23231-91-6

Dissolve it in MeOH or acetone, and crystallise by adding distilled water. It also crystallises from EtOH or EtOAc. Dry it in a vacuum at 70o. It has also been successively recrystallised from isopropyl ether, isopropyl ether/acetone (50:1) and isopropyl ether/EtOH (50:1) for 10hours, then isopropyl ether/acetone for 1hour, and dried at 65o under reduced pressure for 1 week. [Kondo et al. J Chem Soc, Faraday Trans 1 76 812 1980, Beilstein 4 III 293, 4 III 558.]