It can be recrystallised from Et2O, *C6H6/pet ether (b 40-60o) or toluene and distilled in a vacuum. It has been purified by dissolving in Et2O, drying over K2CO3, filtering, evaporating to a small volume, cooling in ice and collecting the plates. Store them in the presence of KOH (i.e. CO2—free atm). [Karrer & Ehrhardt Helv Chim Acta 34 3203 1951, Oeda Bull Chem Soc Jpn 13 465 1938.] The picrate has m 141-141.5o (from EtOH/pet ether). The hydrogen oxalate has m 177o, 161-162o [Hunt & McHale J Chem Soc 2073 1957]. The racemate has m 87-88o from *C6H6/pet ether (75-77o from Et2O), and the hydrochloride has m 139-141o [Fodor et al. J Chem Soc 1858 1951]. [Beilstein 13 IV 1920.]
