and the mixture was cooled to 0° C. Raney-Ni (30 mg) and hydrazine hydrate (0.79 mL, 12.9 mmol) were added within 10 minutes, and the reaction was stirred for 4 hours at room temperature, when 50 mg of Raney-Ni were added. After stirring for 16 hours, another 50 mg of Raney-Ni were added, and after further stirring for 4 hours, another 50 mg of Raney-Ni were added. Stirring was continued for 4 hours at room temperature, when the starting material had completely disappeared. The reaction mixture was filtered through celite, and the solvent was removed under reduced pressure to provide N-(3-bromo-5-methoxy-phenyl)-N-hydroxylamine as a solid, which was dissolved in 80 ml of toluene. Sodium bicarbonate (597 mg, 7.11 mmol) was added, followed by acetyl chloride (0.51 mL, 7.11 mol). Stirring at room temperature was continued for 20 hours. The reaction mixture was then filtered and concentrated under reduced pressure. The residue was purified by column chromatography (40 g SiO2; EtOAc/heptane in a gradient from 5/95 to 1/3) to yield the title compound as a solid (360 mg, 21% over 2 steps). LC-MS at 254 nm; [M+H] 260.0/262.1; Rt 0.82 min; (LCMS method 1). 1H-NMR (600 MHz; DMSO-d6): 10.85 (brs, 1H), 7.50 (dd, 1H), 7.26 (dd, 1H), 6.94 (dd, 1H), 3.77 (s, 3H), 2.22 (s, 3H).

1. stirringAfter stirring for 16 hours
2. stirringafter further stirring for 4 hours
3. stirringStirring
4. waitwas continued for 4 hours at room temperature
5. filtrationThe reaction mixture was filtered through celite
6. customthe solvent was removed under reduced pressure

ORD record

ord-243c4595c9cb44ce8e0ae99bb4ec0f48

Source dataset

uspto-grants-2016_05

DOI

10.6084/m9.figshare.5104873.v1

Patent number

US09334271B2