Diisopropylamine → 5-(Benzyloxy)-2-fluoropyridin-3-ylboronic acid

Temperatur

0 °C

A solution of diisopropylamine (Aldrich) (0.33 mL, 2.16 mmol) in THF (5 mL) was cooled to 0° C. and treated with n-butyllithium (Aldrich) (0.94 mL, 2.36 mmol). The resulting mixture was stirred at 0° C. for 30 min and then cooled to −78° C. 5-(Benzyloxy)-2-fluoropyridine (Aldrich) (0.200 g, 0.982 mmol) in THF (3 mL) was added dropwise and the solution was stirred at −78° C. for 40 min before being treated with triisopropyl borate (Aldrich) (0.50 mL, 2.16 mmol) in THF (2 mL). After the addition, the cooling bath was removed and the reaction mixture slowly warmed up to rt and and was stirred for 1 h. The reaction mixture was quenched with 5% NaOH (10 mL). The aqueous layer was separated and acidified to pH 5 using 5 N HCl. The resulting mixture was extracted with EtOAc (2×15 mL). The combined organic extracts were dried over MgSO4 and concentrated to give the crude product as yellow solid (0.210 g). m/z (ESI, +ve ion) 248.0 (M+H)+. 1H NMR (300 MHz, d4-MeOH) δ 6.60 (br. s., 1H); 6.36 (br. s., 1H); 6.00-6.24 (m, 5H); 3.87 (s, 2H).

1. temperaturecooled to −78° C
2. stirringthe solution was stirred at −78° C. for 40 min
3. additionAfter the addition
4. customthe cooling bath was removed
5. temperaturethe reaction mixture slowly warmed up to rt
6. stirringwas stirred for 1 h
7. customThe reaction mixture was quenched with 5% NaOH (10 mL)
8. customThe aqueous layer was separated
9. extractionThe resulting mixture was extracted with EtOAc (2×15 mL)
10. dry with materialThe combined organic extracts were dried over MgSO4
11. concentrationconcentrated

ORD-Eintrag

ord-bddac5209f014291b05b7f612111ff80

Quelldatensatz

uspto-grants-2013_01

DOI

10.6084/m9.figshare.5104873.v1

Patentnummer

US08362241B2