Tetrahydrofuran → 4-Methylpyridine-2-boronic acid

To a stirred solution of 2-bromo-4-methylpyridine (0.5 g, 2.9 mmol) in diethyl ether (5 mL) was added a 1M solution of ethylmagnesium bromide in tetrahydrofuran (3.48 mL, 3.48 mmol) slowly at 0° C. over 10 minutes under a nitrogen atmosphere. The reaction mixture was slowly warmed to room temperature and stirred for 3 hours. To the above mixture was added tri-isopropyl borate (0.65 g, ˜0.8 mL, 3.48 mmol) dropwise at 0° C. The reaction mixture was slowly warmed to room temperature and stirred for another 1 hour. The reaction was quenched with saturated aqueous ammonium chloride solution (6 mL) at 0° C. and then extracted with diethyl ether (50 mL×4). The combined organic layers were dried over anhydrous sodium sulfate, filtered and concentrated under reduced pressure to give 4-methylpyridine-2-boronic acid, which was used without further purification.

1. temperatureThe reaction mixture was slowly warmed to room temperature
2. stirringstirred for another 1 hour
3. customThe reaction was quenched with saturated aqueous ammonium chloride solution (6 mL) at 0° C.
4. extractionextracted with diethyl ether (50 mL×4)
5. dry with materialThe combined organic layers were dried over anhydrous sodium sulfate
6. filtrationfiltered
7. concentrationconcentrated under reduced pressure

ORD-Eintrag

ord-3d8c87a8429144ef920335f0c18dce79

Quelldatensatz

uspto-grants-2012_04

DOI

10.6084/m9.figshare.5104873.v1

Patentnummer

US08163781B2