Reacción #2304275

Ecuación de reacción

hydrobromic acid

5-amino-2-methylphenol

sodium nitrite

hydrobromic acid

→

title compound

5-Bromo-2-methylphenol

Disolventes

water

water

Condiciones de reacción

Tratamiento posterior

1. 1
   Temperaturathe reaction was subsequently heated
2. 2
   Temperaturaat reflux for 2 hours
3. 3
   Extracciónwas extracted with ethyl acetate (2×200 mL)
4. 4
   Lavadothe combined organic extracts were washed with aqueous potassium hydroxide solution (˜1 M, 200 mL)
5. 5
   Secadodried (magnesium sulphate)
6. 6
   Concentraciónconcentrated under reduced pressure
7. 7
   OtroThe crude product was purified by column chromatography [SiO2; light petroleum to 4:1 light petroleum-ethyl acetate]

Procedimiento

To a solution of 5-amino-2-methylphenol (10 g, 81.2 mmol) in hydrobromic acid (40 mL, 48% solution) and water (50 mL) at 0° C. was added a solution of sodium nitrite (5.6 g, 81.2 mmol) in water (15 mL) and the mixture stirred at this temperature for 30 minutes. To this was added copper (I) bromide (11.6 g, 81.2 mmol) in hydrobromic acid (15 mL, 48% solution) and the reaction was subsequently heated at reflux for 2 hours. Upon cooling to room temperature the resulting mixture was extracted with ethyl acetate (2×200 mL) and the combined organic extracts were washed with aqueous potassium hydroxide solution (˜1 M, 200 mL), dried (magnesium sulphate) and concentrated under reduced pressure. The crude product was purified by column chromatography [SiO2; light petroleum to 4:1 light petroleum-ethyl acetate] to give the title compound as a colourless oil, which crystallised to give fine colourless needles upon standing overnight (4 g, 26%). Rf=0.26 [4:1 light petroleum-ethyl acetate]. 1H NMR δ 2.21 (3 H, s), 4.89-4.95 (1 H, br, s), 6.96-6.97 (1 H, br, m), 6.99-7.00 (2 H, m).

Fuente