Phosphorus oxybromide → 4-Bromo-2-tert-butylpyridine
Reaction equation
[C:1]([C:5]1[NH:6][CH:7]=[CH:8][C:9](=O)[CH:10]=1)([CH3:4])([CH3:3])[CH3:2].P(Br)(Br)([Br:14])=O>>[Br:14][C:9]1[CH:8]=[CH:7][N:6]=[C:5]([C:1]([CH3:4])([CH3:3])[CH3:2])[CH:10]=1Participants
3
Conditions
- Temperature
- 120 °C
Procedure
A mixture of 2-tert-butyl-1H-pyridin-4-one (Step 1.5) (4.25 g, 28 mmol) and POBr3 (8.88 g, 31 mmol, 1.1 eq) is heated to 120° C., stirred for 15 min, allowed to cool, quenched by addition of a saturated solution of NaHCO3 and extracted with DCM/MeOH (9:1, v/v). The organic phase is washed with a saturated solution of NaHCO3, dried (Na2SO4), filtered and concentrated. The residue is purified by silica gel column chromatography (Hex/EtOAc, 95:5) to afford 5.18 g of the title compound as a yellow oil: ESI-MS: 214.0/216.0 [M+H]+; tR=2.49 min (System 1); TLC: Rf=0.35 (Hex/EtOAc, 1:1).