Triisopropyl borate → [4-(Trifluoromethyl)pyridin-3-yl]boronic acid

Temperatur

-78 °C

n-Butyllithium (2.5 M in hexane, 2 mL) is added to a mixture of 3-bromo-4-(trifluoromethyl)pyridine (Matrix Scientific, 1 g, 0.022 mol) and triisopropylborate (1.25 mL) in anhydrous THF (9 mL) at −78° C. under nitrogen. The reaction mixture is stirred at −78° C. for 3.5 hr before warming gradually to room temperature. The reaction is quenched with water (9 mL). The organic solvent is removed under reduced pressure. The resulting aqueous phase is treated with NaOH (10 N) to obtain pH 10, washed with diethyl ether (1×8 mL), and aqueous phase is acidified to pH 5 using acetic acid. The solution is extracted with EtOAc (1×25 mL) and the organic layer is dried and evaporated to dryness to give the title compound (0.150 g, 15% yield). LCMS m/z=192.2 [M+H]+, tR=0.36 min.

1. temperaturebefore warming gradually to room temperature
2. customThe reaction is quenched with water (9 mL)
3. customThe organic solvent is removed under reduced pressure
4. additionThe resulting aqueous phase is treated with NaOH (10 N)
5. customto obtain pH 10
6. washwashed with diethyl ether (1×8 mL), and aqueous phase
7. extractionThe solution is extracted with EtOAc (1×25 mL)
8. customthe organic layer is dried
9. customevaporated to dryness

ORD-Eintrag

ord-6eba614c617a4b55acfbe1acbae64e49

Quelldatensatz

uspto-grants-2014_10

DOI

10.6084/m9.figshare.5104873.v1

Patentnummer

US08871767B2