Recrystallise the bromide from MeOH/Et2O. [Horner & Brich Justus Liebigs Ann Chem 710 1978.] The chloride is recrystallised from EtOAc/n-hexane, m 198-199o [] D -8.67o (c 1.45, MeOH). [Julia et al. J Chem Soc, Perkin Trans 1 574 1981, Beilstein 13 IV 1890.]
