[CH3:1][CH:2]([CH3:13])[CH2:3][C:4](=[N:11][OH:12])[C:5]1[CH:10]=[CH:9][CH:8]=[CH:7][CH:6]=1.[Br:14][CH2:15][CH2:16]Br.[OH-].[Na+]>[Br-].C([N+](CCCC)(CCCC)CCCC)CCC.O>[Br:14][CH2:15][CH2:16][O:12][N:11]=[C:4]([C:5]1[CH:10]=[CH:9][CH:8]=[CH:7][CH:6]=1)[CH2:3][CH:2]([CH3:13])[CH3:1]A mixture of the above oxime (5.0 g, 28 mmol), 1,2-dibromoethane (25 ml) and N,N,N,N-tetrabutylammoniumbromide (1.0 g, 3 mmol) was cooled to 0° C. and 9N sodium hydroxide (35 ml) was carefully added. The mixture was stirred vigorously at room temperature for 3 days. Water (50 ml) was added and the resulting mixture extracted with dichloromethane (2×100 ml). To the combined organic phases was added water (50 ml) and pH in the aqueous phase was adjusted to 5 with 10% aqueous citric acid. The organic phase was washed with water (50 ml) and brine (50 ml) and dried (MgSO4). The solvent was evaporated in vacuo to give 8.0 g of 3-methylbutyrophenone O-(2-bromoethyl)oxime.
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