[Br:1][CH2:2][C:3]([C:5]1[CH:10]=[CH:9][C:8]([Br:11])=[CH:7][C:6]=1[CH3:12])=[O:4].[CH2:13]([OH:17])[CH2:14]CC.CC1C=CC(S(O)(=O)=O)=CC=1.C1C=CC=CC=1>O.C(O)CO>[Br:1][CH2:2][C:3]1([C:5]2[CH:10]=[CH:9][C:8]([Br:11])=[CH:7][C:6]=2[CH3:12])[O:17][CH2:13][CH2:14][O:4]1
To a stirred mixture of 78.8 parts of 2-bromo-1-(4-bromo-2-methylphenyl)-1-ethanone and 200 parts of butanol are added 3 parts of 4-methylbenzenesulfonic acid and 225 parts of benzene. Then there are added dropwise 33.5 parts of 1,2-ethanediol. Upon completion, stirring is continued overnight at reflux temperature with water-separator. The reaction mixture is evaporated and the residue is dissolved in 2,2'-oxybispropane. The solution is stirred with 15 parts of a concentrated sodium hydroxide solution. The layers are separated and the aqueous phase is extracted with 2,2'-oxybispropane. The combined organic layers are washed with water (till neutralization), dried, filtered and evaporated. The solid residue is crystallized from methanol, yielding 30.5 parts of 2-(bromomethyl)-2-(4-bromo-2-methylphenyl)-1,3-dioxolane; mp. 86° C.
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