Hydrochloric Acid → HCID 59855523, compound

Temperature

-78 °C

To a solution of 1,3-dihydro-1-(4-chloro-2-methoxyphenyl)-2,1-benzoxaborole as a white solid (AN-2551, 0.5 g, 1.93 mmol) in anhydrous methylene chloride (25 mL) at −78° C. Was added dropwise a solution of boron tribromide in methylene chloride (1.0 M, 1.93 mL, 1.93 mmol) under nitrogen. The mixture was stirred at −78° C. for 1 h and at room temperature for 4 h. Then the reaction flask was re-cooled to −78° C. and methanol (10 mL) was added. The reaction mixture was warmed to room temperature and 6N HCl (2 mL) was added. The mixture was evaporated to give a residue that was mixed with ethyl acetate. The organic layer was washed with brine, dried and evaporated. The residue was purified by flash column chromatography eluted with a mixed solvent of hexanes and ethyl acetate (4:1, v/v) to provide the desired compound 1,3-dihydro-1-(4-chloro-2-hydroxyphenyl)-2,1-benzoxaborole as a white solid (0.32 g, 1.31 mmol) in 67.8% yield. M.p. 96-98° C.; 1H NMR (MeOH-d4, 300 MHz): δ 8.19 (d, J=7.5 Hz, 1H), 7.92 (d, J=8.1 Hz, 1H), 7.52-7.51 (m, 2H), 7.43-7.38 (m, 1H), 6.96-6.91 (m, 1H), 6.89-6.88 (m, 1H) and 5.41 (s, 2H) ppm.

1. customat −78° C
2. temperatureThen the reaction flask was re-cooled to −78° C.
3. temperatureThe reaction mixture was warmed to room temperature
4. customThe mixture was evaporated
5. customto give a residue that
6. washThe organic layer was washed with brine
7. customdried
8. customevaporated
9. customThe residue was purified by flash column chromatography
10. washeluted with a mixed solvent of hexanes and ethyl acetate (4:1

ORD record

ord-ba041fa046834567a183ee8c2ef6402a

Source dataset

uspto-grants-2008_12

DOI

10.6084/m9.figshare.5104873.v1

Patent number

US07465836B2