Hydrogen Bromide → 2-Bromo-3-nitrophenol

Temperatur

0 °C

2-Amino-3-nitrophenol (24.6 g, 160 mmol) is suspended in mixture of water (150 ml) and dioxane (75 ml). At 80° C. hydrobromic acid (48%, 85 ml) is added dropwise. This mixture is stirred at reflux temperature for 30 minutes and then cooled to 0° C. A solution of sodium nitrite (11.04 g, 160 mmol) in water (100 ml) is added dropwise and the reaction mixture is stirred at 0° C. for 1 hour. The reaction mixture is added dropwise to a solution of CuBr (26.4 g, 184 mmol) in water (150 ml) and hydrobromic acid (48%, 85 ml). The resulting suspension is stirred at 0° C. for 30 minutes and at 60° C. for 1 hour. The reaction mixture is cooled to room temperature, diluted with water and extracted three times with ethyl acetate. The combined organic phases are dried over sodium sulfate and concentrated. The residue is purified by column chromatography on silica gel (eluent: dichloromethane/cyclohexane 7:3) to give 2-Bromo-3-nitro-phenol (19.5 g, 56% yield) as a yellow solid. 1H-NMR (CDCl3, 400 MHz): 7.50 (d, 1H), 7.35 (t, 1H), 7.25 (d, 1H), 6.05 (s, 1H) ppm.

1. temperatureat reflux temperature for 30 minutes
2. stirringthe reaction mixture is stirred at 0° C. for 1 hour
3. stirringThe resulting suspension is stirred at 0° C. for 30 minutes and at 60° C. for 1 hour
4. temperatureThe reaction mixture is cooled to room temperature
5. extractionextracted three times with ethyl acetate
6. dry with materialThe combined organic phases are dried over sodium sulfate
7. concentrationconcentrated
8. customThe residue is purified by column chromatography on silica gel (eluent: dichloromethane/cyclohexane 7:3)

ORD-Eintrag

ord-72ccec5520784e22985dd67bb469c85f

Quelldatensatz

uspto-grants-2013_09

DOI

10.6084/m9.figshare.5104873.v1

Patentnummer

US08524896B2