Reaktion #421654

Reaktionsgleichung

NaCNBH3

HOAc

5-bromopyridin-3-amine

acetone

→

5-bromo-N-isopropylpyridin-3-amine

Lösungsmittel

MeOH

Reaktionsbedingungen

Aufarbeitung

1. 1
   workup.STIRRINGstirred at room temperature overnight
2. 2
   SonstigeThe MeOH was removed under vacuum
3. 3
   Sonstigethe residue was partitioned between EtOAc and saturated aqueous NaHCO3
4. 4
   TrocknenThe organic layer was dried over MgSO4
5. 5
   Sonstigeevaporated under vacuum
6. 6
   SonstigeThe crude product was purified on a silica gel column (100% hexane→90:10 hexane:EtOAc)

Vorschrift

To a solution of 5-bromopyridin-3-amine (XXV) (535 mg, 3.09 mmol) in MeOH (62 mL) was added acetone (296 μL, 4.02 mL). The pH was adjusted to 4 using HOAc and stirred for 30 min. NaCNBH3 (272 mg, 4.33 mmol) was added and stirred at room temperature overnight. The MeOH was removed under vacuum and the residue was partitioned between EtOAc and saturated aqueous NaHCO3. The organic layer was dried over MgSO4 and evaporated under vacuum. The crude product was purified on a silica gel column (100% hexane→90:10 hexane:EtOAc) to produce 5-bromo-N-isopropylpyridin-3-amine (XLVI) as an oil which slowly solidified into an off-white solid (309 mg, 1.44 mmol, 47% yield). 1H NMR (DMSO-d6, 500 MHz) δ ppm 1.12 (d, J=6.3 Hz, 6H), 3.55-3.59 (m, 1H), 6.03 (d, J=7.9 Hz, 1H), 7.05-7.06 (m, 1H), 7.75 (d, J=2 Hz, 1H), 7.90 (d, J=2 Hz, 1H); ESIMS found C8H11BrN2 m/z 215 (M+H).

Quelle