반응 #2304275

반응 방정식

hydrobromic acid

5-amino-2-methylphenol

sodium nitrite

hydrobromic acid

→

title compound

5-Bromo-2-methylphenol

용매

water

water

반응 조건

후처리

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

실험 절차

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).

출처