Phosphorus tribromide → 6-(1-Bromoethyl)quinoxaline
Reaction equation
O[CH:2]([C:4]1[CH:5]=[C:6]2[C:11](=[CH:12][CH:13]=1)[N:10]=[CH:9][CH:8]=[N:7]2)[CH3:3].P(Br)(Br)[Br:15]>CCOCC>[Br:15][CH:2]([C:4]1[CH:5]=[C:6]2[C:11](=[CH:12][CH:13]=1)[N:10]=[CH:9][CH:8]=[N:7]2)[CH3:3]Participants
4
Reactant 2
Product 1
Reagents, catalysts & solvents 1
Procedure
To a solution of 6-(1-hydroxyethyl)quinoxaline (0.4 g, 0.23 mMol) in ether (4 mL) and hexanes (2 mL) at zero degrees was added phosphorus tribromide (0.196 mL, 2.07 mMol) and the mixture stirred at zero degrees for one hour and then allowed to warm to room temperature. After two hours at room temperature the reaction mixture was poured over ice and then partitioned between ethyl acetate (100 mL) and water (100 mL). The aqueous layer was discarded and the organics washed with saturated sodium bicarbonate, then dried (MgSO4), and concentrated to dryness to yield 20 mg (37% yield) of 6-(1-bromo-ethyl)-quinoxaline as a light yellow oil. 1H NMR (CDCl3): δ=8.79 (m, 2H), 8.06 (d, 1H, J=9.0 Hz), 8.04 (d, 1H, J=2.2 Hz), 7.85 (dd, 1H, J=9.0, 2.2 Hz), 5.34 (q, 1H, J=6.9 Hz), 2.10 (d, 3H, J=6.9 Hz).