Triisopropyl borate → 1H-Pyrrolo(2,3-b)pyridin-4-ylboronic acid

Temperature

20 °C

4-Bromo-1H-pyrrolo[2,3-b]pyridine (0.944 g, 4.79 mmol) in THF (10 ml) was added dropwise to sodium hydride (0.240 g, 5.99 mmol) in THF (10 ml) at 20° C. under nitrogen. The resulting mixture was stirred at 20° C. for 10 minutes. The reaction mixture was cooled to −78° C. and n-butyllithium in hexanes (2.396 mL, 5.99 mmol) was added dropwise over 10 minutes and stirred at −78° C. for 10 minutes. Triisopropyl borate (3.32 mL, 14.37 mmol) was added dropwise over 2 minutes and the reaction mixture allowed to warm to RT over 1.5 hours. The reaction mixture was quenched with water (10 ml) and C18 silica gel was added (10 g) and the mixture was concentrated in vacuo. The resultant solid was purified by reverse phase flash silica chromatography, eluting with a gradient of 5 to 40% acetonitrile in water. Pure fractions were evaporated to afford 1H-pyrrolo[2,3-b]pyridin-4-ylboronic acid (0.590 g, 76%); m/z: (ES+) MH+, 162.88.

1. temperatureThe reaction mixture was cooled to −78° C.
2. stirringstirred at −78° C. for 10 minutes
3. temperatureto warm to RT over 1.5 hours
4. customThe reaction mixture was quenched with water (10 ml)
5. additionC18 silica gel was added (10 g)
6. concentrationthe mixture was concentrated in vacuo
7. customThe resultant solid was purified by reverse phase flash silica chromatography
8. washeluting with a gradient of 5 to 40% acetonitrile in water
9. customPure fractions were evaporated

ORD record

ord-31a10012c5fa46efb65028e0b04db185

Source dataset

uspto-grants-2012_08

DOI

10.6084/m9.figshare.5104873.v1

Patent number

US08252802B2