[Cl:1][CH:2]([C:8]([CH3:10])=O)[C:3]([O:5][CH2:6][CH3:7])=[O:4].[H-].[Na+].BrCC1[CH:20]=[CH:19][C:18]([CH2:21][C:22](=[O:24])[CH3:23])=[CH:17][CH:16]=1.Cl>CN(C)C=O>[CH2:21]([C:18]1[CH:19]=[CH:20][C:10]([CH2:8][CH:2]([Cl:1])[C:3]([O:5][CH2:6][CH3:7])=[O:4])=[CH:16][CH:17]=1)[C:22]([CH3:23])=[O:24]
A solution of ethyl 2-chloroacetoacetate (8.25 g) in dry dimethylformamide was treated with sodium hydride (1.3 g and stirred at ambient temperature for 0.5 h. A solution of 4-(bromomethyl)phenylpropan-2-one, ethylene ketal (12.0 g) in dry dimethylformamide (20 ml) was then added and the mixture was heated at 70° C. for 4 h. The reaction mixture was cooled, poured into ice/water, acidified with 2N-hydrochloric acid, extracted with ethyl acetate (4×50 ml) and the combined organic extracts dried (magnesium sulphate), filtered and evaporated in vacuo. The residue was dissolved in ethanol and treated at 0°-5° C. with barium hydroxide hydrate (7.7 g). The mixture was stirred for 0.5 h, poured into ice/water, extracted with ethyl acetate (3×50 ml) and the combined organic extracts dried (magnesium sulphate), filtered and evaporated in vacuo to leave a red oil, which was purified by column chromatography on silica using diethyl ether: petroleum ether (60°-80°) (30:70) as eluent to give ethyl 3-(4-acetonylphenyl)-2-chloropropionate, ethylene ketal, (6.0 g).
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