It is recrystallised repeatedly from de-aerated cyclohexane in the dark or from pet ether/*C6H6 and forms yellow needles. It is soluble in H2O, EtOH and *C6H6, and forms a monohydrate which loses H2O at 60o. The picrate has m 207o(dec). [Nozoe et al. J Am Chem Soc 76 3352 1954, Nukai et al. Bull Chem Soc Jpn 40 1967 1967, Beilstein 23 III/IV 1216.]
