Hydrogen Bromide → 5-Bromo-2-methylphenol

5-Amino-2-methylphenol (5 g, 0.04 mol) was dissolved in HBr (20 mL) and H2O (20 mL) was added dropwise maintaining a temperature below 0° C. The resulting mixture was stirred for 5 min and a solution of NaNO2 (2.76 g, 0.04 mol) in H2O (7.5 mL) was added dropwise. The mixture was stirred for 30 min below 0° C. Then a solution of cuprous bromide (5.73 g, 0.04 mol) in HBr (7.5 mL) cooled to 0° C. was added dropwise. The resulting mixture was warmed to RT and then refluxed for 2 h. The reaction was cooled and filtered through celite. The filtrate was diluted with water and extracted with EtOAc. The organic extract was dried over Na2SO4, and concentrated under reduced pressure. The residue was purified by column chromatography (2.5% EtOAc-97.5% Hexane) to give the pure title compound (1.57 g, 20%). 1H NMR (500 MHz, CDCl3): δ 6.97 (s, 3H), 4.89 (s, 1H), 2.19 (s, 3H).

1. temperaturemaintaining a temperature below 0° C
2. stirringThe mixture was stirred for 30 min below 0° C
3. additionwas added dropwise
4. temperaturerefluxed for 2 h
5. temperatureThe reaction was cooled
6. filtrationfiltered through celite
7. additionThe filtrate was diluted with water
8. extractionextracted with EtOAc
9. extractionThe organic extract
10. dry with materialwas dried over Na2SO4
11. concentrationconcentrated under reduced pressure
12. customThe residue was purified by column chromatography (2.5% EtOAc-97.5% Hexane)

ORD record

ord-efc38553f19849af8266be6d757f7491

Source dataset

uspto-grants-2011_10

DOI

10.6084/m9.figshare.5104873.v1

Patent number

US08044052B2