Peracetic Acid → 3-Bromo-6-chloro-2-fluorophenol

Temperatur

-20 °C

A solution of 1-bromo-4-chloro-2-fluorobenzene (20.4 g, 0.100 mol) in tetrahydrofuran (THF; 50 mL) was slowly added to lithium diisopropylamide (LDA; 0.125 mol) in THF (600 mL) at −50° C. After addition, the solution was warmed to −20° C. and then cooled to −50° C. A solution of trimethyl borate (13.5 g, 0.130 mol) in THF (20 mL) was added slowly and the temperature was warmed to −20° C. The mixture was then cooled to −70° C. and a solution of peracetic acid (32% in acetic acid, 0.150 mol) was slowly added and the mixture was warmed to ambient temperature. Water (250 mL) was added and the solution was extracted with ethyl acetate (2×200 mL). The combined organic phases were dried and concentrated. The black oil was purified by column chromatography (20% ethyl acetate in hexanes) to give 3-bromo-6-chloro-2-fluorophenol (14.1 g, 0.063 mol) 1H NMR (CDCl3): δ 7.05 (m, 2H), 5.5 (br s, 1H).

1. additionAfter addition
2. temperaturecooled to −50° C
3. temperaturethe temperature was warmed to −20° C
4. temperatureThe mixture was then cooled to −70° C.
5. temperaturethe mixture was warmed to ambient temperature
6. extractionthe solution was extracted with ethyl acetate (2×200 mL)
7. customThe combined organic phases were dried
8. concentrationconcentrated
9. customThe black oil was purified by column chromatography (20% ethyl acetate in hexanes)

ORD-Eintrag

ord-18a3d36067c548a8b93a25d7a9dd5ea2

Quelldatensatz

uspto-grants-2009_05

DOI

10.6084/m9.figshare.5104873.v1

Patentnummer

US07538214B2