Diisopropylamine → 2-Fluoro-5-methoxypyridine-3-boronic acid

Temperatur

0 °C

To a 100 mL round-bottomed flask, diisopropylamine (Aldrich, 1.40 mL, 9.99 mmol) was dissolved into THF (6 mL). nBuLi (Aldrich, 2.5 M in hexanes, 3.60 mL, 8.99 mmol) was added slowly at 0° C. The mixture was stirred at 0° C. for 30 min then cooled to −78° C. 2-fluoro-5-methoxypyridine (0.520 g, 4.09 mmol) in 4 mL of THF was added slowly, and the mixture was stirred at that temperature for 40 min. Triisopropyl borate (Aldrich, 2.07 mL, 8.99 mmol) in a total of 4 mL of THF was added slowly and the mixture was stirred at −78° C. for 5 min. The cold bath was removed and the reaction mixture was stirred at room temperature for 1 h. 1 N NaOH (20 mL) was added to the mixture to quench the reaction. The layers were separated and the aqueous phase was treated with 5 N HCl to adjust the pH to around 5. The aqueous phase was extracted with EtOAc (2×20 mL). The combined organic phases were dried over sodium sulfate, filtered and concentrated in vacuo to afford 0.593 g of tan color solid. This material was used in the next step without further purification.

1. temperaturethen cooled to −78° C
2. stirringthe mixture was stirred at that temperature for 40 min
3. stirringthe mixture was stirred at −78° C. for 5 min
4. customThe cold bath was removed
5. stirringthe reaction mixture was stirred at room temperature for 1 h
6. addition1 N NaOH (20 mL) was added to the mixture
7. customto quench
8. customthe reaction
9. customThe layers were separated
10. additionthe aqueous phase was treated with 5 N HCl
11. extractionThe aqueous phase was extracted with EtOAc (2×20 mL)
12. dry with materialThe combined organic phases were dried over sodium sulfate
13. filtrationfiltered
14. concentrationconcentrated in vacuo
15. customto afford 0.593 g of tan color solid
16. customThis material was used in the next step without further purification

ORD-Eintrag

ord-1c78278a360b4081835657ec07a8e3d2

Quelldatensatz

uspto-grants-2013_01

DOI

10.6084/m9.figshare.5104873.v1

Patentnummer

US08362241B2