Reaktion #67497

Reaktionsgleichung

hydrobromic acid

2-Amino-3-nitrophenol

dioxane

hydrobromic acid

sodium nitrite

→

2-Bromo-3-nitro-phenol

Ausbeute 56.0%

Lösungsmittel

water

water

water

water

Reaktionsbedingungen

Aufarbeitung

1. 1
   Temperaturat reflux temperature for 30 minutes
2. 2
   workup.STIRRINGthe reaction mixture is stirred at 0° C. for 1 hour
3. 3
   workup.STIRRINGThe resulting suspension is stirred at 0° C. for 30 minutes and at 60° C. for 1 hour
4. 4
   TemperaturThe reaction mixture is cooled to room temperature
5. 5
   Extraktionextracted three times with ethyl acetate
6. 6
   TrocknenThe combined organic phases are dried over sodium sulfate
7. 7
   Einengenconcentrated
8. 8
   SonstigeThe residue is purified by column chromatography on silica gel (eluent: dichloromethane/cyclohexane 7:3)

Vorschrift

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.

Quelle