Hydrochloric Acid → 5-Chloro-2-(2,2,2-trifluoro-ethoxy)-phenylboronic acid

Temperature

-70 °C

To a mixture of 2-bromo-4-chloro-1-(2,2,2-trifluoro-ethoxy)-benzene (3.0 g, 10.4 mmol) and tetrahydrofuran (60 ml), cooled to −70° C., was added a solution of isopropylmagnesium chloride in tetrahydrofuran (2 M, 5.7 ml). After warming to 0° C., the mixture was stirred for 1 hour. After cooling to −70° C., the mixture was treated with trimethylborate (1.2 g, 11.4 mmol). After stirring at room temperature for 12 hours, the mixture was treated with hydrochloric acid (2 M, 20 ml). After stirring for 40 minutes, the mixture was extracted with ethyl acetate (2×50 ml). The combined extracts were dried over magnesium sulfate and concentrated under reduced pressure. The residue was triturated with hexane (50 ml). Filtration and drying of the solid under reduced pressure gave 5-chloro-2-(2,2,2-trifluoro-ethoxy)-phenylboronic acid (1.6 g, 61% yield). 1H NMR (acetone-d6) δ 4.86 (q, 2H, J=8.5 Hz, CH2), 7.12 (d, 2H, J=4.6 Hz, OH), 7.20 (d, 1H, J=8.8 Hz, Ar), 7.49 (dd, 1H, J=8.8 Hz, J=2.8 Hz, Ar), 7.76 (d, 1H, J—2.7 Hz, Ar).

1. temperatureAfter warming to 0° C.
2. temperatureAfter cooling to −70° C.
3. stirringAfter stirring at room temperature for 12 hours
4. stirringAfter stirring for 40 minutes
5. extractionthe mixture was extracted with ethyl acetate (2×50 ml)
6. dry with materialThe combined extracts were dried over magnesium sulfate
7. concentrationconcentrated under reduced pressure
8. customThe residue was triturated with hexane (50 ml)
9. filtrationFiltration
10. customdrying of the solid under reduced pressure

ORD record

ord-abfc7fff02714648a50487ff850dc82a

Source dataset

uspto-grants-2008_09

DOI

10.6084/m9.figshare.5104873.v1

Patent number

US07419984B2