Triisopropyl borate → 3-(1-Methylpiperidin-4-yl)-1H-Indole-5-Boronic Acid

Temperature

0 °C

To a slurry of potassium hydride (20% suspension in mineral oil, 0.72 g, 3.58 mmol) in 7 mL of anhydrous tetrahydrofuran at 0° C. was slowly added dropwise 5-bromo-3-(1-methylpiperidin-4-yl)-1H-indole (1.0 g, 3.41 mmol) in 7 mL of anhydrous tetrahydrofuran. After stirring at 0° C. for 30 minutes, the mixture was cooled to −78° C., and tert-butyl lithium (1.7M in pentane, 7.51 mmol, 4.42 mL) was added dropwise. After 15 minutes, a solution of triisopropyl borate (6.82 mmol, 2.0 eq, 1.57 mL) in 2 mL of anhydrous tetrahydrofuran was added dropwise. The stirred mixture was allowed to warm to room temperature, and was quenched with 5N aqueous hydrochloric acid. The aqueous phase was extracted with diethyl ether, and the ether extracts were separated, washed with brine, dried over sodium sulfate, filtered and concentrated in vacuo to give a crude white solid which was treated with hexanes, sonicated for 30 minutes, filtered and dried to give 0.252 g (29%) of the title compound as an amorphous white material which was used without further purification.

1. temperaturethe mixture was cooled to −78° C.
2. waitAfter 15 minutes
3. temperatureto warm to room temperature
4. customwas quenched with 5N aqueous hydrochloric acid
5. extractionThe aqueous phase was extracted with diethyl ether
6. customthe ether extracts were separated
7. washwashed with brine
8. dry with materialdried over sodium sulfate
9. filtrationfiltered
10. concentrationconcentrated in vacuo
11. customto give a crude white solid which
12. customsonicated for 30 minutes
13. filtrationfiltered
14. customdried

ORD record

ord-4bb00c960662401b9bc6e443d0706c84

Source dataset

uspto-grants-2002_03

DOI

10.6084/m9.figshare.5104873.v1

Patent number

US06358972B1