Triisopropyl borate → 5-Ethoxymethoxy-benzofuran-2-boronic acid

To a stirred solution of 5-ethoxymethoxy-benzofuran (3) (265 mg, 1.38 mmol) in THF (5 mL) at −78° C., n-butyllithium (2.5M solution in hexane, 0.56 mL, 1.44 mmol) was added drop wise. After the reaction mixture was stirred for 1 hour, triisopropylborate (0.635 mL, 2.76 mmol) was added slowly and the stirring was continued for additional 20 minutes at −78° C. The reaction mixture was quenched with saturated ammonium chloride solution (10 mL) and was allowed to warm to room temperature. Water (10 mL) was added and the resulting mixture was extracted in diethyl ether (2×50 mL). The combined extracts were washed with brine, dried over MgSO4, and concentrated under reduced pressure. Purification of the crude product by recrystallization from ethyl acetate and hexane afforded the desired compound (4) (170 mg) as a white solid.

1. waitthe stirring was continued for additional 20 minutes at −78° C
2. customThe reaction mixture was quenched with saturated ammonium chloride solution (10 mL)
3. additionWater (10 mL) was added
4. extractionthe resulting mixture was extracted in diethyl ether (2×50 mL)
5. washThe combined extracts were washed with brine
6. dry with materialdried over MgSO4
7. concentrationconcentrated under reduced pressure
8. customPurification of the crude product
9. customby recrystallization from ethyl acetate and hexane

ORD record

ord-d66d5be0d58e4bfeb2c30059bfd91c4c

Source dataset

uspto-grants-2016_04

DOI

10.6084/m9.figshare.5104873.v1

Patent number

US09309267B2