Crystallise the lactone from EtOH, aqueous EtOH, MeOH or EtOAc. It is also purified by passage through a column of Amberlite IR-120 (H+ form), and the effluent and washings are then freeze-dried [Wolfrom & Thompson Methods in Carbohydrate Chemistry I 67 1963, Academic Press]. The 5,6-O-isopropylidene-D-galactono-1,4-lactone is purified by chromatography (EtOAc) and has m 165-167o (from EtOH/hexane), and 167.5-168.5o (from Me2CO/*C6H6) [NMR: Copel & Stick Aust J Chem 31 1371 1978.] [Beilstein 18 III/IV 3026, 18/5 V 18.]
