Hydrochloric Acid → (4-Methoxy-3-phenylphenyl)boronic acid

Temperature

-75 °C

To a mixture of 2-phenyl-4-bromoanisole (26.00 g, 0.0988 mol) in THF (240 mL) cooled to −75° C. under an atmosphere of argon was added n-BuLi (68 mL, 1.6 M, 0.109 mol) dropwise maintaining a temperature below −70° C. The resulting suspension was stirred for 30 minutes and triisopropylborate (34.2 mL, 27.87 g, 0.148 mol) was added dropwise. The mixture was warmed to 0° C. over 1 hour and 1.0 N HCl (190 mL) was slowly added and allowed to warm to RT overnight. The mixture was diluted with ether and the layers separated, the aqueous layer was extracted ether (3×) and the organic layers combined. The resulting organic layer was washed with water, brine and dried (Mg2SO4). The mixture was filtered, evaporated and the resulting reddish residue solidified overnight. The solid was collected and washed with hexane and dried under high vacuum to afford 17.29 g of 3-phenyl-4-methoxyphenyl boronic acid (77%). 1H NMR (300 MHz; DMSO-d6): δ 3.78 (s, 3H), 7.07 (d, J=8.1 Hz, 1H), 7.28–7.50 (m, 5H), 7.72–7.80 (m, 2H), 7.92 (brs, 2H).

1. temperaturedropwise maintaining a temperature below −70° C
2. temperatureThe mixture was warmed to 0° C. over 1 hour
3. temperatureto warm to RT overnight
4. customthe layers separated
5. extractionthe aqueous layer was extracted ether (3×)
6. washThe resulting organic layer was washed with water, brine
7. dry with materialdried (Mg2SO4)
8. filtrationThe mixture was filtered
9. customevaporated
10. waitthe resulting reddish residue solidified overnight
11. customThe solid was collected
12. washwashed with hexane
13. customdried under high vacuum

ORD record

ord-515307020a944ee49b87cd2b242c426f

Source dataset

uspto-grants-2006_12

DOI

10.6084/m9.figshare.5104873.v1

Patent number

US07153875B2