[CH3:1][O:2][CH2:3][CH2:4][CH2:5][CH2:6]/[C:7](/[C:10]1[CH:15]=[CH:14][CH:13]=[CH:12][CH:11]=1)=[N:8]/[OH:9].[Br:16][CH2:17][CH2:18]Br.[OH-].[Na+].Cl>[Br-].C([N+](CCCC)(CCCC)CCCC)CCC.ClCCl.O>[Br:16][CH2:17][CH2:18][O:9][N:8]=[C:7]([C:10]1[CH:15]=[CH:14][CH:13]=[CH:12][CH:11]=1)[CH2:6][CH2:5][CH2:4][CH2:3][O:2][CH3:1]A mixture of the above oxime (6.5 g, 31 mmol), 1,2-dibromoethane (27 ml, 31 mmol), N,N,N,N-tetrabutylammonium bromide (0.96 g, 3 mmol) and 12N sodium hydroxide (30 ml) was cooled on an icebath with vigorous stirring until the initial exotherm had subsided. The mixture was then stirred at ambient temperature for 16 h. Water (50 ml), 4 N hydrochloric acid (50 ml) and dichloromethane (100 ml) were added and the phases were separated. To the organic phase was added water (50 ml) and pH in the aqueous phase adjusted to 5 with 10% aqueous citric acid. The organic phase was washed with water (50 ml), brine (25 ml) and dried (Na2SO4). The solvent was evaporated in vacuo to give 9.1 g of 5-methoxy-1-phenyl-1-pentanone O-(2-bromoethyl)oxime.
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