[CH3:1][CH:2]([C:4](=[O:8])[CH:5]([CH3:7])[CH3:6])[CH3:3].[Br:9]Br.Br>C(Cl)(Cl)Cl.C(=O)([O-])[O-].[Na+].[Na+]>[Br:9][C:2]([CH3:3])([C:4](=[O:8])[CH:5]([CH3:7])[CH3:6])[CH3:1]2,4-dimethyl-3-pentanone (330 g, 2.89M) in chloroform (800 ml) was cooled in an ice water bath to 10° C. and bromine (462 g, 2.89M) was added slowly over 3 hours. After the addition, a slow stream of nitrogen was introduced to the mixture and HBr gas was slowly evolved from the flask. The nitrogen was left bubbling over a weekend to remove all of the HBr produced and then sodium carbonate (5 g) was added. The reaction mixture was then filtered through Celite and the chloroform removed using a rotary evaporator. Distillation of the crude product using a 1′ (2.54 cm) vigreux gave essentially pure 2-bromo-2,4-dimethyl-3-pentanone (478 g, 2.47M) b.pt. 50-52° C./10 mb (1000 Nm−2).
Wird geladen…
