Acetyl chloride → (2,4-Dichloro-3-methoxyphenyl)boronic acid

To a solution of 1-bromo-2,4-dichloro-3-methoxybenzene (5.12 g, 20 mmol) in diethyl ether cooled to −70° C. was added 2.5M n-butyl lithium (8.8 mL, 22 mmol) in portions keeping the temperature below −60° C. The resulting reaction mixture was then stirred for 10 minutes before triisopropylborate (6.9 mL, 30 mmol) was added in portions keeping the temperature below −60° C. The reaction mixture was then allowed to warm to room temperature and acetyl chloride (60 mmol) was added. The reaction mixture was stirred for an hour at room temperature and concentrated. The residue was partitioned between ethyl acetate and 1N NaOH (40 mL) and the organic phase was extracted with additional 1N NaOH (10 mL). The sodium hydroxide extracts were combined, ice was added, and the solution was acidified to pH 3-4 with concentrated HCl. The product was then extracted with ethyl acetate and the organic phase was dried and concentrated to yield 2,4-dichloro-3-methoxyphenylboronic acid (3.27 g, 14.8 mmol): 1H NMR (CDCl3): δ 8.44 (br s, 2H), 7.42 (d, 1H), 7.15 (d, 1H), 3.8 (s, 3H).

1. customthe temperature below −60° C
2. customThe resulting reaction mixture
3. additionwas added in portions
4. customthe temperature below −60° C
5. concentrationconcentrated
6. customThe residue was partitioned between ethyl acetate and 1N NaOH (40 mL)
7. extractionthe organic phase was extracted with additional 1N NaOH (10 mL)
8. additionice was added
9. extractionThe product was then extracted with ethyl acetate
10. customthe organic phase was dried
11. concentrationconcentrated

ORD-Eintrag

ord-3472fe11f58a49288663707c6c1e0337

Quelldatensatz

uspto-grants-2011_02

DOI

10.6084/m9.figshare.5104873.v1

Patentnummer

US07888287B2