C=C1OC(=O)C1.BrBr.[CH:9]([OH:22])([C:16]1[CH:21]=[CH:20][CH:19]=[CH:18][CH:17]=1)[C:10]1[CH:15]=[CH:14][CH:13]=[CH:12][CH:11]=1.[Br:23][CH2:24][C:25](=[O:30])[CH2:26][C:27](Br)=[O:28]>C(Cl)Cl.C(N(CC)CC)C>[Br:23][CH2:24][C:25](=[O:30])[CH2:26][C:27]([O:22][CH:9]([C:16]1[CH:17]=[CH:18][CH:19]=[CH:20][CH:21]=1)[C:10]1[CH:15]=[CH:14][CH:13]=[CH:12][CH:11]=1)=[O:28]In 10.5 ml of methylene chloride there were dissolved 2.1 g of diketene, and at a temperature not exceeding -30° C., a solution of 4.0 g of bromine in 12.5 ml of methylene chloride was added dropwise to the solution with stirring. After the dropwise addition was completed, the mixture was maintained at 0° C. for 10 minutes. Separately, 3.68 g of benzhydrol were dissolved in 25 ml oof methylene chloride, followed by addition of 2.02 g of triethylamine. Under stirring at a temperature not exceeding -30° C., the solution of bromoacetoacetyl bromide prepared above was added dropwise. After the dropwise addition, the mixture was stirred at 0° C. for 40 minutes, at the end of which time it was washed with water. After drying over magnesium sulfate the solvent was distilled off under reduced pressure, whereupon 6.99 g of benzhydryl 4-bromo-3-oxobutyrate were obtained.
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