Purify the hydrochloride by recrystallisation from isopropanol/di-isopropyl ether (charcoal) and recrystallise it twice more. The free base, b 55-56o/11mm, 60-63o/23mm and 90o/56mm, is relatively unstable and should be converted to the hydrochloride immediately, by dissolving in isopropanol and bubbling dry HCl through the solution at 0o, filtering off the hydrochloride and recrystallising it. The picrate has m 107.3-107.8o (from EtOH) [Cason J Org Chem 24 247 1959, Wright et al. J Am Chem Soc 70 3098 1948]. [Beilstein 20 III/IV 66.]
